外源硒肥对茶树叶中硒代氨基酸形态及含量影响的研究

Effects of Selenium Application on Selenoamino Acids Contents and Morphology in the Leaves of Tea Plant

通过土施和喷施不同浓度亚硒酸钠的盆栽及大田实验,研究不同浓度的外源硒肥对茶树叶中硒代氨基酸形态及含量的影响;采用离子色谱-积分脉冲安培检测法(HPAEC-IPAD)对茶树叶中硒代氨基酸进行定性和定量分析。结果显示:3种硒代氨基酸在其线性范围内的相关系数R2在0.9994～0.9999之间,相对标准偏差RSD(%)分别为2.47、3.17和3.77,具有很好的相关性;茶树叶中硒代甲基半胱氨酸(SeMeCys)是硒代氨基酸存在的主要形式,随着喷施和土施亚硒酸钠浓度的增加,其含量呈现先增加后降低的趋势,茶树叶中总的硒代氨基酸的含量变化与此变化相符;茶树叶中总的硒代氨基酸在喷施Se180μg ml-1、12天左右时采摘最为理想,所含硒代氨基酸总量为336.1μg g-1,但喷施浓度不宜高于Se 180μg ml-1,否则茶树叶面上会出现褐色的斑点及焦化,影响其外观和品质;土施亚硒酸钠时以Se 0.25～0.5 mg kg-1,施后6个月采摘较佳,茶树叶中总的硒代氨基酸的含量为293.9～471.7μg g-1,大田试验结果与盆栽试验结果相符。

Potted and field experiments were carried out to study the effects of soil and spraying application at different concentrations of sodium selenite on the contents and morphologies of selenoamino acids. The selenoamino acids were analyzed qualitatively and quantitatively by method of ion chromatography - integral pulse ampere assay （HPAEC-IPAD）. The results showed that the standard deviation R2 of the three selenoamino acids in the linear range were 0.9994 - 0.9999. The relative standard deviation RSD%） were 2.47, 3.17 and 3.77 respectively, and there existed a high correlation. In the leaves of the tea plant, Selenomethylcysteine （SeMeCys） was the main existence form of the selenoamino acids. With increasing of sodium selenite concentrations by the spray and soil application, the contents of SeMeCys increased at low concentrations and then decreased at high concentrations in the leaves tea plant. The variation of total selenoamino acid content was consistent with that of SeMeCys. The total selenoamino acid content was 336.1 μg g^-1, and was the most ideal for picking when spraying time was for 12 days or so at concentration for Se 180 μg ml^-1. But spraying concentration should not be higher than Sel80 μg ml^-1, otherwise the tea leaves would appear on the brown spots and eoking which affected the appearance and quality of tea. It was better for picking when soil application of sodium selenite was at concentration of Se 0.25 - 0.5 mg kg-1 for 6 months. The total selenoamino acid of the tea was 293.9 - 471.7 μg g^-1, the results of the field test were matched with pot experiment.