遮荫处理对4种草本植物生理生化特性的影响

研究了遮荫处理对少花龙葵、三叶鬼针草、胜红蓟和莶叶片的生理生化特性的影响,结果表明:遮荫处理提高了4种草本植物叶绿素a b含量,叶绿素a/b存在物种差异;4种草本植物叶片最大净光合速率(Pn-max)、光饱和点(LSP)和光补偿点(LCP)均明显下降;少花龙葵叶片MDA和POD含量降低,三叶鬼针草、胜红蓟和莶升高;遮荫处理使少花龙葵、三叶鬼针草和胜红蓟叶片可溶性糖含量增加,可溶性蛋白含量均呈不同程度下降。少花龙葵耐阴性较强,适度遮荫利于少花龙葵生长发育;三叶鬼针草、胜红蓟和莶受到弱光胁迫。

Effects of shading treatments on physiological and biochemical characteristics of four species of herbaceous plants

Through pot cultivation experiments under shading conditions, the physiological and biochemical indexes of the leaves of S. photeinocarpum, B. pilosa, A. conyzoides and S. orientalis were measured. The results showed that the contents of chlorophyll a b in leaves of four species increased, and the chlorophyll a/b displayed diversities among different species with shading treatments. The net photosynthetic rate(Pn-max), light saturation point (LSP) and light compensation point (LCP) of four species of herbaceous plants were reduced evidently under shading conditions. In contrast with full light treatments, the contents of MDA and POD (pro- tecting enzymes) activities of S. photeinocarpum were higher, but that of B. pilosa, A. conyzoides and S. orientalis were lower. The shading treatments made for accumulation of soluble sugar in leaves of S. photeinocarpum, B. pilosa and A. conyzoides, but that made against accumulation of soluble protein. These revealed that S. photeinocarpum had obvious shade-endurance, moderate shad- ing was helpful to its growth and development; There were low irradiance stress for B. pilosa, A. conyzoides and S. orientalis under shading conditions.