EFFECTS OF WHITE, BLUE, RED-LIGHT AND DARKNESS ON PH OF THE APOPLAST IN THE SAMANEA PULVINUS
EFFECTS OF WHITE, BLUE, RED-LIGHT AND DARKNESS ON PH OF THE APOPLAST IN THE SAMANEA PULVINUS
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DOI：
10.1007/bf00392524
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发表时间：
1989-05-01
期刊：
影响因子：
4.3
通讯作者：
SATTER, RL
中科院分区：
文献类型：
--
作者：
LEE, YS;SATTER, RL
Samanea saman (Jacq.) Merrill 的小叶运动是由 K+、阴离子和水通过枕丘运动细胞膜的通量驱动的（R.L. Satter et al., 1974, J. Gen. Physiol. 64, 413-430）。伸肌细胞吸收 K+ 并在白光下膨胀 (WL)，而屈肌细胞吸收 K+ 并在黑暗中膨胀 (D)。切除的伸肌和屈肌运动组织条在通常促进完整组织中 K+ 增加的条件下酸化其沐浴介质，并在通常诱导 K+ 减少的条件下碱化介质（A. Iglesias 和 R.L. Satter, 1983, Plant Physiol. 72, 564）。为了获得整个叶枕 pH 值变化的信息，我们使用对 H+ 敏感的液膜微电极测量了光对质外体 pH 值的影响。我们报告如下：（1）WL 和 D 中伸肌质外体的 pH 值高于屈肌质外体的 pH 值（WL 中 pH 梯度为 1.0 个单位，D 中为 2.0 个单位）。质外体 pH 值可能会影响 K+ 通过 Samanea 运动细胞质膜的转运，因为其他系统中离子通道的电导、门控和选择性取决于外部 pH 值。 (2) 伸细胞酸化和屈肌细胞碱化其环境以响应 WL 照射，而响应 D 则发生相反的变化。这些结果与 Iglesias 和 Satter (1983) 的结果一致，并支持用切除组织获得的数据的生理相关性。 (3) 红光照射下的pH变化与D相似；此外，蓝光响应的 pH 值变化与 WL 获得的结果相似。枕骨在黑暗中在红光下关闭，在 WL 下打开，但在蓝光下未能打开。讨论了质外体 pH 测量用于分析 H+ 转运的优点和局限性。
Leaflet movements in Samanea saman (Jacq.) Merrill are driven by fluxes of K+, anions, and water through membranes of motor cells in the pulvinus (R.L. Satter et al., 1974, J. Gen. Physiol. 64, 413-430). Extensor cells take up K+ and swell in white light (WL) while flexor cells take up K+ and swell in darkness (D). Excised strips of extensor and flexor motor tissue acidify their bathing medium under conditions that normally promote increase in K+ in the intact tissue, and alkalize the medium under conditions that normally induce decrease in K+ (A. Iglesias and R.L. Satter, 1983, Plant Physiol. 72, 564). To obtain information of pH changes in the whole pulvinus, we measured effects of light on pH of the apoplast, using liquid membrane microelectrodes sensitive to H+. We report the following: (1) The pH of the extensor apoplast was higher than that of the flexor apoplast in WL and in D (pH gradient of 1.0 units in WL and 2.0 units in D). Apoplastic pH might affect K+ transport through the plasma membranes of Samanea motor cells, since the conductance, gating, and selectivity of ionic channels in other systems depend upon external pH. (2) Extensor cells acidified and flexor cells alkalized their environment in response to irradiation with WL, while the reverse changes occurred in response to D. These results are consistent with the results of Iglesias and Satter (1983), and support the physiological relevance of data obtained with excised tissue. (3) The pH changes in response to irradiation with red light were similar to those obtained with D; also, the pH changes in response to blue light were similar to those obtained with WL. The pulvinus closed in red light as in darkness and opened in WL, but failed to open in blue light. The advantages and limitations of apoplastic pH measurements for assaying H+ transport are discussed.