土壤含水量对外来入侵杂草黄顶菊生长发育的影响

Influence of Soil Water Content on Growth and Development of Invading Exotic Weed Flavera bidentis

以外来入侵杂草黄顶菊为研究对象,研究不同土壤含水量对其生长发育的影响。结果表明,武汉市是黄顶菊潜在的入侵区域,在该地区完成整个生育期的时间为5～6个月。黄顶菊在土壤含水量15%～60%的条件下均能出苗、生长,其中25%～35%的土壤含水量最适合黄顶菊的出苗及生长。经淹水70d后黄顶菊仍能出苗,表明黄顶菊有可能入侵水田,但在该条件下黄顶菊的长势较弱,生物量及繁殖量明显降低。黄顶菊具有很强的繁殖能力,单株种子量最高可达5万粒以上。种子量大、出苗率高及其对各种生态环境的良好适应性是黄顶菊成功入侵并迅速扩散的主要原因。

The invading exotic weed Flavera bidentis（L.） Kuntza was used to study the effects of soil water content on its growth. The results suggested that F. bidentis undergo its whole growth for 5 to 6 months in Wuhan as the potential invasion region. During this period, soil water content affected the emergence and further upgrowth. F. bidentis emerged and growed when soil water content reached between 15% and 60%, while the optimum condition was 25%~35%. The fact that F. bidentis could emergent even after the seeds were submerged for 70 days, indicated that the weeds could invade irrigated field with lower growth vigour. Naturally, the maximum seed amount of individual plant was over 50 thousands. In brief, rapid invasion of this weed can be attributed to its large amout of seeds, high emergence ratio and suitability in different environments.