Tiedemann J, Neubohn B, Müntz K
Institut für Pflanzengenetik und Kulturpflanzenforschung, Gatersleben, Germany.
Planta. 2000 Jun;211(1):1-12. doi: 10.1007/s004250000259.
The temporal and spatial patterns of storage-globulin mobilization were immunohistochemically pursued in the embryonic axis and cotyledons of vetch seed (Vicia sativa L.) during germination and early seedling growth. Embryonic axes as well as cotyledons of mature seeds contain protein bodies with stored globulins. Prevascular strands of axes and cotyledons, the radicle and epidermal layers of axis organs were nearly exclusively stained by vicilin antibodies whereas the cotyledonous storage mesophyll gave similar staining for vicilin and legumin. Globulin breakdown started locally where growth and differentiation commenced in the axis. There, vicilin mobilization preceded legumin mobilization. Thus vicilin represents the initial source of amino acids for early growth and differentiation processes in vetch. Legumin presumably only serves as a bulk amino acid source for subsequent seedling growth during postgerminative globulin degradation. During the first 2-3 d after the start of imbibition the axis was depleted of globulins whereas no decrease in immunostainability was detected in the cotyledons except in their vascular strands where immunostainability was almost completely lost at this time. Continuous vascular strands were established at the third day when globulin breakdown was finished in the axis but had just started in the cotyledon mesophyll. Protein mobilization proceeded in a small zone from the epidermis towards the vascular strands in the center of the cotyledons. In this zone the storage cells, which initially appeared densely packed with starch grains and protein bodies, concomitantly transformed into cells with a large central vacuole and only a thin cytoplasmic layer attached to the cell wall. These results agree well with the hypothesis that during the first 2 d after imbibition the axis is autonomous in amino acid provision. After the endogenous reserves of the axis are depleted and the conductive tissue has differentiated, globulins are mobilized in the cotyledons, suggesting that then the amino acid supply is taken over by the cotyledons. For comparison with other degradation patterns we used garden bean (Phaseolus vulgaris L) and rape (Brassica napus L.) as reference plants.
在萌发和幼苗早期生长过程中，采用免疫组织化学方法研究了巢菜种子（野豌豆）胚轴和子叶中贮藏球蛋白的时空动员模式。成熟种子的胚轴和子叶均含有贮藏球蛋白的蛋白体。胚轴和子叶的维管束前体、胚根以及轴器官的表皮层几乎仅被豌豆球蛋白抗体染色，而子叶贮藏叶肉对豌豆球蛋白和豆球蛋白的染色相似。球蛋白分解始于胚轴中生长和分化开始之处。在那里，豌豆球蛋白的动员先于豆球蛋白的动员。因此，豌豆球蛋白是巢菜早期生长和分化过程中氨基酸的初始来源。豆球蛋白可能仅在萌发后球蛋白降解期间作为随后幼苗生长的大量氨基酸来源。在吸胀开始后的最初2 - 3天内，胚轴中的球蛋白耗尽，而子叶中除了其维管束外，免疫染色性未检测到降低，此时维管束中的免疫染色性几乎完全丧失。在第三天建立了连续的维管束，此时胚轴中的球蛋白分解完成，但子叶叶肉中的分解刚刚开始。蛋白质动员在子叶中心从表皮向维管束的一个小区域内进行。在这个区域，最初看起来充满淀粉粒和蛋白体的贮藏细胞同时转化为具有大中央液泡且仅在细胞壁附着有薄细胞质层的细胞。这些结果与以下假设非常吻合：在吸胀后的最初2天内，胚轴在氨基酸供应方面是自主的。当胚轴的内源储备耗尽且传导组织分化后，子叶中的球蛋白被动员，这表明此时氨基酸供应由子叶接管。为了与其他降解模式进行比较，我们使用菜豆（菜豆）和油菜（甘蓝型油菜）作为参考植物。
