Abstract:To clarify the effect of stoichiometric of soil available nitrogen (N) and phosphorus (P) on the photosynthetic characteristic of wheat, we conducted a pot experiment with 16 different NP levels to examine the characteristic of photosynthetic gas exchange and fluorescence parameters of ‘Zhenmai168’ in response to different NP treatments. Our results showed that: (1) The chlorophyll content of the wheat leaves increased with an increase of soil available N and P. (2) Photosynthesis (Pn) exhibited a continuously increasing trend with decline of soil N/P ratio under the condition that soil available N was less than 258.4 mg·kg-1. In contrast, photosynthesis (Pn) firstly showed an increasing trend and then decreased under higher N level with 308.4 mg·kg-1. (3) F0, Fm, qP and ΦPSⅡ values of wheat increased 7.27%-20.00%, 5.28%-16.15%, 6.64%-20.92% and 6.95%-18.82%, respectively, and NPQ value decreased 7.42%-25.63% under decline of soil N/P treatments with the same level of available N. Our results suggested that both of Pn and ΦPSⅡ of Zhenmai168 reached the highest level and showed strong light energy use efficiency under higher NP level condition with 2.88 value of N∶P ratio.