Effects of Soil Moisture on Gas Exchange, Partitioning of Fed 14CO2 and Stable Carbon Isotope Composition (δ13C) of Leymus chinensis Under Two Different Diurnal Temperature Variations |
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| Authors: | Z Z Xu G S Zhou |
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| Institution: | Authors' addresses: Dr Z. Z. Xu and Prof. Dr G. S. Zhou (corresponding author;e-mail: ), Laboratory of Quantitative Vegetation Ecology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing 100093, China;Institute of Atmospheric Environment, China Meteorological Administration, Shenyang 110016, China |
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| Abstract: | In a pot experiment under controlled condition, Leymus chinensis was grown at five soil water contents and two diurnal temperature variation levels. The leaf relative water content of L. chinensis decreased under soil drought conditions, and increased at high diurnal temperature variation (30/20 °C). Severe and very severe soil drought remarkably reduced photosynthetic rate, stomatal conductance, transpiration rate and water use efficiency (WUE), especially at the low temperature variation. Severe drought mainly increased the specific radioactivity of 14C of sheaths, roots and rhizomes, but significantly decreased that of fed leaves and the not fully expanded leaves. Root percentage of total radioactivity remaining in the whole plant increased from 15 % at 30/25 °C to 28 % at 30/20 °C. Leaf carbon stable isotope composition (δ13C) increased with soil drought, ranged from ?26 ‰ of the well‐watered to ?24 ‰ of severe drought treatments. High diurnal temperature variation improved leaf water status, and increased partitioning of carbon to root and δ13C values, especially under severe soil drought conditions. In conclusion, higher diurnal temperature variation enhanced the resistance of the plant to drought. |
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| Keywords: | carbon isotope composition carbon partitioning diurnal temperature variation leaf gas exchange Leymus chinensis soil moisture |
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