准噶尔盆地荒漠植物碳同位素组成研究

通过对准噶尔盆地古尔班通古特沙漠南缘17个科、41个属的53种荒漠植物的稳定碳同位素分析，结果显示准噶尔盆地荒漠植物的叶片稳定碳同位素值在-7.77‰~-30.10‰之间变化，其稳定碳同位素比值分布范围较广，C3和C4植物资源丰富。其中，C3植物有34种，δ13C值分布区间为-23.27‰~-30.10‰，平均值为-26.77‰；C4植物有19种，δ13C值的变化范围为-7.77‰～-14.90‰，平均值为-13.04‰。研究区内木本植物和草本植物的δ13C平均值分别为-16.74‰和-19.81‰，说明木本植物的水分利用效率明显高于草本植物，这种现象可能是全球荒漠生态系统的一种共性。但是一年生草本植物的δ13C平均值（-19.54‰）却高于多年生草本植物的δ13C平均值（-20.07‰），由于植物叶片δ13C可以用来间接指示植物的长期水分利用效率，即δ13C值越大，植物的水分利用效率越高；也就是说在该地区，相对于多年生草本植物而言，一年生草本植物对环境的适应能力较强。

The Study of Stable Carbon Isotope Composition in Desert Plants of Junggar Basin

The stable carbon isotopes(δ13C) of 53 plant species were measured in the south edge of Gurbantonggut Desert of Junggar Basin in Xinjiang, China. The results showed that the δ13C values of plants have an extensive range from -7.77‰ to -30.10‰. Among them,34 species were C3 plants,and 19 species were C4 plants. The δ13C values of C3 species ranged from -23.27‰ to -30.10‰ and the average δ13C value was -26.77‰; the δ13C values of C4 species ranged from -7.77‰ to -14.90‰ and the average δ13C value was -13.04‰ respectively. The δ13C values of shrubs were more positive than these of grasses significantly,which were closely similar to those from the previous literature sources. This indicated that shrubs had stronger adaptability to arid environments than grasses. In addition,the average δ13C value of annual plants （-19.54‰） was more positive than that of perennial plants （-20.07‰）. Since a strong correlation was observed between δ13C of plants and water use efficiency,it suggested that annual species tended to be more adaptable than perennial species in this area.