| Physiological response mechanism of summer maize seedlings to drought\|rewatering of different durations |
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| DOI：10.7606/j.issn.1000-7601.2020.05.09 |
| Key Words: summer maize seedling stage drought\|rewatering treatment stress resistance physiology photosynthesis |
| Author Name | Affiliation | | XIAO Gang | Key Laboratory of Agricultural Water and Soil Engineering, Ministry of Education, Northwest A&F University, Yangling, Shaanxi 712100, China
Institute of Water\|Saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling, Shaanxi 712100, China | | CAI Huanjie | Key Laboratory of Agricultural Water and Soil Engineering, Ministry of Education, Northwest A&F University, Yangling, Shaanxi 712100, China
Institute of Water\|Saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling, Shaanxi 712100, China | | MU Qing | Key Laboratory of Agricultural Water and Soil Engineering, Ministry of Education, Northwest A&F University, Yangling, Shaanxi 712100, China
Institute of Water\|Saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling, Shaanxi 712100, China | | ZHAO Long | Key Laboratory of Agricultural Water and Soil Engineering, Ministry of Education, Northwest A&F University, Yangling, Shaanxi 712100, China
Institute of Water\|Saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling, Shaanxi 712100, China |
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| Abstract: |
| To investigate the physiological regulation mechanism of summer maize seedlings under drought\|rewatering conditions,this experiment adopted a method of barrel planting by using three water stress treatments: normal treatment 75%~85% of θf(θf is field moisture capacity)(CK), mild (W1) at 60%~70% of θf, moderate (W2) at 50%~60% of θf, and three stress durations: 7 days (T1), 10 days (T2), and 13 days (T3). Osmotic adjustment substances, antioxidant enzymes and photosynthetic indexes in leaves of summer maize seedlings during stress and rewatering were determined. The results showed that under mild and moderate stresses, the content of proline (Pro) showed a trend of increasing first and then decreasing. It peaked on the third day and increased by 32.7% and 44.1%, respectively, compared with the normal treatment.After rewatering, the cumulative amount of 10 day stress treatment was higher than that on 7 day stress treatment, but no significant cumulative effect on 13 day stress treatment.The activity of superoxide dismutase (SOD) increased first and then decreased during the stress period, and peaked on the third day, which increased by 22.0% and 12.4%, respectively, compared with the normal treatment. The activity was enhanced after rewatering, and the activity of 13 day stress treatment was higher than that of 10 day stress and 7 day stress. The activity of peroxidase (POD) increased first and then decreased under mild stress treatment, and peaked on the third day, which was 28.5% higher than that of normal treatment. But, under moderate stress treatment, POD activity showed a decreasing trend and was lower than normal treatment, and after rewatering, the enzyme activity returned to normal level. The content of malondialdehyde (MDA) increased during the stress period, and the longer the stress duration, the greater the increase was.Under the 13 day stress treatment, the MDA content under moderate and mild stresses increased by 140% and 281% compared with the normal treatment. After rewatering, the stress was relieved and the MDA content of all treatment groups returned to normal level. Under mild and moderate stresses, the net photosynthetic rate, stomatal conductance and transpiration rate of summer maize were 92.5% and 77.7%, 93.9% and 74.3%, 87.9% and 74.5% of normal treatment, respectively, and photosynthesis was restricted. After rewatering, the photosynthesis compensation effect appeared in the moderate stress treatment, and the photosynthesis indicators were higher than other treatments.This study indicated that maintaining soil water holding capacity of 50% to 60% in the field for 10 days was more suitable for the growth of the summer maize. After rewatering, it had a significant photosynthesis compensation effect. |
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