The changes of gas exchange character and photosynthetic enzyme activity in different cassava varieties

Changes of gas exchange character and relevant photosynthetic enzyme activity and the correlation among them were studied.The results suggested that during the senescence of cassava leaves the significant decline of net photosynthetic rate and photosynthesis was closely related to the changes of inside photosynthetic apparatus and the photosynthetic enzyme.There were highly significant and positive correlations between any two of the indexes of stomata conductance,intercellular CO_2 concentration,transpiration rate and net photosynthesis rate.The correlations between net photosynthetic rate and photophosphorylation and Ca~(2+)-ATPase activity were significant and positive,and GO activity was highly significant and positive.