为揭示硅(Si)、硒(Se)及其相互作用对铬(Cr)胁迫下水稻幼苗生长的缓解机制,开展了盆栽土培试验。试验以不施加Cr、Si、Se为对照(CK),在Cr胁迫(30 mg/kg)条件下,设置Si、Se单一处理以及组合处理,深入探究Si、Se对Cr胁迫下水稻生理生化特性、元素吸收情况以及Cr亚细胞分布的影响。结果表明,与CK相比,Cr胁迫下水稻幼苗的生物量、光合色素含量、可溶性渗透物质含量以及矿质元素(N、P、K、Ca、Mg、Si、Se)含量均有所降低;而抗氧化酶(GR、SOD、CAT、POD)活性、活性氧产物(MDA、H₂O₂)含量以及氧化还原物质(GSH、Pro)含量则显著升高。在Cr胁迫下,施用Se或Si均能改善上述指标,且单独施Se的处理效果优于单独施Si的处理。此外,施用Si和Se也降低了水稻植株中Cr的含量,同时改变了水稻根系中Cr的亚细胞分布比例。具体表现为,增加了细胞壁(Fc)中Cr的分布比例,减少了细胞膜(Fm)、细胞器(Fo)以及细胞质(Fs)中Cr的分布比例,且单独施Si的作用效果优于单独施Se。综上所述,Cr胁迫下,Se在改善植株生理生化特性以及促进矿质元素吸收方面表现更为突出;而Si在抑制Cr吸收方面效果更佳;二者表现出协同效应,使得植株Cr含量相较于Cr胁迫下未施Si和Se的处理显著降低了72.18%。

To elucidate the mitigation mechanisms of silicon (Si), selenium (Se), and their interaction on rice seedlings under chromium (Cr) stress, a pot soil culture experiment was conducted. The experiment used a treatment without applying Cr, Si, and Se as the control (CK). Under Cr stress (30 mg/kg), single treatments of Si and Se as well as a combined treatment were set up to thoroughly investigate the effects of Si and Se on the physiological and biochemical characteristics, element absorption, and Cr subcellular distribution in rice under Cr stress. The results showed that, compared with CK, the biomass, photosynthetic pigment content, soluble osmotic substance content, and mineral element (N, P, K, Ca, Mg, Si, Se) content of rice seedlings decreased under Cr stress. In contrast, the activities of antioxidant enzymes (GR, SOD, CAT, POD), the contents of reactive oxygen species (MDA, H₂O₂), and the contents of redox substances (GSH, Pro) significantly increased. Under Cr stress, the application of either Se or Si could improve the aforementioned indicators, and the Se treatment exhibited a better effect than the Si treatment. Additionally, the application of Si and Se also reduced the Cr content in rice plants and altered the subcellular distribution ratio of Cr in rice roots. Specifically, it increased the distribution ratio of Cr in the cell wall and decreased the distribution ratios of Cr in the cell membrane, organelles, and cytoplasm. Moreover, the effect of Si was superior to that of Se in this regard. In summary, under Cr stress, Se demonstrated more prominent performance in improving plant physiological and biochemical characteristics and promoting mineral element absorption, while Si showed a better effect in inhibiting Cr uptake. The two elements exhibited a synergistic effect, resulting in a significant 72.18% reduction in plant Cr content compared to the treatment under Cr stress without applying Si and Se.