模拟增温对川西北高寒草甸两种典型植物生长和光合特征的影响

在野外自然条件下采用开顶式生长室(OTC)模拟增温的方法,研究了增温对川西北高寒草甸两种典型植物--单子叶草本植物发草(Deschampsia caespitosa)和双子叶草本植物遏蓝荣(Thlaspi arvense)生长和光合特征的影响.结果表明,增温有利于发草地上生物量的增加,其光响应曲线明显高于对照处理,净光合速率(P_n)、蒸腾速率(T_r)、气孔导度(C_s)、最大净光合速率(P_(max))、暗呼吸速率(R_d)、表观量子效率(AQY)和光饱和点(LSP)显著高于对照处理,而光补偿点(LCP)却显著低于对照处理,并且最大光能转化效率(F_v/F_m)、光合量子产量(Yield)、光化学猝灭系数(q_p)和非光化学猝灭系数(q_N)与对照处理相比,都显著增加;增温后遏蓝菜的单株生物量积累显著下降,其光响应曲线也明显低于对照处理,P_n、T_r、C_s、P_(max)、R_d、AQY和LSP显著低于对照处理,F_v/F_m、Yield和q_p在增温后显著减少,而q_N却显著增加.图5表3参25

Effect of Simulated Temperature Enhancement on Growth and Photosynthesis of Deschampsia caespitosa and Thlaspi arvense in Northwestern Sichuan, China

Open-top chamber (OTC) was adopted to simulate temperature enhancement in the field, and this study focused on the effect of temperature enhancement on the growth and photosynthetic characteristics of two alpine plants Deschampsia caespitosa (gramineous grass) and Thlaspi arvense (forb) in northwestern Sichuan, China. The temperature enhancement evidently increased the aboveground biomass of D. caespitosa compared to the control plot, and the net photosynthesis rate (P_n), transpiration rate (T_r), stomatal conductance (C_s), maximum net photosynthesis rate (P_(max) ), dark respiration rate (R_d), apparent quantum yield (AQY), and light saturation point (LSP) of D. caespitosa were obviously higher than those of the control plot. However, the photosynthetic light compensation (LCP) of D. caespitosa in OTC was significantly decreased. The chlorophyll fluorescence kinetic parameters such as F_v/F_m, yield, q_p and q_N were markedly increased compared to the control. However, warming treatment significantly decreased the individual aboveground biomass accumulation of T. arvense, and evidently decreased the light response curves compared to the control plot, and the P_n , T_r, C_s, P_(max) , R_d, AQY and LSP were obviouslylower than those of the control plot. Besides, F_v/F_m, yield, and q_p were markedly decreased after temperature enhancement, butq_N evidently increased. Fig 5, Tab 3, Ref 25