| Effects of water deficit on photosynthetic characteristic and sucrose\|starch synthesis of wheat awns and flag leaf |
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| DOI：10.7606/j.issn.1000-7601.2021.06.06 |
| Key Words: water deficit wheat awns flag leaf photosynthesis characteristic sucrose starch |
| Author Name | Affiliation | | HE Juan | College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China | | TANG Yan | College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China | | LI Xiaorui | College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China | | LI Hailan | College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China | | ZHOU Chunju | College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China | | L Jinyin | College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China |
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| Abstract: |
| To understand the effects of water deficit on photosynthetic characteristic and sucrose\|starch synthesis of wheat awns and flag leaf, potted wheat plants growing in normal water supply (CK) and water deficit (WD) conditions during the filling period were set up to determine photosynthetic parameters, relative water content (RWC), content of chlorophyll (Chl) and malondialdehyde (MDA), and activities of key enzymes for sucrose and starch synthesis of wheat flag leaf and awns. The expression of SS1, SS2, SPS1, AGPase, and SSS for sucrose and starch synthesis were also measured. The results showed that the net photosynthetic rate (Pn), Chl content and RWC of the flag leaf decreased significantly under water deficit conditions compared with that of awns. Specifically, the Pn was decreased by 87.7% in flag leaf but 14.4% in awns at 24 days after anthesis. The Chl content was decreased by 54.1% in flag leaf but 12.3% in awns. Moreover, RWC was decreased by 13.9% in the flag leaf but 1.5% in awns. Meanwhile, the content of sucrose of the flag leaf and awns was reduced by 50.1% and 18.2% at 24 days after anthesis, respectively, and starch was reduced by 50.8% and 14%, indicating the synthesis of carbon assimilates in awns was less affected by water deficit condition than in flag leaf. During the filling stage, the malondialdehyde (MDA) content of flag leaf and awns increased continuously. The MDA content of flag leaf and awns was increased by 50.8% and 14.0% at 24 days after anthesis under water deficit condition, respectively, indicating a better antioxidant capacity in awns than in flag leaf under adverse conditions. In conclusion, compared with flag leaf, awns maintained relatively normal photosynthetic contribution to wheat grain yield under water deficit conditions because of its high photosynthetic efficiency, water retention, senescence delay characteristics, and prominent ability of sucrose and starch synthesis during the middle and late filling stages of wheat. |
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