供氮水平对菠菜产量、硝酸盐和草酸累积的影响

采用溶液培养方法研究了不同供氮水平对菠菜生物量、硝酸盐和不同形态草酸含量的影响。结果表明,供氮水平由4.mmol/L增加到8.mmol/L,菠菜产量显著增加,继续提高氮水平对产量没有显著影响。叶片中的维生素C(Vc)含量随着供氮浓度从4.mmol/L提高到8.mmol/L而显著增加,再增加氮水平,叶片中的Vc含量明显下降;而菠菜叶柄Vc的含量则随供氮水平的提高显著下降。叶片硝酸盐含量随着氮浓度的提高而增加,当供氮水平由4mmol/L增加到8.mmol/L时,叶柄硝酸盐含量显著下降,而氮水平由8.mmol/L提高到20.mmol/L时,叶柄硝酸盐含量则随之升高。供氮浓度从4.mmol/L增加到8.mmol/L,叶片可溶态草酸含量略有下降,再提高供氮水平则明显上升,供氮水平低于12.mmol/L时,叶柄中的可溶态草酸和菠菜叶片和叶柄中的草酸总量则随着氮水平的提高而升高,高于12.mmol/L草酸含量反而降低。由此可见,菠菜在供氮浓度为8mmol/L(N2)时能够获得较高的产量和Vc含量,较低的硝酸盐和草酸含量,表明适宜的供氮水平下可获得高产优质的菠菜。

Influence of different nitrogen levels on biomass,nitrate and oxalate accumulation in spinach

An experiment of soluble culture was carried out to determine the effects of different solution N levels (4,8,12,16,20 mmol/L) on biomass, nitrate and oxalate content of spinach (Spinacia oleracea ). Results showed that spinach biomass was drastically increased by increasing N level from 4 to 8 mmol/L and was not obviously different at higher N level. Vitamin C content of leaf increased up to 8 mmol/L N and then decreased as N level further increased, while Vitamin C content in petiole decreased obviously as N rate increased. Nitrate content in leaf increased with increasing N rate, whereas nitrate content of petiole decreased when nitrogen level was increased from 4 to 8mmol/L then increased at the range of 8 ~ 20 mmol/L N. Soluble oxalate in leaf decreased slightly from 4 to 8 mmol/L N and then increased with further increasing N level, while soluble oxalate in petiole and total oxalate in leaf and petiole of spinach were increased up to 12 mmol/L N and then decreased at over 12 mmol/L. It follows that spinach has higher biomass and Vc content, lower nitrate and oxalate content as 8 mmol/L N was supplied in solution. This shows that spinach has high yield and high quality under proper nitrogen level.