The gas exchange characteristics of A.ordosica and C.korshinskii grown on Shaptou artificial stabilized dunes,was studied under natural conditions by using a portable Li 6200 gas analysis system.The results indicated that the diurnal courses of photosynthetic rate in A.ordosica and C.korshinskii displayed significantly less symmetrical two peak pattern,with a predominant morning peak on hot,bright sunny day.The diurnal course of stomatal conductance exhibited also a similar diurnal course ...