College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
Chongqing Key Laboratory of Environmental Materials & Remediation Technologies, College of Chemistry and Environmental Engineering, Chongqing University of Arts and Sciences, Yongchuan 402160, China.
Ecotoxicol Environ Saf. 2021 Jan 1;207:111544. doi: 10.1016/j.ecoenv.2020.111544. Epub 2020 Nov 4.
Selenium (Se)-enriched wheat can be improved by altering Se sources and selecting wheat cultivars. Such improvement can affect subcellular distribution and speciation of Se in wheat. Thus, a pot experiment was conducted to investigate Se uptake and distribution when Se was applied as selenite or selenate at low and high rates (1 and 10 mg kg, respectively). Moreover, Se's impact on the grain and biomass yield of eight wheat cultivars was also investigated. The subcellular distribution and speciation of Se were also explored to elucidate Se metabolism and micro-distribution pattern in wheat. Results showed that biomass and grain yield were decreased with the application of both selenite and selenate in almost all the cultivars, regardless of the Se rate. Application high Se rate resulted in a significant (p < 0.05) decrease in grain yield and biomass compared with low rate of Se. Compared with the low rate of selenite application, the grain and the biomass yield of ZM-9023 significantly (p < 0.05) increased by about 15% for low rate of selenate application. In addition, both selenite and selenate treatment increased the uptake of Se in each part of wheat, compared with the control. Selenium was mostly accumulated in the grain and root of wheat under selenite treatment, while more Se accumulation was found in leaves and straw for selenate application. Further investigation on the subcellular distribution of Se showed that the proportion of Se in soluble fraction was significantly (p < 0.05) higher in wheat leaves than that in organelle fraction and cell walls (46%-66%). Meanwhile, Se was the main species found in soluble fraction, whereas SeMet and MeSeCys were the species predominantly stored in organelle fraction. In conclusion, wheat cultivar ZM-9023 is the most Se-rich potential cultivar, and the isolation of Se in the soluble fraction plays an important role in Se tolerance and accumulation.
富硒小麦可以通过改变硒源和选择小麦品种来改良。这种改良可以影响小麦中硒的亚细胞分布和形态。因此，进行了一项盆栽实验，研究了在低浓度（分别为 1 和 10mg/kg）和高浓度（分别为 1 和 10mg/kg）下将亚硒酸盐或硒酸盐作为硒源添加时硒的吸收和分布情况。此外，还研究了硒对 8 个小麦品种的籽粒和生物量产量的影响。还探索了硒的亚细胞分布和形态，以阐明硒在小麦中的代谢和微观分布模式。结果表明，无论硒的浓度如何，几乎所有品种的生物量和籽粒产量都随着亚硒酸盐和硒酸盐的施用而降低。与低硒浓度相比，高硒浓度处理显著（p<0.05）降低了籽粒产量和生物量。与低浓度亚硒酸盐处理相比，低浓度硒酸盐处理使 ZM-9023 的籽粒和生物量产量分别显著（p<0.05）增加了约 15%。此外，与对照相比，亚硒酸盐和硒酸盐处理均增加了小麦各部位对硒的吸收。在亚硒酸盐处理下，硒主要积累在小麦的籽粒和根部，而在硒酸盐处理下，更多的硒积累在叶片和秸秆中。对硒的亚细胞分布的进一步研究表明，与细胞器和细胞壁（46%-66%）相比，硒在小麦叶片中的可溶部分的比例显著（p<0.05）更高。同时，可溶部分中主要发现了硒，而细胞器部分中主要储存了硒代蛋氨酸和硒代半胱氨酸。总之，ZM-9023 是富硒潜力最大的小麦品种，可溶性部分中硒的分离在硒的耐受和积累中起着重要作用。
