摘要:为提高烟叶钾肥利用率及改善烟叶品质，以烤烟品种‘K326’为材料，利用接触角法测定了烟叶的临界表面张力；选取蔗糖脂肪酸酯、茶皂素、洗衣粉3种表面活性剂，利用表面张力法确定其临界胶束浓度；以喷施清水和单独喷施钾肥为对照，分别在钾肥中加入3种表面活性剂进行大田喷施试验（CK：喷施清水；CK1：喷施钾肥；T1：喷施钾肥+蔗糖脂肪酸酯；T2：喷施钾肥+茶皂素；T3：喷施钾肥+洗衣粉），测定不同生育期不同处理烟叶钾含量、抗氧化酶活性以及质体色素含量，并对烤后烟叶进行化学成分测定，研究了表面活性剂辅助钾肥喷施对烤烟润湿性能、生理指标及烤后烟叶品质的影响。结果表明：1）烟叶临界表面张力为30.41 mN·m-1，属于临界表面张力较低的叶片，较难被液体润湿。表面活性剂蔗糖脂肪酸酯和茶皂素的临界胶束浓度为1 000 mg·L-1、5 000 mg·L-1，对应的表面张力值为32.64 mN·m-1、40.33 mN·m-1，而洗衣粉浓度2 000 mg·L-1时的表面张力最接近烟叶的临界表面张力，对应的表面张力值为30.30 mN·m-1。加入表面活性剂后，钾肥溶液表面张力显著降低，润湿性能增加。2）表面活性剂促进了烟叶对钾肥的吸收。与单独喷施钾肥相比，加入表面活性剂后，烟叶生长过程中钾含量提高，其中T1、T2处理4个生育期烟叶钾含量均高于CK1处理。表面活性剂辅助钾肥喷施不同程度提高了烟叶SOD、POD酶活性，降低了MDA含量，烟叶抗氧化能力增强，膜脂过氧化程度降低，烟株抗逆性增强。此外，加入表面活性剂后，烟叶功能盛期叶绿素含量、类胡萝卜素含量提高，进而增强了烟叶的光合作用，有利于光合产物的合成和积累。3）加入表面活性剂后，烤后烟叶总氮和烟碱含量降低，钾含量和总糖、还原糖含量升高，化学成分更协调，烟叶品质更加优异。综合来看，添加蔗糖脂肪酸酯处理在提高烟叶润湿性能、促进钾肥吸收以及改善烟叶生理指标、提升品质方面效果最佳。
关键词:表面活性剂/
钾肥/
烤烟/
润湿性能/
生理指标/
品质
Abstract:The 'K326' flue-cured tobacco variety was used to investigate the improvement of potassium fertilizer utilization and quality of tobacco leaf under combined application of surfactant and potassium fertilizer. While in the study the contact angle method was used to determine critical surface tension of tobacco leaf, the study critical micelle concentrations of surfactants of sucrose fatty acid ester, tea saponin and washing powder were measured by using surface tension method. By spraying water and potassium fertilizer as the control, the 3 surfactants were added to potassium fertilizer in the field spraying test. In the experiment, CK was the control involving water, CK1 was the control involving potassium fertilizer, T1 was the treatment involving potassium fertilizer plus sucrose fatty acid ester, T2 was the treatment involving potassium fertilizer plus tea saponin, and T3 was the treatment involving potassium fertilizer plus washing powder. The potassium content, antioxidant enzymes activities and plastid pigments contents of tobacco leaves in 5 treatments in different times were measured, and the chemical constituents of flue-cured tobacco leaf were determined. The effects of spraying potassium fertilizer with surfactant on the wettability, physiology and quality indexes of flue-cured tobacco leaf were determined. The results indicated that:1) critical surface tension of tobacco leaf was 30.41 mN·m-1 indicating lower wettability of tobacco leaf. The critical micelle concentrations (CMC) of sucrose fatty acid ester and tea saponin were 1 000 mg·L-1 and 5 000 mg·L-1, with corresponding surface tensions of 32.64 mN·m-1 and 40.33 mN·m-1, respectively. When washing powder concentration was 2 000 mg·L-1, its surface tension (30.30 mN·m-1) was close to the critical surface tension of tobacco leaf. Under the addition of surfactant, the surface tension of potassium fertilizer solution decreased significantly while the wettability increased. 2) Surfactants promoted the absorption of potassium in tobacco leaf. Potassium contents under T1 and T2 treatments were higher than under CK1 during the growth period of tobacco. Application of potassium fertilizer with surfactant increased the activities of SOD and POD and decreased MDA content in tobacco leaf. This increased antioxidant capacity of tobacco leaf and reduced membrane lipid peroxidation. Also after the addition of surfactant, chlorophyll and carotenoid contents of tobacco leaf increased at the peak function stage. This enhanced photosynthesis of tobacco leaf which in turn was conducive for the synthesis and accumulation of photosynthetic products. 3) With the addition of surfactant, the contents of total nitrogen and nicotine decreased, while those of potassium, total sugar and reducing sugar increased in flue-cured tobacco leaf. The chemical constituents were more harmonious and the quality of tobacco leaf better. In summary, the addition of sucrose fatty acid ester had the best effect in terms of improving wettability of tobacco leaf, absorption of potassium fertilizer, physiology of tobacco and quality of tobacco leaf.
Key words:Surfactant/
Potassium fertilizer/
Flue-cured tobacco/
Leaf wettability/
Physiology/
Quality
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