<正>通过对石蒜（Lycoris radiata）鳞茎芽的解剖观察，研究了石蒜在花芽分化过程中内源激素含量的动态变化，分析了内源激素与核酸变化的相关性。结果表明：花芽形态建成期中，IAA、ABA在孕育期，GA在雄蕊形成期，zR在雌蕊形成期依次出现峰值从而引起核酸峰值的出现，表明4种内源激素调控了核酸的代谢，且IAA，ABA在花芽分化进程中起主要作用。研究发现高水平的ABA/GA有利于花芽孕育和花芽形态的分化；高水平的IAA/zR及ABA/zR有利于花芽形态分化，但不利于雌雄蕊的形成。由此说明在花芽分化过程中4种内源激素的含量此起彼伏发生着激烈的变化，最终达到平衡状态，花芽分化完成。

Tree species selection was a basis on urban forest construction, and the selection of tree species composition was the most important one. Through investigating and analyzing the tree species composition in the urban green-space in Yangzhou city build-up area, the sequencing of integrate evaluation of various tree species was obtained and the existing status of tree species distribution in Yangzhou built-up area was analyzed. According to their integral evaluation, Osmanthus fragrans, Sabina chinensis ’ Kaizuka’, Ligustrun lucidum, Ginkgo biloba, Prunus persica ’ duplex’, Cinnamomum camphora and Salix babylonica were the predominant species. They might be used as the key tree species in the urban green-space in Yangzhou city. By using correlation analysis among tree species with the Jaccard quantitative coefficient of correction, one optimal tree species composition, four good tree species composition and five reference tree composition of Yangzhou urban green-space were recommended. Some advices about tree species planning of green-space were made finally in the paper.