薇甘菊不同生长方式下的繁殖特征比较

Comparative Analysis of Growth Types and Reproductive Characteristics of Mikania micrantha

利用实验生态学方法,对攀缘生长与伏地生长的薇甘菊(Mikania micrantha)的形态特征、生物量分配和繁殖特征进行了比较研究。结果表明:在潮湿生境条件下,攀缘生长的植株与伏地生长的植株相比对主茎的生物量投资较大,而对分枝茎的生物量投资则相对较小;但在干旱生境条件下,攀缘生长的植株对主茎和分枝茎的生物量投资均较伏地生长的植株小。在潮湿与干旱生境中,攀缘植株的繁殖投资分别为0.429g·g-1和0.342g·g-1,显著高于相同生境中的伏地植株。在薇甘菊种群的补充与更新过程中,攀缘生长的植株以有性生殖占主导地位,在潮湿与干旱生境中产生的个体分别占种群数量的84.7%和62.6%;伏地生长的植株则主要以无性(克隆)繁殖为主,在潮湿与干旱生境中有性生殖产生的个体仅占种群数量的40.4%和35.9%。生长方式与土壤水分二因子互作效应对薇甘菊的生物量分配和繁殖指标影响均达到显著水平(P<0.05)。通过研究得出以下结论:不同生长方式的薇甘菊对环境条件具有不同的生长与繁殖适应对策。

Mikania micrantha is a highly invasive plant species in tropical and subtropical regions. To analyze the adaptability and plasticity of climbing and prostrating M. micrantha plants, we here performed field experiments on morphological characteristics, biomass allocation and reproduction of growth patterns under different environmental moisture conditions. Under moist conditions, climbing plants showed more biomass in the main stem and less in the branches than did prostrating plants. Under dry conditions, climbing plants invested less biomass in the main stem and branch than did prostrating plants. Under both wet and dry conditions, climbing plants had a reproductive investment of 0.429 and 0.342 g·g–1, respectively, which was significantly higher than that of prostrating plants under the same conditions. Sexual reproduction was the most important approach for climbing plants to produce offspring, which in wet and dry habitats accounted for 84.7% and 62.6%, respectively, of the population. Prostrating plants relied mainly on asexual reproduction to increase their population, with only 40.4% and 35.9% of the population produced by sexual reproduction in wet and dry habitats, respectively. Growth patterns and soil moisture had a significant impact on the biomass and reproduction allocation in plants. Climbing and prostrating M. micrantha plants use different reproductive strategies to adapt to environmental moisture conditions.