Photosynthetic Transpiration And Water Consumption Regularity Of Typical Desert Plants In Manas River Valley

Water is a key factor for plants’survival and grouwth in arid region. Desert plants drawwater from the soil to maintain water and nutrients transmitting in the body. Plant is a key linkin the SPAC system, while transpiration is an important way for plant to emit water. In thisconnection, this paper, adopting the theory of thermal diffusion stem flow meter technology,studies on the two kinds of typical desert plants in Manas river basin---Haloxylonammodendron and Tamarisk. It focuses on correlation between the water consumptionpattern in transpiration, sap flux of the tree, and meteorological factors, the relation betweenPhotosynthesis transpiration and environmental factors. Then, the paper establishes a modelof the relation between transpiration and surface evaporation, evaporation of reference crop.The main findings are as follows:Sap flux density of Haloxylon ammodendron and Tamarisk changes a lot between dayand night. Sap flux density is affected mainly by solar radiation, temperature, and air humidity.The average value of sap flux density of Haloxylon ammodendron and Tamarisk is ordered inthis way: sunny day after rain>sunny day before rain>rainy day. The branch size is partlydetermined by the transpiration in canopy. The determination coefficient is large（R20.857、 R20.719）.In the pit test and field test, PAR is the main decision variable of Haloxylonammodendron and Tamarisk. In field test, RH’s decision coefficient is negative, with a largeabsolute value; it is the main limiting variable. In these two tests, the average Trof theTamarisk is the largest in July. The daily average of WUE of Haloxylon ammodendron isbetween1.18and1.48, and that WUE of Tamarisk is about1.12.In pit test, the amounts of Haloxylon ammodendron’s sap flow in2012and2013arerespectively188mm and195mm. The figures of Tamarisk are97mm and103mm. In field testof2013, the amounts of Haloxylon ammodendron’s sap flux are122mm and91mm, theTamarisk’45mm and53mm. Overall, the fastigium of water consumption for Haloxylonammodendron and Tamarisk is June and July.There is a remarkable linear relation between the amount of reference crop’sevaporation(ET0) and water consumption in Haloxylon ammodendron’s transpiration(SF):ET00.4271.366SF, R20.7209;The relation between the amount of reference crop’sevaporation(ET0) and water consumption in Tamarisk’s transpiration(SF):ET00.4271.937SF, R20.7594.