不同土壤田间含水量对紫云英生长及生理代谢的影响

Effects of different soil moisture on growth and physiological characteristics of Astragalus sinicus

通过设置5个不同的田间含水量(25%～30%,50%～55%,75%～80%,95%～100%田间持水量和浸水)研究紫云英生长及生理对土壤含水量的响应。结果表明,75%～80%田间持水量下植株生长最好,株高、茎粗、叶面积、生物量等都优于其他处理,且植株的养分含量及其积累量也最高,是适合紫云英幼苗生长的最佳土壤田间含水量;与75%～80%田间持水量处理相比,25%～30%田间持水量和浸水处理下,SOD、POD、CAT和MDA含量均明显上升,叶绿素荧光参数最小荧光产量(Fo)上升,最大荧光产量(Fm)、可变荧光产量(Fv)、Fv/Fm和Fv/Fo均下降,表明植株受到逆境胁迫,生物量和养分含量显著下降,养分积累量明显减少,不利于紫云英幼苗生长;而50%～55%,75%～80%和95%～100%田间持水量3个处理的植株叶片SOD、POD、CAT、MDA分别为12.0,11.0,15.6U/(mg蛋白.min),673,668,725U/(mg蛋白.min),2.08,1.77,2.07U/(mg蛋白.min)和14.21,12.41,15.32mmol/g,处理间未出现明显的差异,最大光化学效率(Fv/Fm)分别为0.828,0.837,0.826,也未出现明显的差异,说明在50%～100%的田间持水量条件下,紫云英幼苗能够正常生长。

Five treatments （25%--30%, 50%--55%, 75%--80%, 95%--100% of field moisture capacity and submergence） were installed to study the effects of soil moisture on growth and physiological characteristics of Astragalus sinicus. Growth and accumulation of the nutrients absorbed by A. sinicus were greatest at 75 % -- 80% of field moisture capacity, which was the best fit to growth. Disease symptoms of water stress were shown by A. sinicus at 25%--30% of field moisture capacity and at submergence. Compared with the 75%-- 80 % of field moisture capacity treatment, superoxide dismutase （SOD）, peroxidase （POD）, catlase （CAT） activities and malondialdehvde （MDA） contents in leaves of A. sinicus and the minimal fluorescence （Fo） all increased significantly, while the maximal fluorescence （Fm）, variable fluorescence （Fv）, light energy transformation efficiency of PS II （Fv/Fro） and activity potential of PS II （Fv/Fo） declined significantly as did the yield and accumulation of nutrients absorbed. SOD, POD, and CAT activities, MDA content and chlorophyll fluorescence parameters did not change significantly in the three treatments （50%--55%, 75%--80% and 95%%- 100 % of field moisture capacity） which therefore showed that A. sinicus could normally grow at 50 %--100% of field moisture capacity.