渗透胁迫对番木瓜若干生理性状的影响

研究了渗透胁迫下番木瓜幼苗的细胞伤害程度、净光合速率的变化及其与气孔导度之间的关系。试验结果表明渗透胁迫导致番木瓜幼苗叶片细胞相对电导率和MDA含量分别增加了 1 1 .72倍和 1 1 .0 7倍、可溶性蛋白质及叶绿素含量则分别下降了 5 7.3 %和 5 7.6%、POD及SOD活性先升后降 ,但SOD活性降低时间早于POD ,渗透胁迫降低了番木瓜的净光合速率和叶片水势 ,轻度胁迫时 (处理前期 )气孔导度的限制是导致净光合速率降低的主要原因 ,重度胁迫时(处理后期 )叶肉光合能力的下降是引起净光合速率降低的主要原因。

The influence of osmotic stress on some physiological characters of papaya

Responses of relative physiological index,photosynthesis rate and stomatal conductance to osmotic stress as well as the relationship between photosynthetic rate and stomatal conductance were investigated with papaya seedlings. The results showed that under osmotic stress relative electrical conductivity and MDA content increased by 11.72 and 11.07 times respectively,soluble protein and chlorophyll content decreased by 57.3% and 57.6%,POD and SOD activity increased first and then decreased but the time when SOD activity decreased was prior to that of POD. Under mild water stress,the decline of photosynthesis was mainly due to the decline of stomatal conductance. However,under severe water stress the principal cause of the reduction in photosynthesis was attributed to the decline of photosyntheisis capacity of mesophyll cells.