The regulation of plasma membrane H+-ATPase was considered in imbibing Vicia faba seeds, a distinctive feature of which is germination by cell elongation, whereas the mitotic activity starts later. The enzyme activation is known to precede germination because it provides H+ ion efflux from the cytoplasm to cell walls which favours their modification and loosening, being the prerequisites of cell elongation commencement. The presence of an enzyme in imbibing embryo axes was confirmed immunochemically. H+ ion efflux was recorded with a pH-meter as acidification of ambient solution by the embryonic axes for 5 min. The activation of the enzyme and its subsequent activity are regulated in different ways. Enzyme activation is hydration-driven, it starts when water content increases up to the threshold level of 55% (fresh weight basis). This value was confirmed by imbibition in the presence of the osmoticum polyethylene glycol 6000, at various osmotic potentials. The activation does not depend on indolylacetic or abscisic acid treatment. Hydration-triggered activation of the enzyme favours rapid seed germination and its correspondence to the soil water potential. Enzyme activity after its activation is inhibited by 60–70% by 10−5–10−7 M abscisic acid, whereas indolylacetic acid exerted no effect. The regulation of plasma membrane H+-ATPase activity is presumably accomplished by the interaction of the enzyme with 14-3-3 proteins and endogenous fusicoccin, present in imbibing axes.

中文翻译：

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质膜H+-ATP酶的激活和活性：蚕豆种子发芽的关键事件

质膜H的调节+-ATP酶被认为是吸收蚕豆种子，其显着特征是通过细胞伸长发芽，而有丝分裂活动开始较晚。已知酶激活在发芽之前，因为它提供 H+离子从细胞质流出到细胞壁，有利于它们的修饰和松动，是细胞伸长开始的先决条件。免疫化学证实了吸收胚胎轴中酶的存在。H+离子流出用pH计记录为胚胎轴对环境溶液的酸化5分钟。酶的活化及其随后的活性以不同的方式进行调节。酶的活化是由水合作用驱动的，当水含量增加到 55% 的阈值水平（以鲜重计）时，它就开始了。该值通过在渗透聚乙二醇 6000 存在下在各种渗透势下的自吸得到证实。活化不依赖于吲哚乙酸或脱落酸处理。水合触发的酶活化有利于种子快速发芽及其与土壤水势的对应。酶活性在其激活后被 10 抑制 60-70%-5–10−7M脱落酸，而吲哚乙酸没有作用。质膜H的调节+-ATP酶活性可能是通过酶与14-3-3蛋白和内源性fusicoccin的相互作用实现的，存在于吸收轴中。