Plant Molecular Biology Center and Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois 60115.
Plant Physiol. 1992 Nov;100(3):1494-502. doi: 10.1104/pp.100.3.1494.
Axillary buds of intact pea seedlings (Pisum sativum L. cv Alaska) do not grow and are said to be dormant. Decapitation of the terminal bud promotes the growth of these axillary buds, which then develop in the same manner as terminal buds. We previously showed that unique sets of proteins are expressed in dormant and growing buds. Here we describe the cloning, sequencing, and expression of a cDNA clone (pGB8) that is homologous to ribosomal protein L27 from rat. RNA corresponding to this clone increases 13-fold 3 h after decapitation, reaches a maximum enhancement of about 35-fold after 12 h, and persists at slightly reduced levels at later times. Terminal buds, root apices, and elongating internodes also contain pGB8 mRNA but fully expanded leaflets and fully elongated internodes do not. In situ hybridization analysis demonstrates that pGB8 mRNA increases in all parts of the bud within 1 h of decapitation. Under appropriate conditions, growing buds can be made to stop growing and become dormant; these buds subsequently can grow again. Therefore, buds have the capacity to undergo multiple cycles of growth and dormancy. RNA gel blots show that pGB8 expression is reduced to dormancy levels as soon as buds stop growing. However, in situ hybridization experiments show that pGB8 expression continues at growing-bud levels in the apical meristem for 2 d after it is reduced in the rest of the bud. When cultured stems containing buds are treated with indoleacetic acid at concentrations >/=10 mum, bud growth and expression of pGB8 in the buds are inhibited.
完整豌豆幼苗（Pisum sativum L. cv Alaska）的腋芽不生长，被认为是休眠的。切除顶芽可以促进这些腋芽的生长，然后它们以与顶芽相同的方式发育。我们之前曾表明，休眠和生长芽中表达独特的蛋白质组。在这里，我们描述了一个 cDNA 克隆（pGB8）的克隆、测序和表达，该克隆与大鼠核糖体蛋白 L27 同源。该克隆的 RNA 在切除后 3 小时增加 13 倍，在 12 小时后达到约 35 倍的最大增强，并在稍后时间保持略低水平。顶芽、根尖和伸长节间也含有 pGB8 mRNA，但完全展开的小叶和完全伸长的节间没有。原位杂交分析表明，pGB8 mRNA 在切除后 1 小时内芽的所有部位都增加。在适当的条件下，生长的芽可以停止生长并进入休眠状态；这些芽随后可以再次生长。因此，芽具有经历多次生长和休眠循环的能力。RNA 凝胶印迹显示，一旦芽停止生长，pGB8 的表达就会降低到休眠水平。然而，原位杂交实验表明，pGB8 的表达在顶芽的分生组织中以生长芽的水平持续 2 天，尽管在芽的其余部分已经降低。当含有芽的培养茎用吲哚乙酸处理浓度>/=10 mum 时，芽的生长和芽中 pGB8 的表达被抑制。
