常春藤秋季光合日变化特性研究

采用Li-6400光合测定系统,以三年生常春藤(Hedera nepalensis var.sinednsis Rehd.)为研究对象,测定其秋季光合特性日变化.结果表明,常春藤净光合速率日变化呈双峰曲线,“午休”现象并不明显,净光合速率最高峰出现在8:00,次峰出现在11:00,日最大净光合速率为4.943 3 μmol/(m2·s).净光合速率与蒸腾速率、气孔导度呈正相关,与胞间CO2浓度呈负相关.常春藤的光合日变化特性表明其为典型的耐阴植物,对光照的适应性较强.

Photosynthetic Characteristics of Hedera nepalensis var.sinednsis Rehd.in Autumn

Diurnal photosynthetic characteristics of three-year-old ivy(Hedera nepalensis var.sinednsis Rehd.) was determined by a Li-6400 photosynthesis system.The result showed that the ivy net photosynthetic rate presented a two-peak pattern curve,and "midday depression" phenomenon was not significant.The peak of net photosynthetic rate emerged at 8∶00 am,and the sub-peak emerged at 11∶00 am.The maximum net photosynthetic rate was 4.943 3 μmol/(m2·s).There was a positive relation between the net photosynthetic rate and transpiration rate and stomatal conductance,while a negative relation between the net photosynthetic rate and intracellular CO2 concentration.The photosynthetic characters of diurnal variation indicted that ivy was a typical shade-tolerant plant;and it showed a strong adaptability to the light.