不同施氮量对麻竹光合特性和氮代谢关键酶活性的影响

Effects of Different Nitrogen Application Levels on Photosynthetic Characteristics and Key Enzymes Activities in Nitrogen Metabolism of Dendrocalamus latiflorus

本试验以麻竹为材料,分别设置0 g/丛(N0,对照)、11.2 g/丛(N1)、13.5 g/丛(N2)、22.5 g/丛(N3)共4个施氮量水平,于盆栽条件下研究不同施氮量对笋期麻竹叶片光合特性、氮代谢关键酶活性及出笋数量的影响,并分析出笋数量与各出笋期叶片光合特性、氮代谢关键酶活性的相关性。结果表明,施用氮肥可显著增强笋期麻竹叶片光合特性、氮代谢关键酶活性,显著提高出笋数量。麻竹叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸合成酶(GOGAT)活性及出笋数量均随施氮量的增加而增加,N3处理即施氮量为22.5 g/丛时各指标达到最大值,而胞间二氧化碳(Ci)则呈相反趋势。相关性分析表明,各出笋期叶片Pn、Gs、Tr和NR、GS、GOGAT活性与出笋数量呈极显著正相关关系。综上看出,施氮量22.5 g/丛(N3)能够更好地协调碳氮代谢水平,增强麻竹光合特性,提高氮代谢关键酶活性,增加麻竹出笋数量。

In this experiment,Dendrocalamus latiflorus was chosen as material,and four nitrogen application levels were set as 0 g(N0,control),11.2 g(N1),13.5 g(N2)and 22.5 g(N3)per clump to study the effects of nitrogen levels on photosynthetic characteristics and activities of key enzymes in nitrogen metabolism in leaves,and yield of D.latiflorus during shoot stage by pot test.The correlations of shoot number with photosynthetic characteristics and key enzymes activities in nitrogen metabolism of leaves at different shooting stages were also analyzed.The results showed that the application of nitrogen fertilizer significantly enhanced the photosynthetic characteristics and the activities of key enzymes in nitrogen metabolism of D.latiflorus leaves druing shoot stage,and increased the shoot number significantly.The net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr),activities of nitrate reductase(NR),glutamine synthetase(GS)and glutamate synthetase(GOGAT)of leaves and the shoot number increased with the increase of nitrogen level,and all reached the maximum values in N3 treatment with nitrogen level at 22.5 g per clump,whereas the interstitial carbon dioxide(Ci)showed a reverse trend.Correlation analysis showed that Pn,Gs,Tr and activities of NR,GS and GOGAT at each shooting stage were positively correlated with shoot number.In conclusion,the application of 22.5 g nitrogen per clump(N3)could coordinate carbon and nitrogen metabolism level better,enhance the photosynthetic characteristics,improve the activities of key enzymes in nitrogen metabolism,and increase the shoot number of D.latiflorus.