Objective] To discuss the concentration effects of exogenous nitric(NO) oxide on photosynthesis and activity of antioxidant en-zymes in Pinus koraiensis seedlings.[Method] 3-year-old P.koraiensis seedlings were treated with sodium nitroprusside (SNP), a NO donor, at 5 different concentrations (0, 0.01, 0.10, 0.50 and 1.00 mmol/L).The contents of photosynthetic pigment, malondialdehyde (MDA) and hydrogen peroxide (H2O2), and the activity of antioxidant enzymes in the needles of P.koraiensis were determined.[Result] Net photo-synthetic rate (Pn), transpiration rate (Tr) and respiration rate (Rd) increased with the increase of SNP concentration, and reached a maxi-mum when SNP concentration was 0.10 or 0.50 mmol/L.Spraying 0.01 mmol/L SNP would significantly increase stomatal conductance (Gs), intercellular CO2 concentration (Ci) and photosynthetic pigment content, the activity of catalase (CAT) and peroxidase (POD).On the con-trary, the activity of superoxide dismutase (SOD), H2O2 and MDA content would decrease after the spraying of SNP.[Conclusion] Appropri-ate concentration of nitric oxide (NO) can significantly increase photosynthetic parameters, photosynthetic pigment content, CAT, APX and POD activity.Spraying SNP can decrease SOD activity, H2 O2 and MDA content.Exogenous NO can relieve the membrane lipid peroxidation of P.koraiensis seedlings to reduce the damage to the seedlings.%[目的]探讨不同浓度外源NO对红松针叶光合色素和抗氧化酶活性的影响。[方法]以3年生红松针叶为试验材料，测定喷施不同浓度外源NO供体硝普钠溶液（0、0．01、0．10、0．50和1．00 mmol／L SNP）处理下其光合色素含量、抗氧化酶活性、丙二醛（MDA）含量和过氧化氢（H2O2）含量等生理指标。[结果]净光合速率（Pn）、蒸腾速率（Tr）和呼吸速率（Rd）会随着SNP浓度增加而增加，分别在SNP喷施0．10和0．50 mmol／L时达到最大值；喷施0．01 mmol／L SNP有效提高了气孔导度（Gs）、胞间CO2浓度（Ci）、光合色素含量、过氧化氢酶（CAT）活性、过氧化物酶（POD）活性，而超氧化物歧化酶（SOD）活性、H2O2含量和MDA含量在喷施外源NO时显著降低。[结论]施加适量浓度外源NO会显著增加光合参数、光合色素含量、CAT活性、抗坏血酸过氧化物酶（APX）活性、POD活性，但施加外源NO降低了SOD活性、H2 O2含量、MDA含量，从而降低了细胞膜脂过氧化程度，减轻了红松幼苗受到的伤害。
展开▼
