水培生菜适宜营养液氮素供应浓度优化
Optimization of Nitrogen Supply Concentration in Nutrient Solution for Hydroponics Lettuce
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摘要: 以生菜为试验材料，设置5个营养液氮素浓度水平0.9、3.5、7、14和28 mmol/L（分别标记为T1、T2、T3、T4、T5），分析水培生菜生长、品质对营养液氮素浓度的响应。结果发现：各处理生菜茎粗无显著差异；T1处理生菜叶片数较少，显著低于T2、T3、T4、T5处理；T3处理生菜叶片叶绿素含量（SPAD值）较大，显著高于T1处理；T3处理生菜产量最佳，单株产量与T1、T2、T4、T5处理相比，分别高482.11%、53.53%、14.48%、32.49%；提高营养液氮素浓度有利于提高生菜可溶性总糖含量，随着营养液氮素浓度的增加，生菜维生素C含量和硝酸盐含量均呈先增加后减小趋势；利用生菜产量与营养液氮素浓度的关系优化得到生菜适宜营养液氮素浓度为9.69 mmol/L，在该条件下生菜可获得较高产量。Abstract: Lettuce was chosen in this study and five treatments of nitrogen levels were set，i.e.0.9，3.5，7，14 and 28 mmol/L，denoted as T1，T2，T3，T4，T5，respectively.Response of growth and quality of hydroponic lettuce to concentration of nitrogen in nutrient solution was analyzed.Test results showed that there was no significant difference for lettuce stem diameter among five treatments.The lettuce leaf number for treatment T1 was less than that for T2，T3，T4 and T5.Lettuce leaf SPAD value for T3 was significantly higher than that for treatment T1.The highest yield of lettuce for T3 treatment was obtained，and higher of 482.11%，53.53%，14.48%，32.49%，compared to T1，T2，T4，T5 treatments，respectively.Increasing the nitrogen concentration of nutrient solution was beneficial to soluble sugar content of lettuce was improved by increasing nitrogen concentration of nutrient solution.The content of Vc and nitrate in lettuce showed a similar trend of firstly increasing and then decreasing with increasing of nutrient solution nitrogen concentration.The suitable nitrogen supplying concentration for hydroponic was optimal as 9.69 mmol/L using relationship between lettuce yield and nutrient solution nitrogen concentration.Therefore，the higher yield was achieved under this situation.
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