Effects Of Different Soil Water And Light Intensity On The Growth And Photosynthetic Characteristics Of Galinsoga Parviflora And Acalypha Australis L.

Galinsoga parviflora and Acalypha australis L.were materials for this experiment.Setting80%soil moisture (HW),60%soil moisture (MW) and40%soil moisture (LW) tomeasure the effects of soil moisture on growth and photosynthetic characteristics ofGalinsoga parviflora and Acalypha australis L..Selecting two plots in different lightintensities of Shenyang University and carrying out the test for once a week. Thisexperiment needed five times testing to measure the effects of light intensity on growth andphotosynthetic characteristics of Galinsoga parviflora and Acalypha australis L.. Setdifferent drought gradients by use of polyethylene glycol6000and measure Galinsogaparviflora physiological indicators in drought environment. They are MDA, Solubleprotein, Superoxide dismutase activity and Peroxidase activity. This test was based onprevious studies of Galinsoga parviflora. It studied growth and photosyntheticcharacteristics from the responses of physiological growth, photosynthesis and chlorophyllfluorescence to the soil water and light intensity. The purpose of the test was to predictGalinsoga parviflora potential distributions and provide a scientific basis for the effectivemanagement of invasive species.The main results were as follows:120%PEG concentration was the limit of drought resistance for Galinsoga parviflora.MDA and antioxidant activity would decrease if the PEG concentration continues toincrease.2Vegetative organs of Galinsoga parviflora had morphological plasticity with thedecrease of soil water. Stems and leaves of Galinsoga parviflora got more Nutrients. Thebiomass reduced and leaf area increased the effective photosynthetic of Acalypha australisL.3The stomatal conductance, transpiration rate, net photosynthetic rate of Galinsogaparviflora were downward trends with the decrease of soil water. The diurnal variationcurves were changeable with the soil water change. 4The stomatal conductance iron amaranth, intercellular CO2concentration andtranspiration rate of Acalypha australis L. were increasing first and decreased then with thedecrease of soil water. The diurnal variation laws of Acalypha australis L. were in contrastwith Galinsoga parviflora’s.5The chlorophyll contents were downward trends and the carotenoid contents wererising trend of Acalypha australis L.with the decrease of soil water. Acalypha australis L.educed energy use in photosynthesis with the decrease of soil water.6The Nutrients were allocated from roots to stems with the decrease of light intensity.This showed that Galinsoga parviflora had morphological plasticity.7Native species Acalypha australis L. had a growth advantage. The ability of usingresources was low compared to the invasive species Galinsoga parviflora with thedecrease of light intensity.8The negative resistance, resistance of low light and maximum net photosyntheticrate decreased with the decrease of light intensity. The ability of esistance to strong lightenhanced with the decrease of light intensity.The effects of light intensity decrease on thediurnal variation were little. Stomatal conductance, transpiration rate and netphotosynthetic rates under strong light were higher than it under the low light forGalinsoga parviflora. The cell CO2concentration under strong light was less than it underthe low light for Galinsoga parviflora.9The negative resistance of Acalypha australis L. increased with the decrease of lightintensity. The ability of resistance to strong light and low light reduced with the decreaseof light intensity. The maximum net photosynthetic rate reduced with the decrease of lightintensity. The net photosynthesis under low light showed plasticity in the afternoon forAcalypha australis L.. Stomatal conductance, transpiration rate and net photosyntheticrates under strong light were higher than it under the low light for Acalypha australis L..The cell CO2concentration under strong light was higher than it under the low light forAcalypha australis L..