| 摘要: |
| 【目的】研究不同浓度钾对水培生菜生长、品质、矿质元素利用效率以及矿质元素动态吸收的影响，以期筛选出适宜生菜生长的钾浓度。【方法】2014年3-5月，采用水培试验，设置5个不同的钾浓度（6，5，4，3，2 mmol/L）处理生菜，在生菜生育期每隔10 d测定1次生长指标，在收获后测定生菜品质，并计算生菜对不同矿质元素的利用效率，同时测定营养液中氮、磷、钾、钙、镁的浓度变化，以分析各阶段生菜对矿质元素的吸收情况。【结果】当钾浓度为2～6 mmol/L时，生菜叶面积、根干(鲜)质量、地上部分干（鲜）质量、根冠比均随钾浓度的增加先增大后减小，当钾浓度为3 mmol/L时，生菜以上生长指标均较大；随着钾浓度的增加，生菜硝酸盐、可溶性糖、可溶性蛋白含量均先增大后减小，Vc含量不断增大，其中当钾浓度为4 mmol/L时，生菜的综合品质最好。各处理生菜总干物质积累量在整个生育期不断增大且差异越来越明显，其中3～4 mmol/L钾素处理生菜收获时干质量明显高于其他处理，不同钾素处理生菜对氮、磷的吸收都是在第三阶段（05 03-05 13）达到最大，在其他生育阶段吸收较少；对钾的吸收量呈不断增加的趋势；对钙镁的吸收在整个生育阶段都较均匀，其中在第三阶段（05 03-05 13）吸收强度略有增加。较低的钾浓度处理（2～4 mmol/L）生菜对矿质元素的利用效率均较高。【结论】当钾浓度为4 mmol/L时，有利于生菜生长，获得较好的产量及品质，且矿质元素利用效率较高。 |
| 关键词: 水培生菜 钾浓度 动态吸收 矿质元素 |
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| 基金项目:国家“863”计划项目“植物工厂营养液管理与蔬菜品质调控技术装备研究”(2013AA103004) |
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| Effect of potassium concentration on growth and dynamic absorption of mineral elements of hydroponic lettuce |
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SU Yuanjun,HU Xiaotao,WANG Wen’e,et al
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| Abstract: |
| 【Objective】This study investigated the effects of different potassium levels on growth,quality,use efficiency and dynamic absorption of mineral elements of hydroponic lettuce to obtain suitable potassium level for lettuce.【Method】Hydroponic experiments were conducted from March to May 2014 with five different potassium levels to determinate the growth of the lettuce every 10 days.The quality was determined after harvest and use efficiencies of mineral elements were calculated.At last,concentrations of N,P,K,Ca,and Mg in nutrient solution were measured and their absorption at different stages was analyzed.【Result】When potassium concentration was 2-6 mmol/L,the leaf area,root dry (fresh) weight,above ground dry (fresh) weight and root cap ratio of the lettuce firstly increased and then decreased with the best indexes at the concentration of 3 mmol/L.With the increase of potassium concentration,contents of nitrate,soluble sugar and soluble protein increased before decreasing,while content of Vc increased consistently.The best quality was obtained when potassium concentration was 4 mmol/L.The total dry matter amounts of different treatments accumulated constantly in the whole growth period and the differences increased as well.The treatments with 3-4 mmol/L had the highest dry matter amounts.The absorption of nitrogen and phosphorus of all treatments reached the maximum during May 03 to May 13,while the absorption at other stages was much less.The lettuce absorption of potassium had a tendency to strengthen continuously,while the absorption of calcium and magnesium in the whole stage was relatively uniform with slightly increase in the third stage.When potassium concentration was low (2-4 mmol/L),lettuce had high utilization efficiency of mineral elements.【Conclusion】The potassium concentration of 4 mmol/L was beneficial to lettuce growth,good yield and quality,and high use efficiency of mineral elements. |
| Key words: hydroponic lettuce potassium concentration dynamic absorption mineral elements |
