Vetiver grass (</span><i><span style="font-family:Verdana;">Vetiveria</span></i> <i><span style="font-family:Verdana;">zizanioides</span></i>&l...Vetiver grass (</span><i><span style="font-family:Verdana;">Vetiveria</span></i> <i><span style="font-family:Verdana;">zizanioides</span></i><span style="font-family:Verdana;"> L.) is widely used for soil and water conservation, and land management. In practice, all vetiver seedlings are propagated via ramets or tillers, which cannot meet the market demand and would also destroy the original habitat. Most</span><span style="color:red;"> </span><span style="font-family:Verdana;">vetiver genotypes flower but do not produce seeds. A wild ecotype of vetiver grass originated in southern China is fertile, but the rate of seed germination is very low. This study aimed to develop a novel method to improve its seed germination and seedling establishment. In the field, the inflorescences of wild vetiver were wrapped using a transparent plastic bag with a pot containing wet soils. The effects of inflorescence bagging and Tween 80 application on seed germination and seedling growth were examined. The results showed that seed development was characterized by low seed setting rate (19.2%), uneven maturity time, easy shedding (more than 95% of spikelets shed off 20 days after flowering), therefore difficult harvest of viable seeds. Bagging the inflorescence with moist soils in pot ensured the mature seeds falling onto the nursery soil surface and absorbing water for germination while the immature seeds continued to grow on the inflorescence. Bigging not only improved seed development and maturity, saved the procedure of seed collection and storage, but also provided a humid micro-environment for seed germination and seedling growth. Tween 80 as a surfactant promoted seed water absorption, germination and seedling growth. This simple and novel method has integrated the procedures of seed collection, storage, germination and seedling establishment, and enables </span></span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">produc</span><span style="font-family:Verdana;">tion</span><span style="font-family:""> </span><span style="font-family:Verdana;">of </span><span style="font-family:Verdana;">a large </span><span style="font-family:Verdana;">number</span><span style="font-family:Verdana;"> of healthy seedlings. The possible reasons for the degeneration and disappearance of the original population were also discussed from the perspective of the disadvantages of vetiver propagation.展开更多
A generalization of the usual Green function to a kind of nonlinear elliptic equation of divergence form is discussed. The regularity and comparison principle of Green function in the sense of distribution are shown.
Under the premise of infinitely many pure strategies, by defining the new LP* metric, striking an equivalence of topology and weak* topology, we prove that the existence of the essential component.
通过实地调查取样和室内分析,研究铜陵水木冲铜尾矿废弃地不同时期种植香根草(Vetiveria zizanioides L.)群落(近期种植香根草群落(V.zizanioides communities were established in the recent stage,JX),中期种植香根草群落(V.zizanioi...通过实地调查取样和室内分析,研究铜陵水木冲铜尾矿废弃地不同时期种植香根草(Vetiveria zizanioides L.)群落(近期种植香根草群落(V.zizanioides communities were established in the recent stage,JX),中期种植香根草群落(V.zizanioides communities were established in the middle stage,ZX)和早期种植香根草群落(V.zizanioides communities were established in the early stage,OX))对尾矿基质化学性质、微生物量和土壤酶活性的影响,探讨人工植被恢复对铜尾矿废弃地基质系统的修复作用。结果表明:香根草的定植能延缓铜尾矿的酸化过程,且随着香根草定植时间的延长,0—5 cm和5—20 cm层尾矿基质中总氮和速效磷含量提高(其中,0—5 cm层总氮积累更加显著),OX下0—5 cm表层基质总氮和速效磷的平均值分别是JX下的4.64倍和22.44倍。基质微生物量C、N含量和脱氢酶、过氧化氢酶、脲酶活性也随香根草种植时间的延长而有不同程度的升高,且基质化学性质对微生物量和酶活性有影响,其中基质微生物量C、N含量、脱氢酶和过氧化氢酶活性均与电导率呈显著或极显著负相关性;而基质微生物量N和4种酶活性均与总氮含量呈显著或极显著正相关性,表明总氮含量是影响基质微生物量N和酶活性的主要因子;基质微生物量N、脱氢酶和过氧化氢酶活性还与速效磷含量呈极显著正相关性。基质中Cu、Pb含量对脱氢酶、过氧化氢酶活性和微生物量均有显著抑制作用,而Zn对基质微生物活性有一定的激活作用。生长在尾矿废弃地上的香根草不仅显著地改善了铜尾矿废弃地的基质化学性质,且有利于基质微生物量和酶活性的增加,是一种良好的矿业废弃地生态修复物种。展开更多
文摘Vetiver grass (</span><i><span style="font-family:Verdana;">Vetiveria</span></i> <i><span style="font-family:Verdana;">zizanioides</span></i><span style="font-family:Verdana;"> L.) is widely used for soil and water conservation, and land management. In practice, all vetiver seedlings are propagated via ramets or tillers, which cannot meet the market demand and would also destroy the original habitat. Most</span><span style="color:red;"> </span><span style="font-family:Verdana;">vetiver genotypes flower but do not produce seeds. A wild ecotype of vetiver grass originated in southern China is fertile, but the rate of seed germination is very low. This study aimed to develop a novel method to improve its seed germination and seedling establishment. In the field, the inflorescences of wild vetiver were wrapped using a transparent plastic bag with a pot containing wet soils. The effects of inflorescence bagging and Tween 80 application on seed germination and seedling growth were examined. The results showed that seed development was characterized by low seed setting rate (19.2%), uneven maturity time, easy shedding (more than 95% of spikelets shed off 20 days after flowering), therefore difficult harvest of viable seeds. Bagging the inflorescence with moist soils in pot ensured the mature seeds falling onto the nursery soil surface and absorbing water for germination while the immature seeds continued to grow on the inflorescence. Bigging not only improved seed development and maturity, saved the procedure of seed collection and storage, but also provided a humid micro-environment for seed germination and seedling growth. Tween 80 as a surfactant promoted seed water absorption, germination and seedling growth. This simple and novel method has integrated the procedures of seed collection, storage, germination and seedling establishment, and enables </span></span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">produc</span><span style="font-family:Verdana;">tion</span><span style="font-family:""> </span><span style="font-family:Verdana;">of </span><span style="font-family:Verdana;">a large </span><span style="font-family:Verdana;">number</span><span style="font-family:Verdana;"> of healthy seedlings. The possible reasons for the degeneration and disappearance of the original population were also discussed from the perspective of the disadvantages of vetiver propagation.
基金Supported by Beijing Jiaotong University Science Research Foundation (2004SM056)
文摘A generalization of the usual Green function to a kind of nonlinear elliptic equation of divergence form is discussed. The regularity and comparison principle of Green function in the sense of distribution are shown.
文摘Under the premise of infinitely many pure strategies, by defining the new LP* metric, striking an equivalence of topology and weak* topology, we prove that the existence of the essential component.
文摘通过实地调查取样和室内分析,研究铜陵水木冲铜尾矿废弃地不同时期种植香根草(Vetiveria zizanioides L.)群落(近期种植香根草群落(V.zizanioides communities were established in the recent stage,JX),中期种植香根草群落(V.zizanioides communities were established in the middle stage,ZX)和早期种植香根草群落(V.zizanioides communities were established in the early stage,OX))对尾矿基质化学性质、微生物量和土壤酶活性的影响,探讨人工植被恢复对铜尾矿废弃地基质系统的修复作用。结果表明:香根草的定植能延缓铜尾矿的酸化过程,且随着香根草定植时间的延长,0—5 cm和5—20 cm层尾矿基质中总氮和速效磷含量提高(其中,0—5 cm层总氮积累更加显著),OX下0—5 cm表层基质总氮和速效磷的平均值分别是JX下的4.64倍和22.44倍。基质微生物量C、N含量和脱氢酶、过氧化氢酶、脲酶活性也随香根草种植时间的延长而有不同程度的升高,且基质化学性质对微生物量和酶活性有影响,其中基质微生物量C、N含量、脱氢酶和过氧化氢酶活性均与电导率呈显著或极显著负相关性;而基质微生物量N和4种酶活性均与总氮含量呈显著或极显著正相关性,表明总氮含量是影响基质微生物量N和酶活性的主要因子;基质微生物量N、脱氢酶和过氧化氢酶活性还与速效磷含量呈极显著正相关性。基质中Cu、Pb含量对脱氢酶、过氧化氢酶活性和微生物量均有显著抑制作用,而Zn对基质微生物活性有一定的激活作用。生长在尾矿废弃地上的香根草不仅显著地改善了铜尾矿废弃地的基质化学性质,且有利于基质微生物量和酶活性的增加,是一种良好的矿业废弃地生态修复物种。
