Role of Abscisic Acid in the Regulation of Root and Shoot Growth at Low Water Potentials

根的生长在水中受到的抑制往往小于枝的生长 强调植物。 尽管这种反应对植物的重要性 在干旱条件下的表现，调节的生理机制， 差异生长敏感性是未知的，并且很少研究。 这项建议将详细研究植物激素的作用 脱落酸（阿坝）在玉米生长对水分胁迫的响应中的作用。 初步结果表明，自然产生的阿坝维持根 生长，同时抑制水分胁迫玉米幼苗的芽生长。 此外，PI表明，增长的巨大差异 对水分胁迫的反应存在于植物内部密切相关的组织之间。 根和茎的生长区。 在拟议的工作中， 阿坝的水平将在根的生长区中被操纵， 使用阿坝合成缺陷突变体以及抑制剂 阿坝合成 高分辨率技术将用于确定 生长速率、阿坝水平和组织对 阿坝在生长区的一毫米部分。 结果将 大大有助于确定生物化学和生物物理过程 受激素调节，并将为育种策略奠定基础 改善玉米在干旱环境中的表现。

Root growth is frequently less inhibited than shoot growth in water stressed plants. Despite the importance of this response to plant performance under drought, the physiological mechanisms regulating the differential growth sensitivities are not known and little studied. This proposal will examine in detail the role of the plant hormone abscisic acid (ABA) in the growth responses of maize to water stress. Preliminary results suggest that naturally-occurring ABA maintains root growth while inhibiting shoot growth of water stressed maize seedlings. Additionally, the PI has shown that large differences in the growth response to water stress exist among closely related tissues within the growing zone of the root and shoot. In the proposed work, internal levels of ABA will be manipulated in the growing zones of roots and shoots using a mutant deficient in ABA synthesis as well an inhibitor of ABA synthesis. High resolution techniques will be used to determine growth rate, ABA levels and molecular indicators of tissue response to ABA in one-millimeter sections of the growing zones. Results will greatly assist in determining the biochemical and biophysical processes regulated by the hormone and will set the stage for breeding strategies to improve maize performance drought-prone environments.