Department of Botany, University of Kansas, Lawrence, Kansas 66045.
Plant Physiol. 1986 Jan;80(1):23-6. doi: 10.1104/pp.80.1.23.
Spanish moss (Tillandsia usneoides L.) was collected in South Carolina, maintained in a greenhouse, then exposed to five levels of photosynthetic photon flux density (PPFD) for 3 weeks. Following this treatment, plants were sampled for chlorophyll concentrations, nocturnal acid accumulations, and photosynthetic responses to subsequent exposure at a range of PPFD. No acclimation to PPFD was observed; all plants exhibited similar patterns of nocturnal CO(2) uptake and acid accumulation regardless of initial PPFD treatment. These patterns revealed that at a PPFD level of approximately 200 micromoles per square meter per second (daytime integrated PPFD of 10 moles per square meter per day), CAM saturated or, in low-PPFD plants, was optimal. The results of this study indicate that adaptation to high PPFD is not necessarily a requirement of CAM.
西班牙苔藓（Tillandsia usneoides L.）于南卡罗来纳州采集，在温室中培养，然后在 3 周内暴露于 5 个不同水平的光合光子通量密度（PPFD）下。经过此处理后，对植物的叶绿素浓度、夜间酸积累和随后在一系列 PPFD 下的光合作用响应进行采样。没有观察到对 PPFD 的适应；无论初始 PPFD 处理如何，所有植物的夜间 CO2 吸收和酸积累模式都相似。这些模式表明，在约 200 微摩尔/平方米/秒（白天整合的 PPFD 为 10 摩尔/平方米/天）的 PPFD 水平下，CAM 达到饱和，或者在低 PPFD 植物中，CAM 达到最佳状态。本研究结果表明，对高 PPFD 的适应不一定是 CAM 的必要条件。
