濒危植物长柄双花木的花部综合特征与繁育系统  

FLORAL SYNDROME AND BREEDING SYSTEM OF THE ENDANGERED PLANT DISANTHUS CERCIDIFOLIUS MAXIM. VAR. LONGIPES

作　　者：肖宜安[1,2] 何平[1] 李晓红[3] 

机构地区：[1]西南师范大学生命科学学院 [2]井冈山师范学院生命科学系,江西吉安343009 [3]井冈山师范学院生命科学系

出　　处：《植物生态学报》2004年第3期333-340,共8页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金项目 ( 3 0 0 70 0 80 )

摘　　要：通过野外观察 ,运用杂交指数、花粉_胚珠比、人工授粉和套袋实验及等位酶电泳等方法 ,对长柄双花木(DisanthuscercidifoliusMaxim .var.longipesH .T .Chang)自然种群和人工种群的开花状态、繁育系统进行了研究。结果如下 :该种单花花期一般 6～ 7d,开花过程中柱头始终高于花药的位置 ,花药散粉具有先后顺序 ,一般 2花药先散粉 ,其余 3花药滞后 1～ 2d。单花花期依其形态和散粉时间可分为 5个时期 :即散粉前期、散粉初期、散粉盛期、凋谢期。种群开花一般历时 4 9～ 5 5d ,但不同地点、年份之间有所差异 ,推测开花持续时间不同主要是环境条件所致。由于其杂交指数大于 4 ,花粉_胚珠比等于 12 5 0 ,结合人工套袋和授粉实验以及等位酶电泳结果可以确定该种的繁育系统属于异交为主 ,部分自交亲和 ,传粉过程需要传粉者。花粉竞争可能是导致该种濒危的主要的生殖生物学原因。We conducted a field investigation of the floral syndrome and breeding system of Disanthus cercidifolius Maxim. var. longipes H. T. Chang, an endangered plant species, in both artificial and natural populations in Mt. Jinggang, a National Reserve in Jiangxi, China. We describe our findings below. There are two inflorescences, often on opposite axillaries at the same node, each inflorescence with two opposite bisexual flowers with no pedicels. Flowering lasted 5 to 6 days. On the day of anthesis, the styles are longer than the filaments; the length between anthers and stigmas is about 1.02 mm. The color of petals changes from light red to brown. The stigma changes from light green to pale yellow, to brown, and lastly to black. The anthers dehisce in order of priority. Two of the anthers whose dehiscence pattern is longitudinal and synclinal upward always dehisce first, followed by the others. The pollen forms an obvious 'pollen circle' surrounding the stigma when the anthers all dehisce. The flowering span among populations is 49-55 days. The flowering process for one flower of this species can be divided into four periods by the flower morphology and dehiscence: 'Pre-dehiscence' in which two filaments stretch out with no dehiscence; 'Initial dehiscence'-after two days of flowering, one or two anthers dehisce; 'Full dehiscence' is between the third and fifth day when three to five anthers dehisce, and the color of the stigma changes to yellow; and the last period is 'Withering period', that occurs from the sixth to seventh day, when all anthers have dehisced, some have begun to wither, and the color of some stigmata changes to brown or black yellow. The floral diameter is ca. 15 mm. There are both temporal and spatial isolations of male and female organs within the same flower. It is protandrous with an outcrossing index of 4. According to criteria put forward by Dafni, the breeding system of this species can be determined as outcrossing with partly self-compatible and needs pollinators during the pollination

关 键 词：濒危植物 长柄双花木 繁育系统 遗传变异 杂交指数 花粉-胚珠比 

分 类 号：Q944[生物学—植物学]