Department of Horticultural Science, University of Minnesota, St. Paul, Minnesota 55108.
Plant Physiol. 1992 Nov;100(3):1238-42. doi: 10.1104/pp.100.3.1238.
Exogenous applications of gibberellins (GAs) increased the extractable activity of leaf sucrose phosphate synthase (SPS) in soybean (Glycine max [L.]) and spinach (Spinacia oleracea [L.]). The response to GA applications was detectable within 2 h postapplication and was still observed 6 h, 24 h, and 7 d after treatment. When paclobutrazol, a GA biosynthesis inhibitor, was applied to intact soybean and spinach plants, decreased extractable SPS activity resulted within 24 h following the treatment. Different methods of GA application (spray, injection, capillary wick, and excised leaf systems) produced similar effects on SPS activity of soybean leaves. Protein synthesis in soybean leaves appeared to be necessary for GA-promoted SPS activity because gibberellic acid only partially reversed the inhibitory effect of pretreatment with cycloheximide. Levels of SPS protein from crude extracts of spinach plants were measured by a dot blot technique using monoclonal antibodies against SPS. Application of gibberellic acid to spinach leaves increased levels of SPS protein 2 h, 24 h, and 7 d after treatment. The results suggest that, in both soybean and spinach, GA is one of the endogenous hormonal factors that regulate the steady-state level of SPS protein and, hence, its activity.
外源赤霉素 (GA) 的应用增加了大豆 (Glycine max [L.]) 和菠菜 (Spinacia oleracea [L.]) 叶片蔗糖磷酸合成酶 (SPS) 的可提取活性。在应用 GA 后 2 小时内即可检测到对 GA 应用的反应，并且在处理后 6 小时、24 小时和 7 天仍可观察到。当 GA 生物合成抑制剂多效唑应用于完整的大豆和菠菜植株时，处理后 24 小时内可观察到可提取 SPS 活性降低。GA 应用的不同方法（喷雾、注射、毛细管吸液和离体叶片系统）对大豆叶片 SPS 活性产生相似的影响。GA 促进的 SPS 活性似乎需要大豆叶片中的蛋白质合成，因为赤霉素仅部分逆转了环己酰亚胺预处理的抑制作用。使用针对 SPS 的单克隆抗体通过斑点印迹技术测量来自菠菜植物粗提物的 SPS 蛋白水平。GA 处理后 2 小时、24 小时和 7 天，向菠菜叶片应用赤霉素可增加 SPS 蛋白的水平。结果表明，在大豆和菠菜中，GA 是调节 SPS 蛋白及其活性的内源性激素因素之一。
