亚硒酸钠对苦荞光合特性及抗氧化酶活性的影响

Effects of Sodium Selenite Application on Photosynthesis and Antioxidant Enzyme Activity of Tartary Buckwheat

【目的】探究亚硒酸钠对苦荞光合特性及抗氧化酶活性的影响。【方法】基于盆栽试验,分别设置CK(0 mg/kg)、Se_(5)(5 mg/kg)、Se_(10)(10 mg/kg)、Se_(20)(20 mg/kg)、Se_(40)(40 mg/kg)共5个亚硒酸钠施用量,研究亚硒酸钠施用量对苦荞株高、鲜质量、干质量、光合特性和抗氧化酶活性的影响。【结果】①当亚硒酸钠施用量在5~10 mg/kg时,施硒显著增加苦荞生物量;与CK相比,5 mg/kg亚硒酸钠施用量的地下部干质量、鲜质量增加66.28%、80.00%,10 mg/kg亚硒酸钠施用量的苦荞株高增加7.05%。②施硒改善了苦荞光合特性。与CK相比,5~10 mg/kg亚硒酸钠施用量的苦荞净光合速率、蒸腾速率、气孔导度和叶绿素量平均显著增加7.57%、32.70%、28.12%、6.96%。同时5 mg/kg亚硒酸钠施用量的苦荞胞间CO_(2)摩尔分数显著下降13.95%,CO_(2)同化能力提升。施用亚硒酸钠对苦荞盛花期光合特性的影响最显著。③施硒对苦荞抗氧化酶活性影响作用较大;5 mg/kg亚硒酸钠施用量处理过氧化氢酶活性,较CK增幅最大,为3.29%;10 mg/kg亚硒酸钠施用量处理的超氧化物歧化酶和过氧化物酶较CK显著增加261.74%、88.63%。④当亚硒酸钠施用量为20、40 mg/kg时,苦荞生长发育受到抑制。【结论】5~10 mg/kg亚硒酸钠施用量能提高苦荞光合特性和抗氧化酶活性,盛花期效果尤为显著。

【Objective】Selenium is a vital nutrient but deficient in many soils.Sodium selenium can be used as a selenium fertilizer.This paper investigates the impact of its application on photosynthesis and activity of antioxidant enzymes of Tartary buckwheat.【Method】The experiment was conducted in pots using the variety Xiyang as the model plant.There were 5 treatments by mixing the sodium selenite with soil at a ratio(weight/weight)ranging from 0(control)to 40 mg/kg.In each treatment,we measured the height,fresh and dried weight,photosynthetic parameters,and antioxidant enzyme activities of the crop.【Result】①Applying sodium selenite can significantly increase biomass and height of the crop,compared to the control,but only when application ratio did not exceed 10 mg/kg.②Compared to the control,applying sodium selenite increased net photosynthetic rate,transpiration rate,stomatal conductance,and chlorophyll by 7.57%,32.70%,28.12%and 6.96%respectively,while reduced the intercellular CO_(2)concentration by 13.95%.It was found that applying 5 mg/kg of sodium selenite increased CO_(2)assimilation capacity.The effect of sodium selenite in improving the photosynthesis was most effective during the full flowering stage.③Compared to the control,applying 5 mg/kg of sodium selenite increased activity of catalase by 3.29%;however,increasing the application to 10 mg/kg enhanced the activity of superoxide dismutase and peroxidase by 261.74%and 88.63%,respectively.④The growth and development of Tartary buckwheat were inhibited when the concentrations of disodium selenite were 20 mg/kg and 40 mg/kg.【Conclusion】Our results show that applying sodium selenite to soil can improve photosynthesis and antioxidant enzyme activities of Tartary buckwheat,especially at the flowering stage,but only when the application ratio did not exceed 10 mg/kg.