Gobu Ramasamy, Dash Goutam Kumar, Lal Jai Prakash, Swain Padmini, Mahender Anumalla, Anandan Annamalai, Ali Jauhar
Crop Improvement Division, Indian Council of Agricultural Research (ICAR)-National Rice Research Institute (NRRI), Cuttack 753006, Odisha, India.
Division of Crop Improvement and Biotechnology, Indian Council of Agricultural Research (ICAR)-Indian Institute of Spices Research (IISR), Kozhikode 673012, Kerala, India.
Plants (Basel). 2022 May 9;11(9):1270. doi: 10.3390/plants11091270.
Drought stress severely affects plant growth and development, causing significant yield loss in rice. This study demonstrates the relevance of water use efficiency with deeper rooting along with other root traits and gas exchange parameters. Forty-nine rice genotypes were evaluated in the basket method to examine leaf-level water use efficiency (WUEi) variation and its relation to root traits. Significant variation in WUEi was observed (from 2.29 to 7.39 µmol CO2 mmol−1 H2O) under drought stress. Regression analysis revealed that high WUEi was associated with higher biomass accumulation, low transpiration rate, and deep rooting ratio. The ratio of deep rooting was also associated with low internal CO2 concentration. The association of deep rooting with lower root number and root dry weight suggests that an ideal drought-tolerant genotype with higher water use efficiency should have deeper rooting (>30% RDR) with moderate root number and root dry weight to be sustained under drought for a longer period. The study also revealed that, under drought stress conditions, landraces are more water-use efficient with superior root traits than improved genotypes.
干旱胁迫严重影响植物生长发育，导致水稻产量大幅损失。本研究证明了水分利用效率与更深根系以及其他根系性状和气体交换参数之间的相关性。采用篮式法对49个水稻基因型进行评估，以研究叶片水平的水分利用效率（WUEi）变化及其与根系性状的关系。在干旱胁迫下，观察到WUEi存在显著差异（从2.29到7.39 μmol CO2 mmol−1 H2O）。回归分析表明，高WUEi与较高的生物量积累、低蒸腾速率和深根比率相关。深根比率还与低内部CO2浓度相关。深根与较少的根数和根干重相关，这表明具有较高水分利用效率的理想耐旱基因型应具有更深的根系（>30% RDR），根数和根干重适中，以便在干旱条件下维持更长时间。研究还表明，在干旱胁迫条件下，地方品种比改良基因型具有更高的水分利用效率和优良的根系性状。
