不同浓度甘氨酸替代硝态氮对雾培叶用莴苣生长及品质的影响

Effect of Replacement of Nitrate by Glycine on Growth and Quality of Lettuce under Conditions of Aeroponic

为了降低夏季气雾栽培叶用莴苣中硝酸盐的含量,以华南农大叶菜B配方为基础,研究了不同浓度甘氨酸〔0(CK)、1、3、5、7 mmol·L^(-1)〕替代硝态氮对叶用莴苣农艺性状、生物量和品质的影响。采用主成分分析法、多元线性回归模型和方差分析法对不同浓度甘氨酸处理的叶用莴苣农艺性状指标进行分析,结果显示叶长可以作为叶用莴苣生长情况的评价指标。随着营养液中替代硝态氮的甘氨酸浓度增加,叶用莴苣中的硝酸盐含量显著降低,生长情况逐渐变差,其中5 mmol·L^(-1)处理的硝酸盐含量为401.33 mg·kg^(-1),达到生食标准(<432 mg·kg^(-1)),且VC、可溶性糖、氨基酸含量均显著高于对照,地上部鲜质量与对照无显著差异,可以作为夏季气雾栽培叶用莴苣的营养液配方。

To reduce the nitrate content in lettuce under the conditions of aeroponic during summer,this study investigated the effects of different concentrations of glycine〔0(CK),1,3,5,7 mmol·L~(-1)〕as a substitute for nitrate on the agronomic traits,biomass,and quality of lettuce,based on the South China Agricultural University formula B for leafy vegetables.Principal component analysis(PCA),multiple linear regression models(MLR),and analysis of variance(ANOVA)were employed to analyze the agronomic traits of lettuce treated with different concentrations of glycine.The results showed that the leaf length could serve as an evaluation index for the growth status of lettuce.As the concentration of glycine substituting nitrate in the nutrient solution increased,the nitrate content in lettuce significantly decreased,accompanied by a gradual deterioration of its growth conditions.When the concentration of glycine was 5 mmol·L~(-1),the nitrate content in lettuce was 401.33 mg·kg~(-1),which meets the raw food standard(<432 mg·kg~(-1)).Furthermore,the contents of VC,soluble sugars,and amino acids were significantly higher than the control,while the aboveground fresh mass remained comparable to the control.Consequently,this formulation can be recommended as a nutrient solution for aeroponic cultivation of lettuce during summer.