Objective We aimed to understand the seasonal dynamics of leaf water use efficiency and its response to environmental factors in Artemisia ordosica, a typical sandy plant in the semi-arid ecosystem of northwestern China for the purpose of ecosystem process modeling.
Method The leaf stomatal conductance (gs), net photosynthetic rate (Pn) and transpiration (E) of Artemisia ordosica were measured using Li-6 400 portable photosynthetic analyzer from May to September, 2018. Water use efficiency (WUE, WUE = Pn / E) was analyzed in relation to soil water content (SWC), saturated water vapor pressure deficit (VPD1), photosynthetically active radiation (PAR) and leaf surface temperature (Tl).
Result The gs, Pn, E and WUE were more sensitive to VPD1 when SWC ≤ 0.08 m3/m3. When SWC > 0.08 m3/m3, the gs, Pn, E and WUE were more sensitive to the response of PAR and Tl.
Conclusion The results of this study further prove that Artemisia ordosica acclimates to drought conditions through changing gs and relative magnitude of Pn and E, and thus changing WUE. And WUE is lower during drought, indicating that soil drought stress restricts leaf photosynthesis and WUE. It is concluded that Artemisia ordosica acclimats to dry environmental conditions through conservative strategy of water resource.