环境因素对薇甘菊开花结实影响初探

2001—2002年度在广东东莞市选取不同的自然小生境，研究土壤肥力、土壤水分和生境郁闭度对薇甘菊(Mikania micrantha H．B．K)开花结实的影响，结果表明：土壤肥力较高，花数较多，花期较长，结实率较高，种子千粒重较大；但土壤肥力过高，虽然种子千粒重大，花期长，但花数少，结实率低。在开阔的生境中，薇甘菊花数多，花期长；在林荫处花期短，花数少，但种子千粒重反而有所升高；植株在郁闭度为10％-20％的生境中结实率最高，高于20％或低于10％结实率均有所降低，过强或过弱的光照均不利于结实。土壤湿度虽然对种子千粒重无明显影响，但对薇甘菊花数、花期和结实率的影响显著，土壤湿度大，花数多，结实率高，花期长。在自然生境中，三种因素的影响既相对独立又相互制约。

An Investigation of the Effects of Environmental Factors on the Flowering and Seed Setting of Mikania micrantha H.B.K (Compositae)

The effects of soil fertility,soil moisture content and shade density on flowering and seed setting of Mikania microtha were investigated at different habitats in Dongguan City,Guangdong Province,during2001to2002.The plants growing on less fertile soil caused fewer flowers,lower seed setting percentage,less1000-grain weight and shorter flowering duration than those on more fertile soil.However,over-fertile soil also resulted in fewer flowers and low seed setting percentage.The plants growing in open habitat had more flowers with longer flowering duration,whereas under shade the1000-grain weight was shown to have a slight increase.The seed setting percentage was highest at10%-20%of shade density.Moist soil had no significant effect on1000-grain weight,but obviously led to more flowers,high seed setting percentage and longer flowering duration.