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钾营养对水稻光合速率(Pn)、Hill反应及SOD活力日变化的影响

蒋德安, 翁晓燕, 陆庆, 谢学民, 饶立华

浙江农业大学基础课部.浙江,杭州 310029

摘要

晴天,田间水稻顶部完全展开叶最大的Pn出现在上午8时半左右。低钾营养加剧了"午睡"。8:30-14:30高光强期间Pn与气孔导度和Ci分别呈显著直线正相关。Hill反应活力午后最低,但该时低钾水稻的Hill反应活力较钾充足水稻高。SOD活力早晨最低,中午该酶活力增加程度在低钾水稻中更为明显。上述各项均存在着品种间的差异。因此,低钾下水稻"午睡"的加剧由低气孔导度所致,较长时间的低Ci会诱发低的Hill反应活力。

关键词： 钾营养; 水稻; Pn; Hill反应; SOD; 日变化

Effect of potassium on diurnal variations in Pn, Hill reaction and SOD activities in rice plant

Jiang Dean, Weng Xiaoyi, Lu Qing, Xie Xuemin, R

Division of Basic Courses,Zhejiang Agricultural University.Hangzhou 310029,Zhejiang

Abstract

Two rice cultivars grown in pots with normal and low potassium supply were used to explore the cause of deeper midday depression of Pn under low-potassium condition.Maximum Pn occurred at about 8:30 when the photosynthetic photon flux (PPF) was about 1200#mu#mol m~(-2)s~(-1) and was slightly higher in low-potassium plants than in normal plants. Under low-potassium condition the midday depression of Pn was deeper, particularly,for cv.Erjiufeng,a cultivar more sensitive to potassium deficieny.Hill reaction rate stayed unchanged throughout the morning,fell at noon and rose again in late afternoon.The rate at noon was higher in the low-potassium plants. SOD activity was lower in early morning than at noon and afternoon and was also higher in low-potassium plants than in normal -potassium plants. Although a prolonged low Ci under strong irradiance can reduce PSⅡ activity reversibly, positive correlation of Pn with stomatal conductance and Ci from 8:30 to 14:30 indicats that midday depression results from the lowering of stomatal conductance rather than from the low ering of Hill reaction rate. At noon the higher SOD activity in the low-potassium plants may be a mechanisum of avoidance of the damage from excessive PPF.

Key words: Potassium nitrition;Rice;Pn;Hill reaction;SOD;Diurnal change

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引用本文：

蒋德安, 翁晓燕, 陆庆, 谢学民, 饶立华. 钾营养对水稻光合速率(Pn)、Hill反应及SOD活力日变化的影响[J]. 生理学报 1996; 48 (1): .

Jiang Dean, Weng Xiaoyi, Lu Qing, Xie Xuemin, R. Effect of potassium on diurnal variations in Pn, Hill reaction and SOD activities in rice plant. Acta Physiol Sin 1996; 48 (1): (in Chinese with English abstract).