| 李海涛,吴泳霖,梁新然,湛方栋,李元,何永美.温度和UV-B辐射增加对水稻根系分泌物和土壤氮转化的影响[J].农业环境科学学报,2026,45(5):1105-1116. |
| 温度和UV-B辐射增加对水稻根系分泌物和土壤氮转化的影响 |
| Effects of elevated temperature and UV-B radiation on rice root exudates and soil nitrogen transformation |
| 投稿时间：2025-07-11 |
| DOI：10.11654/jaes.2025-0657 |
| 中文关键词: 温度 UV-B辐射 根系分泌物 细菌数量 酶活性 氮含量 N2O |
| 英文关键词: temperature UV-B radiation root exudates bacteria number enzyme activity nitrogen content N2O |
| 基金项目:云南省农业联合基金重点项目（202301BD070001-014）；国家自然科学基金项目（32460294） |
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| 中文摘要: |
| 为揭示气候变化背景下温度升高与UV-B辐射增加对水稻根系分泌物的差异化影响及其介导的土壤氮循环响应机制，本研究在元阳梯田(海拔1 600 m)开展田间试验，以地方水稻品种白脚老粳为研究对象，探究大气温度增加2.0℃和UV-B辐射增加5.0 kJ·m-2对水稻根系分泌物及其介导下稻田土壤氮素转化的影响。结果表明：温度增加显著提高水稻拔节期根系分泌物氨基酸、可溶性糖含量及低分子量有机酸含量(柠檬酸除外)，增幅分别为56.4%、30.2%和24.6%~143.8%，UV-B辐射增加降低氨基酸(分蘖期氨基酸除外)和可溶性糖含量(成熟期除外)，降幅分别为37.3%和47.7%~62.5%。温度增加显著提高土壤固氮细菌和硝化细菌数量，增加硝酸还原酶活性和土壤可溶性有机氮(SON)含量；UV-B辐射增加降低土壤反硝化细菌数量及N2O排放通量；温度和UV-B增加处理提高了土壤固氮细菌数量和SON含量。Mantel test分析表明，固氮细菌与SON呈显著正相关(P<0.05)，硝化细菌与N2O排放通量呈极显著正相关(P<0.001)。研究表明，温度升高增加根系分泌物中氨基酸和可溶性糖含量，提高了固氮细菌数量，进而促进生物固氮过程；UV-B辐射增加抑制反硝化细菌数量，弱化反硝化过程，使N2O排放量减少；二者协同作用形成“增固氮-减排”的氮素效应，在增加SON含量的同时减少了N2O排放。 |
| 英文摘要: |
| To elucidate the differential effects of elevated temperature and enhanced UV-B radiation on rice root exudates and their mediated soil nitrogen cycling responses under climate change scenarios, a field experiment was conducted in the Yuanyang Terraces(1 600 m above sea level)using the local rice cultivar Baijiao Laojing. The study investigated the impacts of elevated atmospheric temperature (+2.0 ℃)and enhanced UV-B radiation(+5.0 kJ·m-2)on rice root exudates and their subsequent effects on soil nitrogen transformation. The results showed that elevated temperature significantly increased the contents of amino acids, soluble sugars, and low-molecular-weight organic acids(except citric acid)in rice root exudates at the jointing stage, with respective increments of 56.4%, 30.2%, and 24.6%-143.8%. In contrast, enhanced UV-B radiation reduced the content of amino acids(except for amino acids at the tillering stage)and soluble sugars(except for maturity stage), with decreases of 37.3% and 47.7%-62.5%, respectively. Elevated temperature significantly increased the abundance of nitrogen-fixing and nitrifying bacteria, enhanced nitrate reductase activity, and raised the soil soluble organic nitrogen(SON)content. Conversely, enhanced UV-B radiation reduced the population of denitrifying bacteria and decreased N2O emission flux. Both elevated temperature and UV-B radiation treatments increased the abundance of nitrogen-fixing bacteria and SON content. Mantel test analysis revealed a significant positive correlation between nitrogen-fixing bacteria and SON(P<0.05), as well as a highly significant positive correlation between nitrifying bacteria and N2O emission flux(P<0.001). The study demonstrates that elevated temperature increases amino acid and soluble sugar contents in root exudates, thereby enhancing the population of nitrogen-fixing bacteria and subsequently promoting biological nitrogen fixation. Conversely, enhanced UV-B radiation suppresses denitrifying bacterial populations and attenuates the denitrification process, leading to reduced N2O emissions. The synergistic interaction between these factors creates a "nitrogen fixation promotion-emission reduction" effect, which simultaneously increases soil soluble organic nitrogen content while decreasing N2O emissions. |
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