麻疯树开花数量大小及其生态适应性

Study on the floral quantity size and ecological adaptability of Jatropha curcas

采用随机取样和跟踪调查的方法,对不同立地环境下,半野生麻疯树前两次开花时开花数量大小及其座果特征进行了比较研究。结果表明：麻疯树雄性花序和两性花序分别着生于多年生老枝和1年生小枝上,两性花序的产生量占有绝对优势,常为雄性花序的1.8~17倍;两性花序中,雌花朵数量相对较少,且变化较大,单个两性花序中常有1~25朵雌花,而雄花朵大量产生,常为雌花数量的10~20倍;同时,麻疯树座果率较高,且相对稳定,平均可达90%以上,而单个果实平均可产2.6~2.9粒种子。立地环境和开花时间对麻疯树雄性花序、两性花序以及两性花序中雄花朵和雌花朵的产生数量均存在着显著影响。两性花序大量发生保证了在可利用资源有限时雌性功能的加强,是非常有利的生殖策略;而雄性花序以及两性花序中雄花的适应意义可能大于其功能作用,大量雄花的产生对其吸引昆虫传粉更为有利。

Random sampling and tracking investigation were applied to determine comparatively the floral quantity,size and the fruiting rate of Jatropha curcas during the first two flowering of semi-field in different site conditions.The results showed that,male inflorescence usually produced on the old branches,and polygamous inflorescence produced on the 1-year-old twigs.The number of polygamous inflorescence is 1.8—17 times than that of male inflorescences.There are a few female flowers,usually varies from 1 to 25 per inflorescence,and a large number of male flowers,usually 10—20 times than that of the female ones within polygamous inflorescences.The fruiting rate of J.curca is relatively stable and high,commonly more than 90 % higher than the average,and the number of seeds per fruit set varies from 2.6—2.9.Site conditions and flowering order could significantly affect the number of male inflorescence,polygamous inflorescence,and the number of male and female flowers within polygamous inflorescence.It would be a very useful strategy of reproduction for J.curcas to produce a large number of polygamous inflorescences,for that it could ensure the female function strengthened,and the suitable function of male inflorescence and male flowers in polygamous inflorescences were probably more important than that of reproduction.The flora size and the environment of pollination of J.curcas were closely related,and a large amount of male flowers were very useful to attract pollinators.