基于δ13C值的黄土高原生态林和经济林水分利用效率差异及对环境响应分析

Difference of Water Use Efficiency Between Ecological and Economic Forest and Its Response to Environment Using Carbon Isotope in the Loess Plateau of China

为探明黄土高原典型人工生态林(刺槐)和人工经济林(苹果)叶片水分利用效率(WUE)对环境因子的响应及在气候分区中之间的差异。以黄土高原22个样点的叶片样本为例,基于稳定碳同位素技术可以反映植物长期WUE的特点,测定其成熟叶片δ^(13)C值,分析其与黄土高原年均降水量、温度、日照时间、水汽压和相对湿度的关系及在不同气候分区的差异。结果表明:(1)因存在人为管理措施,苹果叶片平均WUE显著大于刺槐叶片平均WUE,分别为4.29,3.83 mmol CO_(2)/mol H_(2)O;(2)在气候分区中,同一植物半干旱区的叶片WUE高于半湿润区的叶片WUE,其中半干旱区苹果叶片WUE比半湿润区苹果叶片WUE提高12.5%,半干旱区刺槐叶片平均WUE比半湿润区刺槐叶片WUE提高6.4%;(3)苹果和刺槐叶片WUE与环境因子的响应一致,叶片WUE的变化对年平均水汽压的响应更明显。研究结果对黄土高原WUE的研究进行了扩充,为该地区提升水分利用效率提供了理论指导。

In order to explore the response of foliar water use efficiency(WUE)of typical artificial ecological forest(Robinia pseudoacacia)and artificial economic forest(Apple)to environmental factors and the difference in different climate zones in the Loess Plateau,leaf samples from 22 samples were taken as research subject in the Loess Plateau.The stable carbon isotope technique was used,which could reflect the long-term WUE of plants.We measured theδ^(13)C value of mature leaves of plants,analyzed its response to annual precipitation,temperature,solar radiation,relative humidity and water vapor pressure,and examined the difference between artificial ecological forest and economic forest in different climate zones.The results showed that:(1)The foliar WUE of apple was significantly higher than that of Robinia pseudoacacia,the values were 4.29 mmol CO_(2)/mol H_(2)O and 3.83 mmol CO_(2)/mol H_(2)O respectively.(2)The foliar WUE of the same plant in semi-arid area was higher than that in semi-humid area in climate regionalization.The foliar WUE of apple in semi-arid area was 12.5%higher than that in semi-humid area.The foliar WUE of Robiniapseudoacacia in semi-arid area was 6.4%higher than that in semi-humid area.(3)The foliar WUE of apple and Robinia pseudoacacia had the same response to environmental factors,and the response of foliar WUE to average water vapor pressure was more sensitive than other factors.The results expand the study of WUE and provide theoretical guidance for the improvement of WUE in the Loess Plateau.