Experimental Research On Effect Of Winter Wheat Physiological And Ecological Characteristics Under Different Soil Moisture

we designed five different degrees of drought stress though plot culture winter wheat in rainproof installations, which were45%,55%,65%,70%and80%in this experiment. Determination of growth and eco-physiological indices of winter wheat. The research shows the results as follows:(1) As the moisture stress is increased, winter wheat growth season be shorted, the leaf area index, leaf dry weight, spike dry weight, grain number per spike,1000-grain weight and yield etc. decreased, sterility spike number increased. Meanwhile, net photosynthesis (Pn), stomatal conductance(Gs), transpiration(Tr) and leaf water potential(LWP) etc. decreased. Diurnal variation of net photosynthesis (Pn) and transpiration(Tr) which under condition of water enough(Tl and T2) has no "midday depression" phenomenon; Indices of winter wheat also differences at different growth stages. Drought stress also makes maximum net photosynthetic rate(Pnmax), LCP, LSP decreased. Differences between the various indicators of winter wheat under different water treatments became clear as the water stress time.(2) With increasing irrigation volume, the average and maximum canopy temperature showing a downward trend for each treatment. Correlation analysis showed that canopy temperature and air saturation deficit was very significant positive correlation in heading stage of the winter wheat(p<0.01), and in the flowering stage, canopy temperature and leaf water potential was significant negative correlation (p<0.05), canopy temperature and air saturation deficit was very significant positive correlation, air saturation deficit and transpiration rate was significant negative correlation, canopy temperature and water use efficiency was significant positive correlation. To sum up, in wheat heading and flowering stage, canopy temperature can be used as one of the effective indexes to monitoring water status of crops. (3) Analyzed the relationship between stomatal conductance (Gs), photosynthetic rate(Pn) and related meteorological environmental factors, and introduced soil moisture factor to modify stomatal conductance model and photosynthesis rate model. The results showed, the models have better explanatory capability if the they considered the soil moisture factor, correlation coefficients between actual values and the simulating ones increased to0.967and0.987from0.907and0.769, while the correlation coefficients between actual values and predictive values the simulating ones increased to0.768and0.874from0.572and0.316, but also the corresponding root mean squared error (RMSE) decreased significantly. So, soil moisture is so important in regulating stomatal conductance and photosynthetic rate, the effect of it cannot be neglected in stomatal conductance and photosynthesis rate models building.