不同氮素形态及配比对蔬菜生长和品质的影响

Effect of Different Nitrogeous Forms and NO - 3 to NH + 4 Ratio on Growth and Quality of Vegetables

分别以纯水和自来水为生长介质对莴笋和菠菜进行水培试验，以揭示不同氮素形态及配比对蔬菜生长和品质的影响。结果表明，以纯水为水培水源，ＮＯ－３－Ｎ∶ＮＨ＋４－Ｎ为１∶１或单独供应ＮＨ＋４－Ｎ，对作物生长均有一定程度的抑制作用，而以后者的生长量最低。以自来水作水培介质时，以ＮＯ－３－Ｎ为唯一氮源预培养一段时间后，再提高营养液中ＮＨ＋４－Ｎ比例，有利于蔬菜的生长发育及硝酸盐含量的降低，使莴笋维生素Ｃ含量也有所降低，菠菜则无明显变化。当植物生长量较大时。

In order to investigate the effect of different nitrogen forms and NO - 3 to NH + 4 ratio on growth and quality of vegetables,solution culture experiment in which the distilled water and the running water were supplied as growth medium respectively was conducted.The results are as follows:with the distilled water as growth medium,vegetable growth is inhibited to some extent when NO - 3 N:NH + 4 N ratio is 1∶1 or NH + 4 N is supplied solely,when NH + 4 N is only nitrogen source,the vegetable growth amount is least.When the running water in which the small amount of nitrate existes is supplied as culture medium,at first the vegetable was cultured for some time only NO - 3 N as nitrogen source,then increasing the NH + 4 N percentage in nutrient solution ,which favours growth and development of vegetables,in the meantime the nitrate content in vegetables decreased,vitamin C content in lettuce decreased and vitamin C in spinaches didnt show apparently change. When the vegetable growth amount is relatively large,the nitrogen source mainly supplied by urea cant meet the demand of vegetable to nitrogen.