Low temperature is the most common abiotic stress factors during the eggplant cultivation in solar greenhouses.Melatonin plays important roles in plant resistance to low temperature.However,the role of melatonin in re...Low temperature is the most common abiotic stress factors during the eggplant cultivation in solar greenhouses.Melatonin plays important roles in plant resistance to low temperature.However,the role of melatonin in regulating chilling tolerance and extending the preharvest shelf life of eggplant fruits is still unknown.In this study,we investigated the effects of exogenous melatonin on eggplant plants and fruits in response to low temperature.Under simulated low-temperature conditions,exogenous melatonin significantly relieved the chilling symptoms of seedlings by reducing reactive oxygen species (ROS) and malondialdehyde (MDA) levels and relative leakage rates.These reductions were caused by higher superoxide dismutase (SOD) and catalase (CAT) activities and increased endogenous polyamine and melatonin levels compared with those in untreated seedlings.Notably,the expression levels of SOD,CAT1/2,and polyamine synthesis genes (ADC and ODC) were also increased by 100μmol·L~(-1)melatonin,as well as those of genes involved in melatonin synthesis (TDC,T5H,SNAT,ASMT,and COMT) and cold regulation (COR1,CBFa/b,and ZAT2/6/12).To further investigate the effects of melatonin on eggplant leaves and fruits under natural low temperature conditions,100μmol·L~(-1)melatonin was sprayed on the functional leaves at three days before commodity maturation.Melatonin significantly alleviated chilling injury in the leaves and pericarp and extended the preharvest shelf life of the fruit by increasing the expression of COR1,CBF,ZAT2/6/12,and API5 and decreasing the expression of senescence-related genes (NCED1/2 and SAG12).Therefore,100μmol·L~(-1)melatonin improved chilling tolerance and fruit shelf life by upregulating ZAT2/6/12 to affect ROS-and senescence-related processes,which provides a reference for alleviating cold stress and extending the preharvest fruit shelf life in eggplant.展开更多
To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conduct...To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conducted at 0,1,3,and 5 days before harvest.The appearance,respiration rate,mass-loss rate,electrolyte leakage,glucosinolate,ascorbic acid,total phenol,total flavonoid,total sugar and sucrose contents,and sucrose phosphate synthase(SPS),invertase(INV),sucrose synthase synthesis(SSS)and cleavage(SSC)activities of broccoli samples were observed after 0,2,4,6,8,and 10 days of storage.The results showed that spraying arginine at 5 days preharvest(5-ARG)helped to inhibit broccoli respiration during storage,delay electrolyte leakage,and maintain broccoli color.Furthermore,during the growth stage,total sugar accumulation was higher in the 5-ARG group.In addition,during the storage period,sucrose synthesis was accelerated,while sucrose cleavage was inhibited,resulting in more sucrose retention in postharvest broccoli.In conclusion,5-ARG resulted in the accumulation of more nutrients during the growth process and effectively delayed the quality decline during storage,thereby prolonging the shelf life of broccoli.Therefore,this study provides a theoretical basis for improving postharvest storage characteristics of broccoli through preharvest treatments.展开更多
Throughout the world, aflatoxin contamination is considered one of the most serious food safety issues concerning health. Chronic problems with preharvest afiatoxin contamination occur in the southern US, and are part...Throughout the world, aflatoxin contamination is considered one of the most serious food safety issues concerning health. Chronic problems with preharvest afiatoxin contamination occur in the southern US, and are particularly troublesome in corn, peanut, cottonseed, and tree nuts. Drought stress is a major factor to contribute to preharvest afiatoxin contamination. Recent studies have demonstrated higher concentration of defense or stress-related proteins in corn kerners of resistant genotypes compared with susceptible genotypes, suggesting that preharvest field condition （drought or not drought） influences gene expression differently in different genotypes resulting in different levels of ＂end products＂： PR（pathogenesis-related） proteins in the mature kernels. Because of the complexity of Aspergillus-plant interactions, better understanding of the mechanisms of genetic resistance will be needed using genomics and proteomics for crop improvement. Genetic improvement of crop resistance to drought stress is one component and will provide a good perspective on the efficacy of control strategy. Proteomic comparisons of corn kernel proteins between resistant or susceptible genotypes to Aspergillus flavus infection have identified stress-related proteins along with antifungal proteins as associated with kernel resistance. Gene expression studies in developing corn kernels are in agreement with the proteomic studies that defense-related genes could be upregulated or downregulated by abiotic stresses.展开更多
Jelly seed, a physiological disorder in ‘Amrapali' mango fruit, is characterized by the excessive softening of pulp around the stone in ripe fruits. The disorder is caused by the onset of germination associated e...Jelly seed, a physiological disorder in ‘Amrapali' mango fruit, is characterized by the excessive softening of pulp around the stone in ripe fruits. The disorder is caused by the onset of germination associated events in the seed of developing fruit due to decreased level of very-longchain fatty acids(VLCFAs) in seed. Field trials involving preharvest application of spray formulations on developing fruits, between 50% and 60%maturity, showed that formulation V(10 g·L^(-1) NaCl, 25 g·L^(-1) CaCl_2, 0.5 g·L^(-1) KCl, 0.01 g·L^(-1) H_3 BO_3, 0.01 g·L^(-1) Cu SO_4, 0.01 g·L^(-1) Zn SO_4,0.01 g·L^(-1) FeSO_4, 0.01 g·L^(-1) MnSO_4, and 0.002 g·L^(-1) EDTA) was the most effective in preventing the jelly seed disorder. Further studies to understand the mode of action of the formulation in controlling jelly seed development, revealed increased synthesis of VLCFAs in seed followed by the rapid production of ABA and germination-inhibiting phenolic acids, besides increased accumulation of calcium in seed. These factors acting in unison delayed seed germination and decreased the activities of pectinolytic enzymes in pulp to produce healthy fruits, free from jelly seed disorder.There was an increase of mineral nutrient content in pulp of treated healthy fruits. Thus, the study helped to develop a remedy to prevent jelly seed besides revealing the biochemical mechanism by which formulation V acted to produce ‘Amrapali' mango fruits free of jelly seed with improved nutritional quality.展开更多
基金Introduction of Talents for Scientific Research of State Key Laboratory of North China Crop Improvement and Regulation (Grant No.NCCIR2020RC-11)Hebei Fruit Vegetables Seed Industry Science and Technology Innovation Team Project (Grant No.21326309D)+2 种基金Vegetable Innovation Team Project of Hebei Modern Agricultural Industrial Technology System (Grant No.HBCT2018030203)Introduction of Talents for Scientific Research of Hebei Agriculture University (Grant No.YJ2020048)Basic Scientific Research Funds of Provincial Universities of Hebei Province (Grant No.KY2021056) for the provision of funds。
文摘Low temperature is the most common abiotic stress factors during the eggplant cultivation in solar greenhouses.Melatonin plays important roles in plant resistance to low temperature.However,the role of melatonin in regulating chilling tolerance and extending the preharvest shelf life of eggplant fruits is still unknown.In this study,we investigated the effects of exogenous melatonin on eggplant plants and fruits in response to low temperature.Under simulated low-temperature conditions,exogenous melatonin significantly relieved the chilling symptoms of seedlings by reducing reactive oxygen species (ROS) and malondialdehyde (MDA) levels and relative leakage rates.These reductions were caused by higher superoxide dismutase (SOD) and catalase (CAT) activities and increased endogenous polyamine and melatonin levels compared with those in untreated seedlings.Notably,the expression levels of SOD,CAT1/2,and polyamine synthesis genes (ADC and ODC) were also increased by 100μmol·L~(-1)melatonin,as well as those of genes involved in melatonin synthesis (TDC,T5H,SNAT,ASMT,and COMT) and cold regulation (COR1,CBFa/b,and ZAT2/6/12).To further investigate the effects of melatonin on eggplant leaves and fruits under natural low temperature conditions,100μmol·L~(-1)melatonin was sprayed on the functional leaves at three days before commodity maturation.Melatonin significantly alleviated chilling injury in the leaves and pericarp and extended the preharvest shelf life of the fruit by increasing the expression of COR1,CBF,ZAT2/6/12,and API5 and decreasing the expression of senescence-related genes (NCED1/2 and SAG12).Therefore,100μmol·L~(-1)melatonin improved chilling tolerance and fruit shelf life by upregulating ZAT2/6/12 to affect ROS-and senescence-related processes,which provides a reference for alleviating cold stress and extending the preharvest fruit shelf life in eggplant.
文摘To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conducted at 0,1,3,and 5 days before harvest.The appearance,respiration rate,mass-loss rate,electrolyte leakage,glucosinolate,ascorbic acid,total phenol,total flavonoid,total sugar and sucrose contents,and sucrose phosphate synthase(SPS),invertase(INV),sucrose synthase synthesis(SSS)and cleavage(SSC)activities of broccoli samples were observed after 0,2,4,6,8,and 10 days of storage.The results showed that spraying arginine at 5 days preharvest(5-ARG)helped to inhibit broccoli respiration during storage,delay electrolyte leakage,and maintain broccoli color.Furthermore,during the growth stage,total sugar accumulation was higher in the 5-ARG group.In addition,during the storage period,sucrose synthesis was accelerated,while sucrose cleavage was inhibited,resulting in more sucrose retention in postharvest broccoli.In conclusion,5-ARG resulted in the accumulation of more nutrients during the growth process and effectively delayed the quality decline during storage,thereby prolonging the shelf life of broccoli.Therefore,this study provides a theoretical basis for improving postharvest storage characteristics of broccoli through preharvest treatments.
文摘Throughout the world, aflatoxin contamination is considered one of the most serious food safety issues concerning health. Chronic problems with preharvest afiatoxin contamination occur in the southern US, and are particularly troublesome in corn, peanut, cottonseed, and tree nuts. Drought stress is a major factor to contribute to preharvest afiatoxin contamination. Recent studies have demonstrated higher concentration of defense or stress-related proteins in corn kerners of resistant genotypes compared with susceptible genotypes, suggesting that preharvest field condition （drought or not drought） influences gene expression differently in different genotypes resulting in different levels of ＂end products＂： PR（pathogenesis-related） proteins in the mature kernels. Because of the complexity of Aspergillus-plant interactions, better understanding of the mechanisms of genetic resistance will be needed using genomics and proteomics for crop improvement. Genetic improvement of crop resistance to drought stress is one component and will provide a good perspective on the efficacy of control strategy. Proteomic comparisons of corn kernel proteins between resistant or susceptible genotypes to Aspergillus flavus infection have identified stress-related proteins along with antifungal proteins as associated with kernel resistance. Gene expression studies in developing corn kernels are in agreement with the proteomic studies that defense-related genes could be upregulated or downregulated by abiotic stresses.
文摘Jelly seed, a physiological disorder in ‘Amrapali' mango fruit, is characterized by the excessive softening of pulp around the stone in ripe fruits. The disorder is caused by the onset of germination associated events in the seed of developing fruit due to decreased level of very-longchain fatty acids(VLCFAs) in seed. Field trials involving preharvest application of spray formulations on developing fruits, between 50% and 60%maturity, showed that formulation V(10 g·L^(-1) NaCl, 25 g·L^(-1) CaCl_2, 0.5 g·L^(-1) KCl, 0.01 g·L^(-1) H_3 BO_3, 0.01 g·L^(-1) Cu SO_4, 0.01 g·L^(-1) Zn SO_4,0.01 g·L^(-1) FeSO_4, 0.01 g·L^(-1) MnSO_4, and 0.002 g·L^(-1) EDTA) was the most effective in preventing the jelly seed disorder. Further studies to understand the mode of action of the formulation in controlling jelly seed development, revealed increased synthesis of VLCFAs in seed followed by the rapid production of ABA and germination-inhibiting phenolic acids, besides increased accumulation of calcium in seed. These factors acting in unison delayed seed germination and decreased the activities of pectinolytic enzymes in pulp to produce healthy fruits, free from jelly seed disorder.There was an increase of mineral nutrient content in pulp of treated healthy fruits. Thus, the study helped to develop a remedy to prevent jelly seed besides revealing the biochemical mechanism by which formulation V acted to produce ‘Amrapali' mango fruits free of jelly seed with improved nutritional quality.
