本文關(guān)鍵詞：大氣氮沉降對海北高寒草甸優(yōu)勢種葉片光合作用過程的影響　出處：《環(huán)境科學(xué)研究》2016年11期 　論文類型：期刊論文

  更多相關(guān)文章： 氮沉降 光合參數(shù) 葉片w(TN) 葉面積指數(shù)(LAI) 高寒草甸

【摘要】：為研究大氣氮沉降對海北高寒草甸光合作用過程的影響,對不同施氮水平和氮沉降類型〔KNO3、(NH4)2SO4和NH4Cl〕下5個(gè)群落優(yōu)勢種葉片w(TN)、異針茅葉片光合參數(shù)和冠層LAI(葉面積指數(shù))進(jìn)行測定和分析,并利用Farquhar植物光合作用模型估算光合參數(shù)變化對GPP(總初級生產(chǎn)力)的可能影響,其中,氮沉降設(shè)置4個(gè)水平,即對照〔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計(jì).結(jié)果表明:除了施加(NH4)2SO4、低氮處理下甘肅棘豆葉片w(TN)顯著增加9.4%以外,其他施氮水平和施氮類型對5個(gè)優(yōu)勢種葉片w(TN)均無顯著影響.高氮處理下Vcmax25(25℃時(shí)最大羧化速率)、J25(25℃時(shí)電子傳輸速率)、TPU25(25℃時(shí)丙糖磷酸傳輸速率)和Rd25(25℃時(shí)暗呼吸速率)分別較對照處理高出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強(qiáng)效果,使得整體上GPP的增加趨勢不顯著.不同施氮水平和施氮類型下海北高寒草甸群落優(yōu)勢種的LAI均未發(fā)生顯著變化.研究顯示,當(dāng)大氣氮沉降量低于40 kg湓(hm2·a)時(shí),氮沉降量的增加會(huì)促進(jìn)海北高寒草甸植物葉片光合作用的反應(yīng)速率,但對植物葉片w(TN)、LAI和GPP的影響并不顯著.
[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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