Abstract: Abscisic acid(ABA)plays important roles in the adaptation of plants to a variety of environmental stresses.The oxidative cleavage of cis-epoxy carote-noids catalyzed by 9-cis-epoxy carotenoid dioxy genase(NCED)isthe key step in the regulation of abscisic acid(ABA)biosynt hesis in higher plants.The environmental stresses induce the expression of NCED and there by regulate the endogenous ABA level.Stylosanthes guianensis is animportant drought-tolerant pasture legume of the tropical and subtropical regions.The objectives of this studywere to clone the NCED gene from S.guianensis and to analyze its function in response to abiotic stresses as well as to provide a method for the molecular breeding of stress-to lerant crops.The results are sum marized inthe following 4 sections.

Key words: Stylosanthes guianensis, Abscisic acid, 9-cisepoxycarotenoid dioxygenase(NCED), Environ-mental stresses, Transgenic tobacco

摘要： 脱落酸(ABA)作为一种调控生长发育的激素,对植物多种生理过程起着调控作用。9-顺式环氧类胡萝卜素双加氧酶(9-cis-epoxycarotenoid dioxygenase,NCED)是高等植物ABA生物合成途径的关键酶。NCED基因受逆境胁迫诱导,导致逆境ABA的积累。研究NCED基因克隆、表达,调控ABA的生物合成,是提高植物抗逆性的重要途径。柱花草(Stylosanthesgu ianensis)是一种热带和亚热带地区广泛种植的耐旱草种。

关键词: 柱花草, ABA, NCED, 逆境胁迫, 转基因烟草