频率,持续时间,陆地生态系统中的热浪(HW)强度正在增加,给农业生产带来潜在风险。二氧化铈纳米颗粒(CeO2NPs)由于具有增强光合作用和改善胁迫耐受性的潜力,在农业领域引起了越来越多的关注。在本研究中,CeO2NPs降低了谷物产量,谷物蛋白质含量,氨基酸含量分别为16.2%、23.9%和10.4%,分别,在HW条件下。个别地,CeO2NPs和HWs都不会单独对水稻产量产生负面影响或引发气孔关闭。然而,在HW条件下,CeO2NPs使气孔导度和净光合速率分别降低了67.6%和33.5%,分别。此外,在存在HWs和CeO2NPs的情况下,气孔关闭会触发活性氧(ROS)积累(增加32.3-57.1%),导致叶绿体畸变和光系统II活性降低(降低9.4-36.4%)。代谢,转录组,和定量实时聚合酶链反应(qRT-PCR)分析显示,在HW条件下,CeO2NPs通过调节基因表达激活了由脱落酸(ABA)和ROS介导的气孔关闭途径(PP2C,NCED4、HPCA1和RBOHD上调,而CYP707A和ALMT9下调)和代谢物水平(γ-氨基丁酸(GABA)含量增加,而没食子酸含量降低)。这些发现阐明了在CeO2NP和HW存在下气孔关闭引起的产量和营养损失的潜在机制,从而突显了CeO2NP在HW期间对水稻生产构成的潜在威胁。
The frequency, duration, and intensity of heat waves (HWs) within terrestrial ecosystems are increasing, posing potential risks to agricultural production. Cerium dioxide nanoparticles (CeO2 NPs) are garnering increasing attention in the field of agriculture because of their potential to enhance photosynthesis and improve stress tolerance. In the present study, CeO2 NPs decreased the grain yield, grain protein content, and amino acid content by 16.2, 23.9, and 10.4%, respectively, under HW conditions. Individually, neither the CeO2 NPs nor HWs alone negatively affected rice production or triggered stomatal closure. However, under HW conditions, CeO2 NPs decreased the stomatal conductance and net photosynthetic rate by 67.6 and 33.5%, respectively. Moreover, stomatal closure in the presence of HWs and CeO2 NPs triggered reactive oxygen species (ROS) accumulation (increased by 32.3-57.1%), resulting in chloroplast distortion and reduced photosystem II activity (decreased by 9.4-36.4%). Metabolic, transcriptomic, and quantitative real-time polymerase chain reaction (qRT-PCR) analyses revealed that, under HW conditions, CeO2 NPs activated a stomatal closure pathway mediated by abscisic acid (ABA) and ROS by regulating gene expression (PP2C, NCED4, HPCA1, and RBOHD were upregulated, while CYP707A and ALMT9 were downregulated) and metabolite levels (the content of γ-aminobutyric acid (GABA) increased while that of gallic acid decreased). These findings elucidate the mechanism underlying the yield and nutritional losses induced by stomatal closure in the presence of CeO2 NPs and HWs and thus highlight the potential threat posed by CeO2 NPs to rice production during HWs.