MSU/AEC Plant Research Laboratory, Michigan State University, East Lansing, U.S.A..
Planta. 1970 Mar;95(1):1-17. doi: 10.1007/BF00431116.
Stomatal opening movements in response to illumination, and stomatal closure following darkening were studied in leaf sections of Zea mays, using air-flow porometers. Stomatal opening is characterized by a phase of linear increase of air flow through the leaf (slope = "opening velocity"); stomatal closure follows a relaxation curve from which a time constant ("closing coefficient") can be derived.Apparent energies of activation, μ, were computed for the opening velocity and for the closing coefficient from stomatal movements recorded at tissue temperatures between 5° and 50°. It was assumed that the closing coefficient can be used as a measure of the closing force, and that the opening force has to exceed the closing force in order to bring about stomatal opening. μ is about 7 kcal mole(-1) for the closing coefficient and between 12 and 18 kcal mole(-1) for the opening force. Thus, during stomatal opening, metabolism must provide energy to build up a pressure difference between guard cells and the surrounding tissue.The process controlling the velocity of closure is essentially a passive loss of water (and solutes?) from the guard cells. The μ of 7 kcal mole(-1) found for the closing coefficient is, however, higher than that for the viscosity of water or for the coefficient of self diffusion of water. It is, therefore, concluded either that water interacts with the cell structures which it has to permeate during stomatal closure, or that the rate of salt loss from guard cells controls the velocity of stomatal closure.The closing force decreases when leaf temperature rises above 35° or falls below 15°. Therefore, stomata of maize open relatively faster and wider above 35° and below 15°, and the μ's of the opening velocity appear to be very large above 35° (up to 50 kcal mole(-1)) while they have a negative sign below 15°.
用气流式蒸腾计研究了玉米叶片切段对光照的气孔开启运动和暗诱导的气孔关闭运动。气孔开启的特点是通过叶片的气流呈线性增加（斜率=“开启速度”）；气孔关闭后会遵循一个弛豫曲线，从中可以得出一个时间常数（“关闭系数”）。在组织温度为 5°至 50°的条件下，记录气孔运动，计算出开启速度和关闭系数的表观活化能μ。假定关闭系数可用于衡量关闭力，并且为了实现气孔开启，开启力必须超过关闭力。对于关闭系数，μ约为 7 千卡/摩尔（-1），对于开启力，μ在 12 至 18 千卡/摩尔（-1）之间。因此，在气孔开启过程中，代谢必须提供能量，以在保卫细胞和周围组织之间建立压力差。控制关闭速度的过程本质上是保卫细胞中水分（和溶质？）的被动流失。然而，对于关闭系数，发现的 7 千卡/摩尔（-1）的μ 值高于水的粘度或水的自扩散系数。因此，可以得出结论，要么水与它在气孔关闭过程中必须穿透的细胞结构相互作用，要么盐从保卫细胞中的流失速率控制着气孔关闭的速度。当叶片温度高于 35°或低于 15°时，关闭力会降低。因此，在 35°以上和 15°以下，玉米的气孔会相对更快和更宽地打开，而在 35°以上（高达 50 千卡/摩尔（-1））时，开启速度的μ 值似乎非常大，而在 15°以下时，μ 值则为负。
