| Effects of nitrogen forms on root porosity and water absorption of rice under drought stress |
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| DOI：10.7606/j.issn.1000-7601.2019.02.21 |
| Key Words: water stress nitrogen forms rice root root porosity water absorption |
| Author Name | Affiliation | | YANG Xiu-xia | College of Land Resources and Environmental Sciences, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China | | YAN Hui | College of Land Resources and Environmental Sciences, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China | | ZHOU Chun-huo | College of Land Resources and Environmental Sciences, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China | | GUO Shi-wei | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China |
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| Abstract: |
| Hydroponic experiment was conducted in a greenhouse in this study to explore the nitrogen (N) fertilizer forms, nitrate (NO-3-N) and ammonium (NH+4-N), on the root porosity and water usage of rice plants. Water stress was simulated by treatment with polyethylene glycol (PEG, 10% in w/v, MW6000). Four rice varieties, indica (Shanyou 63 and Yangdao 6) and japonica (86you 8 and Wuyunjing 7), were utilized in the experiment. The results showed that, under non-water stress conditions, there was no significant difference in root xylem sap flow rate on indica rice varieties fertilized with NH+4-N and NO-3-N, while the rate on japonica rice varieties with NO-3-N fertilization was 56% higher than that with NH+4-N. Compared with non-water stress conditions, however, the root xylem sap flow rate under water stress conditions dramatically reduced by 64%, 76%, 60%, and 70% on Shanyou 63, Yangdao 6, 86you 8 and Wuyunjing 7 with NO-3-N, while only 46%,29%，38% and 77% on the four varieties with NH+4-N, respectively. Under water stress, the water absorption capacity of the root significantly decreased by 22%~30% and 35%~44% for the varieties of Shanyou 63, Yangdao 6, 86you 8 and Wuyunjing 7 with NH+4-N and NO-3-N, respectively. Under water stress, root porosity increased by 267%, 151%, 133% and 255% respectively for the varieties of Shanyou 63, Yanddao 6, 86you 8 and Wuyunjing 7 with NO-3-N fertilization than that under non-water stress conditions. There was negligible effects on the plants with NH+4-N under the water stress conditions. Correlation analysis indicated that the root xylem sap flow rate was negatively correlated with root porosity (aerenchyma formation) in the plants with NO-3-N, and there was no correlation between these two indexes with NH+4-N fertilization. Consequently, the increased root porosity might be a key factor for the decreased water absorption in the plants with NO-3-N under water stress conditions. |
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