过氧化脲及尿素配比对水培上海青生长及品质的影响

Effects of Urea Hydrogen Peroxide and Urea Ratios on Growth of Brassica campestris in Hydroponic Culture

水培蔬菜中硝酸盐富集及供氧状况是当前水培体系亟待解决的问题。为降低水培上海青Brassica campestris ssp.Chinensis(L.)硝酸盐含量,本研究分别通过部分尿素替代日本园试配方中硝酸盐,以及不同过氧化脲(UHP)与尿素配比的方式,探究减硝增氧对水培叶菜生长及品质的影响。首先以30%、40%、50%、100%尿素替代硝态氮来优化日本园试配方,其中50%尿素替代处理能显著提高叶菜产量,同时对根系有明显促生作用。然后在此基础上以10%、30%、50%和80%UHP替代改良日本园试配方中的尿素,从而确定UHP、尿素及硝态氮的最佳比例。结果表明:随着UHP浓度的增加,营养液中溶解氧浓度显著增加,与对照相比,施用UHP的处理溶解氧浓度提高7.63%~39.70%。与对照相比,30%UHP处理增产27.65%,总根长、根表面积、根粗、根体积及根尖数分别增加24.68%、36.92%、16.90%、28.19%和28.89%,但高浓度(50%和80%)UHP处理显著抑制上海青生长。30%UHP处理显著提高上海青叶绿素含量及VC含量,与对照相比,分别增加71.25%和34.91%。随着UHP浓度的增加,上海青叶片硝酸盐含量呈下降趋势,与对照相比,10%、30%、50%和80%UHP处理硝酸盐含量显著降低3.89%、9.69%、22.71%和26.87%。因此,在蔬菜水培栽培管理中,适量增氧减硝能够刺激根系发育,同时有利于提高上海青的产量及品质,其中UHP∶尿素∶硝酸盐中氮含量比例为3∶7∶10为最佳配比。

Nitrate enrichment and oxygen supply in hydroponic vegetables are urgent problems that need to be solved in the current hydroponic system.In order to reduce the nitrate content of Brassica campestris ssp.Chinensis(L.)in hydroponic culture,firstly,urea was used to replace partial nitrate in the Japanese garden test nutrition solution,and then different ratios of urea-hydrogen peroxide(UHP)to urea were designed to study the effects of nitrate reduction and increment oxygen on the growth and quality of B.campestris in hydroponic.First of all,30%,40%,50%and 100%urea were used to replace nitrate to optimize the Japanese garden test nutrition solution.Compared to the control treatment,50%urea substitution treatment significantly increased the yield and had a significant effect on root growth of B.campestris.Furthermore,10%,30%,50%and 80%UHP were used to replace partial urea in the modified Japanese garden test nutrition solution to determine the best ratio of UHP to urea and nitrate.The results showed that with increase of UHP concentration,the dissolved oxygen concentration in the nutrient solution increased significantly by 7.63%–39.70%compared with the control.Moreover,the yield of 30%UHP treatment increased by 27.65%compared with the control,as well as the total root length,root surface area,average root diameter,root volume and root tip number respectively increased by 24.68%,36.92%,16.90%,28.19%and 28.89%,however the growth of B.campestris significantly inhibited in 50%and 80%of UHP treatments.Chlorophyll and VC contents in 30%UHP treatment were significantly increased by 71.25%and 34.91%,respectively,than the control.With increase of UHP concentration,the nitrate content of leaves showed a downward trend,nitrate content significantly decreased by 3.86%,9.69%,22.71%and 26.87%respectively in 10%,30%,50%and 80%UHP treatments compared with the control.It was concluded that appropriate nitrate reduction and increment of oxygen could stimulate root development,improve yield and quality of B.campestris.The optimized ratio of nitrogen content in UHP︰urea︰nitrate was 3︰7︰10.