光对入侵性植物黄顶菊种子萌发及植株生长的影响

入侵性杂草黄顶菊原产南美，2003年在我国河北省衡水湖首次报道。采用室内控制试验，对光与黄顶菊种子发芽及植株生长的关系进行了研究。结果表明：黄顶菊种子属光敏型，种子需要光刺激才能发芽。但其萌发对光强要求不严，1 000 lx光照强度30 ℃培养6、12 h和24 h转入暗培养，5 d后黄顶菊种子发芽率分别为67.0%、88.0%和95.8%。黄顶菊种子出苗与光照关系密切，播种在土壤表面、0.5 cm和1 cm深土层的种子出苗率分别为96.0%、8.0%和0。随光照强度减弱，植株的生物量及繁殖力显著降低。黄顶菊在35%自然光强下生长时其生物量、结实数比自然光强下分别降低55.0%和55.6%。上述结果为预测黄顶菊的适生区域及制订有效的防除策略提供了科学依据。

Effects of light on seed germination and plant growth of the invasive weed Flaveria bidentis

Flaverla bidentis is an invasive weed native to South America,which was firstly reported m Hengshui of Hebei Province in 2003.The effects of light on seed germination and plant growth of this weed were examined in the laboratory and greenhouses.F.bidentis has positively photoblastic seeds which need light stimulation in gerruination.Seed germination for 5d was 67.0%,88.0%and 95.8%,respectively,incubated at 1000 lx and 30℃for 6 h,12 h and 24 h before dark incubation.Seedling emergence Was 96%,8%and 0 at a depth of 0 cm,0.5 cm and 1 cm,respectively.Plant biomass and seed production decreased bv 55.0%and 55.6%,when F.bidentb was cultivatedin 35%full sunlight,compared with grown in full sunlight.The data gained from this study could help predict its potential spread area and facilitate the development of effective weed control programs.