| Mitigation effect analysis of different exogenous regulatory substances on different drought\|tolerance maize inbred lines under drought stress |
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| DOI：10.7606/j.issn.1000-7601.2020.03.08 |
| Key Words: maize inbred line drought tolerance exogenous GB exogenous Pro drought stress mitigation effect |
| Author Name | Affiliation | | ZENG Wenjing | College of Agronomy,Gansu Agricultural University, Lanzhou, Gansu 730070, China | | CHEN Fenqi | College of Agronomy,Gansu Agricultural University, Lanzhou, Gansu 730070, China | | ZHUANG Zelong | College of Agronomy,Gansu Agricultural University, Lanzhou, Gansu 730070, China | | DING Yongfu | College of Agronomy,Gansu Agricultural University, Lanzhou, Gansu 730070, China | | PENG Yunling | College of Agronomy,Gansu Agricultural University, Lanzhou, Gansu 730070, China |
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| Abstract: |
| Drought\|sensitive maize inbred line TS141 was treated with five different concentrations of exogenous glycine betaine (GB) or proline (Pro)’s treatments under 20% PEG\|simulated drought stress at seedling stage, and distilled water treatment and drought stress treatment were used as positive (CK+) and negative (CK-) control checks.The optimum treatment concentration for maize seedling drought stress mitigation effect was selected: 30 μmol·L-1 of GB and 400 μmol·L-1 of Pro. The drought\|tolerant inbred line Chang 7-2 and drought\|sensitive inbred line TS141 were treated with optimum concentration of exogenous GB or Pro under drought stress. The drought tolerance difference of different drought\|tolerant maize inbred lines and the mitigation effects of exogenous GB or Pro were compared and analyzed from growth parameters, physiological characteristics, stomatal characteristics and leaf anatomical structure. The results showed that both exogenous GB and Pro alleviated the drought stress damage of maize seedlings and restored physiological and biochemical metabolic homeostasis. The mitigation effect of exogenous GB was greater than that of Pro under drought stress. After adding exogenous GB, the growth parameters of TS141 were significantly increased and the cell structure of the leaves was restored and arranged in order, while the seedling length did not change significantly after adding exogenous Pro, and no significant difference was found in the leaf cell structure; the proline content, SOD activity, POD activity and CAT activity of Chang 7-2 decreased by 47.01%, 26.33%, 15.00% and 66.08% respectively after adding exogenous GB, but only decreased by 27.74%, 17.65%, 11.45% and 44.32% respectively after adding exogenous Pro. In addition, exogenous GB or Pro had more effective alleviating effects on drought\|sensitive maize inbred line: The growth parameters of TS141 increased significantly after adding exogenous GB or Pro, while Chang 7-2 showed significant difference only in root length; after adding exogenous GB, the proline content, SOD activity, POD activity and CAT activity of TS141 decreased by 46.22%, 16.58%, 35.24% and 60.52% respectively, while Chang 7-2 decreased by 47.01%, 26.33%, 15.00% and 66.08% respectively, which were lower than TS141. Under drought stress, the leaves of maize inbred lines reduced the diameter of xylem vessel, thus reduced the water potential of the catheter system, induced the decrease of stomatal aperture, and reduced water loss. The deformation of the kranz anatomy, the scattered arrangement of bundle sheath cells, and vascular bundles cells led to a decrease in the tolerance of maize inbred lines to drought stress. |
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