Ecological Safety Of Glechoma Hederacea In China

In Shanghai and the surrounding areas,the introduced plant Glechoma hederacea which has strong propagation interested us.The focuses on the G.hederacea were about the asexual reproduction behavior,the structure morphology,physiology and so on,while the ecology safety of G.hederacea entering a new region studies little.This dissertation focuses on the ecological safety of G.hederacea in China.To find whether the introduced species G.hederacea would become an invasive plant in China or not,we make three kinds of experiments.The native species Glechoma longituba which is the same family and same genus with G.hederacea was studied in every experiment as the control.The first kind experiment includes three kinds of ecological factors:the water,the light and the soil nutrient.Each ecological factor was designed as three grades to study the phenotypic plasticity of G.hederacea and G.longituba.Some time as a period,recorded some morphological parameters of caulis and branches in each ecological factor experiment.The results of water experiment show that the G. longituba has better plasticity than the G.hederacea.The results of soil nutrient experiment are that G.longituba shows good plasticity in both the vegetative growth and the vegetative propagation while G.hederacea just show good plasticity in the vegetative propagation not in the vegetative growth.The results of light intensity experiment are that G.longituba shows little plasticity in the vegetative growth and the vegetative propagation while G.hederacea shows good plasticity in vegetative propagation and little plasticity in vegetative growth.The second kind experiment is about the competition between the G.hederacea and G. longituba.The competition experiment includes two.One is that the G.hederacea was planted among the G.longituba and the other is reverse which did like that the G. longituba was planted among the G.hederacea.Some time as a period,recorded some morphological parameters of two species caulis and branches.After the harvesting,recorded the dry weight of roots,stolons and leaves.The results show the G.longituba is more competitive than the G.hederacea.The third kind experiment is to measure the change of soil nutrients of the plots where the G.hederacea and the G.longituba were planted in.Two months later,took some soil from the plots where the G.hederacea and the G.longituba were growing then measured four indexes of the soil:pH,pools of soil nitrogen(N),extractable inorganic nitrogen including NH₄-N and NO₃-N.After recording the morphological parameters of two species caulis and branches,harvested them.Divided the roots,the stolons and the leaves then cleaned every part.Dried every part for 80℃until every part was dry completely.The four soil indexes show two plants just changed the soil a little.The reducing of inorganic nitrogen is mainly because of two plants growing and absorbing. They absorbed the inorganic nitrogen.However,the G.longituba absorbed the inorganic nitrogen more than G.hederacea did,which is corresponding with two plants morphological differences.The soil nutrient experiments show the G.longituba is able to extract more nutrients from soil to promote its growing then it could take possession of more space while G.hederacea is unable.With the results of three kinds of experiments,it is concluded that the native plant G. longituba is more competitive than the introduced plant G.hederacea.It is preliminarily believed that the G.hederacea has little severe invasive ability.