喷施微肥对定位施肥烟株成熟期生理代谢的影响

为探究叶面喷施微肥对烟叶成熟的影响，提高烟叶适烤性，以‘翠碧一号’为试验材料，在连续10年纯化肥定位施肥烟田，于烟株打顶后10、20天时喷施不同中微量元素，测定其对烟叶生理代谢的影响。叶面喷施不同中微量元素后，叶绿素a、叶绿素b和叶绿素总量均有较明显上升，叶片光合速率、蒸腾速率和气孔导度明显提高，荧光参数中Fo和Fo/Fm显著下降，Fm、Fv、Fv/Fm和Fv/Fo显著上升；硝酸还原酶活性显著提升；细胞膜相对透性显著降低；过氧化氢酶和超氧化物歧化酶均能保持较高的活性，而丙二醛含量显著下降。表明在长期纯施化肥烟田的烤烟生长后期喷施中微量元素有利于提高细胞膜结构稳定性，减轻膜脂过氧化程度，维持光合结构的稳定性，减少叶绿体色素的降解，提高光能转化效率，减缓活性氧伤害。喷施微肥有利于提高烟叶光合作用能力，缓解烟株叶片伤害与衰老，提高上部烟叶的适烤性。

Effects of Spraying Microelement-fertilizer on Physiological Metabolism of Tobacco Plant at Mature Stage Under Localized Fertilization

To explore the effect of foliar application of microelement-fertilizer on the maturity of tobacco leaves and improve tobacco leaf quality, ‘CB-1’ was selected as the experimental material. After 10 years’ localized fertilization with pure chemical fertilizer in tobacco fields, the effects of different medium and trace elements on the physiological metabolism of tobacco leaves were determined by foliar application 10 days and 20 days after topping of tobacco plants. The results showed that after spraying different medium and trace elements on leaves, the total content of chlorophyll a, chlorophyll b and total chlorophyll increased significantly, the leaf photosynthetic rate, transpiration rate and stomatal conductance increased significantly, the fluorescence parameters Fo and Fo/Fm decreased significantly, and Fm, Fv, Fv/Fm and Fv/Fo increased significantly. Nitrate reductase activity increased significantly. The relative permeability of cell membrane decreased significantly. Both CAT and SOD maintained high activities, while MDA content decreased significantly. The results indicated that spraying medium and trace elements in the late growth stage of flue-cured tobacco in the field with long-term pure chemical fertilizer application was beneficial to improving the stability of cell membrane structure, reducing the degree of membrane lipid peroxidation, maintaining the stability of photosynthetic structure, reducing the degradation of chloroplast pigments, improving the efficiency of light energy conversion, and slowing down the damage of reactive oxygen species. Spraying microelement-fertilizer is conducive to improving the photosynthetic capacity of tobacco leaves, alleviating the injury and aging of tobacco leaves, and improving the flue-curing adaptability of upper leaves.