温室栽培的3种石斛冬季叶绿素荧光动力学研究

Study on Chlorophyll Fluorescence Kinetics of Three Speices in Genus Dendrobium Cultivated in Greenhouse in the Winter Season

石斛属包括重要的药用植物和世界著名花卉,一些种具有景天酸代谢植物特征。试验选用报春石斛、金钗石斛、鼓槌石斛为材料,采用气体交换与叶绿素荧光动力学测定相结合的方法,研究冬季温室栽培条件下石斛的光合作用和生长状况。结果表明:报春石斛具有较为明显的景天酸代谢特征,11:00以前,表观光合作用速率为负值,但PSII电子传递速率依然较高,表现为CAM植物光合作用日变化的阶段III趋势;金钗石斛和鼓槌石斛表观光合作用速率低、适应较低强度光照环境;相比之下,鼓槌石斛的C3植物特征更为明显。早晨16℃的低温会对报春石斛造成一定程度的胁迫,金钗石斛和鼓槌石斛较能适应低温环境。

The Dendrobium genus includes some important medicinal and famous ornamental plant species over the world. Some species in this genus demonstrated the characteristics of crassulasean acid mechanism plant. Three species i. e. , Dendrobium primulinum, D. nobile and D. chrysotoxum were selected as the experiment objects to study their photosynthesis and growth status in greenhouse during the winter season by means of measuring the gas exchange in combination with determining the chlorophyll fluorescence kinetics. The results showed that D. primu- linum exhibited typical traits of CAM plants, when its apparent photosynthetic rate was still minus value before l 1：00 am while the electron transport rate was relatively high, which resembled the stage III tendency of diurnal fluctuation of CAM plants. With low apparent photosynthetic rate, D. nobile and D. chrysotoxum were adaptive to shade environment with weaker solar radiation. Comparatively speaking, D. chrysotoxum manifested more typical C3 plant characteristics. The 16~C temperature in the early morning posed a c stress to D. primulinum to certain extent, meanwhile D. nobile and D. chrysotoxum were not negatively effected, showing that the later two species were more adaptive to low temperature.