影响水稻光合日变化的酶和相关因素的分析

水稻叶片的最大光合速率出现在上午１０：００时，Ｒｕｂｉｓｃｏ初始活力也在此时达到最大，然后逐渐降低，下午１４：００时略上升后又下降．Ｒｕｂｉｓｃｏ初始活力与光合速率之间极显著相关，相关系数为 ０．９４７４．运用相关性分析、回归分析、通径分析，对晴（有时有云）天气水稻叶片的光合速度、光合关键酶及有关因素的日变化进行综合评估，结果发现中午光合下降主要来自气孔限制，同时Ｒｕｂｉｓｃｏ活性也下降；Ｒｕｂｉｓｃｏ活性是影响光合日变化的又一重要生化因子．体内Ｒｕｂｉｓｃｏ活性受Ｒｕｂｉｓｃｏ活化酶的调节．

Influence of Enzymes and Relative Factors on Diurnal Variation of Photosynthetic Rate in Rice

To clarify the factors determining the diurnal courses of photosysthesis in a day, photosynthetic rate (Pn). initial Rubisco activity, total Rubisco activity, RCA activity, stomatal conductance (Sc), photosynthetic photon flux (PPF), intercellular CO_2 concentration(Ci), relative humidity and temperature were measured. Maximum occurred at about 10:00 a.m. when Rubisco initial activity was reached the maximum. Then both of them gradually decreased down. After 14:00 p.m. they rose up positively correlated with Pn and the regression coefficient between them was 0.9474. By the correlation analysis, regression analysis and path analysis, stomatal conductance and Rubisco initial activity were found to be major factors limiting photosynthetic rate. The results also suggested that RCA (Rubisco activase) activity had a effect on Pn by its regulation to the initial Rubisco activity.