高寒草甸不同坡向条件下植物叶片δ^(13)C及水分利用效率的变化  

Variation in δ^(13)C and water use efficiency of plant leaf at different slopes in an alpine meadow

作　　者：刘旻霞[1] 刘洋洋[1] 陈世伟[1] 王振乾[1] 

机构地区：[1]西北师范大学地理与环境科学学院,兰州730070

出　　处：《应用生态学报》2016年第12期3816-3822,共7页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(31360114)资助~~

摘　　要：通过对高寒草甸不同坡向条件下25科86种C3植物叶片稳定性碳同位素组成(δ^(13)C)的测定,研究了高寒草甸C3植物δ^(13)C和水分利用效率对坡向变化的响应以及环境因子对其产生的影响,分析了坡向上控制植物δ^(13)C变化的主要环境因子.结果表明:从北坡到南坡的生境梯度上,土壤含水量不断减少,而土壤温度及光照强度不断增加,植物群落结构也发生了相应变化.5个坡向中,植物叶片δ^(13)C值为-31.19‰^-21.80‰,均值为(27.18±0.13)‰;生长季植物叶片δ^(13)C均值在南坡最高,其次为西南坡、西坡、西北坡,最低值出现在北坡.坡向间δ^(13)C值的差异主要是由不同坡向土壤含水量和土壤温度,以及光照强度的不同导致的,其中土壤含水量是主要的限制因子.北坡-南坡梯度上植物叶片δ^(13)C值随土壤含水量下降、土壤温度及光照强度升高而变大,表明不同坡向植物的水分利用状况对干旱胁迫的响应不同,植物逐渐提高了水分利用效率以适应干旱胁迫的生境.Through the systematical measurements of δ^13C values of samples representing 25 families and 86 C3 herb species along the slope aspects in an alpine meadow, the responses of δ^13C values and water use efficiency （WUE） for C3 plants to slope aspect changes and influence of environmental factors were analyzed and main environmental factors related to plant δ^13C values change were revealed. Along the northfacing to southfacing slope, soil water content decreased gradually, the soil temperature and light intensity increased gradually, and plant community structure also had corresponding change. The δ^13C values of C3 plant species in 5 slope aspects were from -31.19‰ to -21.8‰, with an average value of （-27.18±0.13）‰. The average δ^13C value was the highest along the southfacing slope, followed by that along the southwest slope, west slope and northwest slope, with the lowest along the north slope during the whole growing season. The difference of δ^13C values among the different slope aspects were caused by discrepancy in soil water content, soil temperature and light intensity. Soil water content was the main limiting factor. From north slope to south slope, plant δ^13C value increased with the increasing soil temperature, light intensity and the reducing soil water content, which suggested that different species had different strategies to adapt to environmental changes of drought stress in different slope aspects, and water use efficiency was improved gradually in order to adapt to the environment of drought stress.

关 键 词：高寒草甸 植物叶片 碳同位素 水分利用效率 土壤含水量 

分 类 号：Q945[生物学—植物学]