摘要
进行叶片尺度气孔行为特征、对水分利用的影响及对环境因子的响应研究,并进行叶片气孔导度的模拟,对于理解区域植被和生态系统对环境的适应机制和进行水资源管理具有重要意义.采用LI-COR6400光合作用测定系统,对柽柳(Tamarix chinensis)各项光合生理特征进行野外观测,分析了柽柳叶片气孔导度(Gs)对环境因子的响应特征.结果表明:(1)大气相对湿度(hs)、光合有效辐射(PAR)和空气温度(Ta)对柽柳叶片Gs影响较大,与Gs的相关性hs(0.662)＞PAR(0.613)＞Ta(0.601).(2)柽柳叶片Gs日变化趋势为先升高后降低.06:00开始,随着PAR增强和Ta升高,Gs升高,随后PAR减弱和Ta降低,Gs降低.6、7月正午Ta过高引起叶片气孔闭合,Gs最大值出现在10:00左右;8、9月Gs最大值出现在14:00左右.(3)在生长季末期,柽柳能够通过Gs的调节,实现对水分的高效利用来适应干旱的环境.(4)用经验模型(Jarvis)、半经验模型(BWB)和气孔导度机理模型(USO)模拟Gs,模拟结果的决定系数(R2)、修正效率系数(MEC)和均方根误差(RMSE)分别是(0.713、0.409、0.024)、(0.482、0.309、0.158)和(0.260、0.135、0.255).在3个模型中,Jarvis模拟R2和MEC值最大且RMSE值最小,说明其模拟精度最高.
Abstract
Research on stomatal behavior characteristics,influence on water use and response to environmental factors at blade scale,and stomatal conductance of the simulation,to understand the regional mechanism of veg-etation and the ecological system to adapt to the environment and water resources management is of great signifi-cance.In this study,the photosynthetic physiological characteristics of Tamarix chinensis were observed by the LI-COR 6400 photosynthesis measurement system in the field,and the characteristics,influence,and response to environmental factors of stomatal conductance(Gs)of Tamarix chinensis leaves were analyzed.The results showed that:(1)Atmospheric relative humidity(hs),photosynthetically active radiation(PAR)and air tempera-ture(Ta)had significant effects on Gs,and the correlation between the three environmental factors and leaves Gs was ranked as hs(0.662)＞PAR(0.613)＞Ta(0.601)in descending order.(2)The diurnal variation trend of leaf Gs of Tamarix chinensis increased at first and then decreased.At 06:00,Gs increased with PAR enhancement and Ta increase,then PAR weakened and Taa decreased,then Gs decreased.Due to the high midday Ta in June and July,stomatal closure of leaves was caused,and the maximum Gs value appeared at around 10:00 in June and July,and around 14:00 in August and September.(3)At the end of the growing season,Tamarix chinensis could adapt to the arid environment by increasing WUE by regulating Gs to achieve efficient water use.(4)By using three dif-ferent models:an experience model(Jarvis),a semi-empirical model(BWB),and the mechanism of stomatal conductance model(USO)to simulate Gs,the determination coefficient(R2),the modified efficiency coeffi-cient(MEC)and the root mean square error(RMSE)of the simulation results were(0.713,0.409,0.024),(0.482,0.309,0.158)and(0.260,0.135,0.255),respectively.Among the three models,the results of the Jar-vis model simulation were obtained with the highest R2 and MEC values and the lowest RMSE value,indicating that its simulation accuracy was the highest.
基金项目
山西省高等学校科技创新项目(2022L414)
山西省基础研究计划(自由探索类)项目(202303021212257)
山西省基础研究计划(自由探索类)项目(202403021211205)
山西省哲学社会科学规划课题(2023YY228)
山西省哲学社会科学规划课题(2023YY226)
维普
万方数据