毛竹光合生理对气候变化的短期响应模拟

Climate change response using a simulation study of photosynthetic physiology on Phyllostachys pubescens

为揭示毛竹Phyllostachys pubescens在全球气候变化大背景下对气候因子的响应,通过模拟不同温度、相对湿度、二氧化碳摩尔分数环境,利用Li-6400测定拟合毛竹的光响应曲线和二氧化碳响应曲线。结果表明:在短期二氧化碳摩尔分数倍增的条件下,毛竹的气体交换参数,包括光饱和点均成倍增加,蒸腾速率下降,且二氧化碳响应曲线符合米氏方程;温度在其稳定基础上突然增加或降低都会导致毛竹气孔导度增加,净光合速率减小,而蒸腾速率与温度呈正相关;在大气湿度突然降低的情况下,气孔导度增加,净光合速率有所增加,但蒸腾速率增加的幅度达7倍之多。由此推断,在短期二氧化碳摩尔分数增加的情况下,"施肥效应"会使毛竹的净光合速率增加,但是二氧化碳摩尔分数增加所带来的"温室效应",及由此可能带来的干旱,使得毛竹的气孔灵敏度和活化的Rubisco数量成为限制性因子,最终限制毛竹的正常生理生长活动。

To reveal the response of Phyllostachys pubescens to climate change,an Li-6400 was used to measure CO2 response curves and light response curves under different temperatures,humidity,and CO2 concentrations.The data above was used to simulate climate change in a short time with SPSS.Results showed that photosynthesis doubled as did the light saturation point,the transpiration rate decreased,and the CO2 response curve fit a quadratic function where the CO2 concentration doubled from 400 to 800 μmol·mol-1 in a short time.Temperatures above or below external temperature 3 ℃ caused a net photosynthetic rate increase with stomatal conductance surge increasing sharply.Also,the transpiration rate continuously increased with temperature.As stomatal conductance increased,the net photosynthetic rate increased slightly.When humidity decreased suddenly the transpiration rate had a seven-fold increase.Therefore,the＂fertilization effect＂could lead to an increase in the net photosynthetic rate with the CO2 concentration increasing in the short-term;however,the greenhouse effect and possible drought caused by an increase in CO2 concentration could make stomatal sensitivity and the quantity of Rubisco activity limiting factors,even limited the whole plant＇s normal physiology and growth.