两种生态型榕树的叶绿素含量、荧光特性和叶片气体交换日变化的比较研究

比较盆栽 生榕树和两栖型树的形态差异、叶片叶绿素含量、叶绿素荧光特性和气体交换的日变化。两栖型榕树具有较发达的气生根和水生不定根，叶片比陆生榕树宽，并有向中生性 倾向，陆生榕树的叶绿素含量比两栖榕树高，净光合速率略高于水培两栖型榕树，但明显高于土培两栖型榕树，蒸腾速率以水培两栖型树最高，陆生榕树次之，土培两栖型榕树最低，线性回归分析表明，三者的叶片气孔导度与净光合速率变化均呈正相关，气孔导度的变化

A comparative study on chlorophyll content, chlorophyll fluorescence and diurnal course of leaf gas exchange of two ecotypes of banyan

The morphological differences,chlorophyll contents,fluorescence and diurnal course of leaf gas exchange between terrestrial banyan and amphibious banyan were compared with pot culture.The amphibious banyan possesses well developed aerial and hydro adventitious roots, and wider leaf with inclination of evolution toward mesophytic traits.The chlorophyll content of terrestrial banyan was higher than that of amphibious banyan.The diurnal course of leaf gas exchange indicated that net photosynthetic rate of terrestrial banyan was slightly higher than that of amphibious banyan grown in water,but much higher than that grown in soil.The amphibious banyan grown in water had the highest transpiration rate,the terrestrial banyan had a lower one, and the amphibious banyan grown in soil had the lowest.Linear regression analysis showed a positive correlation between net photosynthetic rate and stomatal conductance,implying that the stomatal conductance was dominant factor controlling the gas exchange.In this study,the term of intrinsic water use efficiency (net photosynthetic rate/stomatal conductance ratio,Intrinsic WUE) was applied to describe the photosynthesis and water properties, and the result showed that it was a more suitable measure compared to the usual WUE(net photosynthetic rate/transpiration rate).Among the three banyan plants examined,the amphibious banyan had the highest intrinsic WUE.