外源硅对生菜生长、光合及品质特性的影响

Effects of Exogenous Silicon on the Growth,Photosynthesis and Quality Characteristics of Lettuce

以"意大利耐抽薹"生菜(Lactuca sativa L.)为试材,采用基质栽培,研究根施不同浓度的外源硅(0、0.5、1.0、2.0、5.0 mmol·L^(-1))对酒糟基质栽培生菜生长和品质特性的调控效应,以期为酒糟和硅肥在叶菜类蔬菜栽培中的推广应用提供参考依据。结果表明:硅浓度在0~1.0 mmol·L^(-1)范围内,生菜叶宽和单株产量均随硅浓度的升高而增加,当硅浓度高于1.0 mmol·L^(-1)时,相关指标随其升高而降低,在1.0 mmol·L^(-1)时达到最大值;同时叶片净光合速率(Pn)、气孔导度(Gs)及蒸腾速率(Tr)也随栽培基质中硅水平的增加呈先升高后降低的趋势,硅浓度在2.0 mmol·L^(-1)时最高;生菜叶片中的还原性糖、维生素C含量也随硅素水平的提高呈先升高后降低的趋势,硅浓度1.0 mmol·L^(-1)时还原性糖含量最高,维生素C含量则在硅浓度2.0 mmol·L^(-1)处理时最高;此外,根施硅溶液可显著提高生菜Fe元素的含量,降低Na元素和MDA含量,但对K元素影响不显著。综合考虑,在20%酒糟复合基质栽培的基础上,增施浓度为1.0~2.0 mmol·L^(-1)的硅肥,对生菜生物量的提高和品质的改善有显著效果。

Taking‘Italian Bolting-resistant’lettuce(Lactuca sativa L.)as the test material,substrate culture method was used,the regulation effects of different concentrations of exogenous silicon(0,0.5,1.0,2.0,and 5.0 mmol·L^(-1))on roots on the growth and quality characteristics of lettuce cultured on distiller′s grains were explored,in order to provide a reference for the promotion and application of distiller′s grains and silicon fertilizer in soilless cultivation of leafy vegetables.The results showed that when the silicon concentration was in the range of 0-1.0 mmol·L^(-1),the leaf width,and yield per plant of lettuce all increased with the increase of silicon concentration.When the silicon concentration was higher than 1.0 mmol·L^(-1),the related indicators decreased with the increase,and reached the maximum at 1.0 mmol·L^(-1).At the same time,the leaf net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)also increased first and then decreased with the increase of the silicon level in the cultivation substrate,which were the highest when the silicon concentration was 2.0 mmol·L^(-1).The contents of reducing sugar,vitamin C,in lettuce leaves also increased first and then decreased with the increase of silicon level.When the silicon concentration was 1.0 mmol·L^(-1),the content of reducing sugar was the highest,and the content of vitamin C was of the highest level when the silicon concentration was 2.0 mmol·L^(-1).In addition,the root application of silicon solution could significantly increase the content of Fe in lettuce and reduce the content of Na and MDA,but the effect on K content was not significant.Considering comprehensively,increasing the concentration of silicon fertilizer with a concentration of 1.0-2.0 mmol·L^(-1),which is based on 20%distiller′s grains compound substrate cultivation,has a significant effect on the increase of lettuce biomass and quality.