科尔沁沙地4种生境少花蒺藜草表型特征和生物量分配

Phenotypic characteristics and biomass allocation of Cenchrus pauciflorus in four different habitats in Horqin Sandy Land

少花蒺藜草(Cenchrus pauciflorus)是我国北方主要的入侵物种之一,内蒙古西辽河平原的科尔沁沙地是其入侵的重灾区,近年来呈逐步扩散趋势,对当地农牧业生产的发展具有深远的影响。本研究以科尔沁沙地沙丘、草地、林地和农田4种生境中的少花蒺藜草为研究对象,通过对少花蒺藜草表型性状分析比较,探讨了其表型特征和生物量分配对生境的响应,有助于全面认识少花蒺藜草的形态学和生物学特征,对揭示科尔沁沙地少花蒺藜草的入侵机制具有一定的科学意义,同时亦能为其相关生态防控技术的研发提供一定的理论依据。结果表明:1)生境对少花蒺藜草表型性状有显著影响,其表型可塑性较高,4种生境所有表型从大到小依次为农田>沙丘>林地>草地。2)同一表型的变异系数在不同生境中无显著差异(P>0.05),但相同生境不同表型间差异显著(P<0.05)。3)生境对生物量分配有显著影响(P<0.05),4种生境中,农田生境的茎叶比最高,而根冠比和刺苞比最低。4)生境对根冠比的变异系数没有影响(P>0.05),但对茎叶比和刺苞比有显著影响(P<0.05)。少花蒺藜草通过调整表型和生物量分配策略适应不同的生境条件,其营养性状、克隆性状、生殖性状和生物量分配都具有一定的可塑性。胁迫、干扰和繁殖体质量的差异很可能是不同生境少花蒺藜草表型差异和变异的重要因素。

Cenchrus pauciflorus is one of the main invasive species in northern China,and Horqin Sandy Land is the most severely invaded region in the West Liaohe Plain of Inner Mongolia.It has had a steady spread trend in recent years and a profound impact on the development of local agriculture and animal husbandry.In this study,the phenotypic characteristics and biomass allocation of C.pauciflorus in different habitats of Horqin Sandy Land were explored.The phenotypic characteristics of C.pauciflorus in four habitats were analyzed and compared.In addition,the response of the phenotypic characteristics and material distribution of C.pauciflorus to these habitat were discussed to comprehensively elucidate the morphological and biological characteristics of C.pauciflorus in Horqin Sandy Land and reveal the scientific significance of the invasion mechanism of C.pauciflorus in Horqin Sandy Land.The results of this study can provide a theoretical basis for the research and development of the related ecological prevention and control technologies for C.pauciflorus.Our findings were as follows:1)habitat had a significant effect on the selected phenotypic variables of C.pauciflorus,and the order of all the phenotypic variables in the four habitats from large to small was:field,sand dune,forestland and grassland,respectively.2)The coefficient of variation of the same phenotype showed no significant differences among the four habitat populations;however,the same habitat showed significant differences among the different phenotypes.3)The biomass allocation of C.pauciflorus was significantly affected by the habitat.In the farmland habitat,the ratio of stem to leaf of C.pauciflorus was significantly higher than that in other habitats;however,the ratio of root to shoot and the proportion of spiny burs to the whole plant were significantly lower than those in other habitats.4)Habitat had no significant effect on the variation of root to shoot but had a significant effect on the variation of stem to leaf and spiny burs to the whole plant.Cenchrus pauciflorus adapts to different habitats by adjusting its phenotype and biomass allocation strategies,and its nutritional traits,clonal traits,reproductive traits,and biomass allocation have habitat plasticity.Stress,disturbance,and propagule quality differences may be the cause of the phenotypic difference and variation of C.pauciflorus in different habitats.