Ma Jian-Ying, Chen Fa-Hu, Xia Dun-Sheng, Sun Hui-Ling, Duan Zheng-Hu, Wang Gang
Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China.
Ying Yong Sheng Tai Xue Bao. 2008 May;19(5):1166-71.
Reaumuria soongorica is a dominant species in the desert shrubbery vegetation in arid regions of northwestern China, playing an important role in the maintenance of the stability and continuity of desert ecosystem. In this paper, a total of 407 individuals in 21 natural populations of R. soongorica were selected from its main distribution areas to measure the leaf stable carbon isotope composition (delta13C) and nitrogen, phosphorus, potassium, water, proline and chlorophyll contents, with the correlations between the delta13C value and the test physiological parameters analyzed. The results showed that leaf delta13C value was significantly correlated with the contents of leaf potassium, water, and proline (P <0.001), and the correlation with leaf potassium content was most profound (r = 0.793), followed by that with leaf water content (r = -0.786), indicating that the variation of leaf delta13C value could reflect the nutritional status of the plants, and also, their water-deficient degree. The different distribution trends in leaf delta13C value of R. soongorica were likely caused by stomatal conductance, rather than by nutrient-related changes in photosynthetic efficiency under extremely low available water conditions.
红砂是中国西北干旱地区荒漠灌丛植被中的优势种，在维持荒漠生态系统的稳定性和连续性方面发挥着重要作用。本文从红砂主要分布区选取了21个自然种群中的407个个体，测定其叶片稳定碳同位素组成（δ13C）以及氮、磷、钾、水分、脯氨酸和叶绿素含量，并分析了δ13C值与所测生理参数之间的相关性。结果表明，叶片δ13C值与叶片钾、水分和脯氨酸含量显著相关（P<0.001），与叶片钾含量的相关性最为显著（r = 0.793），其次是与叶片水分含量的相关性（r = -0.786），这表明叶片δ13C值的变化能够反映植物的营养状况及其缺水程度。在极低有效水分条件下，红砂叶片δ13C值的不同分布趋势可能是由气孔导度引起的，而非光合效率与养分相关的变化所致。
