Photosynthetic and yield responses of an old and a modern winter wheat cultivars to short-term ozone exposure

• Published in: Photosynthetica Vol. 47; no. 2; pp. 247 - 254
• Main Authors: Xu, H, Chen, S.-B, Biswas, D.K, Li, Y.-G, Jiang, G.-M
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01-06-2009; Springer Netherlands
• Subjects: air pollution; Biomedical and Life Sciences; gas exchange; Life Sciences; Original Paper; Plant Physiology; post-anthesis; stomatal conductance; Triticum aestivum; stomatal conductance; post-anthesis; air pollution; gas exchange
• ISSN: 0300-3604; 1573-9058
• DOI: 10.1007/s11099-009-0039-y

In order to study the responses of winter wheat cultivars released in different years to short-term high O₃ exposure, an old cultivar ('Nongda 311', released in 1960s) and a modern one ('Yannong 19', released in 1990s) were treated with an O₃ exposure (145 ± 12 mm³ m⁻³, 4 h d⁻¹ for 3 d) shortly after anthesis stage (> 50 % main stems blossomed). During the O₃ exposure, light-saturated photosynthetic rate (P N) and stomatal conductance (g s) of both cultivars decreased considerably. Elevated O₃ did not decrease dark-adapted maximum photochemical efficiency, but induced significant reduction in actual photochemical efficiency and thereby considerably increase in non-photochemical quenching. P N, g s of the modern cultivar 'Yannong 19' decreased more than the older one 'Nongda 311', indicating the former exhibited higher sensitivity to O₃ than the latter. After O₃ exposure, P N, g s and chlorophyll (Chl) content in flag leaf decreased more quickly than control, indicating induction of faster premature leaf senescence. As a result, the short-term O₃ exposure caused substantial yield loss, with larger reduction in 'Yannong 19' (-19.2 %) than in 'Nongda 311' (-8.4 %). Our results indicated that high O₃ exposure at grain filling stage would have greater negative impacts on the high yielding modern cultivar relative to the old one with lower yield.