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作 者 ：林植芳，林桂珠，孔国辉，张鸿彬

期 刊 ：热带亚热带植物学报 1995年 3卷 2期 页码：77~82

关键词：生长光强；碳同位素比；细胞间CO_2浓度；水分利用效率；荷木；黧蒴；

Keywords:Growth irradiance, Carbon isotope ratio, Intercellular CO_2 concentration, Water-use efficiency, Schima superba and Castanopsis fissa,

摘 要 ：生长于１００％、４０％和１６％自然光下的荷木和黧蒴幼苗叶片稳定碳同位素比（δ１３Ｃ，－‰），细胞间ＣＯ２浓度（Ｃｉ）和水分利用效率（ＷＵＥ）有一定的差别。１６％和４０％弱光下，δ１３Ｃ的负值增加－０．５４Ｊ‰到－０．８９‰。Ｃｉ增大８．１－１３．２μｉＬ－１，ＷＵＥ则下降６－２４％。结果表明，叶片的水分和气体交换特性受生长光强的调节，叶片的δ１３Ｃ值可反映其生长过程中受光的强弱状况。

Abstract:Pot seedlings of Schima superba and Castanopsis fissa were grown under 100 %, 40% and 16% of natural light. The light intensity was cotrolled by using black sieve-cloth. Leaf samples were collected in March,June and September after treatments for one and more than one year. Stable carbon isotope ratio (δ13C value) was determined by a ratio mass-spectrometer, then the intercellular CO2 concentration (Ci) and water-use efficiency (WUE) were calculated from the δ13C values. The decrease of growth irradiance resulted in the rise of both Ci and negative value of δ13C (-‰), and the reduction of WUE. Under 40% and 16 % of irradiance, the δ13C value of Schima us Perba leaves increased - 0. 76‰, and - 0. 89‰, while that in Castanopsis fissa leaves increased - 0. 54‰ and -0. 66‰,respectively. The calculated Ci went up by 11 - 13μl L- 1 in Schima superba and by 8 - 10μl L-1in Castanopsis fissa under low irradiance. Water-use efficiency of seedlings in 100%natural irradiance was about 4μmol CO2 mmol-1 H2O, but it was reduced by 6 - 12% (in 40%light). or 8 - 24 % (in 16 % light). It is concluded that more 12C and less 13C were fixed during photosynthesis of these two woody species under low irradiance. The properties of exchange in water and CO2 were regulated by growth irradiance, and the δ13C value might reflect the incident light status of leaves in the life duration.

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