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| DOI：10.13522/j.cnki.ggps.20180118 |
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| The Effects of Water Stress on Growth and Resistance of Super Rice Against Loading |
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HAO Shurong, DONG Bohao, ZHOU Peng, PAN Yongchun, WANG Zixin
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College of Water Conservancy and Hydropwer Engineering, Hohai University, Nanjing 2100985, China
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| Abstract: |
| 【Objective】 Turgor pressure in plant determines its resistance against loading and the purpose of this paper is to investigate how this is impacted by water stress. 【Method】 Pot experiments were conducted using Nanjing 5055 and Xinliangyou 6380 as the model plants. For each plant, we examined three water levels: moderate drought（C1）and severe drought（C2), with sufficient irrigation as the control (CK). During the experiment from May 2016 to October 2016 conducted in the key laboratory of the Ministry of Education, Southern China Efficient Irrigation-Drainage and Agricultural Soil and Water Environment at Hohai University, the morphological and the resistance of the super rice against loading under different water stresses were measured and compared. 【Result】 In early jointing stage, water stress inhibited plant growth, lowered the gravitational centroid of the plan and reduced the internode length, while increasing the internode diameter, wall thickness and internode fullness. Compared to CK, C1 and C2 treatments reduced the falling-over rate of Nanjing 5055 by 24.49% and 33.67% respectively, while enhancing the cumulative destructive energy by 8.44% and 2.58% respectively. Similarly, the falling-over rate of Xinliangyou 6380 under C1 and C2 was reduced by 34.78% and 32.61%, while the cumulative destructive energy was enhanced by 15.43% and 2.32%, respectively, compared CK. Compared with Nanjing 5055, Xinliangyou 6380 has a better internode dry quality and inter-flushness, which improve the flexural rigidity and the resistance against bending and loading, apart from its high drought-tolerance. The bending moment and resistance of the plants against loading were positively correlated with plant height, gravitational centroid, internode length, yet negatively correlated with the breaking resistance and bending rigidity. The dry weight per unit length, breaking resistance, bending rigidity were positively correlated with the cumulative damage energy. 【Conclusion】 Plant height, internode length and the resistance against breaking, as well as the dry weight per unit length were the main factors that affect the resistance of the super rice against loading. Occurrence of water stress at the early jointing stage increased the resistance of the plant against loading by inhibiting internode elongation, reducing the bending moment, and increasing the internode enrichment. The moderate water stress was most effective, and Xinliangyou 6380 was more resistant than Nanjing 5055 against loading. |
| Key words: water stress; super-rice; lodging; morphological traits; mechanical traits |
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