硝化抑制剂对小白菜内源硝酸盐代谢的影响

为了提高蔬菜体内硝态氮的代谢有效利用性,采用土培盆栽试验方法,以NO3-N︰NH4+-N为2︰3的处理(以S1表示)为对照,研究在对照基础上分别添加3种硝化抑制剂(即,双氰胺、咪唑、吡啶,分别以S2、S3、S4表示)对小白菜内源硝酸盐代谢的影响。结果表明:3种硝化抑制剂的添加可提高小白菜产量6.06%~28.55%,增加植株氮吸收量2.38%~38.42%,降低蔬菜硝酸盐含量2.69%~19.66%,分别提高小白菜叶片硝酸还原酶活性、叶肉细胞硝态氮的代谢库大小和贮藏库大小24.28%~77.32%、29.45%~272.17%和2.78%~17.38%,并增加代谢库与贮藏库的比值0.04%~0.59%,从而提高了小白菜内源硝酸盐的有效利用性。其中,以S2处理对提高小白菜内源硝酸的有效利用性相对最佳,植株产量和植株氮吸收量相对最高,分别为56.72 g.盆1和0.156 g.盆1;植株硝酸盐含量较低,为1 749 mg·kg-1;而叶片的硝酸还原酶活性和叶肉细胞硝态氮代谢库相对最高,分别为1.90μg(NO2-N).30 min-1·g-1(FW)和0.33μg(NO2-N)·g-1(FW)。

Effect of nitrate inhibitors on endogenous nitrate metabolism in Chinese cab-bage

Soil-pot experiment consisting of a control treatment(with nitrate-N∶ammonium-N = 2∶3 denoted as S1) and 3 trial treatments(with application of dicyandiamide,imidazole and pyridine nitration inhibitors on the base of S1 and respectively denoted as S2,S3 and S4) were conducted to study the effects of nitrate inhibitors on endogenous nitrate metabolism in Chinese cabbage.Results showed that the 3 nitrate inhibitors increased vegetable cabbage yield by 6.06%~28.55%,N absorption by 2.38%~38.42% compared with S1.S2,S3 and S4 treatments decreased plant nitrate concentration by 2.69%~19.66% and increased leaf NRA(nitrate reductase activity),MPS(metabolic pool size),SPS(storage pool size) and MPS/SPS by 24.28%~77.32%,29.45%~272.17%,2.78%~17.38% and 0.04%~0.59%,respectively.This subsequently enhanced the availability of endogenous nitrate in Chinese cabbage.Treatment S2 had the highest improvement in yield,N absorption and availability of endogenous nitrate in Chinese cabbage.Treatment S2 yield and absorption amounts of N were 56.72 g·pot-1 and 0.156 g·pot-1,respectively.However,plant nitrate content in S2(1 749 mg·kg-1) was relatively low.Leaf NRA and MPS in S2 were 1.90 μg(NO2--N)·30 min-1·g-1(FW) and 0.33 μg(NO2--N)·g-1(FW),respectively.