紫茎泽兰营养生长和抗虫性的海拔差异研究

通过同质种植园试验测定了昆明西山山顶和山脚紫茎泽兰的生长参数和叶片碳水化合物、蛋白质的物质含量,并测定了山顶和山脚紫茎泽兰对广食性昆虫斜纹夜蛾的抗虫性。结果表明,紫茎泽兰的比叶面积、叶干物质含量和叶片氮含量在山顶和山脚之间差异不显著,但山顶的株高、叶面积、叶片干重和抗虫性均显著低于山脚,而叶片的碳氮比山顶显著大于山脚,表现出明显的遗传分化。株高、叶面积和叶片干重减小表明植物的营养生长减弱,竞争力降低,植物可利用的总资源降低;抗虫性降低表明植物用于防御的资源减小;而碳氮比升高表明植物用于产生种子的资源增加。由此推测山顶紫茎泽兰通过调节资源分配模式来提高有性繁殖的相对资源投入,最终实现种群繁殖的最大化,所以对山顶紫茎泽兰的治理不容忽视。

Variation of Vegetative Growth and Insect Resistance in Populations of Eupatorium adenophorum from Different Altitudes

Eupatorium adenophorum populations from the top and the foot of Kumming Xishan, China, were planted in a field common-garden in Wuhan. The growth parameters, as well as leaf material content （carbon and protein） were compared between the two populations. The plant resistance to tobacco caterpillar Prodenia litura （Lepidoptera： Noetuidae） was also tested. The results showed that specific leaf area, leaf dry matter content and leaf nitrogen content did not differ significantly between the two populations of the top and the foot, but plant height, leaf are- a, leaf dry mass and plant resistance to insect were significantly lower population of the top than population of the foot, and the C： N of leaves in the population of the top was significantly higher than that in the population of the foot, showing genetic differentiation. Low plant height, leaf ar- ea and leaf dry mass mean low competitiveness of a resource, weak vegetative growth and decreased total resources;low plant resistance to insect means that less resources were allocated to defense ;the increased C： N shows that the plant use more resources to produce seeds. Therefore, we conclude that the E. adenophorum population of the top has weak vegetative growth but it realized maximum reproduction through adjusting re- source allocation strategy. Thus, the controlling of the population on the mountain top cannot be ignored.