Photosynthesis, transpiration, and water use efficiency of Leymus dasystachys on the Hunshandake desert

Abstract

Net photosynthetic rate (P N), transpiration rate (E), and stomatal conductance (g s) declined from upper leaves to the lower ones during dry and rainy seasons, indicating that long-term carbon budget should take into account P N variations for different leaf types. Relatively greater P N in the dry season suggested that this species is more able to maintain higher P N under drought, but the relatively higher E in the dry season might reduce water use efficiency (P N/E) for the species. Significant correlations between P N and g s indicated that g s may be the critical factor for P N variability in the desert region.