Baulcombe D, Lazarus C, Martienssen R
J Embryol Exp Morphol. 1984 Nov;83 Suppl:119-35.
The production of hydrolytic enzymes in the germinating cereal grain is considered as a model for plant cell differentiation. Recent literature is reviewed which suggests that gibberellins are involved in this process, but in a less straightforward manner than considered previously. It seems likely that only a subfraction of gibberellin is active and that production of this gibberellin is actually in the hydrolase-producing cells. These include aleurone cells and also the scutellar epithelial cells. At the intracellular level the action of gibberellin results in the accumulation of alpha-amylase mRNA and also mRNA for other unidentified proteins, referred to as gibb-ons. The alpha-amylase mRNAs are transcribed from two distinct gene families. The pattern of expression of alpha-amylase and gibb-on mRNAs is consistent with a common gibberellin-stimulated mechanism of control of for all of these genes. However it seems likely from experiments with ABA and from observations on gibb-on gene expression in non-aleurone cells that gibberellin does not have a role determining the specificity of gene expression, but rather acts as a general stimulator of mRNA accumulation.
萌发谷物种子中水解酶的产生被视为植物细胞分化的一个模型。本文综述了近期文献，这些文献表明赤霉素参与了这一过程，但方式比之前认为的更为复杂。似乎只有一部分赤霉素具有活性，而且这种赤霉素实际上是在产生水解酶的细胞中产生的。这些细胞包括糊粉层细胞和盾片上皮细胞。在细胞内水平，赤霉素的作用导致α-淀粉酶mRNA以及其他未鉴定蛋白质（称为赤霉素诱导蛋白）的mRNA积累。α-淀粉酶mRNA由两个不同的基因家族转录而来。α-淀粉酶和赤霉素诱导蛋白mRNA的表达模式与所有这些基因受赤霉素共同刺激的控制机制一致。然而，从脱落酸实验以及对非糊粉层细胞中赤霉素诱导蛋白基因表达的观察来看，赤霉素似乎并不决定基因表达的特异性，而是作为mRNA积累的一般刺激因子起作用。
