氮素水平对宽杆芥菜幼苗生长及酶活性的影响

以NH4NO3作为变量,试验设7个处理,以普良尼柯夫配方营养液进行试验来研究氮素对芥菜幼苗生长及酶活性的影响。水培试验结果表明,芥菜幼苗移栽后14 d,营养液中的总氮量为9 mmol.L-1(N3处理)的株高、叶数、最大叶长和最大叶宽均最大,分别为4.03 cm、3.00片.株-1、2.43 cm和1.08 cm,与N0处理的差异均达到极显著水平。芥菜苗移栽后42 d,以N3处理的株高、叶数、最大叶长、地上部、地下部、总生物量、根系活跃吸收面积和最长根长均最多,分别为4.30 cm、5.00片.株-1、3.36 cm、367.87 mg、27.13 mg、395.00 mg、53.03%和6.03 cm,它们与N0的差异均达到极显著水平,除最大叶长与N0处理的差异达到显著水平外。N3处理叶片的CAT和POD活性均较高,分别为16.89 U.mg-1.min-1和134.27 U.mg-1.min-1,MDA含量最小(2.29 nmol.g-1),与N0的差异均达到极显著水平。因此,在本试验条件上,营养液中的总氮量为9 mmol.L-1(N3)处理芥菜的幼苗生长和酶活性指标最好。建议营养液中施总氮量为9 mmol.L-1。

Effects of the content of available nitrogen in water on the growth and enzymatic activity of Brassica juncea

Taken NH₄NO₃ as variable value, seven treatments were designed to study the effects of the content of available nitrogen in nutrient solutions on the growth and enzymatic activity of Brassica juncea. The result of water culture experiment indicated that: after Brassica juncea seedlings were transplanted for 14 days, the height, number of leaves, the maximum leaf length and the maximum leaf width of the leaf mustard plants treated with N₃ (9 mmol·L^-1 N) could reach 4.03 cm, 3.00 piece per plant, 2.43 cm and 1.08 cm, respectively, which showed significant difference in contrast with N₀ treatment. After 42 days, the height, number of leaves, the maximum leaf length, overground biomass, belowground biomass, total biomass, root active absorption area and the longest root length of the treated Brassica juncea plants were found to be 4.30 cm, 5.00 piece per plant, 3.36 cm, 367.87 mg, 27.13 mg, 395.00 mg, 53.03% and 6.03 cm, respectively, which showed significant difference in contrast with N₀ treatment, except that the maximum leaf length attained notable level in contrast with N₀ treatment. CAT and POD activities in the leaf with N₃ treatment reached the peak value of 16.89 U·mg^-1·min^-1 and 134.27 U·mg^-1·min^-1, respectively, while the MDA content reached the bottom of 2.29 nmol·g^-1, which also revealed the significant difference in contrast with N₀ treatment. Under the experimental conditions, growth status and enzymatic activity of Brassica juncea with N₃ treatment obtained the best indices. So 9 mmol·L^-1 of total nitrogen was recommended as the suitable applied concentration in the nutrient solutions .