施氮水平对水稻生育后期地上部氨挥发的影响

Effects of N fertilization levels on ammonia volatilization from rice shoot at later growth stages

采用温室盆栽模拟试验,研究了不同施氮水平下水稻开花后地上部氨挥发及其影响因素.结果表明:不同品种水稻开花后地上部日氨挥发量和开花至成熟期的氨挥发总量均随施氮量的增加而增加,且不同施氮水平间存在一定差异.花期和成熟期水稻地上部氨挥发量(y)与功能叶片谷氨酰胺合成酶(GS)活性(x1)呈显著负相关,而与功能叶片质外体NH4+浓度(x2)呈显著正相关:y=-0.37846x1+0.41821x2+0.04925(R2=0.9471,n=16).水稻氮素收获指数(x1)和氮肥生理利用率(x2)均与地上部氨挥发总量(y)呈显著负相关:y=-0.02117x1+0.75186(R2=0.8426,n=8)和y=-1.10386x2+35.52676(R2=0.8489,n=8),说明高氮水平下水稻氮肥利用率的下降与水稻地上部氨挥发量的增加有关.

With simulated pot culture in greenhouse,the ammonia volatilization from rice shoot and its affecting factors after flowering was studied under different N fertilization levels.The results showed that the daily and total amount of volatilized ammonia increased with increasing N application rate,with a certain variance among different N levels observed.At flowering and maturing stages,the ammonia volatilization from rice shoot（y）had significant negative correlations with functional leaf GS activity（x1）and positive correlations with functional leaf apoplastic NH4＋ concentration（x2）,with y=-0.37846x1 ＋0.41821x2＋0.04925（R^2=0.9471,n=16）,and negative correlations with N harvest index（x1）and physiological N use efficiency（x2）,following y=-0.02117x1＋0.75186（R^2=0.842,n=8）and y=-1.10386x2＋35.52676（R^2=0.8489,n=8）,respectively.It was suggested that the increasing ammonia volatilization from rice shoot under high N fertilization level was correlated with the decrease of N use efficiency by rice.