5种国兰(Cymbidium)的光合特性

The Photosynthetic Characteristics of Five Species of Cymbidium

通过气体交换和叶绿素荧光分析等方法研究了5种国兰(Cymbidium)的光合特性。其光饱和 点、光补偿点、CO2补偿点和CO2饱和点表明它们具有C3植物特征;光合速率在3.0～5.9μmol· m-2·s-1之间,在低于2000μmol·mol-1CO2浓度下,光合速率受CO2浓度影响较大;5种国兰的光合能 力、表观量子效率、羧化效率等都有所差异;光饱和点在350～650μmol·m-2·s-1之间,属于喜阴植物, 其中春兰、建兰耐阴性相对较低,墨兰、春剑耐阴性相对较高,蕙兰居中。从暗处暴露到强光下,5种国 兰的光化学反应启动差异较大,启动后的光化学效率差异也较大,这可能与国兰不同种起源地的生态环境, 适应性及进化有关。

The photosynthetic characteristics of five species of Cymbidium were studied by gas exchange and analysis of chlorophyll fluorescence. According to the light saturation points, the light compensation points, the CO 2 saturation points and the CO 2 compensation points,the five species of cymbidium have the characteristics of C 3 plants. The photosynthetic rates were between 3.0-5.9 μmol·m -2·s -1. The results also demonstrated that the photosynthetic rates were largely affected by the concentrations of the CO 2 while the CO 2 concentrations were below 2000 μmol·mol -1. And there were also some differences among the photosynthetic capacities, the apparent quantum yields and the carboxylation efficiencies in leaves of the five species. The light saturation points were between 350-650 μmol·m -2·s -1 indicating that all five species of Cymbidium were shade-acclimated plants, among which C. goeringii and C.ensifolium have relatively lower shade-endured capacities; while C. sinense and C. longibracteatum have relatively higher shade-endured capacities; and C. faberi has relatively moderate shade-endured capacity.The light activation of photochemical reaction and photochemical efficiencies after the activations in the five species exhibited obvious differences, which maybe correlate with the originally ecological conditions, the acclimations and the evolutions of different species of cybidium.