Action of Hormones in Plant Development

与另一种激素赤霉素（GA）一起，脱落酸（阿坝）是 已知调节几种水解酶的合成和分泌 酶，如α-淀粉酶和蛋白酶，其是必需的， 许多谷物发芽后的生长。 作为博士的延续。 他长期致力于阐明植物激素的作用方式， 他计划分析阿坝作用的分子机制， 几乎没有糊粉层--负责合成 发芽特异酶 先前的研究揭示了两种模式 阿坝在该系统中的作用：一种正调节， 几个新的蛋白质，和一个负调控，以抑制GA- α-淀粉酶 在ABA诱导的蛋白质中， 淀粉酶抑制剂、凝集素样蛋白和丰富的29 kD蛋白。 阿坝对α-淀粉酶合成的抑制作用表现在两个部位： 转录水平和mRNA稳定性水平。 为落实 根据这些初步观察，何博士提出了三套主要的 在这个项目中的实验，以调查监管过程， 阿坝诱导的新蛋白。 他将使用重组DNA技术 制备DNA探针，并使用它们1）分析结构， 编码阿坝诱导蛋白的基因的表达，和2）测量 α-淀粉酶mRNA的稳定性，并确定阿坝对 mRNA的周转率。 最后，他将研究 ABA诱导的α-淀粉酶mRNA降解的潜在过程。 植物激素阿坝在几个重要的生物学过程中发挥调节作用。 生理和发育过程，如种子发育， 萌发、气孔功能和植物对干旱的反应。 该项目的目的不仅是深入了解 阿坝本身以及它与赤霉素的相互作用。

Together with another hormone, gibberellin (GA), abscisic acid (ABA) is known to regulate the synthesis and secretion of several hydrolytic enzymes, such as alpha-amylase and protease, that are essential to the post-germination growth of many cereal grains. As a continuation of Dr. Ho's long term effort to elucidate the mode of action of plant hormones, he plans an analysis of molecular mechanisms underlying ABA action in barely aleurone layers--a tissue responsible for the synthesis of germination specific enzymes. Previous research has revealed two modes of action of ABA in this system: a postitive regulation to induce several new proteins, and a negative regulation to inhibit the GA- induced alpha-amylase. Among the ABA-induced proteins are an alpha- amylase inhibitor, a lectin like protein, and an abundant 29kD protein. The ABA inhibition of alpha-amylase synthesis appears to be at both the level of transcription and the level of mRNA stability. To follow up on these inital observations, Dr. Ho has proposed three major sets of experiments in this project to investigate the regulatory processes in ABA induction of new proteins. He will use recombinant DNA techniques to prepare DNA probes, and use them 1) to analyze the structures and expression of genes encoding the ABA induced proteins and 2) to measure the stability of alpha-amylase mRNA and determine the effect of ABA on the turnover rate of the mRNA. Finally he will study the molecular processes underlying the ABA-induced degradation of alpha-amylase mRNA. The plant hormone ABA exerts regulatory roles in several important physiological and developmental processes such as seed development and germination, stomatal function, and the response of plants to drought. This project is aimed at obtaining insights into not only the action of ABA itself but also its interactions with gibberellin.