腐植酸对水培生菜生长和品质的影响
Effects of Humic Acid Application on Growth and Quality of Lettuce in Hydroponic Culture

为了研究腐植酸对水培生菜生长和品质的影响，设计出最优的机-腐植酸复合营养液配方，为腐植酸在水培领域的研究提供理论依据。于采收前15 d，在日本山崎配方中添加6种不同质量分数的腐植酸，试验处理后每5 d测定生菜的产量和品质指标(硝酸盐、维生素C等)。结果表明：腐植酸质量分数在0~1.13 mg/g内随着质量分数的增加，生菜地上部和地下部鲜质量随之增加，腐植酸质量分数为1.13 mg/g时，两者同时达到最大；当腐植酸质量分数高于1.13 mg/g时，两者随腐植酸质量分数的增加而逐渐减小。随着腐植酸质量分数的增加，生菜叶片中硝酸盐质量分数逐渐减小，而可溶性糖和可溶性蛋白质量分数逐渐增加，维生素C质量分数呈现先增大后减小的趋势。综合考虑产量和品质因素，采用山崎+1.13 mg/g腐植酸的复合营养液配方水培生菜可达到高产优质的效果。
To investigate the influence of humic acid application on growth and quality of lettuce in hydroponic culture, enact the optimal inorganic-humic acid complex nutrient solution formula, and provide theoretical basis for research in the field of humic acid in water planting, six different mass fraction of humic acid were added in the famous Yamazaki formula 15 d before harvest. The yield and quality indexes(nitrate mass fraction and vitamin C and so on) of lettuce were measured per five days after treatments. The results showed that the top fresh mass and the root fresh mass of hydroponic lettuce increased with the increase of humic acid mass fraction with 0-1.13 mg/g.The 1.13 mg/g mass fraction humic acid, which was the mass fraction of the highest volume for each aforementioned index. At the condition of above 1.13 mg/g mass fraction humic acid, each aforementioned index decreased with the humic acid mass fraction rising. The nitrate mass fraction of lettuce reduced obviously with increase of the humic acid mass fraction , however, the soluble sugar and soluble protein increased gradually and the vitamin mass fraction of lettuce increased first then decreased. Synthesizing the yield and quality factor, hydroponic lettuce would produce higher yield and improve quality when humic acid with 1.13 mg/g mass fraction were added in Yamazaki formula.