Effects of Irrigations on Photosynthetic Characteristic and Water Use Efficiency of Calligonum mongolicum and Hedysarum scoparium
Field experiment on the photosynthetic characteristic and water use efficiency of two kinds of desert shrubs was carried out under different irrigation amounts.The results showed that:(1) with increasing irrigation amounts,the photosynthetic rate of Calligonum mongolicum and Hedysarum scoparium increased,whereas the transpiration rate(Tr),stomata conductance(Gs) and intercellular CO2 concentration (Ci) did not alter notably.(2) the irrigation increased the predawn and midday water potential of the C.mongolicum,and only the midday water potential had a notable difference under the conditions between the irrigation and no irrigation(p<0.05),while only the midday water potential of the H.scoparium increased with increasing irrigation,and the difference between the sufficient irrigation and no irrigation is only distinct(p<0.05).(3) the δ13C did has little change under the conditions between the different irrigation conditions,the δ13 C average value of C.mongolicum was-12.267,-12.147 and-11.958 respectively in the no irrigation,moderate irrigation and sufficient irrigation,while the δ13C average value of H.scoparium was-27.928、-28.068、-27.166,respectively.(4) the water use efficiency of no irrigation of C.mongolicum and H.scoparium was obviously higher than that of the irrigation.Moreover,one time irrigation did not alter their water use efficiency.
irrigationCalligonum mongolicumHedysarum scopariumphotosynthetic characteristicwater use efficiency