模拟增温对高寒草甸4种优势植物功能性状的影响

Effects of simulated warming on the functional traits of four dominant plants in alpine meadow

为研究气候变暖对青藏高原高寒草甸主要植物功能性状的影响,本文采用室内模拟增温为单独可控因子,在人工气候箱设置3个温度梯度,通过测定不同温度下高寒草甸优势植物无脉苔草(Carex enervis)、草地早熟禾(Poa pratensis)、矮嵩草(Kobresia humilis)、线叶嵩草(Kobresia capillifolia)的高度、地上生物量、叶片形态特征及周围群落光合速率、呼吸速率及CO_(2)通量,分析其不同温度下的差异性,以探讨高寒草甸优势植物对气候变暖的响应。结果表明:(1)与对照相比,T2(增温10℃)处理下高寒草甸4种优势植物的高度、生物量及叶长显著增加(P<0.05),植物高度在3个温度梯度间差异显著(P<0.05)。(2)叶长在T2处理下最长,叶宽在T1(增温5℃)处理下最宽,且叶面积与叶宽呈正相关。长宽比、形状因子在T2处理下呈现最小值。(3)高寒草甸植被的呼吸速率对温度的变化无显著响应(P> 0.05),而光合速率随着温度的升高呈先增加后降低的趋势,净生态系统碳交换与光合速率呈正相关,在20℃温度下碳交换量最大。综上,4种优势植物个体功能性状对温度上升有着积极的响应。

Indoor simulated warming is used as a single controllable factor and three temperature gradients are set in the artificial climate box to investigate the influence of climate warming on the main plant functional traits of alpine meadow in Qinghai-Tibet Plateau.The differences with various temperatures are analyzed to explore the response of dominant plants in alpine meadow to climate warming by measuring the height,aboveground biomass,leaf morphological characteristics and community photosynthetic rate,respiratory rate and CO_(2) flux of dominant plants includingCarex enervis,Poa pratensis,Kobresia humilisandKobresia capillifoliawith different temperatures.The results show that:(1)Compared with the control,the height,biomass and leaf length of four dominant plants are significantly increased under T2 treatment(increase temperature by 10℃)(P<0.05).The difference of vegetation height is extremely significant among the three temperature gradients(P<0.05).(2)The leaf length is the longest under T2 treatment.The leaf width is the widest under T1 treatment(increase temperature by 5℃).The leaf area is positively correlated with leaf width.The aspect ratio and shape factor are the smallest under T2 treatment.(3)The respiration rate of alpine meadow vegetation has no significant response to the variation of temperature(P>0.05),while the photosynthetic rate increases first and then decreases with the increase of temperature.The carbon exchange of net ecosystem is positively correlated with photosynthetic rate.The carbon exchange capacity is the largest at 20℃.