The Relationship Between The Photosynthetic Characteristics And Environmental Factors Of Betula Platyphylla Suk. And Spiraea Pubescens Trucz. Etc On Daqing Mountain

In this paper, photosynthesis, stomatal conductance, transpiration rate, intercellular CO₂ concentration and chlorophyll fluorescence indexes of five tree species such as Betula platyphylla suk., Populus davidiana Dode., Quercus wutaishanica Blume., Spiraea pubescens Trucz., Cotoneaster acutifolius Turcz. under the soil water controlled in the room and the field natural conditions in Daqing Moutain were measured to study the relationship between photosynthesis and chlorophyll fluorescence characteristics and environmental factors, the main results are as follows:(1) The related analysis and stepwise regression analysis on the field photosynthetic rate and environmental factors pointed that the major environmental factors are light intensity and temperature, even in the same site conditions; the same environmental factors play the different role on species and environmental factors'influence on species with month difference.(2) The net photosynthetic rate, stomatal conductance, transpiration rate and NPQ and ETR of chlorophyll fluorescence indexes of the trees tested and light intensity relationships is a positive correlation, it can be simulated for the equation y=a+b(1-e^-kx), the chlorophyll fluorescence index Fv'/Fm' and qP and light intensity presents a negative correlation.(3) The relationship between photosynthetic rate of the tested trees and the soil moisture can be modeled as equation y=a+b(1-e^-kx). The soil moisture of Betula platyphylla suk., Quercus wutaishanica Blume., Spiraea pubescens Trucz. and Cotoneaster acutifolius Turcz. at the initial decline of photosynthetic rate are respectively 8.99%, 15.63%, 11.12% and 13.89%; the soil moisture compensation point of Quercus wutaishanica Blume., Spiraea pubescens Trucz., Cotoneaster acutifolius Turcz. and Betula platyphylla suk. photosynthesis are respectively 5.63%, 8.05%, 5.27% and 5.18%. The soil moisture at initial decline in Fv/Fm of chlorophyll fluorescence indexes: Spiraea pubescens Trucz.(7.11%)> Cotoneaster acutifolius Turcz.(5.43%)>Betula platyphylla suk.(5.03%)>Quercus wutaishanica Blume.(4.43%); that in Fv'/Fm': Cotoneaster acutifolius Turcz.(9.46%)>Spiraea pubescens Trucz.(8.10%)>Quercus wutaishanica Blume.(5.52%)>Betula platyphylla suk.(5.37%).(4) The soil moisture compensation point of photosynthesis and soil water content of at initial decline point of Fv / Fm and Fv '/ Fm' can be as the evaluation index of trees to adapt to the soil moisture, and the order of adaptation:of the tested trees to soil moisture stress is:Quercus wutaishanica Blume.(5.19%),Betula platyphylla suk.(5.20%),Cotonea- ster acutifolius Turcz.(6.72%) and Spiraea pubescens Trucz. (7.75%).