Ophiorrhiza pumila is a medicinal plant distributed on the floors of humid inland forests in subtropical areas and accumulates camptothecin (CPT) in whole plant organs. To elucidate the proper light and air temperature conditions for plant growth and CPT yield, we conducted two experiments under controlled environments. In experiment 1, we measured the net photosynthetic rate (P_n) and transpiration rate (E) of the whole plant O. pumila using an open-type assimilation chamber under different photosynthetic photon flux densities (PPFDs) and air temperatures. The result showed that the combination of an air temperature of 28 °C and a PPFD of 100 μmol m^-2 s^-1 was a good condition for photosynthesis and transpiration. In experiment 2, O. pumila was cultivated for 35 days under three PPFDs and three light periods at an air temperature of 28 °C. At a PPFD of 100 μmol m^-2 s^-1 and a light period of 16 h, growth was accelerated by the generating the lateral shoots and branches, and total CPT content per plant was the highest among these treatments. The present study revealed that the proper PPFD and light period conditions could enhance growth and CPT accumulation of O. pumila.

中文翻译：

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受控环境下光合光子通量密度和光周期对桔梗生长和喜树碱积累的影响

Ophiorrhiza pumila是一种药用植物，分布在亚热带湿润内陆森林的地上，并在整个植物器官中积累喜树碱（CPT）。为了阐明适合植物生长和CPT产量的光照和空气温度条件，我们在受控环境下进行了两个实验。在实验1中，我们使用开放式同化室在不同的光合作用光子通量密度（PPFD）和空气温度下测量了整个植物O. pumila的净光合速率（P _n）和蒸腾速率（E）。结果表明，空气温度为28°C，PPFD为100μmolm ^-2 s ^-1是光合作用和蒸腾作用的良好条件。在实验2中，在28℃的空气温度下，在三个PPFD和三个光照期下将O. pumila培养35天。PPFD为100μmolm ^-2 s ^-1，光照时间为16 h时，通过产生侧枝和枝条促进了生长，在这些处理中，每株植物的总CPT含量最高。目前的研究表明，适当的PPFD和光周期条件下可以提高增长和CPT积累O.荔。