UV-B辐射增强对元阳梯田地方水稻叶片氮代谢及产量的影响

Effects of Enhanced UV-B Radiation on the Nitrogen Metabolism of Rice Leaves and Yield of Traditional Rice in Yuanyang Terraces

【目的】研究不同UV-B辐射处理对水稻不同生育时期(分蘖期、拔节期和抽穗期)叶片氮代谢及其产量的影响。【方法】以元阳梯田水稻品种白脚老粳为材料,大田原位种植,研究不同UV-B辐射强度(0、2.5、5.0和7.5 kJ/m~2)对水稻各生育时期叶片氮代谢关键酶[硝酸还原酶(NR)、谷氨酰胺合成酶(GS)和谷氨酸合成酶(GOGAT)]活性、含氮物质(可溶性蛋白与总游离氨基酸)含量及产量构成指标(有效穗数、穗粒数、千粒质量、结实率及产量)的影响。【结果】与对照相比,2.5 kJ/m~2 UV-B辐射时水稻抽穗期GS活性、拔节期GOGAT活性、分蘖期和抽穗期总游离氨基酸含量显著提高(P<0.05);5.0 kJ/m~2 UV-B辐射时水稻分蘖期NR活性、各生育期GS和GOGAT酶活性、可溶性蛋白及游离氨基酸含量显著增加(P<0.05),拔节期NR活性显著降低(P<0.05);7.5 kJ/m~2 UV-B辐射时水稻各生育时期叶片的NR、GS与GOGAT活性、可溶性蛋白含量及总氨基酸含量均显著降低(P<0.05)。UV-B辐射增强抑制白脚老粳有效穗数、穗粒数、结实率和千粒质量,导致产量下降,7.5 kJ/m~2 UV-B辐射强度下产量下降幅度最大为22.8%。【结论】大田增强UV-B辐射对元阳梯田地方水稻品种叶片氮代谢影响有显著的"剂量+生育时期"效应,中低强度UV-B辐射对水稻氮代谢有促进作用,UV-B辐射强度为5.0 kJ/m~2时最为显著,高强度UV-B辐射对水稻氮代谢有抑制作用。增强UVB辐射导致水稻产量下降。

[Purpose]To study the effects of different UV-B radiation treatments on leaves nitrogen metabolism at different growth stages(tillering stage,jointing stage and heading stage)and yield of rice.[Methods]In Yuanyang terrace,the local traditional rice variety Baijiaolaojing as research material was cultivated in situ,the effects of UV-B radiation(0,2.5,5.0 and 7.5 kJ/m2)on the activit-ies of key enzymes of nitrogen metabolism(NR,GS and GOGAT),the content of nitrogen-containing substances(soluble protein and total free amino acids)in leaves of rice at different growth stages and yield component index(effective panicle number,panicle number,1000-grain weight,seed setting rate and yield)were studied.[Results]Compared with the control,the activity of GS at heading stage,the activity of GOGAT at jointing stage,total free amino acids content at tillering and heading stage of rice were significantly increased at 2.5 kJ/m2 UV-B radiation(P<0.05);the activity of NR at tillering stage,the activity of GS and GOGAT,the content of soluble protein and total free amino acids of rice were significantly increased at all growth stages(P<0.05),and the activity of NR was significantly decreased at jointing stage at 5.0 kJ/m2 UV-B radiation(P<0.05);the activity of NR,GS and GOGAT,the content of soluble protein and total free amino acids were significantly decreased at different growth stages of rice at 7.5 kJ/m2 UV-B radiation treatment(P<0.05).The increase of UV-B radiation inhibited the effective panicle number,grain number per panicle,seed setting rate and 1000-grain weight of Baijiaolaojing,which led to the decrease of yield,the maximum decrease of yield was 22.8%at 7.5 kJ/m2 UV-B radiation intensity.[Conclusion]Enhanced UV-B radiation in the field had significant“dose+growth period”effect on the nitrogen metabolism of local rice leaves in Yuanyang terrace,middle and low intensity UV-B radiation could promote nitrogen metabolism of rice,the most significant with UV-B radiation was 5.0 kJ/m2,while high intensity UV-B radiation could inhibit it.The increase of UV-B radiation resulted in the decrease of rice yield.