Contrasting winter wheat cultivars, salt-tolerant DK961 and intolerant JN17, which sown in no salinity (-S) and salinity (+S) boxes were exposed to charcoal filtered air (CF) and elevated O3 (+O3) in open top chambers (OTCs) for 30 days. In-S DK961 and JN17 plants,+O3 DK961 and JN17 plants had significantly lower light-saturated net photosynthetic rates (Asat, 26% and 24%), stomatal conductance (gs, 20% and 32%) and chlorophyll contents (10% and 21%), while O3 considerably increased foliar electrolyte leakage (13% and 39%), malondialdehyde content (9% and 23%), POD activity and ABA content. However, responses of these parameters to O3 were significant in DK961 but not in JN17 in+S treatment. Correlation coefficient of DK961 reached significance level of 0.01, but it was not significant in JN17 under interaction of O3 and salinity. O3-induced reductions were larger in shoot than in root in both cultivars. Results indicate that the salt-tolerant cultivar sustained less damage from salinity than did the intolerant cultivar but was severely injured by O3 under+S condition. Therefore, selecting for greater salt tolerance may not lead to the expected gains in yield in areas of moderate (100mM) salinity when O3 is present in high concentrations. In contrast, salinity-induced stomatal closure effectively reduced sensitivity to O3 in the salt-intolerant cultivar. Hence we suggest salt-tolerant winter wheat cultivars might be well adapted to areas of high (>100mM) salinity and O3 stress, while intolerant cultivars might be adaptable to areas of mild/moderate salinity but high O3 pollution.
Bibliographical noteFunding Information:
We thank Dr. Hua Su for her help on artworks. Financial supports by the State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau ( 10501-263 ), the State Key Laboratory of Crop Biology at Shandong Agricultural University of China ( 2010KF08 ) and the National Science Foundation of China ( 30900200 and 31170367 ) are gratefully acknowledged.
- Abscisic acid
- Antioxidant enzyme
- Gas exchange
- Triticum aestivum L