大量元素缺乏对小麦光合、呼吸作用和生理特性的影响

The effects of macronutrient deficiency on photosynthetic activity,respiration and physiological parameters in wheat

对小麦幼苗分别进行缺氮、缺磷和缺钾处理10～30d,研究大量元素缺乏对小麦叶片呼吸作用、光合活性和生理参数的影响。大量元素缺乏导致小麦叶片H_2O_2、丙二醛含量上升,含水量下降,抗氰呼吸被明显诱导。缺氮和缺磷还导致净光合速率(Pn)、PSⅡ光合电子传递量子效率(Φ_(PSⅡ))、PSⅡ原初光化学效率(Fv/Fm)、光适应下PSⅡ最大光化学效率(Fv′/Fm′)和非光化学猝灭系数(NPQ)下降。缺钾只导致NPQ下降,其它光合参数变化不大。通过对以上生理变化的分析,可以看出大量元素缺乏对植物体造成了显著的影响,但损伤机理各不相同。缺氮主要影响蛋白质合成,缺磷影响能量代谢,缺钾则主要影响膜脂透性,其中缺钾的影响在30d内相对较小。同时对大量元素缺乏下小麦叶片光合和呼吸作用变化的原因进行了探讨。

The respiration, photosynthetic activity and some physiological parameters were measured in wheat leaves under N, P or K deficiency for 10～30 days. Under macronutrient deficiency, H_2O_2、MDA increased, the water content decreased, and the cyanide resistant respiration was induced apparently. Net photosynthesis rate (Pn), Φ_(PSⅡ), Fv/Fm, Fv'/Fm' and non-photochemistry quenching (NPQ) declined under N or P deficiency. K deficiency resulted in decline of NPQ, but its other photosynthetic parameters did not change significantly. All these results indicated that macronutrient deficiency had remarkable effects on plants, but individual mechanisms were different. Nitrogen deficiency hampered protein synthesis, phosphorus deficiency affected energy metabolism, potassium deficiency increased membrane penetration. The effects of K deficiency were relatively small. The possible mechanisms of regulation of photosynthesis and respiration under macronutient deficiency were discussed.