UV-B辐射强度变化对冬小麦碳氮代谢的影响

采用室内盆栽实验的方法,研究了UV-B辐射强度改变对冬小麦拔节孕穗期、抽穗期碳氮代谢的影响.结果表明：（1）UV-B辐射增强显著减少小麦拔节孕穗期和抽穗期地上部分干重,以及小麦拔节孕穗期地上部分呼吸速率,而对小麦两个生育期的呼吸系数无显著影响.UV-B增强显著减少了小麦拔节孕穗期和抽穗期叶片中叶绿素a含量,增加类胡萝卜素含量,减少拔节孕穗期叶片中光合产物可溶性糖的含量;（2）UV-B增强对小麦叶片中N代谢过程的影响表现为促进作用,虽对小麦抽穗期叶片硝酸还原酶活性、硝态氮含量无显著影响,却促进谷氨酰胺合成酶活性,显著增加了拔节孕穗期和抽穗期叶片中可溶性蛋白质、游离氨基酸含量.

Influence of Increased UV-B Radiation on C and N Metabolism of Winter Wheat

An indoor pot experiment along with laboratory analysis was done to study the influence of increased UV-B radiation on C and N metabolisms of winter wheat during elongation-pregnant and heading stages. An increase in UV-B radiation could significantly decrease the aboveground dry matter weight of winter wheat during elongation-pregnant and heading stages and the plant-mediated respiration rate in the former stage, but it induced no impact on respiration coefficient during both stages. There was less content of chlorophyll a and more arotenoid in UV-treated leaves than in the untreated ones during both stages. Also, the UV-treated leaves contained less soluble sugar during the elongation-pregnant stage. Although there was no change in nitrate contents and activities of nitrate reductase in the UV-treated leaves during heading stage, the UV treatment could increase glutamine synthetase activity in leaves significantly (P<0.05). Furthermore, the UV treatment increased concentrations of soluble protein and free amino acid in leaves during both stages (P<0.1).These results suggested that N metabolism of winter wheat could be accelerated by UV-B radiation increasing.