The studies about the photosynthetic response of the four desert plants

Populus euphratica Oliv.、Alhagi sparsifolia B.Keller et Shap.、Tamarix ramosissima Lbd. and Calligonum caput-medusae Schrenk., are all constructive plants in Taklamaka Desert. Responses of photosynthetic parameters of the four desert plants to changes light intensity and CO2 concentration were studied, the results are as follows:①Among the four plants, A. sparsifolia has the highest photorespiration rate (Rp) and CO2 compensation point(Γ), and it has the lowest maximal net assimilation rate(Am) and water use efficiency (WUE) in irradiance responses. On the contrary, as a C4 plant, C.caput-medusa has a lower Rp and Γ,and a significantly higher An, light compensation point(LCP) and light saturation point(LSP) than those of the other plants(P≤0.05), it also had the highest WUE owed much to its very low transpiration rate(E).②According to their LCP and respiration in dark(Rd), we arranged them from sunny to less: C.caput-medusa, A. sparsifolia,T. ramosissima, P. euphratica. And our results also favored the view that relative shade-tolerant plants have higher An in weak light environment than those sun ones.③Further studies are expected to be done on if T. ramosissima has a narrow temperature niche or less stomata sensitivity to irradiance than the other plants. ④Having present a striking contrast between the previously reported results and ours, we suggest P.populus could be inducible for some C4-like characteristics in some special environments, growth stages or under some special treatments.