叶面喷施纳米硒对夏茶硒含量及品质的影响

Effects of Foliar Application of Nano-selenium on Selenium Content and Quality of Summer Tea

本试验以茶树品种白叶1号为试材,研究叶面喷施不同浓度纳米硒对夏季茶树叶片总硒含量、有机硒含量及所制绿茶品质的影响。结果表明:(1)茶树叶片总硒和有机硒含量随喷施硒浓度增加而逐渐升高,不同硒浓度处理茶树叶片的硒含量随采摘时间的延长呈降低趋势,10.0 g/L纳米硒喷施处理后7 d采摘,其叶片总硒和有机硒含量最高,分别为0.763、0.609 mg/kg;(2)不同浓度纳米硒处理茶树叶片的硒形态均以有机硒为主,占总硒含量的比例在69.0%~80.8%之间;(3)喷施一定浓度的纳米硒,能够提高夏制绿茶感官品质,显著降低茶叶中的花青素和茶多酚含量,提高游离氨基酸含量,降低酚氨比,其中10.0 g/L纳米硒处理酚氨比最低,为4.47。综上认为,叶面喷施一定浓度的纳米硒可以显著提高茶树叶片的硒含量,提高夏制绿茶品质,其中叶面喷施5.0~10.0 g/L纳米硒并在喷施后7~14 d采摘,叶片富硒效果显著,可用其生产达到国家规定富硒水平的绿茶。

In this experiment,the tea variety Baiye 1 was used as test material to study the effects of foliar spraying different concentrations of nano-selenium on the total and organic selenium contents in summer tea leaves and the quality of its green tea.The results were as follows.(1)The contents of total selenium and organic selenium in tea leaves increased gradually with the increase of nano-selenium concentration,and the selenium content in tea leaves decreased with the prolongation of picking time.The contents of total and organic selenium in tea leaves were the highest at 7 days after 10.0 g/L nano-selenium treatment,which were 0.763 and 0.609 mg/kg,respectively.(2)The main selenium form in tea leaves treated with different concentrations of nano-selenium was organic selenium,accounting for 69.0%~80.8% of the total selenium content.(3)Spraying a certain concentration of nano-selenium could increase the sensory quality,significantly reduce the content of anthocyanins and tea polyphenols,increase the content of free amino acids,and reduce the ratio of total polyphenols to total amino acids.The ratio of total polyphenols to total amino acids was the lowest under 10.0 g/L nano-selenium treatment as 4.47.In summary,foliar application of a certain concentration of nanoselenium could significantly increase the selenium content in tea leaves and improve the quality of processed green tea.Among them,foliar application of 5.0~10.0 g/L nano-selenium and picking leaves at 7~14 days after spraying had the significant selenium-rich effect,which could be used to produce green tea that meets the national selenium-rich level.