Effects Of Botic And Abotic Stress On The Growth And Competition Of Invasive And Native Woody Plants

Biological invasion have great impact and damage on the composition and structure of the native plant community,ecosystem stability,social economy and human health.It is known as the three major issues in the global environment with the loss of habitats of animals and global climate change.The unrestrained and unreasonable production and life of humans during the anthropogene made extreme changes in the global climate.This also affected the level of various resource conditions within the environment,and changed the composition of plant species in the territory,and thus affected the invasiveness of habitats.At present,A large amount of researches were focused on the response of exotic clones herbaceous plants to the patchy and fluctuating nature of a single resource.However,it has not been reported whether stress environments(above-ground enemy,below-ground enemy,light,nutrient and water)had effects on the growth and competition of the invasion and native woody plants.The research is still insufficient about the response mechanisms of invasive woody plants to different stress environment(biotic and abiotic stress).In our study,we select 6 pairs,one pair of invasive and congeneric native woody plants for the greenhouse experiment.Experiment consists of three factors: species origin(invasion and native),stress types(aboveground enemy,belowground enemy,light,nutrient and water stress)and competition(inter-specific competition,invasive individual and native individual),a total of thirty six treatments were used to explore the effects of species origin,stress types,inter-specific competition and their interactions on the growth and competition of invasive alien and native woody plants.The results showed:1.Invasive alien woody plants had significantly higher biomass,leaf mass and stem mass than native congeneric woody plants.Biotic stress(aboveground and belowground enemy)had no significant effect on biomass of woody plants,and the growth of woody plant was mainly affected by abiotic stress(light,nutrient and water stress).inter-specific competition significantly decreased all biomass of invasive and native woody plants.Without competition treatment,there was no significant difference between invasive and native woody plants.However,the invasive woody plants were significantly larger thanthe native woody plants with competition treatment.It indicated that the adverse effects of competition on local woody plants were significantly higher than those of invasive woody plants.2.Invasive and native woody plants had different response mechanisms to different types of stress.In the environment of aboveground and belowground enemy,it was greater with competition than without competition treatments for the difference in leaf biomass between invasive and native woody.However,whether with competition or without competition,there was no difference between the invasive and native woody plants in control treatment.It was significantly less under resource conditions(light,nutrient and water stress)than the control treatment for the difference in leaf or stem biomass between invasive and native woody plants.3.Different biotic stress(light,water,and nutrient stress)had different effects on the content of N,P,and K in soil.The low light treatment promoted the accumulation of nitrogen in the soil.The water stress reduced the increment of total phosphorus content in the soil,and the reduction of soil nutrient was adverse to the accumulation of total potassium in the soil.Compared with competitor treatment,The increment of soil nitrogen was the lowest for invasive individual.Meanwhile,the increment of phosphorus in soil was the highest and was also affected by environmental stress.4.Invasive woody plants had significantly higher carbon and nitrogen content of leaves than native woody plants.The carbon and nitrogen content of leaves were significantly decreased in aboveground enemy and low nutrient treatment,while decreasing light intensity significantly increased the carbon and nitrogen content of the leaves.Meanwhile,invasive woody plants were significantly higher than native woody plants under control treatment.However,the carbon and nitrogen content of the woody plants were not significantly different in the aboveground natural enemy,light and water stress treatment.