Photosynthetic performance of Triticum aestivum L. in response to water and nitrogen deficit

Water and nitrogen deficits are key factors that affect the photosynthesis of wheat in arid and semi-arid areas. Two wheat (Triticum aestivum L.) cultivars were selected to study plant photosynthesis and signals, including nitric oxide (NO) and cytokinin (CTK), under water- and nitrogendeficient conditions. The results indicated that the photosynthetic performance (performance index, PI) as well as its component parameters decreased when wheat was subjected to water or nitrogen stress. P ET , the main component of decreased PI accounted for 64% of the reduction in PI of the general wheat variety under nitrogen stress. P TR was the main component of water and nitrogen cross-stress. The leaf signal density of iP+iPA, Z+ZR and NO decreased whereas that of DHZ+DHZR increased under water and nitrogen deficit, especially in the arid wheat variety. The decrease in P ET and P TR affected the transport of photosynthetic electrons as well as the fixation of CO 2 and showed close relationships with the levels of NO and CTK in plants.