Leopold A C, LaFavre A K
Boyce Thompson Institute, Cornell University, Ithaca, New York 14853.
Plant Physiol. 1989;89(3):875-8. doi: 10.1104/pp.89.3.875.
The effect of red light on orthogravitropism of Merit corn (Zea mays L.) roots has been attributed to its effects on the transduction phase of gravitropism (AC Leopold, SH Wettlaufer [1988] Plant Physiol 87:803-805). In an effort to characterize the orthogravitropic transduction system, comparative experiments have been carried out on the effects of red light, calcium, and abscisic acid (ABA). The red light effect can be completely satisfied with added ABA (100 micromolar) or with osmotic shock, which is presumed to increase endogenous ABA. The decay of the red light effect is closely paralleled by the decay of the ABA effect. ABA and exogenous calcium show strong additive effects when applied to either Merit or a line of corn which does not require red light for orthogravitropism. Measurements of the ABA content show marked increases in endogenous ABA in the growing region of the roots after red light. The interpretation is offered that red light or ABA may serve to increase the cytoplasmic concentrations of calcium, and that this may be an integral part of orthogravitropic transduction.
红光对优良玉米（Zea mays L.）根正向重力性的影响已归因于其对重力性转导阶段的作用（AC·利奥波德、SH·韦特劳弗[1988]《植物生理学》87:803 - 805）。为了表征正向重力性转导系统，已针对红光、钙和脱落酸（ABA）的作用开展了对比实验。添加ABA（100微摩尔）或进行渗透冲击（据推测这会增加内源性ABA）可完全模拟红光效应。红光效应的衰减与ABA效应的衰减密切平行。当应用于优良玉米或一种不需要红光来实现正向重力性的玉米品系时，ABA和外源钙显示出强烈的累加效应。ABA含量的测量结果表明，红光处理后根生长区域内源性ABA显著增加。由此提出的解释是，红光或ABA可能有助于增加细胞质中的钙浓度，而这可能是正向重力性转导的一个组成部分。
