Hou Danping, Liu Kun, Liu Shikun, Li Juncai, Tan Jinsong, Bi Qingyu, Zhang Anning, Yu Xinqiao, Bi Junguo, Luo Lijun
Shanghai Agrobiological Gene Center, Shanghai, China.
Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, Shanghai, China.
Front Plant Sci. 2024 May 8;15:1370297. doi: 10.3389/fpls.2024.1370297. eCollection 2024.
Water-saving and drought-resistance rice (WDR) plays a vital role in the sustainable development of agriculture. Nevertheless, the impacts and processes of water and nitrogen on grain yield in WDR remain unclear.
In this study, Hanyou 73 (WDR) and Hyou 518 (rice) were used as materials. Three kinds of nitrogen fertilizer application rate (NFAR) were set in the pot experiment, including no NFAR (nitrogen as urea applied at 0 g/pot), medium NFAR (nitrogen as urea applied at 15.6 g/pot), and high NFAR (nitrogen as urea applied at 31.2 g/pot). Two irrigation regimes, continuous flooding cultivation and water stress, were set under each NFAR. The relationships between root and shoot morphophysiology and grain yield in WDR were explored.
The results demonstrated the following: 1) under the same irrigation regime, the grain yield of two varieties increased with the increase of NFAR. Under the same NFAR, the reduction of irrigation amount significantly reduced the grain yield in Hyou 518 (7.1%-15.1%) but had no substantial influence on the grain yield in Hanyou 73. 2) Under the same irrigation regime, increasing the NFAR could improve the root morphophysiology (root dry weight, root oxidation activity, root bleeding rate, root total absorbing surface area, root active absorbing surface area, and zeatin + zeatin riboside contents in roots) and aboveground physiological indexes (leaf photosynthetic rate, non-structural carbohydrate accumulation in stems, and nitrate reductase activity in leaves) in two varieties. Under the same NFAR, increasing the irrigation amount could significantly increase the above indexes in Hyou 518 (except root dry weight) but has little effect on Hanyou 73. 3) Analysis of correlations revealed that the grain yield of Hyou 518 and Hanyou 73 was basically positively correlated with aboveground physiology and root morphophysiology, respectively.
The grain yield could be maintained by water stress under medium NFAR in WDR. The improvement of root morphophysiology is a major factor for high yield under the irrigation regime and NFAR treatments in WDR.
节水抗旱稻在农业可持续发展中发挥着至关重要的作用。然而，水分和氮素对节水抗旱稻产量的影响及作用过程仍不清楚。
本研究以旱优73（节水抗旱稻）和沪优518（水稻）为材料。盆栽试验设置三种氮肥施用量，包括不施氮肥（以尿素形式施氮0 g/盆）、中等氮肥施用量（以尿素形式施氮15.6 g/盆）和高氮肥施用量（以尿素形式施氮31.2 g/盆）。在每种氮肥施用量下设置两种灌溉方式，即持续淹水栽培和水分胁迫。探究了节水抗旱稻根系与地上部形态生理与产量之间的关系。
结果表明：1）在相同灌溉方式下，两个品种的产量均随氮肥施用量的增加而增加。在相同氮肥施用量下，灌水量减少显著降低了沪优518的产量（7.1%-15.1%），但对旱优73的产量没有实质性影响。2）在相同灌溉方式下，增加氮肥施用量可改善两个品种的根系形态生理（根干重、根系氧化活性、伤流速率、根系总吸收表面积、根系活跃吸收表面积以及根中玉米素+玉米素核苷含量）和地上部生理指标（叶片光合速率、茎中非结构性碳水化合物积累量以及叶片硝酸还原酶活性）。在相同氮肥施用量下，增加灌水量可显著提高沪优518的上述指标（根干重除外），但对旱优73影响较小。3）相关性分析表明，沪优518和旱优73的产量分别与地上部生理和根系形态生理基本呈正相关。
节水抗旱稻在中等氮肥施用量下通过水分胁迫可维持产量。根系形态生理的改善是节水抗旱稻灌溉方式和氮肥施用量处理下高产的主要因素。
