钾、氮营养对莲藕膨大过程中产量和品质的影响

Yield and quality of Nelumbo Nucifera Gaertn affected by potassium and nitrogen application during root development

为了探明钾、氮营养对莲藕膨大过程中产量和品质的影响,采用盆栽试验,设置2个钾处理(不施钾和适量钾)和3个氮处理(不施氮、适量氮和2倍适量氮),分别于子藕移栽后76 d、97 d、118 d、139 d、160 d和190 d收获莲藕膨大茎,记录其鲜、干重,分析还原糖、可溶性总糖、淀粉和粗蛋白质含量。结果表明:当钾、氮营养不足时,莲藕茎膨大形成的时间提前。在莲藕膨大茎形成早、中期,适量钾处理的产量低于不施钾处理;在莲藕膨大茎形成早期,适量氮处理的产量低于不施氮处理;在莲藕膨大茎成熟后,适量钾处理的莲藕产量比不施钾处理高出20%以上,适量氮处理的产量比不施氮处理高出2.3倍以上。施氮过量时,莲藕膨大形成的时间推迟,且适量氮处理的莲藕最终产量比2倍适量氮处理高出1.2倍以上。适量的钾、氮营养可以提高莲藕膨大前、中期还原糖和可溶性总糖含量以及膨大中、后期淀粉含量,表明适量的钾、氮营养能明显改善莲藕品质。

To explore the effect of potassium（K） and nitrogen （N）on yield and quality of lotus root during root develop- ment, pot experiments with 2 potassium treatments （No potassium treatment, appropriate potassium treatment） and 3 nitrogen treatments（ No nitrogen treatment, appropriate nitrogen treatment, two times of appropriate nitrogen treatment） were designed. The lotus roots were harvested at 76 d, 97 d, 118 d, 139 d, 160 d and 190 d after transplanting, respectively. Fresh and dry weights of lotus root were recorded, and the reducing sugar, total soluble sugar, starch and crude protein contents of lotus root were determined. Results showed that insufficient K and N brough forward the development of lotus root. At early and middle stage of lotus rhizomes development, the yield of rhizome lotus in appropriate K treatment was lower than that in no K fertilization treatment. At early stage of lotus root development, the yield in appropriate N treatment was lower than that in no N fertilization treatment. The final yield of lotus root in appropriate K treatment was 20% higher than that in no K fertilization treatments at ma- turity, and the final yield in appropriate N treatments was 2. 3 times higher than that in no N fertilization treatment. Overdose ap- plication of N delayed yield formation of lotus root, and resulted in 1.2 times higher yield of rhiz lotus root in appropriate N treat-merit compared to that in two times of nitrogen treatment. Appropriate K or N increased the contents of reducing sugar and total soluble sugar of lotus root in early and middle sta- ges, as well as the content of starch in middle and late stages during root development. These results indicated that appro- priate K or N could improve the quality of lotus root.