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植物中稳定碳同位素组成不但与植物的水分利用效率密切相关,而且反映环境因子对植物的影响。选择黑河下游额济纳旗为研究区,以优势物种胡杨(Populus euphratica)为研究对象,利用稳定碳同位素组成分析研究区胡杨受干旱胁迫程度。结果表明:胡杨叶稳定碳同位素组成(δ13 C)处于-25.51‰~-30.21‰,平均值为-28.28‰。随干旱胁迫程度增加,δ13 C值有明显偏正趋势,植物(叶片)碳同位素组成对胡杨成熟木长期适应不同水分胁迫程度有明显的体现。分析δ13 C与胡杨生长状态发现,δ13 C与种群密度相关性不明显,与枯枝比呈显著正相关关系,枯枝比可成为碳同位素组成的替代指标,指示胡杨受干旱胁迫的程度。
Stable carbon isotope composition in plants is not only closely related to plant water use efficiency, but also reflects the impact of environmental factors on plants. The Populus euphratica Populus euphratica was selected as the research area by selecting the Ejina Banner in the lower reaches of the Heihe River as study area and the stable carbon isotope composition analysis was used to study the extent of Populus euphratica under drought stress. The results showed that the stable carbon isotope composition (δ13C) of Populus euphratica leaves was between -25.51 ‰ and -30.21 ‰ with an average value of -28.28 ‰. With the increase of drought stress, δ13C value showed a significant positive trend. The carbon isotope composition of plant (leaf) obviously reflected the long-term adaptability of mature Populus euphratica to different water stress. Analysis of δ13C and Populus euphratica growth state showed that there was no significant correlation between δ13C and population density and a positive correlation with litter ratio, and litter ratio could be used as a surrogate marker of carbon isotope composition, indicating the extent of Populus euphratica drought stress.