部分砍伐干扰下麻疯树繁殖特征的研究

Changes on Propagation Characteristics of Jatropha curcas under Continuing Cutting-off

麻疯树(Jatropha curcas L.)是西南干热河谷地区重要的生物柴油树种.实验以云南元江干热河谷生境相同的两个居群麻疯树(部分砍伐干扰与未砍伐)为研究对象,对麻疯树从花期到果期的繁殖特征,包括分枝数、花枝数、开花频次、单花序雌雄花数量以及结实量进行调查,分析砍伐干扰可能对麻疯树的有性繁殖产生影响.结果表明:砍伐干扰居群麻疯树的部分繁殖特征,包括花枝分化率,开花频度,以及结实量显著低于未砍伐居群;而雌花生物量、雄花生物量、单花序雌花数目、单花序雄花数目与雌雄性比等繁殖特征则砍伐居群与未砍伐居群无明显差异.麻疯树受砍伐干扰时,其营养生长与生殖生长过程是一个动态平衡的过程,并通过调整部分繁殖特征来适应外界干扰;而麻疯树在雌雄花生物量、雌雄性比、单花序雌雄花数目等性别分配间的资源分配特征相对稳定,受砍伐干扰影响较小.

Jatropha curcas is an important bio-diesel tree planted in hot-adrid river valley in southern China and often being cut off by local residents.Cutting-off of J.curcas might influence its sexual propagation strategy such as trade-off between male and female investment,and so on.In Yuanjiang Hot-dry River Valley,two populations of J.curcas under different treatments were selected to make our study （one being cut off one third of its branches annually,the other never being cut off）.Following features were investigated,including total vegetativebranches,flowering branches,flowering frequency,female and male flowers number per inflorescence,and fruits yield.Results showed that some propagation features decreased significantly after being cut-off,including flowering branches differentiation rate,blooming frequency,flower biomass and fruit output.However,other propagation features,including sex ratio of female to male flower,female number per inflorescence,fruit-setting rate,didn＇t show significant difference between two populations.It implied a dynamic balance strategy occur between vegetative growth and some propagation growth for J.curcas under cutting-off stress caused by local residents.However,other propagation characteristics such as sex ratio is relatively consistent to enviromental change.