海拔对入侵植物粗毛牛膝菊种群繁殖力与种子扩散力的影响  

Effects of elevational gradients on reproductivity and seed dispersal ability of Galinsoga quadriradiata in mountain ranges

作　　者：陈晓艳 张文刚 刘芮伶 刘刚[1] CHEN Xiaoyan;ZHANG Wengang;LIU Ruiling;LIU Gang(College of Life Sciences,Shaanxi Normal University,Xi'an 710119,China)

机构地区：[1]陕西师范大学生命科学学院,西安710119

出　　处：《生态科学》2022年第3期44-53,共10页Ecological Science

基　　金：国家自然科学基金(31600445);陕西省自然科学基础研究计划(2020JM-286);中央高校项目(GK201703036,2019CSLY019和2020CSLY014)。

摘　　要：外来入侵植物在高大山体中沿着海拔扩散的过程中,由于环境选择压力的改变,其繁殖力和种子扩散力可能会发生改变。为探究入侵植物粗毛牛膝菊(Galinsoga quadriradiata)在秦巴山区扩散过程中的繁殖力和种子传播力的变化趋势,通过野外调查对比分析了其位于不同海拔梯度(505—1947 m)上的种群密度、盖度、单株种子产量和种子羽流载荷(MAR)等的差异,并对比分析了不同生境类型中的粗毛牛膝菊种群繁殖特性上的差异。研究结果显示:(1)粗毛牛膝菊的种群盖度和密度随海拔升高均未表现出显著的变化趋势;(2)单个花序成熟种子数随海拔升高而增加,但单株花序数、单株种子产量(数量和重量)均随海拔升高而降低;(3)种子MAR随海拔升高而显著升高,即种子传播力呈显著下降趋势;(4)相较于荒地生境中的种群,农田中的粗毛牛膝菊种群盖度和单株种子重量更高,且MAR更小。研究结果说明随着海拔升高,粗毛牛膝菊繁殖力和种子传播力均呈显著下降趋势,农田中的粗毛牛膝菊种群繁殖力和种子传播力均显著高于荒地中的种群,这暗示了秦巴山地在降低该物种的入侵扩散速度方面具有重要意义,但农业生产活动带来的人为干扰可能会促进该种的入侵与扩散进程。Due to changes on natural selection pressure, the reproductive capacity and seed dispersal ability of invasive plants would change along elevational gradients during their expansion in mountain ranges. To test the changing pattern of these traits of invasive plant Galinsoga quadriradiata, we conducted a field survey on the elevational populations of G.quadriradiata(505-1947m) in Qinling-Bashan Mountains. We compared the differences on population coverage, density,seed production per plant, and the mass-area ratio(MAR) of seeds among these elevational populations. In addition, the growth and reproduction traits of G. quadriradiata in different habitats(farmland and uncultivated land) were also compared.The results showed that:(1) the population coverage and density of G. quadriradiata did not change significantly with increasing altitude.(2) The number of seeds per inflorescence increased while the number of inflorescences per plant and the seed production(quantity and mass) per plant decreased with increasing altitude.(3) The MAR of G. quadriradiata seed increased significantly with increasing altitude, which suggested a decreased seed dispersal ability of G. quadriradiata along elevation.(4) Compared to the populations in uncultivated land, populations of G. quadriradiata in farmland had higher coverage, higher seed biomass per plant and smaller mass-area ratio. All in all, our results suggested that the reproductive capacity and the seed dispersal potential of G. quadriradiata decreased significantly with increasing altitude in Qinling-Bashan Mountains. Moreover, G. quadriradiata in farmland had higher reproductive capacity and the seed dispersal ability than those in uncultivated land. It suggests that the Qinling–Bashan Mountains play an important role in reducing the dispersal rate of G. quadriradiata, however, agricultural activities can promote its invasion and expansion process.

关 键 词：入侵植物 粗毛牛膝菊 秦巴山区 种子扩散力 海拔梯度 

分 类 号：Q948.1[生物学—植物学]