| Effects of nitrogen on photosynthesis and antioxidant enzyme activities of sorghum under drought stress and re-watering |
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| DOI：10.7606/j.issn.1000-7601.2019.05.15 |
| Key Words: sorghum drought stress re-watering photosynthetic performance antioxidant enzyme |
| Author Name | Affiliation | | AI Xue-ying | College of Agronomy, Shenyang Agricultural University, Shenyang, Liaoning 110866, China | | WU Qi | College of Agronomy, Shenyang Agricultural University, Shenyang, Liaoning 110866, China | | ZHOU Yu-fei | College of Agronomy, Shenyang Agricultural University, Shenyang, Liaoning 110866, China | | ZHANG Rui-dong | College of Agronomy, Shenyang Agricultural University, Shenyang, Liaoning 110866, China | | CHEN Xiao-fei | College of Agronomy, Shenyang Agricultural University, Shenyang, Liaoning 110866, China | | ZHANG Jiao | College of Agronomy, Shenyang Agricultural University, Shenyang, Liaoning 110866, China | | HUANG Rui-dong | College of Agronomy, Shenyang Agricultural University, Shenyang, Liaoning 110866, China | | XU Wen-juan | College of Agronomy, Shenyang Agricultural University, Shenyang, Liaoning 110866, China |
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| Abstract: |
| In this study, stay-green sorghum (B35) and non-stay green sorghum (Sanchisan) were used as experimental materials. Sorghum plants were planted in pots with two N application levels (0 and 6 g N per pot, respectively) to determine photosynthetic properties and antioxidant enzyme activities under drought stress and re-watering during filling stage. The results showed that nitrogen significantly increased the photosyntheticrate (Pn), intercellular CO2 concentration (Ci), transpiration rate (Tr),and activity of reaction center in photosystem II activity (PSII) under drought stress. Under drought condition, the activities of phosphoenolpyruvate carboxylase (PEPCase) in B35 and Sanchisan were increased by 29.17%and 25.66% with nitrogen application,respectively. Nevertheless, the activity of ribulose diphosphate carboxylase (RuBPCase) was not sensitive to nitrogen.Compared with Sanchisan, the photosynthetic ability of B35 was obviously promoted by nitrogen. Under drought stress, nitrogen significantly increased the activities of superoxide dismutase (SOD) and peroxidase (POD).The activities of SOD and POD in B35 and Sanchisan were increased by 25.56% and 17.07%, and 48.97% and 76.62% with nitrogen application,respectively. The activities of antioxidant enzymes in B35 were higher than that of Sanchisan. At the same time, nitrogen decreased the malondialdehyde (MDA) contents of B35 and Sanchisan. After Re-watering, nitrogen significantly increased Pn, Tr and PEPCase activity and reduced the initial fluorescence value (Fo). Pn, Tr and PEPCase activity of B35 and Sanchisanwere promoted by 33.66% and 60.01%, 36.59% and 41.57%, and 23.47% and 18.64%, respectively. However, Fo was decreased by 18.50% and 10.98%. Nitrogen application was beneficial to improve the activities of antioxidant enzymes of B35 and Sanchisan; and reduced the degree of lipid peroxidation in cell membrane after re-watering. After re-watering, the photosynthetic characteristics and antioxidant enzyme activities of B35 were higher than that of Sanchisan. The yield of B35 in two different nitrogen levels was higher than Sanchisan.The biological and grain yield of B35 and Sanchisan with nitrogen application were increased by 9.73% and 10.08%, and 24.47% and 21.79%, respectively. The damage of photosynthetic apparatus by drought was alleviated with nitrogen application by regulating stomatal conductance and photosystem II activity. After re-watering, the photosynthetic ability was promoted by higher photosystem II activity and the activities of photosynthetic enzyme which were increased with nitrogen application. Under drought and re-watering conditions, nitrogen increased antioxidant enzyme activities and reduced the degree of lipid peroxidation in cell membrane. Nitrogen is beneficial to the enhancement of photosynthetic and antioxidant enzyme systems ability of B35 and Sanchisan under drought and re-watering conditions. |
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