Fischer R A, Hsiao T C
Laboratory of Plant-Water Relations, Department of Water Science and Engineering, University of California, Davis, California 95616.
Plant Physiol. 1968 Dec;43(12):1953-8. doi: 10.1104/pp.43.12.1953.
The stimulation by KCl of stomatal opening in isolated epidermal strips of Vicia faba was examined. In dark + normal air the opening response was maximal at 100 mm KCl while in light + CO(2)-free air it was maximal at about 10 mm KCl. CO(2)-free air was more influential than light in reducing the KCl concentration required for maximal opening. K(+) was essential while Cl(-) seemed to be of secondary importance in these processes.The use of (86)Rb(+) as a tracer for K(+) showed that the increase in stomatal aperture under various conditions was well correlated with K(+) uptake. The estimated amount of K(+) taken up by guard cells, along with a counter ion, was sufficient to account for the changes in solute potential associated with opening. It is suggested that the absorption of extracellular solutes, such as K(+), may be the primary mechanism of stomatal opening. Both opening and K(+) absorption are stimulated by light + CO(2)-free air.The increase in stomatal aperture was also well correlated with the decrease in stainable starch in guard cells under all conditions. It is suggested that this is a secondary change, although perhaps closely linked to K(+) absorption.
研究了氯化钾对蚕豆离体表皮条气孔开放的刺激作用。在黑暗 + 正常空气中，气孔开放反应在100 mM氯化钾时最大，而在光照 + 无二氧化碳空气中，在约10 mM氯化钾时最大。在降低最大开放所需的氯化钾浓度方面，无二氧化碳空气比光照更具影响力。钾离子是必需的，而氯离子在这些过程中似乎是次要的。使用⁸⁶Rb⁺作为钾离子的示踪剂表明，在各种条件下气孔孔径的增加与钾离子吸收密切相关。保卫细胞吸收的钾离子（连同一种抗衡离子）的估计量足以解释与气孔开放相关的溶质势变化。有人提出，细胞外溶质（如钾离子）的吸收可能是气孔开放的主要机制。光照 + 无二氧化碳空气会刺激气孔开放和钾离子吸收。在所有条件下，气孔孔径的增加也与保卫细胞中可染色淀粉的减少密切相关。有人认为这是一种次要变化，尽管可能与钾离子吸收密切相关。
