【目的】探究亚硒酸钠对‘绿岭’核桃种仁抗氧化酶活性及果实品质的影响,为富硒核桃生产中合理施用硒肥提供参考。【方法】以15年生‘绿岭’核桃为试材,叶面喷施不同浓度亚硒酸钠溶液,在果实成熟期采集果实,测定种仁抗氧化酶活性及果实品质,采用主成分分析法对果实性状进行综合评价。【结果】叶面喷施适宜浓度的亚硒酸钠促进了核桃种仁超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性的提高,减少了丙二醛(MDA)在植株内的累积,提高了植株的抗氧化性;种仁SOD、POD、CAT活性分别以喷施200、80、120 mg/L亚硒酸钠处理最高,活性分别为2.65、9.30、246.98 U/(g·min),较清水喷施的对照(CK)分别提高61.59%、31.54%、104.89%;亚硒酸钠喷施质量浓度为120 mg/L处理时,种仁MDA含量最低,为2.27 μmol/g;叶片喷施亚硒酸钠溶液后,提高了核桃坚果产量,但处理间差异不显著;亚硒酸钠质量浓度为160 mg/L时,核桃单果质量最大,为13.42 g,较CK提高了6.85%;种仁可溶性糖、淀粉、可溶性蛋白质、总蛋白质、脂肪含量分别在叶片喷施亚硒酸钠质量浓度120、80、120、200、120 mg/L时达到最大值,质量分数分别为2.41%、0.88%、0.84%、23.09%、70.70%;叶片喷施亚硒酸钠显著提高了核桃种仁内硒含量(0.10~0.16 mg/kg),达到了富硒农产品标准;种仁硒元素含量与种仁SOD活性、产量、单果质量、纵径、可溶性糖含量均呈极显著正相关,相关系数分别为0.96、0.89、0.92、0.91、0.77。【结论】叶面喷施适宜浓度的亚硒酸钠溶液可提高核桃单株产量,可显著提高单果质量、横径、纵径、侧径等外在品质,并显著提高种仁硒含量、可溶性糖、可溶性蛋白、总蛋白质、脂肪含量等内在品质,可提高种仁的抗氧化性。主成分分析综合评价表明,叶面喷施120 mg/L亚硒酸钠,核桃的综合性状表现最好。

【Objective】The aims of this research are to explore the effects of sodium selenite on the antioxidant enzyme activities and fruit qualities of ‘Lvling’ walnut and to provide references for the effective application of selenium fertilizer in selenium rich walnut production.【Method】The 15-year-old ‘Lvling’ walnut trees were used as the materials, and different concentrations of sodium selenite solutions were sprayed onto the leaves. The fruits were collected during the fruit ripening season and the kernel antioxidant enzyme activities and the fruit qualities were determined. Principal component analysis was used to evaluate the fruit traits.【Result】The kernel SOD, POD and CAT activities were increased and the MDA content was decreased by spraying a suitable concentration of sodium selenite onto the leaves, and the antioxidant capacity was improved. The kernel SOD, POD and CAT activities were the highest after spraying 200, 80, 120 mg/L of sodium selenite solution respectively, which were 2.65, 9.30, 246.98 U/(g·min), which increased by 61.59%, 31.54%, 104.89%, respectively, compared with CK. The MDA content of the kernels was the lowest after spraying 120 mg/L sodium selenite, which was 2.27 μmol/g. After sodium selenite solutions had been sprayed onto the leaves, the nut yields increased, but there were no significant differences between the sodium selenite treatments. When the sodium selenite concentration was 160 mg/L, the nut weight was 13.42 g, which was the highest, which was 6.85% higher than the CK. The kernel soluble sugar, starch, soluble protein, total protein, and fat content increased after spraying sodium selenite had been sprayed onto the leaves, and their contents reached their maximum when the spraying concentrations were 120, 80, 120, 200, 120 mg/L, respectively, and the contents were 2.41%, 0.88%, 0.84%, 23.09% and 70.70%, respectively. The selenium content of the kernels increased significantly after sodium selenite was sprayed onto the leaves and the content was 0.10-0.16 mg/kg, which reached the selenium-enriched standard. There was found to be a highly significant positive correlation between the kernel selenium content and the SOD activity, yield, nut weight, nut longitudinal diameter and the soluble sugar content, and the correlation coefficients were 0.96, 0.89, 0.92, 0.91 and 0.77, respectively.【Conclusion】After spraying appropriate concentrations of sodium selenite onto the leaves, the nut yield increased, and the external qualities of the walnuts such as the nut weight, horizontal diameter, vertical diameter, and the side diameter as well as the internal qualities of the walnuts such as the selenium content, soluble sugar, soluble protein, total protein, and the fat content significantly increased, and the kernel antioxidant capacity improved. Evaluation using principal component analysis showed that the walnuts had the best characteristics when 120 mg/L sodium selenite was sprayed onto the leaves.