竹柏2种颜色叶片的光合特性研究

Photosynthetic Characteristics of Two Color Leaves of Podocarpus nagi

摘要:

为了解竹柏（Podocarpus nagi）的光合特性，以3 a生全绿叶和花叶竹柏为材料，测定其光合色素含量和气体交换参数。结果表明，全绿叶竹柏叶片的叶绿素a、叶绿素b、类胡萝卜素、叶绿素a+b、叶绿素a/b和叶绿素a+b/类胡萝卜素均显著高于花叶竹柏；全绿叶竹柏叶片的初始量子效率、最大光合速率和暗呼吸速率均显著高于花叶，而光饱和点和光补偿点均显著低于花叶；全绿叶竹柏叶片的初始羧化效率、光合速率、CO₂饱和点和光呼吸速率均高于花叶，而CO₂补偿点低于花叶。2种颜色叶片的气孔导度、蒸腾速率和水分利用效率均随着光合有效辐射的增大而增大，且均表现为全绿叶>花叶，而胞间CO₂浓度则相反，表现为花叶>全绿叶。因此，全绿叶竹柏利用弱光的能力强于花叶竹柏，而花叶竹柏利用强光的能力更强，在园林绿化配置中，可根据2种颜色叶片的光合特性合理配置。

Abstract:

In order to understand the photosynthetic characteristics of Podocarpus nagi, the photosynthetic pigment content and gas exchange parameters of green and striped leaves of 3-year-old P. nagi seedlings were measured. The results showed that the chlorophyll (Chl) a, Chl b, carotenoid (Car), Chl a+b, Chl a/b and Chl a+b/Car in green leaves were significantly higher than those in striped leaves. The initial quantum efficiency, maximum photosynthetic rate and dark respiration rate in green leaves were significantly higher than those in striped leaves, and the light saturation point and light compensation point were significantly lower than those in striped leaves (P<0.05). The initial carboxylation efficiency, photosynthetic capacity, CO₂ saturation point and photorespiration rate of green leaves were higher than those of striped leaf, and CO₂ compensation point of green leaves was lower than that of striped leaves. The stomatal conductance, transpiration rate and water use efficiency increased with the increment of photosynthetic active radiation with the order of green leaf>striped leaf, while the intercellular CO₂ concentration had opposite trend with striped leaf>green leaf. So, it could be rationally planted according to the photosynthetic characteristics of two different color leaves according to the different phytosynthetic characteristics of two color leaves of P. nagi, which green leaf had strong ability to use weak light and striped leaf had strong ability to use stronger light.