半干旱黄土丘陵区不同立地柠条光合特性研究  

Photosynthetic Characteristics of Caragana korshinskii and Its Influencing Factors Under Different Site Conditions in Semi-arid Loess Region

作　　者：李德丽 蔡国军 莫保儒 林琳 丁爱强 LI De-li;CAI Guo-jun;MO Bao-ru;LIN-Lin;DING Ai-qiang(Gansu Academy of Forestry Sciences,Lanzhou 730020,Gansu,China)

机构地区：[1]甘肃林业科学研究院,甘肃兰州730020

出　　处：《西北林学院学报》2023年第6期38-45,共8页Journal of Northwest Forestry University

基　　金：陇中沿黄走廊灌草融合生态功能稳定性耦合模式实验研究(LCJ20210027);黄土高原干旱缺水区综合植被承载力的形成机制及时空变化(U21A2005)。

摘　　要：以半干旱黄土丘陵区典型流域内不同坡面上广泛分布的人工柠条林为研究对象,利用CIRAS-I型光合仪测定其光合指标和环境因子的日变化进程,并采用通径分析法分析各环境因子对柠条净光合速率的直接和间接影响。结果表明,1)9:00-18:00,光合有效辐射、空气温度及空气湿度的日变化呈先增大后减小,空气CO_(2)浓度在小范围内呈减小态势,各因子之间存在关联性,坡向对环境因子的影响程度大于坡位。2)受环境因子的影响,柠条光合生理特征值在南坡变化活跃,东坡相对稳定,具体在不同坡向间表现为净光合速率、蒸腾速率、胞间CO_(2)浓度东坡大于南坡,叶片温度、水分利用效率、气孔限制值南坡大于东坡;在不同坡位间表现为净光合速率均值在南坡,下坡>中坡>上坡;在东坡,上坡>下坡>中坡。3)南坡净光合速率的决策因子为空气温度,限制因子为光合有效辐射,环境变化能解释53.4%净光合速率的变化;东坡净光合速率的决策因子为光合有效辐射和空气湿度,限制因子为空气温度,环境变化能解释34.4%净光合速率的变化。在半干旱地区,水分和光照是柠条林维持生长必不可少的条件,前人对该区已有的研究表明柠条的生长状况与浅层土壤水分条件一致,东坡优于南坡,下坡优于中、上坡,而且柠条栽植初期较幼依赖光照,中后期较依赖水分。结合本研究结果,认为该区柠条林建植应优先选择在东坡和南坡下坡位,这样才能持续健康生长。The artificial Caragana korshinskii forests widely distributed on different slopes in the typical watershed of the semi-arid loess hilly region were taken as the research objects.The diurnal variation process of photosynthetic indexes and environmental factors were measured by CIRAS-I photosynthetic instrument,and the direct and indirect effects of various environmental factors on the net photosynthetic rate(P_(n))of C.korshinskii were analyzed by path analysis.The results showed that 1)from 9:00 a.m to 6:00 p.m.,the changes of photosynthetically active radiation(PAR),air temperature(T_(a))and relative air humidity(Rh)increased first and then decreased,and the air CO_(2)concentration decreased in a small range.There was a correlation between the factors,and the influence of slope direction on environmental factors was greater than that of slope position.2)Under the influence of environmental factors,the photosynthetic physiological characteristics of C.korshinskii changed actively on the south slope,and were relatively stable on the east slope.Specifically,P n,transpiration rate(T_(r))and intercellular CO_(2)concentration(C Int)on the east slope were higher than those on the south slope,and the leaf temperature(T leaf),water use efficiency(WUE)and stomatal limiting value(L_(s))on the south slope were higher than those on the east slope.On the south slope,the average P n was in the order of lower slope>middle slope>upper slope.On the east slope,the order was upper slope>lower slope>middle slope.3)The decision factor of P n in the southern slope was air temperature(T_(a)),and the limiting factor was PAR.Environmental changes could explain 53.4%of the changes in P n.The decision factors of P n were PAR and R_(h),and the limiting factor was T_(a).Environmental changes could explain 34.4%of the changes in P_(n).In the semi-arid region,water and light were indispensable conditions for the growth of C.korshinskii forest.Previous studies have shown that the growth status of C.korshinskii in this area is consistent with t

关 键 词：黄土丘陵区 森林立地条件 柠条 光合特性 

分 类 号：S718.43[农业科学—林学]