Strategy Of Habitat Selection Of Clonal Plants In Heterogeneous Pb-contaminated Environments

The clonal plant is a large composition of the plant kingdom.Habitat selection behavior is the product of species interaction with the environment in the long evolutionary adaptation process.Previous studies suggest that clonal plants in heterogeneous environments can benefit from habitat selection,by which they can more efficiently use resources,overcome environmental stress,and improve their overall fitness.However,the habitat selection mechanism of clonal plants is still unclear.Toxic habitat selection in clonal plant research helps to reveal this mechanism.The study on clonal plant growth under the heterogeneous toxic environment could contribute to our full understanding of the mechanisms concerning the selective establishment patterns of clonal plants.In this study,a kind of clonal plant named Duchesnea indica growing in the heterogeneous Pb contaminated environment was examined.By conducting two types of experiments based on the understanding of “the effect of clone integration on the growth of D.indica in the Pb contaminated environment”,“the habitat selection strategy of clonal plants in the toxic environment of heterogeneous Pb pollution” was explored.During the experiments,through three different levels of pb contaminated(low,medium,high)levels and two heterogeneity(low and high heterogeneity)degrees under moderate contamination,the growth indexes(stolon length,the number of ramets,biomass and the flowering ratio)of D.indica in different growth periods and pb concentration of different organs belonging to mother/offspring ramets were compared and analysed.From the perspective of growth,labor division strategy,the ratio of sexual reproduction and asexual reproduction,and risk-spreading strategy,the model of the habitat selection of D.indica growing in the heterogeneous Pb contaminated environment was analyzed.The results showed that the integration was beneficial to the growth of D.indica in the heterogeneous Pb contaminated environment.In addition,the clones had optimal growth,which occurred in moderate Pb-contaminated environments,especially under higher heterogeneity.Besides,effective survival strategy appeared by expansive growth architecture,when they expanded its growth-pattern to escape from the toxic environment;more ramets rooted in the unpolluted patches;and there was more aboveground biomass;more Pb in the root accumulated;moreover,parent ramets transported their Pb in the soil to the offspring ramets,and then produced more ramets to share the toxic risk.Through these strategies,clonal plant D.indica in the heterogeneous Pb pollution environment,especially the high heterogeneity of habitat,finished the heterogeneous habitat selection which will help clone plants avoid unfavorable habitat patches,and obtain resources from favorable habitat patches,so as to improve its overall fitness.The results also suggest that D.indica can be adopted as an effective ecological restoration species in heterogeneous Pb contaminated habitats.