Induction of CAM in Mesembryanthemum crystallinum Abolishes the Stomatal Response to Blue Light and Light-Dependent Zeaxanthin Formation in Guard Cell Chloroplasts

作者：Gary Tallman, Jian Zhu, Bruce T. Mawson, Gabriela Amodeo, Z. Nouhi, Kerinne Levy, Eduardo Zeiger · 发表于：Plant and Cell Physiology · 年份：1997 · DOI：10.1093/oxfordjournals.pcp.a029158 · 被引用次数：55 · 研究领域：Plant Stress Responses and Tolerance、Photosynthetic Processes and Mechanisms、Light effects on plants

Facultative CAM plants such as Mesembryanthemum crystallinum (ice plant) possess C3 metabolism when unstressed but develop CAM under water or salt stress. When ice plants shift from C3 metabolism to CAM, their stomata remain closed during the day and open at night. Recent studies have shown that the stomatal response of ice plants in the C3 mode depends solely on the guard cell response to blue light. Recent evidence for a possible role of the xanthophyll, zeaxanthin in blue light photoreception of guard cells led to the question of whether changes in the regulation of the xanthophyll cycle in guard cells parallel the shift from diurnal to nocturnal stomatal opening associated with CAM induction. In the present study, light-dependent stomatal opening and the operation of the xanthophyll cycle were characterized in guard cells isolated from ice plants shifting from C3 metabolism to CAM. Stomata in epidermis detached from leaves with C3 metabolism opened in response to white light and blue light, but they did not open in response to red light. Guard cells from these leaves showed light-dependent conversion of violaxanthin to zeaxanthin. Induction of CAM by NaCI abolished both white light- and blue light-stimulated stomatal opening and light-dependent zeaxanthin formation. When guard cells isolated from leaves with CAM were treated with 100 mM ascorbate, pH 5.0 for 1 h in darkness, guard cell zeaxanthin content increased at rates equal to or higher than those stimulated by light...