【摘要】 通过对沙坡头人工固沙区不同微生境和种植方式下固沙植物油蒿(Artemisia ordosica)和柠条(Caragana korshinskii)叶片稳定碳同位素比率(δ13C)的测定,研究了该区油蒿和柠条叶片δ13C差异及其季节变化,并探讨了不同气候因素对植物δ13C的影响.结果表明:柠条δ13C显著高于油蒿(P=0.003),即柠条的水分利用效率高于油蒿.在生长季内两种植物δ13C变化因种类及种植方式不同而异,除混种柠条的δ13C在整个生长季呈降低趋势外,单种柠条、单种油蒿和混种油蒿的δ13C均呈降低-升高-降低的变化趋势,均在7月份达最高值,即水分利用效率在7月份达最高.油蒿和柠条的δ13C因生境不同表现出明显的差异:引种圃的油蒿和柠条的δ13C分别低于水分平衡场;水分平衡场内单种柠条的δ13C高于混种,油蒿则反之;植物叶片含水量与δ13C的变化呈相反变化趋势.两种植物的δ13C逐月变化量(Δ13Cm)与气象因子的响应程度因其种类而异,其中油蒿Δ13Cm与月降雨量、月均相对湿度和水汽压负相关,与温度正相关,但均未达显著水平;柠条叶片Δ13Cm与温度极显著正相关,表明柠条生长对温度敏感,而油蒿则对水分和温度均有一定程度的响应.更多还原

【Abstract】 By analyzing the stable carbon isotope ratios(δ¹³C) of Caragana korshinskii（CK） and Artemisia ordosica（AO） under different planting regimes and micro-habitats in Shapotou Station,the variations of plant leaf δ¹³C and effects of climatic factors,such as rainfall,relative humidity and temperature,on plant δ¹³C were investigated.Results show that the δ¹³C values of CK were higher significantly than that of AO’s（P=0.003）,namely the efficiency of water use of CK was higher than that of AO.During the growth period,the variations of two plant δ¹³C values varied owing to the difference in species and planting arrangements.The δ¹³C of mixed planting AO and single planting CK and AO had the same change trend,i.e.,a decreasing trend before May,an increasing trend（and increasing to the maximum） at July,and then followed by a decreasing trend.However,variation of δ¹³C of mixed CK decreased during the whole growth period.The δ¹³C of AO and CK increased along with the decrease of soil water content.The δ¹³C ratios of AO and CK in the introduced plants were lower than those in the water cycle test field.In the water cycle test field,the leaf δ¹³C ratios of single planting CK were higher than those of mixed planting CK,and the changing order in δ¹³C between mixed planting AO and mixed planting CK was inversely.The variations between the δ¹³C ratios and the leaf water content of AO and CK are inverse.The responses of the δ¹³C monthly change values(Δ¹³C_m) of AO and CK to climatic factor change with plant species.The Δ¹³C_m of AO exhibited a negative relationship with monthly precipitation,mean monthly relative humidity and vapor pressure,and a positive relationship with temperature.There were significant relationships between the Δ¹³C_m and temperature with CK.It is revealed that the growth of CK was strongly sensitive to temperature change,and the growth of AO was dependent on precipitation,relative humidity and vapor pressure to a certain extent.更多还原