A Study On Water Consumption Of Natural Ulmus Pumila And The Respons To The Environment Affecting Transpiration And Photosynthetic Rate In Otinday Sandland

Owing to the effects of changing climate and human activities, grassland desertification is becoming more and more serious. Otindag Sandy land is one of the most serious desertification regions in Inner Mongolia. Natural plant communities must be protected and conserved to resume the desertification land productivity, maintain the ecological balance. Natural Ulmus pumila is the main vegetation form, plays an important role in the dispersion of surface wind momentum to reduce dust and air flow passing between the terms in Otindag Sandyland. Water is the key factor for maintaining the existence of sandy Ulmus pumila, Ulmus pumila transpiration needs to lose a lot of water. There are complicated relationships among the process of water consumption and influencing factors, which interacts with each other. while there is some connection with the photo synthetic process. Therefore, this paper based on multiple source model to simulate evapotranspiration of the Ulmus pumila at growth periods, analyze Ulmus pumila photosynthesis rate and transpiration rate responding the impact factors. Using it as a basis to study the relationship and mechanism between transpiration and photosynthesis, aiming to provide a theoretical for the study of plant low consumption and high photosynthetic. The main results are:According to principle of energy balance, multiple source model was constructed to estimate vegetation water consumption based on K-theory. This model was used to simulate Ulmus pumila transpiration, bare soil evaporation and soil evaporation under vegetation cover in the growth period, The results reflect the change of them in different growth period.This paper verified multiple source model had good simulation results from the perspective of qualitative and quantitative, using fitting correlation method, regression analysis and residual estimation error indication.Based on a variety methods, analyzed the respons to the factors affecting transpiration and photosynthetic from a different point of view. The effect factors of diurnal variation of Ulmus pumila transpiration rate and photosynthetic rate are slightly different,but they are affected by interaction factors.Based on the relationship between photosynthesis rate and transpiration rate and its influencing factors, the analysis shows that transpiration-photosynthesis has a good linear coupling relationship,Synthetic regulation of photosynthetically active radiation, temperature and stomatal conductance for transpiration and photosynthesis becomes the basic of a linear coupling of transpiration and photosynthesis.