不同氨氮浓度对水蕹菜生长特性的影响

[目的]探讨不同氨氮浓度对水蕹菜生长特性的影响。[方法]通过在营养液中设置不同氨氮浓度(0、0.1、0.5、1.0、5.0、10.0、50.0 mg/L),对优良的水面培植作物——水蕹菜扦插苗展开培养,研究其各项生长指标对氨氮浓度变化的响应及其对氨氮的吸收利用。[结果]氮素缺乏导致水蕹菜植株增高减缓,叶片黄化,分蘖受抑。当氨氮浓度超过0.5 mg/L时,植物快速增高;但超过10.0 mg/L,又会抑制植株增长,根系溃烂,叶片脱落。氨氮初始浓度为1.0 mg/L时,水蕹菜各项生长指标最优,对氨氮净化效率最大,为96.3%。氨氮浓度超过1.0 mg/L时,植株根长偏短,根重偏低,茎叶系统增重明显,总生物量增长状况优于低氨氮处理(1.0 mg/L),但净化效率却随着氨氮浓度的增加而下降。[结论]该研究为鱼虾菜生态养殖模式的推广应用提供了理论依据。

Effects of Different Ammonia Nitrogen Concentrations on the Growth Characters of Ipomea aquatica

[Objective] The study aimed to discuss the influence of various ammonia nitrogen concentrations on the growth characters of Ipomea aquatica.[Method] Seven groups of hydroponics nutrient solutions with different ammonia nitrogen concentrations （0,0.1,0.5,1.0,5.0,10.0,50.0 mg/L） were made up to cultivate the cuttings of Ipomea aquatica,which was identified to be a suitable vegetable crop for water culture.The responses of the plant growth and the nutrient adsorption efficiency were studied.[Result] Nitrogen deficiency caused stunting of the plant growth,chlorosis of old leaves,and inhibition of tiller.When the concentration of ammonia nitrogen exceeded 0.5 mg/L,the plant grew rapidly.As the concentration was higher than 10.0 mg/L,the plant growth was inhibited,and the roots rotted,while the leaves fell off.The most suitable concentration of ammonia nitrogen for the plant growth was 1.0 mg/L,when the growth parameters were the optimum and the purification efficiency of ammonia nitrogen reached the maximum,namely 96.3％.When the concentration exceeded 1.0 mg/L,the roots became shorter and lighter,but the fresh weight of stems and leaves increased obviously.Moreover,the total biomass was greater than that of the treatments with lower concentrations of ammonia nitrogen than 1.0 mg/L.However,the purification efficiency had an inverse correlation with ammonia nitrogen concentration.[Conclusion] The research could provide theoretical references for the popularization and application of ecological breeding model of fish,shrimp and vegetables.