为了研究基于SPAD值精准施氮模式对烤烟生理期碳代谢的影响。以K326为试验材料,设置基于SPAD值的烤烟实时氮肥追施的施氮方式(SPAD阈值为43)和传统农家施氮方式两个处理,以两个处理烟株的第4叶、第10叶和第18叶作为下、中、上3个部叶的代表叶片来研究碳代谢碳水化合物含量及酶的活性。随着烟龄的增加,上、中、下部叶总糖、还原糖、蔗糖和淀粉的含量均表现出增加的趋势,而中、上部叶的蔗糖和淀粉含量在后期又有所回落,与农户惯用施肥模式相比,基于SPAD值施氮模式下的上、中、下部叶的还原糖、总糖、蔗糖磷酸合成酶和淀粉酶的含量均较高,而淀粉和淀粉磷酸化酶含量则相对较低,蔗糖和蔗糖转化酶在烟株生长前期较高,但后期低于传统农家施氮方式。说明基于SPAD施氮模式迎合了烟株生理期碳代谢的变化规律.有利于烟株碳代谢的进行。
In order to study the effects on the physiological carbon metabolism of flue-cured tobacco under precise nitrogen management model based on SPAD value of tobacco leaves, using K326 as experimental material, the research studied the lower, the middle and the upper leaves' carbohydrate content and carbon metabolism enzyme activity under two different treatments: the real-time nitrogen fertilizer topdressing method based on the SPAD value (SPAD threshold is 43) of flue-cured tobacco and the traditional nitrogen fertilizer used by local peasants. The leaves of the 4th, the 10th and the 18th leaf position represent the lower, the middle and the upper leaves separately. The results show that, with the growing of tobacco plant, the content of the total sugar, reducing sugar, sucrose, and starch in different leaf position show an increasing trend in both method of N fertilizing, while the content of the sucrose and starch in the middle and the upper leaves come down in the late stage of tobacco plant growing. The content of the reducing sugar, total sugar, sucrose phosphate synthase and amylase in tobacco plant using the nitrogen fertilizing method based on SPAD value is higher than those using the traditional nitrogen fertilizing method, while the content of the starch and starch phosphorylase is lower. The content of the sucrose and sucrose invertase is higher in the early tobacco plant growing stage, but lower than those using the traditional nitrogen fertilizing method in the late tobacco growing stage. Based on the results, the precise nitrogen fertilizing method based on SPAD value is caters tobacco plant physiological changes of carbon metabolism and conducive to the conduct of tobacco plant carbon metabolism.