叶面施硒对水稻叶片亚细胞组分中硒分布和累积的影响

Effects of foliar-sprayed of selenium on distribution and accumulation of selenium in subcellular components of rice leaves

关键词:  硒, 水稻, 亚细胞分布, 叶施, 表面活性剂

Key words:  selenium, rice, subcellular distribution, foliar spray, surfactant

摘要:

叶面喷硒是一种有效提高作物硒含量的农艺强化手段。为探究硒在水稻叶片组分中的分布、积累特征及影响因子,以及提高叶施硒的利用效率,该研究利用叶片离体培养技术,比较了不同硒形态、浓度、处理时间及不同表面活性剂载体对水稻叶片亚细胞组分中硒的分布和累积的影响。结果表明:(1)硒主要分布在水稻叶片细胞壁中,其次是叶绿体和线粒体组分,细胞液最少。(2)叶施硒肥数小时内叶片对亚硒酸钠的吸收能力显著高于纳米硒、硒代蛋氨酸和酵母硒,分别高出1.25倍、1.32倍和5.43倍,迁移能力高出其余三者约1.26倍。(3)水稻每片叶片的最佳施硒量为0.008 mg,此时叶绿体和线粒体中硒含量达到最大值。(4)叶施硒后3～7 h是叶片吸收转运硒的关键时间点。(5)相较于环糊精和烷基糖苷,在外源硒中添加浓度为30 mg·L^-1的鼠李糖脂可更好地促进水稻叶片对硒的吸收,吸收含量提高了80%。综上认为,该结果为后续了解硒在叶片中的迁移机制提供了理论参考,也为未来硒配方优化、科学施硒制度建立以及降低硒生态环境风险提供技术支撑。

Abstract:

Foliar selenium spraying is an effective agronomic fortification to increase the selenium content of crops. In order to explore the distribution, accumulation characteristics and influencing factors of selenium in rice leaf fractions, and to improve the utilization efficiency of foliar selenium application, we compared the effects of different selenium forms, concentrations, treatment time and different surfactant carriers on the distribution and accumulation of selenium in the subcellular fractions of rice leaves using the leaf in vitro culture technique. The results were as follows:(1)Selenium was mainly distributed in the cell wall of rice leaves, followed by chloroplast and mitochondrial fractions, with the least in the cytosol.(2)The uptake capacity of sodium selenite in leaves within a few hours of leaf application of selenium fertilizer was significantly higher than that of nano-selenium, selenomethionine and yeast selenium, by 1.25-fold, 1.32-fold and 5.43-fold, respectively, and the migration capacity was about 1.26-fold higher than that of the remaining three.(3)The optimal amount of selenium applied to each leaf was 0.008 mg, and at that time the selenium content in chloroplasts and mitochondria reached the maximum value.(4)Three to seven hour after leaf application of selenium was the critical time point for selenium uptake and translocation in leaves.(5)Meanwhile, compared with cyclodextrin and alkyl glycoside, the addition of rhamnolipid to exogenous selenium at a concentration of 30 mg·L^-1 promoted selenium uptake in rice leaves, and the content of the absorbed content increased by 80%. The above results provide the theoretical referecence for the subsequent understanding of selenium transport mechanisms in leaves, and also provide the support for the optimization of selenium formulations, the establishment of scientific selenium application systems, and the reduction of selenium ecological and environmental risks in the future.