In tea plants,the abundant flavonoid compounds are responsible for the health benefits for the human body and define the astringent flavor profile.While the downstream mechanisms of flavonoid biosynthesis have been ex...In tea plants,the abundant flavonoid compounds are responsible for the health benefits for the human body and define the astringent flavor profile.While the downstream mechanisms of flavonoid biosynthesis have been extensively studied,the role of chalcone synthase(CHS)in this secondary metabolic process in tea plants remains less clear.In this study,we compared the evolutionary profile of the flavonoid metabolism pathway and discovered that gene duplication of CHS occurred in tea plants.We identified three CsCHS genes,along with a CsCHS-like gene,as potential candidates for further functional investigation.Unlike the CsCHS-like gene,the CsCHS genes effectively restored flavonoid production in Arabidopsis chs-mutants.Additionally,CsCHS transgenic tobacco plants exhibited higher flavonoid compound accumulation compared to their wild-type counterparts.Most notably,our examination of promoter and gene expression levels for the selected CHS genes revealed distinct responses to UV-B stress in tea plants.Our findings suggest that environmental factors such as UV-B exposure could have been the key drivers behind the gene duplication events in CHS.展开更多
Ethiopia is one of the countries in the world endowed with rich biological resources. However, due to human impacts, the forest cover in Ethiopia has been decreasing rapidly. The study was carried out with the purpose...Ethiopia is one of the countries in the world endowed with rich biological resources. However, due to human impacts, the forest cover in Ethiopia has been decreasing rapidly. The study was carried out with the purpose of finding out the Regeneration Status, Population Structure and Floristic composition of Woody Plant Species in Sheleko Medihanialem Natural Forest in Gondar, North West Ethiopia, from October 2019 to September 2020. The systematic vegetation sampling method was used to collect data from Fifty plots of 20 m × 20 m (400 m2) along five line transects. In addition, five, 5 m × 5 m subplots were laid within the main plot to sample seedlings and saplings. The floristic composition and population structure of woody individuals of trees and shrubs with a diameter at breast height (DBH) ≥ 2.5 cm and height ≥ 2 m were measured. DBH ≤ 2.5 cm and less than 1 m height were considered as seedlings and DBH ≥ 2.5 cm and height of 1 - 2 m as saplings. Vegetation data of density, frequency, basal area, and importance value index were computed. A total of 65 woody plant species in 54 genera and 34 plant families were recorded. Fabaceae, Moraceae and Euphorbiaceae were the dominant families in terms of species richness. Woody species densities for mature individuals were 2202.5 stems∙ha−1, seedling 2419.2 stems∙ha−1 and sapling 1737.6 stems∙ha−1. The forest was dominated by small-sized/young trees and shrubs, indicating the status of secondary growth and/or regeneration.展开更多
Exploring plant behavior at the cellular scale in a minimally invasive manner is critical to understanding plant adaptation to the environment.Phytohormones play vital regulatory roles in multiple aspects of plant gro...Exploring plant behavior at the cellular scale in a minimally invasive manner is critical to understanding plant adaptation to the environment.Phytohormones play vital regulatory roles in multiple aspects of plant growth and development and acclimation to environmental changes.Since the biosynthesis,modification,transportation,and degradation of plant hormones in plants change with time and space,their content level and distribution are highly dynamic.To monitor the production,transport,perception,and distribution of phytohormones within undamaged tissues,we require qualitative and quantitative tools endowed with remarkably high temporal and spatial resolution.Fluorescent probes are regarded as excellent tools for widespread plant imaging because of their high sensitivity and selectivity,reproducibility,real-time in situ detection,and uncomplicated mechanism elucidation.In this review,we provide a systematical overview of the progress in the sensing and imaging of phytohormone fluorescent probes and fluorescently labeled phytohormones to their receptors in plants.Moreover,forthcoming viewpoints and possible applications of these fluorescent probes within the realm of plants are also presented.We hold the conviction that the new perspective brought by this paper can promote the development of fluorescent probes,enabling them to have better detection performance in plant hormone imaging.展开更多
The members of the fourth subgroup of R2R3-MYB(Sg4 members)are well-known inhibitors of phenylpropanoid and lignin synthesis pathways.The C2 domain is closely related to the transcriptional inhibitory activity of Sg4 ...The members of the fourth subgroup of R2R3-MYB(Sg4 members)are well-known inhibitors of phenylpropanoid and lignin synthesis pathways.The C2 domain is closely related to the transcriptional inhibitory activity of Sg4 members.Phosphorylation modification enhances the transcriptional inhibitory activity of Sg4 members.Here,we identified a phosphorylation site on the C2 domain of Cs MYB4a from tea plants(Camellia sinensis).A mitogen-activated protein kinase(MAPK),named Cs MPK3-2,phosphorylated this site on the C2 domain of Cs MYB4a.Further experiments revealed that phosphorylation of Cs MYB4a weakened its ability to inhibit the gene expression of PAL,C4H,and 4CL in the phenylpropanoid pathway and activated the expression of transcription factor YABBY5,maintaining the adaxial-abaxial polarity of the leaf.Knocking out Nt YAB5 in Cs MYB4a transgenic tobacco partially repaired the leaf wrinkling phenotype caused by Cs MYB4a.The C1 domain exhibited an activation function when the C2 domain of Cs MYB4a was phosphorylated by Cs MPK3-2,causing this reversal phenomenon.These results enrich our understanding of the regulatory diversity of Sg4 members.展开更多
This study evaluated the molecular characterization of different ecotypes of B. aegyptiaca populations in the four sites: Koily alpha, Labgar, Ranérou and Ballou according to the environment with the aim of devel...This study evaluated the molecular characterization of different ecotypes of B. aegyptiaca populations in the four sites: Koily alpha, Labgar, Ranérou and Ballou according to the environment with the aim of developing protection strategies. We sampled leaves of B. aegyptiaca in each individual from each site to extract and amplify a fragment of mitochondrial DNA including cytochrome b and then carefully preserved. DNA extraction, polymerase chain amplification and sequencing of MT-CYB were performed in 64 individuals. Genetic diversity and structure of B. aegyptiaca were determined using the MEGA, DNasp and Arlequin software. The results showed a high haplotype diversity and low nucleotide diversity, indicating a population expansion linked to an important gene flow. Genetic distances between populations were positively correlated with geographic distance. The importance of having highlighted this genetic differentiation of the B. aegyptiaca species between these sites is to be able to understand the degree of genetic heterogeneity of each and correlate it with adaptability because genetic diversity influences the adaptation of the species.展开更多
Organic fertilizers generally come from agricultural co-products. Their valuation is therefore a major issue for sustainable development. The main objective of this study aims to develop an organic fertilizer derived ...Organic fertilizers generally come from agricultural co-products. Their valuation is therefore a major issue for sustainable development. The main objective of this study aims to develop an organic fertilizer derived from moringa leaves and cocoa pod husks that can improve soil quality and plant growth. The experimental design consisted of completely randomized blocks in three repetitions. The experiment was carried out in five treatments: T0: no fertilization, T1: 100% cocoa pods, T2: 75% cocoa pods + 25% Moringa leaves;T3: 50% cocoa pods + 50% Moringa leaves;T4: 25% cocoa pods + 75% Moringa leaves;T5: 100% Moringa leaves. Three doses were applied: 1;2;4 kg/m2. The trial took place over three growing cycles. The results of the soil analysis compared to the control revealed a significant improvement in physicochemical parameters. Variation of pH from (6.1 to 7.2), calcium from (1.4 to 4.13), magnesium from (0.450 to 0.870), potassium from (0.096 to 0.365) cmol+/kg. Carbon and nitrogen were recorded (1.02% to 2.77%) and (0.12% to 2.56%) respectively. The CEC (cation exchange capacity) saw a clear improvement (4.2 to 9.03) cmol+/kg. Concerning the growth parameters, the control plants recorded an average height of (31.19 cm) while those that benefited from the treatments oscillated between (55.51 to 105.57 cm). In terms of production, the best yields are attributed to treatments T3 and T4 with (37.66 t/ha) and (51.176 t/ha) respectively. The T3 and T4 formulations could help improve the fertility of agricultural soils and the yield of market garden products such as eggplant.展开更多
Salinity stress is a major challenge for global agriculture,particularly in arid and semi-arid regions,limiting plant productivity due to water and soil salinity.These conditions particularly affect countries along th...Salinity stress is a major challenge for global agriculture,particularly in arid and semi-arid regions,limiting plant productivity due to water and soil salinity.These conditions particularly affect countries along the southern Mediterranean rim,including Algeria,which primarily focuses on pastoral and forage practices.This study investigates salinity tolerance and ecotypic variability in Vicia narbonensis L.,a fodder legume species recognized for its potential to reclaim marginal soils.Morphological,physiological,and biochemical responses were assessed in three ecotypes(eco2,eco9,and eco10)exposed to different salinity levels(low,moderate,and severe).The study was conducted using a completely randomized block design with three blocks per ecotype per dose.The results from the two-way analysis of variance demonstrate significant effects across nearly all attributes studied,revealing distinct ecotypic responses.These findings underscore variations in growth parameters,osmotic regulation mechanisms,and biochemical adjustments.The substantial diversity observed among these ecotypes in their response to salinity provides valuable insights for breeders addressing both agronomic and ecological challenges.Multivariate analyses,including Principal Component Analysis(PCA),revealed key variables distinguishing between ecotypes under salinity stress.Moreover,Classification based on Salinity Tolerance Indices(STI)further differentiated ecotypic performance with more precision,and this is because of the combination of the different parameters studied.These results open up new prospects for the development of strategies to improve the salinity tolerance of forage legumes.展开更多
Abiotic stresses including drought,salinity,heat,cold,flooding,and ultraviolet radiation causes crop losses worldwide.In recent times,preventing these crop losses and producing more food and feed to meet the demands o...Abiotic stresses including drought,salinity,heat,cold,flooding,and ultraviolet radiation causes crop losses worldwide.In recent times,preventing these crop losses and producing more food and feed to meet the demands of ever-increasing human populations have gained unprecedented importance.However,the proportion of agricultural lands facing multiple abiotic stresses is expected only to rise under a changing global climate fueled by anthropogenic activities.Identifying the mechanisms developed and deployed by plants to counteract abiotic stresses and maintain their growth and survival under harsh conditions thus holds great significance.Recent investigations have shown that phytohormones,including the classical auxins,cytokinins,ethylene,and gibberellins,and newer members including brassinosteroids,jasmonates,and strigolactones may prove to be important metabolic engineering targets for producing abiotic stress-tolerant crop plants.In this review,we summarize and critically assess the roles that phytohormones play in plant growth and development and abiotic stress tolerance,besides their engineering for conferring abiotic stress tolerance in transgenic crops.We also describe recent successes in identifying the roles of phytohormones under stressful conditions.We conclude by describing the recent progress and future prospects including limitations and challenges of phytohormone engineering for inducing abiotic stress tolerance in crop plants.展开更多
QTLs for plant height and its components on the substituted segments of fifty-two single segment substitution lines （SSSLs） in rice were identified through t-test （P〈0.001） for comparison between each SSSL and re...QTLs for plant height and its components on the substituted segments of fifty-two single segment substitution lines （SSSLs） in rice were identified through t-test （P〈0.001） for comparison between each SSSL and recipient parent Huajingxian 74. On the 14 substituted segments, 24 QTLs were detected, 10 for plant height, 2 for panicle length, 4 for length of the first internode from the top, 5 for length of the second internode from the top and 3 for length of the third internode from the top, respectively. All these QTLs were distributed on nine rice chromosomes except chromosomes 5, 9 and 11. The additive effect ranged from -4.08 to 3.98 cm, and the additive effect percentages varied from -19.35% to 10.43%.展开更多
In response to limited availability of soil resources in basal root zone, plant extends its roots into nearby resource-rich zones to fulfill essential resource demands for survival and reproduction. This root prolifer...In response to limited availability of soil resources in basal root zone, plant extends its roots into nearby resource-rich zones to fulfill essential resource demands for survival and reproduction. This root proliferation into that enriched zones occupied by other plants constitutes interplant overlapping rooting zones and thereby the overlapping depletion zones, causing reduction in resource uptake by neighboring plants. By incorporating this mechanism into the classic resource competition model, we study interplant direct competition through their rooting system in an overlapping depletion zone. The model results indicate an extension of Tilman’s R* rule that has already been proved true when plants compete indirectly through their effect on shared resources. The results reveal that plant’s direct competitive ability (i.e., the ability to occupy an overlapping depletion zone by excluding others) can be characterized by its R*-value, where a best competitor having lowest R*-value excludes others from an overlapping zone and occupies the zone by depleting the resource level to the lowest as in its non-overlapping depletion zone. By analyzing the model, we find a suite of traits that confers R* variation among directly competing plants. This suite of traits would be a useful proxy measure for R* that do not necessarily require to establish equilibrium field monoculture—a requirement for R* measurement in the field.展开更多
Cotton producers have substantially reduced their inputs(labor,nutrients,and management)mainly by adopting a shortseason cropping management that is characterized by late sowing,high density,and reduced fertilization ...Cotton producers have substantially reduced their inputs(labor,nutrients,and management)mainly by adopting a shortseason cropping management that is characterized by late sowing,high density,and reduced fertilization with one-time application at the first bloom stage without lint yield reduction.However,it has been hypothesized that one-time fertilization at an earlier growth stage could be a more effective and economic management practice.A two-year field experiment was conducted by applying five fertilizer one-time fertilization at 0(FT1),5(FT2),10(FT3),15(FT4),and 20(FT5)days after the first flower appeared in the field and one three-split fertilizer application taken as the conventional control(FT6),making six treatments altogether.Cotton growth period,biomass accumulation,yield,and its formation were quantified.The results showed that the one-time fertilization did not affect the cotton growth progress as compared to FT6,however,the total crop cycles for FT3–FT5 were 3 days shorter.FT1 produced the highest cotton lint yield(1396 kg ha–1),which was similar to the FT6 but higher than the other treatments,and could be attributed to more bolls per unit area and higher lint percentage.Cotton yield was positively correlated with cotton plant biomass accumulated.FT1 had both the highest average(VT)(193.7 kg ha–1 d–1)and the highest maximum(VM)(220.9 kg ha–1 d–1)rates during the fast biomass accumulation period.These results suggest that one-time fertilizer application at the first flower stage might be an adjustment that is more effective than at first bloom,and allowed for easier decision making for application date due to non counting of plants with flowers is needed.展开更多
Flowering locus T(FT)is a primary integrator in the regulation of plant flowering.Overexpressing a blueberry(Vaccinium corymbosum L.)FT gene(VcFT)(herein VcFT-OX)resulted in early flowering and dwarfing in‘Aurora’pl...Flowering locus T(FT)is a primary integrator in the regulation of plant flowering.Overexpressing a blueberry(Vaccinium corymbosum L.)FT gene(VcFT)(herein VcFT-OX)resulted in early flowering and dwarfing in‘Aurora’plants(herein‘VcFT-Aurora’).In this study,we found that VcFT-OX reduced shoot regeneration from leaf explants.To investigate the potential roles of the phytohormone pathway genes associated with VcFT-OX,differentially expressed(DE)genes in leaf tissues of‘VcFT-Aurora’plants were annotated and analyzed using non-transgenic‘Aurora’plants as a control.Three DE floral genes,including the blueberry SUPPRESSOR of Overexpression of constans 1(VcSOC1)(gibberellin related),Abscisic acid responsive elements-binding factor 2(VcABF2)and protein related to ABI3/VP1(VcABI3/VP1)(ethylene-related),are present under both the phytohormone-responsive and the dwarfing-related Gene Ontology terms.The gene networks of the DE genes overall showed the molecular basis of the multifunctional aspects of VcFT overexpression beyond flowering promotion and suggested that phytohormone changes could be signaling molecules with important roles in the phenotypic changes driven by VcFT-OX.展开更多
Mountains are an excellent system for evaluating ecological and biogeographical patterns. The obvious variations of the environmental factors along the altitude create different zones with adapted plant assemblages. H...Mountains are an excellent system for evaluating ecological and biogeographical patterns. The obvious variations of the environmental factors along the altitude create different zones with adapted plant assemblages. However, few studies make use of plant functional type(PFT) for describing the variation of vegetation along altitudinal gradients. A PFT is a group of taxa with similar traits which respond similarly to the environmental gradients. In this study, we used PFTs as indicators describing five vegetation zones in the western Alborz Mt, Iran from 2000 – 4500 m. The plant trait data presented here covers six plant traits including growth form, stemleaf ratio, spinescence, hairiness, leaf consistency and plant height of 297 species. We considered altitude and soil factors to test the importance of environmental variables. We applied a multivariate analysis of three table ordination, i.e. environmental, species, and traits data to identify the PFTs. We further applied fourth-corner statistic to quantify trait-environment relationships. A constrained hierarchical clustering was used to detect five altitudinal zones and two zones of low and high nitrogen concentration. With regard to altitude wediscuss the distribution of species, traits and PFTs. Growth form, plant height and stem-leaf ratio were significantly related to altitude and nitrogen. We identified 19 PFTs from which 18 were significantly associated to one or more altitudinal zones. While the lower altitudinal zones contain a variety of PFTs higher altitudes contain less PFTs with the highest altitude containing only one single PFT, tiny rosette plants with soft mesomorphic leaves. We identified grazing and climatic harshness as well as rockiness as the most important drivers of the distribution of plant functional traits and types across the studied gradient.展开更多
Plant hormones are important molecules which at low concentration can regulate various physiological processes.Mass spectrometry has become a powerful technique for the quantification of multiple classes of plant horm...Plant hormones are important molecules which at low concentration can regulate various physiological processes.Mass spectrometry has become a powerful technique for the quantification of multiple classes of plant hormones because of its high sensitivity and selectivity.We developed a new ultrahigh pressure liquid chromatography–full-scan high-definition accurate mass spectrometry method,for simultaneous determination of abscisic acid and four metabolites phaseic acid,dihydrophaseic acid,7′-hydroxy-abscisic acid and abscisic acid glucose ester,cytokinins zeatin,zeatin riboside,gibberellins(GA1,GA3,GA4 and GA7)and indole-3-acetyl-L-aspartic acid.We measured the amount of plant hormones in the flesh and skin of two processing potato cvs.Sylvana and Russet Burbank stored for up to 30 weeks at 6°C under ambient air conditions.Herein,we report for the first time that abscisic acid glucose ester seems to accumulate in the skin of potato tubers throughout storage time.The method achieved a lowest limit of detection of 0.22 ng g−1 of dry weight and a limit of quantification of 0.74 ng g−1 dry weight(zeatin riboside),and was able to recover,detect and quantify a total of 12 plant hormones spiked on flesh and skin of potato tubers.In addition,the mass accuracy for all compounds(<5 ppm)was evaluated.展开更多
An inhabitant of north western Himalayan region and a gynodioceious plant having a lot of medicinal properties, Valeriana jatamansi Jones (Valerianaceae) is an enlisted endangered plant in the world. It was introduced...An inhabitant of north western Himalayan region and a gynodioceious plant having a lot of medicinal properties, Valeriana jatamansi Jones (Valerianaceae) is an enlisted endangered plant in the world. It was introduced in the research station of North Bengal Agricultural University (27.06°N 88.47°E) situated in north eastern Himalayan region of Darjeeling district in the state of West Bengal from Sikkim Sangtok (27°25'N 88°31'E) of north Sikkim area in India for the purpose of conservation. As we noticed some irregular development of floral organs, we investigated some pertinent questions regarding ecological aberrations found in plants. We found plants introduced in north eastern Himalayan region changed their homology of number flower petals and position of stamens seen naturally in north western Himalayan region as per the reports. Was there any genetic or extreme environmental stress condition caused a sudden change in floral structure as it is generally known as a rare phenomenon and frequently not seen? What were the correlations of different floral parts and fitness of population in different morphotypes? We predicted possible outcomes of seed setting by univariate regression models in a particular environment in addition to this investigation. We proposed three models of heterozygousity for answering the reasons of unstable floral form from a general known floral form, where silent mutations help the plants to survive in adverse conditions in spite of deformed or variable formed of floral morphology.展开更多
This review chronicles the development of the cytokinin research during the last 30 years. Cytokinin and auxin are the two major plant growth hormones that control virtually all aspects of growth and development in hi...This review chronicles the development of the cytokinin research during the last 30 years. Cytokinin and auxin are the two major plant growth hormones that control virtually all aspects of growth and development in higher plants. The pathways for cytokinin biosynthesis and metabolism have been characterized by the identification of isopentenyl pyrophosphate transferase, cytokinin oxidases, cytokinin hydroxylase, zeatin cis-/trans-isomerase, cytokinin phosphoribosyl hydrolases, cytokinin-specific riboside phosphorylase, and others enzymes. Loss-of function mutant phenotypes of cytokinin degradation/activating enzymes indicate the regulation of concentration and spatial distribution of bio-active cytokinin plays a pivotal role in the increase in panicle size, in the numbers of floral organs, and eventually in seed yield. One of the most fundamental questions in the cytokinin field is one concerning the prevalence of cis-zeatin in monocotyledonous crops (rice and maize) and in dicotyledonous legumes (pea, chickpea) and potato/sweet potato. A hypothesis is that cis-zeatin is synthesized by the cis-specific hydroxylation of the terminal methyl group of N6-isopentenyl side chain of N6-isopentenyl adenosine (i6Ado) or of their mono-, di-, or tri-phosphates catalyzed by the cis-specific hydroxylase. A second potential pathway is the isomerization of trans-zeatin to cis-zeatin by zeatin cis-/trans-isomerase. A second fundamental question to be addressed is the physiological role of cis-zeatin. Some have argued for a special function of cis-zeatin to account for the prevalence of the cis-zeatin in the plant kingdom from algae to higher plants.展开更多
Functional traits are predictors of plants in response to environmental stimuli. They represent specific functional adaptations to various environmental stresses. This study deals with the variation in plant functiona...Functional traits are predictors of plants in response to environmental stimuli. They represent specific functional adaptations to various environmental stresses. This study deals with the variation in plant functional traits along elevation gradient and land-use types in Sagarmatha National Park and Buffer Zone, Nepal. Two field investigations in April and September, 2011 were made to collect samples. Sampling was done from 2200 - 3800 m asl varying approx. 400 m. East and west facing aspects of each valley were chosen. In each aspect four land-use type categories including disturbed (cultivated land, exploited forest and meadow) and less disturbed natural forest were selected. A transect of 25 m long and 2.5 m wide was laid. Different eight traits of plants including lifeform, plant height, clonality, spinescence, leaf dry matter content, stem specific density, twig dry matter content and twig drying time were examined for 60 plant species belonging to 31 families, collected from 40 sampled plots. Nine different types of growth forms were recorded. Plant height of the investigated species ranged from 0.03 - 15 m. The stolon consisting species were dominant in exploited forests. Diversity of clonal species was more in meadow and non-clonal species were dominant in all the altitudes. Only eight species consisted of spines. In the disturbed land-use categories, we found high variation in a particular trait. Correlation analyses revealed the significant relationship (p < 0.01) among different traits. Herbs and shrubs were dominant at higher elevation and in disturbed land-use categories. Species from high altitude were mostly short basal herbs, while spinescence and tall trees were observed at lower altitudes. Species recorded in meadows and exploited forests showed high variation in traits due to disturbance mainly grazing, fire, litter collection and trampling. Altitudinal variation, climatic conditions and disturbance most strongly influence trait expression in the study area.展开更多
Soybean cyst nematode Heterodera glycines is one of the most serious soil-borne pathogens in soybean production. However, the researches were limited in China due to lack of an effective pathosystem. In this study, we...Soybean cyst nematode Heterodera glycines is one of the most serious soil-borne pathogens in soybean production. However, the researches were limited in China due to lack of an effective pathosystem. In this study, we screened 21 legume Medicago plants in both Medicago truncatula and Medicago sativa to obtain candidate model plants for establishing a new pathosystem for legume-H. glycines interactions. The nematode infection of tested plants was assayed with Race 3 and 4 respectively, which were two dominant H. glycines inbred races in China soybean producing areas. The results showed that the model legume plant M. truncatula A17 failed to allow Race 3 of H. glycines to complete its life cycle, in contrast, it provided the Race 4 population to form several cyst nematodes, however, the female index（FI） value was approximately 1.6. Three M. sativa cultivars, including Xunlu, Aergangjin and Junren, provided either Race 3 or 4 of H. glycines to develop into mature cysts with their FI value below 5 as well. Our results demonstrated that legume plants in both M. truncatula and M. sativa were not likely to be a model plant for H. glycines because of an extreme high resistance.展开更多
Strigolactones are plant hormones with multiple functions, including regulating various aspects of plant architecture such as shoot branching, facilitating the colonization of plant roots by arbuscular mycorrhizal fun...Strigolactones are plant hormones with multiple functions, including regulating various aspects of plant architecture such as shoot branching, facilitating the colonization of plant roots by arbuscular mycorrhizal fungi, and acting as seed germination stimulants for certain parasitic plants of the family Orobanchaceae. The obligate parasitic species Phelipanche aegyptiaca and Striga hermonthica require strigolactones for germination, while the facultative parasite Triphysaria versicolor does not. It has been hypothesized that P. aegyptiaca and S. hermonthica would have undergone evolutionary loss of strigolactone biosynthesis as a part of their mechanism to enable specific detection of exogenous strigolactones. We analyzed the transcriptomes of P. aegyptiaca, S. hermonthica and T. versicolor and identified genes known to act in strigolactone synthesis (D27, CCD7, CCD8, and MAX1), perception (MAX2 and D14) and transport (PDR12). These genes were then analyzed to assess likelihood of function. Transcripts of all strigolactone-related genes were found in P. aegyptiaca and S. hermonthica, and evidence points to their encoding functional proteins. Gene open reading frames were consistent with homologs from Arabidopsis and other strigolactone-producing plants, and all genes were expressed in parasite tissues. In general, the genes related to strigolactone synthesis and perception appeared to be evolving under codon-based selective constraints in strigolactone-dependent species. Bioassays of S. hermonthica root extracts indicated the presence of strigolactone class stimulants on germination of P. aegyptiaca seeds. Taken together, these results indicate that Phelipanche aegyptiaca and S. hermonthica have retained functional genes involved in strigolactone biosynthesis, suggesting that the parasites use both endogenous and exogenous strigolactones and have mechanisms to differentiate the two.展开更多
Micropropagation from shoot tips and nodal segments was carried out for the conservation and domestication of spontaneous Moroccan thyme, <i><span style="font-family:Verdana;">Thymus broussonetii...Micropropagation from shoot tips and nodal segments was carried out for the conservation and domestication of spontaneous Moroccan thyme, <i><span style="font-family:Verdana;">Thymus broussonetii</span></i><i> </i><span style="font-family:Verdana;">Boiss. subsp. </span><i><span style="font-family:Verdana;">broussonetii</span></i><span style="font-family:Verdana;"> (endemic threatened). The mineral composition of the culture medium, as well as the succession of different growth regulators, influenced the </span><i><span style="font-family:Verdana;">in vitro</span></i><span style="font-family:Verdana;"> growth of this species. Sterilized achenes of </span><i><span style="font-family:Verdana;">T. broussonetii</span></i><i> </i><span style="font-family:Verdana;">were able to germinate on an agar medium containing Gautheret macronutrients with a rate of 25% and a degree of contamination of less than 4%. Shoot apices of 15-day seedlings (two cotyledon leaves) were cultivated on SD + 0.46 μM Kin medium and the explants obtained were transplanted every month. Six macronutrients (MS, B</span><sub><span style="font-family:Verdana;">5</span></sub><span style="font-family:Verdana;">, SH, SD, MS</span><sub><span style="font-family:Verdana;">m</span></sub> <span><span style="font-family:Verdana;">and N</span><sub><span style="font-family:Verdana;">30</span></sub><span style="font-family:Verdana;">K) were tested and N</span><sub><span style="font-family:Verdana;">30</span></sub><span style="font-family:Verdana;">K was chosen for the following experiments. Seven cytokinins (Kin, BAP, 2iP, DPU, adenine, Zeat and TDZ) at 0.46, 0.93 and 2.32 μM/l were evaluated and the addition of 0.93 μM adenine to N</span><sub><span style="font-family:Verdana;">30</span></sub><span style="font-family:Verdana;">K medium favored significantly the induction of buds and the elongation of explants. Three polyamines (putrescine, spermidine and spermine) at 2, 5, 10 and 20 μM/l were tested. A better multiplication of buds, shoots and roots was noted for N</span><sub><span style="font-family:Verdana;">30</span></sub><span style="font-family:Verdana;">K + 10 μM spermine. Cytokinin-auxin combinations led to better root multiplication and an increase in the number of buds a</span></span><span style="font-family:Verdana;">nd the length of explants, particularly for 0.46 μM Kin + 2.85 μM IAA. Acclimatization was successfully carried out using vitroplants developing a good root system. One month after the start of acclimatization, 97% of </span><i><span style="font-family:Verdana;">T. broussonetii</span></i><i> </i><span style="font-family:Verdana;">plantlets were healthy. Three months later, they were transplanted into larger pots. 100% of the acclimatized plants developed flowers in the 2</span><sup><span style="font-family:Verdana;">nd</span></sup><span style="font-family:Verdana;"> year between June and August. Re-initiation of the </span><i><span style="font-family:Verdana;">in vitro</span></i><span style="font-family:Verdana;"> culture was carried out from sterilized twig segments collected from the acclimatized plants of </span><i><span style="font-family:Verdana;">T. broussonetii</span></i><i> </i><span style="font-family:Verdana;">with 1 - 2 nodes on the medium N</span><sub><span style="font-family:Verdana;">30</span></sub><span style="font-family:Verdana;">K + 0.46 μM Kin, and 52.1% of the explants healthily proliferated. Finally, two micropropagation prototypes were developed: shoot tip culture from seedlings obtained after germination of achenes and node culture from acclimatized plants.</span>展开更多
基金supported by the National Natural Science Foundation of China(U21A20232,32372756,and 32202551).
文摘In tea plants,the abundant flavonoid compounds are responsible for the health benefits for the human body and define the astringent flavor profile.While the downstream mechanisms of flavonoid biosynthesis have been extensively studied,the role of chalcone synthase(CHS)in this secondary metabolic process in tea plants remains less clear.In this study,we compared the evolutionary profile of the flavonoid metabolism pathway and discovered that gene duplication of CHS occurred in tea plants.We identified three CsCHS genes,along with a CsCHS-like gene,as potential candidates for further functional investigation.Unlike the CsCHS-like gene,the CsCHS genes effectively restored flavonoid production in Arabidopsis chs-mutants.Additionally,CsCHS transgenic tobacco plants exhibited higher flavonoid compound accumulation compared to their wild-type counterparts.Most notably,our examination of promoter and gene expression levels for the selected CHS genes revealed distinct responses to UV-B stress in tea plants.Our findings suggest that environmental factors such as UV-B exposure could have been the key drivers behind the gene duplication events in CHS.
文摘Ethiopia is one of the countries in the world endowed with rich biological resources. However, due to human impacts, the forest cover in Ethiopia has been decreasing rapidly. The study was carried out with the purpose of finding out the Regeneration Status, Population Structure and Floristic composition of Woody Plant Species in Sheleko Medihanialem Natural Forest in Gondar, North West Ethiopia, from October 2019 to September 2020. The systematic vegetation sampling method was used to collect data from Fifty plots of 20 m × 20 m (400 m2) along five line transects. In addition, five, 5 m × 5 m subplots were laid within the main plot to sample seedlings and saplings. The floristic composition and population structure of woody individuals of trees and shrubs with a diameter at breast height (DBH) ≥ 2.5 cm and height ≥ 2 m were measured. DBH ≤ 2.5 cm and less than 1 m height were considered as seedlings and DBH ≥ 2.5 cm and height of 1 - 2 m as saplings. Vegetation data of density, frequency, basal area, and importance value index were computed. A total of 65 woody plant species in 54 genera and 34 plant families were recorded. Fabaceae, Moraceae and Euphorbiaceae were the dominant families in terms of species richness. Woody species densities for mature individuals were 2202.5 stems∙ha−1, seedling 2419.2 stems∙ha−1 and sapling 1737.6 stems∙ha−1. The forest was dominated by small-sized/young trees and shrubs, indicating the status of secondary growth and/or regeneration.
基金supported by the National Key Research and Development Program of China(2022YFD1700300,2022YFE0199800)the National Natural Science Foundation of China(32072443,82104065,32061143045)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20201323)the Distinguished Young Research Project of Anhui Higher Education Institution(2022AH020035).
文摘Exploring plant behavior at the cellular scale in a minimally invasive manner is critical to understanding plant adaptation to the environment.Phytohormones play vital regulatory roles in multiple aspects of plant growth and development and acclimation to environmental changes.Since the biosynthesis,modification,transportation,and degradation of plant hormones in plants change with time and space,their content level and distribution are highly dynamic.To monitor the production,transport,perception,and distribution of phytohormones within undamaged tissues,we require qualitative and quantitative tools endowed with remarkably high temporal and spatial resolution.Fluorescent probes are regarded as excellent tools for widespread plant imaging because of their high sensitivity and selectivity,reproducibility,real-time in situ detection,and uncomplicated mechanism elucidation.In this review,we provide a systematical overview of the progress in the sensing and imaging of phytohormone fluorescent probes and fluorescently labeled phytohormones to their receptors in plants.Moreover,forthcoming viewpoints and possible applications of these fluorescent probes within the realm of plants are also presented.We hold the conviction that the new perspective brought by this paper can promote the development of fluorescent probes,enabling them to have better detection performance in plant hormone imaging.
基金supported by the joint funds of National Natural Science Foundation of China(Grant Nos.U21A20232,32372756,32072621)。
文摘The members of the fourth subgroup of R2R3-MYB(Sg4 members)are well-known inhibitors of phenylpropanoid and lignin synthesis pathways.The C2 domain is closely related to the transcriptional inhibitory activity of Sg4 members.Phosphorylation modification enhances the transcriptional inhibitory activity of Sg4 members.Here,we identified a phosphorylation site on the C2 domain of Cs MYB4a from tea plants(Camellia sinensis).A mitogen-activated protein kinase(MAPK),named Cs MPK3-2,phosphorylated this site on the C2 domain of Cs MYB4a.Further experiments revealed that phosphorylation of Cs MYB4a weakened its ability to inhibit the gene expression of PAL,C4H,and 4CL in the phenylpropanoid pathway and activated the expression of transcription factor YABBY5,maintaining the adaxial-abaxial polarity of the leaf.Knocking out Nt YAB5 in Cs MYB4a transgenic tobacco partially repaired the leaf wrinkling phenotype caused by Cs MYB4a.The C1 domain exhibited an activation function when the C2 domain of Cs MYB4a was phosphorylated by Cs MPK3-2,causing this reversal phenomenon.These results enrich our understanding of the regulatory diversity of Sg4 members.
文摘This study evaluated the molecular characterization of different ecotypes of B. aegyptiaca populations in the four sites: Koily alpha, Labgar, Ranérou and Ballou according to the environment with the aim of developing protection strategies. We sampled leaves of B. aegyptiaca in each individual from each site to extract and amplify a fragment of mitochondrial DNA including cytochrome b and then carefully preserved. DNA extraction, polymerase chain amplification and sequencing of MT-CYB were performed in 64 individuals. Genetic diversity and structure of B. aegyptiaca were determined using the MEGA, DNasp and Arlequin software. The results showed a high haplotype diversity and low nucleotide diversity, indicating a population expansion linked to an important gene flow. Genetic distances between populations were positively correlated with geographic distance. The importance of having highlighted this genetic differentiation of the B. aegyptiaca species between these sites is to be able to understand the degree of genetic heterogeneity of each and correlate it with adaptability because genetic diversity influences the adaptation of the species.
文摘Organic fertilizers generally come from agricultural co-products. Their valuation is therefore a major issue for sustainable development. The main objective of this study aims to develop an organic fertilizer derived from moringa leaves and cocoa pod husks that can improve soil quality and plant growth. The experimental design consisted of completely randomized blocks in three repetitions. The experiment was carried out in five treatments: T0: no fertilization, T1: 100% cocoa pods, T2: 75% cocoa pods + 25% Moringa leaves;T3: 50% cocoa pods + 50% Moringa leaves;T4: 25% cocoa pods + 75% Moringa leaves;T5: 100% Moringa leaves. Three doses were applied: 1;2;4 kg/m2. The trial took place over three growing cycles. The results of the soil analysis compared to the control revealed a significant improvement in physicochemical parameters. Variation of pH from (6.1 to 7.2), calcium from (1.4 to 4.13), magnesium from (0.450 to 0.870), potassium from (0.096 to 0.365) cmol+/kg. Carbon and nitrogen were recorded (1.02% to 2.77%) and (0.12% to 2.56%) respectively. The CEC (cation exchange capacity) saw a clear improvement (4.2 to 9.03) cmol+/kg. Concerning the growth parameters, the control plants recorded an average height of (31.19 cm) while those that benefited from the treatments oscillated between (55.51 to 105.57 cm). In terms of production, the best yields are attributed to treatments T3 and T4 with (37.66 t/ha) and (51.176 t/ha) respectively. The T3 and T4 formulations could help improve the fertility of agricultural soils and the yield of market garden products such as eggplant.
基金Direction Generale de la Recherche Scientifique et du Developpement Technologique(DGRSDT)Algeria,and the Researchers Supporting Project No.(RSP2025R390),King Saud University,Riyadh,Saudi Arabia.
文摘Salinity stress is a major challenge for global agriculture,particularly in arid and semi-arid regions,limiting plant productivity due to water and soil salinity.These conditions particularly affect countries along the southern Mediterranean rim,including Algeria,which primarily focuses on pastoral and forage practices.This study investigates salinity tolerance and ecotypic variability in Vicia narbonensis L.,a fodder legume species recognized for its potential to reclaim marginal soils.Morphological,physiological,and biochemical responses were assessed in three ecotypes(eco2,eco9,and eco10)exposed to different salinity levels(low,moderate,and severe).The study was conducted using a completely randomized block design with three blocks per ecotype per dose.The results from the two-way analysis of variance demonstrate significant effects across nearly all attributes studied,revealing distinct ecotypic responses.These findings underscore variations in growth parameters,osmotic regulation mechanisms,and biochemical adjustments.The substantial diversity observed among these ecotypes in their response to salinity provides valuable insights for breeders addressing both agronomic and ecological challenges.Multivariate analyses,including Principal Component Analysis(PCA),revealed key variables distinguishing between ecotypes under salinity stress.Moreover,Classification based on Salinity Tolerance Indices(STI)further differentiated ecotypic performance with more precision,and this is because of the combination of the different parameters studied.These results open up new prospects for the development of strategies to improve the salinity tolerance of forage legumes.
文摘Abiotic stresses including drought,salinity,heat,cold,flooding,and ultraviolet radiation causes crop losses worldwide.In recent times,preventing these crop losses and producing more food and feed to meet the demands of ever-increasing human populations have gained unprecedented importance.However,the proportion of agricultural lands facing multiple abiotic stresses is expected only to rise under a changing global climate fueled by anthropogenic activities.Identifying the mechanisms developed and deployed by plants to counteract abiotic stresses and maintain their growth and survival under harsh conditions thus holds great significance.Recent investigations have shown that phytohormones,including the classical auxins,cytokinins,ethylene,and gibberellins,and newer members including brassinosteroids,jasmonates,and strigolactones may prove to be important metabolic engineering targets for producing abiotic stress-tolerant crop plants.In this review,we summarize and critically assess the roles that phytohormones play in plant growth and development and abiotic stress tolerance,besides their engineering for conferring abiotic stress tolerance in transgenic crops.We also describe recent successes in identifying the roles of phytohormones under stressful conditions.We conclude by describing the recent progress and future prospects including limitations and challenges of phytohormone engineering for inducing abiotic stress tolerance in crop plants.
基金the key project ofNational Natural Science Foundation of China(30330370) the team project of Natural ScienceFoundation of Guangdong Province (20003023).
文摘QTLs for plant height and its components on the substituted segments of fifty-two single segment substitution lines （SSSLs） in rice were identified through t-test （P〈0.001） for comparison between each SSSL and recipient parent Huajingxian 74. On the 14 substituted segments, 24 QTLs were detected, 10 for plant height, 2 for panicle length, 4 for length of the first internode from the top, 5 for length of the second internode from the top and 3 for length of the third internode from the top, respectively. All these QTLs were distributed on nine rice chromosomes except chromosomes 5, 9 and 11. The additive effect ranged from -4.08 to 3.98 cm, and the additive effect percentages varied from -19.35% to 10.43%.
基金supported by the U.S.National Science Foundation’s Biocomplexity Program (DEB-0421530)LTER Program (DEB0620482)
文摘In response to limited availability of soil resources in basal root zone, plant extends its roots into nearby resource-rich zones to fulfill essential resource demands for survival and reproduction. This root proliferation into that enriched zones occupied by other plants constitutes interplant overlapping rooting zones and thereby the overlapping depletion zones, causing reduction in resource uptake by neighboring plants. By incorporating this mechanism into the classic resource competition model, we study interplant direct competition through their rooting system in an overlapping depletion zone. The model results indicate an extension of Tilman’s R* rule that has already been proved true when plants compete indirectly through their effect on shared resources. The results reveal that plant’s direct competitive ability (i.e., the ability to occupy an overlapping depletion zone by excluding others) can be characterized by its R*-value, where a best competitor having lowest R*-value excludes others from an overlapping zone and occupies the zone by depleting the resource level to the lowest as in its non-overlapping depletion zone. By analyzing the model, we find a suite of traits that confers R* variation among directly competing plants. This suite of traits would be a useful proxy measure for R* that do not necessarily require to establish equilibrium field monoculture—a requirement for R* measurement in the field.
基金supported by the National Natural Science Foundation of China (31271665)the Pairing Program of Key Laboratory of Oasis Ecology Agriculture, Xinjiang Production and Construction Group with Eminent Scholars in Elite Universities, China (201601)
文摘Cotton producers have substantially reduced their inputs(labor,nutrients,and management)mainly by adopting a shortseason cropping management that is characterized by late sowing,high density,and reduced fertilization with one-time application at the first bloom stage without lint yield reduction.However,it has been hypothesized that one-time fertilization at an earlier growth stage could be a more effective and economic management practice.A two-year field experiment was conducted by applying five fertilizer one-time fertilization at 0(FT1),5(FT2),10(FT3),15(FT4),and 20(FT5)days after the first flower appeared in the field and one three-split fertilizer application taken as the conventional control(FT6),making six treatments altogether.Cotton growth period,biomass accumulation,yield,and its formation were quantified.The results showed that the one-time fertilization did not affect the cotton growth progress as compared to FT6,however,the total crop cycles for FT3–FT5 were 3 days shorter.FT1 produced the highest cotton lint yield(1396 kg ha–1),which was similar to the FT6 but higher than the other treatments,and could be attributed to more bolls per unit area and higher lint percentage.Cotton yield was positively correlated with cotton plant biomass accumulated.FT1 had both the highest average(VT)(193.7 kg ha–1 d–1)and the highest maximum(VM)(220.9 kg ha–1 d–1)rates during the fast biomass accumulation period.These results suggest that one-time fertilizer application at the first flower stage might be an adjustment that is more effective than at first bloom,and allowed for easier decision making for application date due to non counting of plants with flowers is needed.
文摘Flowering locus T(FT)is a primary integrator in the regulation of plant flowering.Overexpressing a blueberry(Vaccinium corymbosum L.)FT gene(VcFT)(herein VcFT-OX)resulted in early flowering and dwarfing in‘Aurora’plants(herein‘VcFT-Aurora’).In this study,we found that VcFT-OX reduced shoot regeneration from leaf explants.To investigate the potential roles of the phytohormone pathway genes associated with VcFT-OX,differentially expressed(DE)genes in leaf tissues of‘VcFT-Aurora’plants were annotated and analyzed using non-transgenic‘Aurora’plants as a control.Three DE floral genes,including the blueberry SUPPRESSOR of Overexpression of constans 1(VcSOC1)(gibberellin related),Abscisic acid responsive elements-binding factor 2(VcABF2)and protein related to ABI3/VP1(VcABI3/VP1)(ethylene-related),are present under both the phytohormone-responsive and the dwarfing-related Gene Ontology terms.The gene networks of the DE genes overall showed the molecular basis of the multifunctional aspects of VcFT overexpression beyond flowering promotion and suggested that phytohormone changes could be signaling molecules with important roles in the phenotypic changes driven by VcFT-OX.
基金the DAAD (Deutscher Akademischer Austausch Dienst) for a grant to H.M. (57214227)
文摘Mountains are an excellent system for evaluating ecological and biogeographical patterns. The obvious variations of the environmental factors along the altitude create different zones with adapted plant assemblages. However, few studies make use of plant functional type(PFT) for describing the variation of vegetation along altitudinal gradients. A PFT is a group of taxa with similar traits which respond similarly to the environmental gradients. In this study, we used PFTs as indicators describing five vegetation zones in the western Alborz Mt, Iran from 2000 – 4500 m. The plant trait data presented here covers six plant traits including growth form, stemleaf ratio, spinescence, hairiness, leaf consistency and plant height of 297 species. We considered altitude and soil factors to test the importance of environmental variables. We applied a multivariate analysis of three table ordination, i.e. environmental, species, and traits data to identify the PFTs. We further applied fourth-corner statistic to quantify trait-environment relationships. A constrained hierarchical clustering was used to detect five altitudinal zones and two zones of low and high nitrogen concentration. With regard to altitude wediscuss the distribution of species, traits and PFTs. Growth form, plant height and stem-leaf ratio were significantly related to altitude and nitrogen. We identified 19 PFTs from which 18 were significantly associated to one or more altitudinal zones. While the lower altitudinal zones contain a variety of PFTs higher altitudes contain less PFTs with the highest altitude containing only one single PFT, tiny rosette plants with soft mesomorphic leaves. We identified grazing and climatic harshness as well as rockiness as the most important drivers of the distribution of plant functional traits and types across the studied gradient.
基金The authors would like to thanks the Potato Council Ltd.for partial financial support of this research(Project R412)。
文摘Plant hormones are important molecules which at low concentration can regulate various physiological processes.Mass spectrometry has become a powerful technique for the quantification of multiple classes of plant hormones because of its high sensitivity and selectivity.We developed a new ultrahigh pressure liquid chromatography–full-scan high-definition accurate mass spectrometry method,for simultaneous determination of abscisic acid and four metabolites phaseic acid,dihydrophaseic acid,7′-hydroxy-abscisic acid and abscisic acid glucose ester,cytokinins zeatin,zeatin riboside,gibberellins(GA1,GA3,GA4 and GA7)and indole-3-acetyl-L-aspartic acid.We measured the amount of plant hormones in the flesh and skin of two processing potato cvs.Sylvana and Russet Burbank stored for up to 30 weeks at 6°C under ambient air conditions.Herein,we report for the first time that abscisic acid glucose ester seems to accumulate in the skin of potato tubers throughout storage time.The method achieved a lowest limit of detection of 0.22 ng g−1 of dry weight and a limit of quantification of 0.74 ng g−1 dry weight(zeatin riboside),and was able to recover,detect and quantify a total of 12 plant hormones spiked on flesh and skin of potato tubers.In addition,the mass accuracy for all compounds(<5 ppm)was evaluated.
文摘An inhabitant of north western Himalayan region and a gynodioceious plant having a lot of medicinal properties, Valeriana jatamansi Jones (Valerianaceae) is an enlisted endangered plant in the world. It was introduced in the research station of North Bengal Agricultural University (27.06°N 88.47°E) situated in north eastern Himalayan region of Darjeeling district in the state of West Bengal from Sikkim Sangtok (27°25'N 88°31'E) of north Sikkim area in India for the purpose of conservation. As we noticed some irregular development of floral organs, we investigated some pertinent questions regarding ecological aberrations found in plants. We found plants introduced in north eastern Himalayan region changed their homology of number flower petals and position of stamens seen naturally in north western Himalayan region as per the reports. Was there any genetic or extreme environmental stress condition caused a sudden change in floral structure as it is generally known as a rare phenomenon and frequently not seen? What were the correlations of different floral parts and fitness of population in different morphotypes? We predicted possible outcomes of seed setting by univariate regression models in a particular environment in addition to this investigation. We proposed three models of heterozygousity for answering the reasons of unstable floral form from a general known floral form, where silent mutations help the plants to survive in adverse conditions in spite of deformed or variable formed of floral morphology.
文摘This review chronicles the development of the cytokinin research during the last 30 years. Cytokinin and auxin are the two major plant growth hormones that control virtually all aspects of growth and development in higher plants. The pathways for cytokinin biosynthesis and metabolism have been characterized by the identification of isopentenyl pyrophosphate transferase, cytokinin oxidases, cytokinin hydroxylase, zeatin cis-/trans-isomerase, cytokinin phosphoribosyl hydrolases, cytokinin-specific riboside phosphorylase, and others enzymes. Loss-of function mutant phenotypes of cytokinin degradation/activating enzymes indicate the regulation of concentration and spatial distribution of bio-active cytokinin plays a pivotal role in the increase in panicle size, in the numbers of floral organs, and eventually in seed yield. One of the most fundamental questions in the cytokinin field is one concerning the prevalence of cis-zeatin in monocotyledonous crops (rice and maize) and in dicotyledonous legumes (pea, chickpea) and potato/sweet potato. A hypothesis is that cis-zeatin is synthesized by the cis-specific hydroxylation of the terminal methyl group of N6-isopentenyl side chain of N6-isopentenyl adenosine (i6Ado) or of their mono-, di-, or tri-phosphates catalyzed by the cis-specific hydroxylase. A second potential pathway is the isomerization of trans-zeatin to cis-zeatin by zeatin cis-/trans-isomerase. A second fundamental question to be addressed is the physiological role of cis-zeatin. Some have argued for a special function of cis-zeatin to account for the prevalence of the cis-zeatin in the plant kingdom from algae to higher plants.
文摘Functional traits are predictors of plants in response to environmental stimuli. They represent specific functional adaptations to various environmental stresses. This study deals with the variation in plant functional traits along elevation gradient and land-use types in Sagarmatha National Park and Buffer Zone, Nepal. Two field investigations in April and September, 2011 were made to collect samples. Sampling was done from 2200 - 3800 m asl varying approx. 400 m. East and west facing aspects of each valley were chosen. In each aspect four land-use type categories including disturbed (cultivated land, exploited forest and meadow) and less disturbed natural forest were selected. A transect of 25 m long and 2.5 m wide was laid. Different eight traits of plants including lifeform, plant height, clonality, spinescence, leaf dry matter content, stem specific density, twig dry matter content and twig drying time were examined for 60 plant species belonging to 31 families, collected from 40 sampled plots. Nine different types of growth forms were recorded. Plant height of the investigated species ranged from 0.03 - 15 m. The stolon consisting species were dominant in exploited forests. Diversity of clonal species was more in meadow and non-clonal species were dominant in all the altitudes. Only eight species consisted of spines. In the disturbed land-use categories, we found high variation in a particular trait. Correlation analyses revealed the significant relationship (p < 0.01) among different traits. Herbs and shrubs were dominant at higher elevation and in disturbed land-use categories. Species from high altitude were mostly short basal herbs, while spinescence and tall trees were observed at lower altitudes. Species recorded in meadows and exploited forests showed high variation in traits due to disturbance mainly grazing, fire, litter collection and trampling. Altitudinal variation, climatic conditions and disturbance most strongly influence trait expression in the study area.
基金supported by grants from the National Natural Science Foundation of China (31301645, 31171827)the National 973 Program of China (2013CB127502)
文摘Soybean cyst nematode Heterodera glycines is one of the most serious soil-borne pathogens in soybean production. However, the researches were limited in China due to lack of an effective pathosystem. In this study, we screened 21 legume Medicago plants in both Medicago truncatula and Medicago sativa to obtain candidate model plants for establishing a new pathosystem for legume-H. glycines interactions. The nematode infection of tested plants was assayed with Race 3 and 4 respectively, which were two dominant H. glycines inbred races in China soybean producing areas. The results showed that the model legume plant M. truncatula A17 failed to allow Race 3 of H. glycines to complete its life cycle, in contrast, it provided the Race 4 population to form several cyst nematodes, however, the female index（FI） value was approximately 1.6. Three M. sativa cultivars, including Xunlu, Aergangjin and Junren, provided either Race 3 or 4 of H. glycines to develop into mature cysts with their FI value below 5 as well. Our results demonstrated that legume plants in both M. truncatula and M. sativa were not likely to be a model plant for H. glycines because of an extreme high resistance.
文摘Strigolactones are plant hormones with multiple functions, including regulating various aspects of plant architecture such as shoot branching, facilitating the colonization of plant roots by arbuscular mycorrhizal fungi, and acting as seed germination stimulants for certain parasitic plants of the family Orobanchaceae. The obligate parasitic species Phelipanche aegyptiaca and Striga hermonthica require strigolactones for germination, while the facultative parasite Triphysaria versicolor does not. It has been hypothesized that P. aegyptiaca and S. hermonthica would have undergone evolutionary loss of strigolactone biosynthesis as a part of their mechanism to enable specific detection of exogenous strigolactones. We analyzed the transcriptomes of P. aegyptiaca, S. hermonthica and T. versicolor and identified genes known to act in strigolactone synthesis (D27, CCD7, CCD8, and MAX1), perception (MAX2 and D14) and transport (PDR12). These genes were then analyzed to assess likelihood of function. Transcripts of all strigolactone-related genes were found in P. aegyptiaca and S. hermonthica, and evidence points to their encoding functional proteins. Gene open reading frames were consistent with homologs from Arabidopsis and other strigolactone-producing plants, and all genes were expressed in parasite tissues. In general, the genes related to strigolactone synthesis and perception appeared to be evolving under codon-based selective constraints in strigolactone-dependent species. Bioassays of S. hermonthica root extracts indicated the presence of strigolactone class stimulants on germination of P. aegyptiaca seeds. Taken together, these results indicate that Phelipanche aegyptiaca and S. hermonthica have retained functional genes involved in strigolactone biosynthesis, suggesting that the parasites use both endogenous and exogenous strigolactones and have mechanisms to differentiate the two.
文摘Micropropagation from shoot tips and nodal segments was carried out for the conservation and domestication of spontaneous Moroccan thyme, <i><span style="font-family:Verdana;">Thymus broussonetii</span></i><i> </i><span style="font-family:Verdana;">Boiss. subsp. </span><i><span style="font-family:Verdana;">broussonetii</span></i><span style="font-family:Verdana;"> (endemic threatened). The mineral composition of the culture medium, as well as the succession of different growth regulators, influenced the </span><i><span style="font-family:Verdana;">in vitro</span></i><span style="font-family:Verdana;"> growth of this species. Sterilized achenes of </span><i><span style="font-family:Verdana;">T. broussonetii</span></i><i> </i><span style="font-family:Verdana;">were able to germinate on an agar medium containing Gautheret macronutrients with a rate of 25% and a degree of contamination of less than 4%. Shoot apices of 15-day seedlings (two cotyledon leaves) were cultivated on SD + 0.46 μM Kin medium and the explants obtained were transplanted every month. Six macronutrients (MS, B</span><sub><span style="font-family:Verdana;">5</span></sub><span style="font-family:Verdana;">, SH, SD, MS</span><sub><span style="font-family:Verdana;">m</span></sub> <span><span style="font-family:Verdana;">and N</span><sub><span style="font-family:Verdana;">30</span></sub><span style="font-family:Verdana;">K) were tested and N</span><sub><span style="font-family:Verdana;">30</span></sub><span style="font-family:Verdana;">K was chosen for the following experiments. Seven cytokinins (Kin, BAP, 2iP, DPU, adenine, Zeat and TDZ) at 0.46, 0.93 and 2.32 μM/l were evaluated and the addition of 0.93 μM adenine to N</span><sub><span style="font-family:Verdana;">30</span></sub><span style="font-family:Verdana;">K medium favored significantly the induction of buds and the elongation of explants. Three polyamines (putrescine, spermidine and spermine) at 2, 5, 10 and 20 μM/l were tested. A better multiplication of buds, shoots and roots was noted for N</span><sub><span style="font-family:Verdana;">30</span></sub><span style="font-family:Verdana;">K + 10 μM spermine. Cytokinin-auxin combinations led to better root multiplication and an increase in the number of buds a</span></span><span style="font-family:Verdana;">nd the length of explants, particularly for 0.46 μM Kin + 2.85 μM IAA. Acclimatization was successfully carried out using vitroplants developing a good root system. One month after the start of acclimatization, 97% of </span><i><span style="font-family:Verdana;">T. broussonetii</span></i><i> </i><span style="font-family:Verdana;">plantlets were healthy. Three months later, they were transplanted into larger pots. 100% of the acclimatized plants developed flowers in the 2</span><sup><span style="font-family:Verdana;">nd</span></sup><span style="font-family:Verdana;"> year between June and August. Re-initiation of the </span><i><span style="font-family:Verdana;">in vitro</span></i><span style="font-family:Verdana;"> culture was carried out from sterilized twig segments collected from the acclimatized plants of </span><i><span style="font-family:Verdana;">T. broussonetii</span></i><i> </i><span style="font-family:Verdana;">with 1 - 2 nodes on the medium N</span><sub><span style="font-family:Verdana;">30</span></sub><span style="font-family:Verdana;">K + 0.46 μM Kin, and 52.1% of the explants healthily proliferated. Finally, two micropropagation prototypes were developed: shoot tip culture from seedlings obtained after germination of achenes and node culture from acclimatized plants.</span>
