Abstract: The photosynthetic characteristics of Citrus microcarpa were determined with the Li-6400 Photosynthetic system.The results showed that the diurnal variation of net photosynthetic rate (Pn) in Citrus microcarpa was a double-peak curve and there also exists a clear depression at noon.The first peak occurred at 11:00,the second one at 14:00.The maximum of net photosynthetic rate (P_max) was 3.4467 μmol/m²·s.Correlation analysis showed that there were positive relationship between Pn and transpiration rate (Tr) and stomatal conductance (Gs),and negative relationship between Pn and internal CO₂ concentration (Ci).Under the concentration of CO₂ 400 μmol/mol,the light compensation point (LCP) of Citrus microcarpa was 67 μmol/m²·s,and light saturation point (LSP) was 672 μmol/m²·s.In sum,Citrus microcarpa is a typical masculine and shade-resistant plant which has strong adaptability to the circumstance.

Key words: Citrus microcarpa, photosynthetic, light saturation point, light compensation point

摘要： 采用Li-6400型便携式光合测定系统对多年生金桔的光合特性进行研究。结果表明,金桔净光合速率日变化呈双峰曲线,存在光合"午休"现象,最高峰出现在11:00左右,次峰出现在14:00,日最大净光合速率为3.4467 μmol/m²·s。净光合速率与蒸腾速率、气孔导度之间呈正相关,与胞间CO₂浓度呈负相关;在400 μmol/mol CO₂浓度下,光补偿点为67 μmol/m²·s,光饱和点为672 μmol/m²·s。金桔的光合特性表现为典型的阳性耐荫植物,对光照的适应性较强。

关键词: 金桔, 光和速率, 光饱和点, 光补偿点