重金属对水稻光合作用和同化物输配的影响

光合速率测定表明,0.025～1.0mmolL的Cu2+、Cd2+和Hg2+显著抑制水稻叶片的光合速率,且抑制程度随Cu2+、Cd2+和Hg2+浓度的增高而增强。示踪动力学分析表明,0.5mmolL的Cu2+、Cd2+和Hg2+抑制光合产物在叶内不同状态间的转化,影响叶中光合产物的输出,导致叶内小分子糖的累积,使叶片光合速率受糖浓度增高的反馈调节而下降。电泳分析表明,Cu2+、Cd2+和Hg2+抑制叶内淀粉酶同功酶的表达,并进而抑制光合同化物在叶内可输配态和暂贮态之间的转化。

EFFECT OF HEAVY METALS ON THE PHOTOSYNTHESIS AND PHOTOSYNTHATES TRANSFORMATION IN RICE

The photosynthetic rate in rice leaf was significantly inhibited by 0.025～1.0mmol/L of Cu~(2+), Cd~(2+) and Hg~(2+). With increasing of Cu~(2+), Cd~(2+) and Hg~(2+) concentration, the inhibiting degree of photosynthetic rate was enhanced. Tracer kinetic analysis indicated that, 0.5mmol/L Cu~(2+), Cd~(2+) and Hg~(2+) inhibited the transformation between starch and sugar, disturbed the translocation of photosynthates from leaves. Consequently, sugar accumulated in the leaves, which might induce a feedback-regulation of photosynthetic rate. Using polyacrylamide concentration gradient gel electrophoresis to analyze the activity of amylase isozymes indicateed that, the amylase isozymes expression in rice leaf was inhibited by 0.1～0.5mmol/L Cu~(2+), Cd~(2+) and Hg~(2+), hence, the transformation between starch and sugar was blocked.