土壤水分条件对刺槐各个器官中还原态氮素含量的影响

摘要

In order to examine the effects of different degrees of soil drought on the contents of reduced nitrogen in tree organs,1-year-old seedlings of black locust (Robinia pseudoacacia) were planted individually in pots and subjected to suitable water condition,medium drought,and severe drought,the corresponding soil water contents were 70％,50％,and 35％ of field water capacity with a fluctuation range of ±5％,respectively,for eight weeks.The results showed that the reduction in soil water contents did not show significant effects on the nitrate reductase activity and amino acid contents in the leaves,stems,course roots and fine roots,as well as on the composition of amino compounds and their contents in the leaves.But soluble protein contents in the organs increased significantly under reduced soil water content.Meanwhile,drought-induced reduction in plant growth resulted in a significant decrease in the accumulation of reduced nitrogen in the organs.%通过对盆栽1年生刺槐(Robinia pseudoacacia)苗进行为期8周的3个土壤水分梯度处理(分别为适宜水分、中度和重度干旱,相对应的土壤含水量控制在田间持水量的70％±5％、50％±5％和35％±5％范围内),以探讨不同土壤含水量对刺槐各个器官中还原态氮素(包括可溶性氨基酸和蛋白质)含量的影响.结果表明,中度和重度土壤干旱对刺槐地上器官(叶子和茎干)以及地下器官(粗根和细根)中硝酸还原酶的活性和氨基酸含量、叶子中氨基化合物组分以及各组分含量等均没有产生显著影响,但这些器官中的可溶性蛋白质含量则随着干旱的加剧而显著升高.同时,干旱引起的生长量降低使得刺槐叶子、茎干和细根、以及整体植株中所积累的还原氮数量显著减少.