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以大白菜[Brassica pekinensis(Lour.)Olsson]中结球小的类型‘金娃娃’品种为试验材料,采用水培的方法,研究了正常光(200μmol·m~(-2)·s~(~(-1)))和弱光(100μmol·m~(-2)·s~(-1))下营养液中不同铵硝配比(0︰100、10︰90、15︰85和25︰75;总N浓度为5 mmol·L~(-1))氮素对幼苗生长以及叶片生理生化特性的影响。处理14 d后,正常光下,铵硝配比15︰85的处理植株长势最佳,较全硝态氮处理叶面积、株幅、鲜质量和干质量分别显著提高了33.8%、30.5%、77.9%和72.9%。弱光抑制了幼苗的生长,植株叶面积、株幅和干鲜质量均低于正常光下生长的植株。弱光下幼苗叶片丙二醛(MDA)、超氧阴离子、过氧化氢(H2O2)含量明显升高,植株遭受膜脂过氧化程度较高。铵硝配比10︰90处理较全硝态氮处理相比,植株叶面积、株幅、鲜质量和干质量分别显著提高了20.4%、14.9%、55.9%和36.5%,而且显著提高叶片的可溶性糖和可溶性蛋白含量及超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性,降低MDA和超氧阴离子含量,有效地抑制了膜脂过氧化。正常光条件下,铵硝配比为15︰85时植株长势最佳;弱光下,铵硝配比为10︰90时植株长势最佳,可降低膜脂过氧化物质含量、提高抗氧化酶活性和渗透调节物质含量,进而提高幼苗耐弱光性。
In this study, we studied the effects of normal light (200μmol · m ~ (-2) · s ~ (-1)) on Chinese cabbage [Brassica pekinensis (Lour.) Olsson] ~ (-1)) and low light (100μmol · m -2 · s -1) : 75; total N concentration 5 mmol·L -1) on the growth of seedlings and the physiological and biochemical characteristics of leaves. After 14 days of treatment, under the normal light, the ratio of ammonium nitrate to 15︰85 was the best, and the leaf area, plant width, fresh weight and dry weight were significantly increased by 33.8%, 30.5% 77.9% and 72.9%. Weak light inhibited seedling growth, plant leaf area, plant width and dry weight were lower than normal light plant growth. The contents of malondialdehyde (MDA), superoxide anion (H2O2) and superoxide anion (H2O2) in leaves of seedlings under low light were significantly increased, while the plants were exposed to higher levels of membrane lipid peroxidation. The leaf area, plant width, fresh weight and dry weight increased significantly by 20.4%, 14.9%, 55.9% and 36.5%, respectively, compared with total nitrate nitrogen treatment, Soluble sugar and soluble protein content and activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX), MDA content and superoxide anion content, Effective inhibition of lipid peroxidation. Under normal light conditions, the plant growth was the best when the ammonium nitrate ratio was 15︰85. When the ammonium nitrate ratio was 10︰90, the plant grew best under low light, which could reduce the membrane lipid peroxidation and increase the antioxidant enzyme Activity and osmotic adjustment of substance content, thereby improving seedling tolerance to poor light.