大气氮沉降对海北高寒草甸优势种叶片光合作用过程的影响

发布时间：2018-01-16 18:29

  本文关键词：大气氮沉降对海北高寒草甸优势种叶片光合作用过程的影响　出处：《环境科学研究》2016年11期 　论文类型：期刊论文

  更多相关文章： 氮沉降 光合参数 叶片w(TN) 叶面积指数(LAI) 高寒草甸

【摘要】：为研究大气氮沉降对海北高寒草甸光合作用过程的影响,对不同施氮水平和氮沉降类型〔KNO3、(NH4)2SO4和NH4Cl〕下5个群落优势种叶片w(TN)、异针茅叶片光合参数和冠层LAI(叶面积指数)进行测定和分析,并利用Farquhar植物光合作用模型估算光合参数变化对GPP(总初级生产力)的可能影响,其中,氮沉降设置4个水平,即对照〔0 kg湓(hm2·a)〕、低氮〔10kg湓(hm2·a)〕、中氮〔20 kg湓(hm2·a)〕和高氮〔40 kg湓(hm2·a)〕,均以N计.结果表明:除了施加(NH4)2SO4、低氮处理下甘肃棘豆叶片w(TN)显著增加9.4%以外,其他施氮水平和施氮类型对5个优势种叶片w(TN)均无显著影响.高氮处理下Vcmax25(25℃时最大羧化速率)、J25(25℃时电子传输速率)、TPU25(25℃时丙糖磷酸传输速率)和Rd25(25℃时暗呼吸速率)分别较对照处理高出38.6%、30.4%、27.8%和164.3%.氮添加后,Rd25的增加抵消了因Vcmax25增加引起的光合作用增强效果,使得整体上GPP的增加趋势不显著.不同施氮水平和施氮类型下海北高寒草甸群落优势种的LAI均未发生显著变化.研究显示,当大气氮沉降量低于40 kg湓(hm2·a)时,氮沉降量的增加会促进海北高寒草甸植物叶片光合作用的反应速率,但对植物叶片w(TN)、LAI和GPP的影响并不显著.
[Abstract]:In order to study the effect of atmospheric nitrogen deposition on photosynthesis process in Haibei alpine meadow, different nitrogen levels and types of nitrogen deposition were studied. Leaf photosynthesis parameters and canopy Lai (leaf area index) of 5 dominant species under NH _ 4N _ 2SO _ 4 and NH _ 4Cl were measured and analyzed. The Farquhar photosynthesis model was used to estimate the possible effects of photosynthetic parameters on the total primary productivity (Farquhar) of which nitrogen deposition was set at 4 levels. That is to say, the control group is 0 kg / hm ~ 2 / hm ~ 2 / hm ~ (2 / a) and 10 kg / hm ~ (2 / a). 20 kg / hm ~ (2 / a) of medium nitrogen and 40 kg / hm ~ (2 / a) of high nitrogen were measured in terms of N. The results showed that: in addition to the application of NH _ 4H _ 4 / 2SO _ 4. Under the low nitrogen treatment, the leaves of Oxytropis kansuensis increased significantly beyond 9.4%. Other nitrogen levels and types of nitrogen application had no significant effect on the leaves of five dominant species, but the maximum carboxylation rate at Vcmax25(25 鈩，

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