Hormonal and Environmental Regulation of Seed Germination Rates

种子发芽率的激素和环境调节

• 批准号: 9204782
• 负责人: Kent Bradford
• 金额: $ 15万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-08-15 至 1995-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9204782&HistoricalAwards=false
• 关键词: Hormonal; Environmental; Regulation; Seed; Germination

Seed germination is a critical phase of the plant life cycle, both ecologically and agriculturally, and is sensitive to both endogenous hormones and environmental factors. A quantitative mathematical model has been developed to characterize the responses of seed germination to abscisic acid (ABA), gibberellins (GA), and water potential (psi). Single-gene mutations in tomato (Lycopersicon esculentum Mill.) resulting in deficiencies of ABA or GA have contrasting effects on dormancy, germination rates, and sensitivity to reduced psi. This project will utilize these mutant genotypes within the framework provided by the mathematical model to identify the biochemical processes controlling germination. Germination occurs when endosperm cell layers opposite the radicle tip weaken and separate to allow embryo expansion. Cell wall hydrolysis in this endosperm tissue and its relationship to germination rates will be investigated. The composition of tomato endosperm cell walls will be characterized, the substrates, products, and enzymes involved in cell wall hydrolysis will be identified, and the relationship of cell wall hydrolysis to tissue weakening will be critically analyzed in mutant and wild-type seeds. Extending the mathematical description of seed germination to the physiological and biochemical levels provides a powerful new method for studying the integration of regulatory controls in plant development.

种子发芽是植物生命周期的关键阶段，无论是生态学还是农业学，并且对内源激素和环境因素都很敏感。 已开发出定量数学模型来表征种子萌发对脱落酸 (ABA)、赤霉素 (GA) 和水势 (psi) 的反应。 番茄 (Lycopersicon esculentum Mill.) 中导致 ABA 或 GA 缺乏的单基因突变对休眠、发芽率和对 psi 降低的敏感性具有相反的影响。 该项目将在数学模型提供的框架内利用这些突变基因型来识别控制发芽的生化过程。 当胚根尖端对面的胚乳细胞层减弱并分离以允许胚胎扩张时，就会发生发芽。 将研究该胚乳组织中的细胞壁水解及其与发芽率的关系。 将表征番茄胚乳细胞壁的组成，鉴定参与细胞壁水解的底物、产物和酶，并严格分析突变型和野生型种子中细胞壁水解与组织弱化的关系。 将种子萌发的数学描述扩展到生理和生化水平，为研究植物发育中调控控制的整合提供了一种强大的新方法。