烤烟上部叶采收时SPAD值与鲜烟组织结构、生理指标及烤后烟叶内在质量的关系

  目的  进一步量化烤烟上部叶成熟度与烟叶质量的关系。  方法  以云烟87为试验材料，应用叶绿素测定仪对上部叶成熟度进行分类，并对各类鲜烟组织结构、生理指标及烤后烟叶质量进行分析。  结果  ① 上部叶SPAD值均值在9~25范围内，与鲜烟叶的自由水/束缚水比值、蛋白质含量呈线性正相关，与海绵组织与栅栏组织比值呈负相关；与烤后叶片TSNAs含量呈线性正相关，与多酚、烟碱含量呈线性负相关；②SPAD值低于17时叶片衰老特征明显，碳氮代谢大幅下降，POD、SOD、CAT等抗氧化酶活性显著增加，H₂O₂、MDA含量大幅增加。  结论  鄂西南烟区上部叶采收SPAD值适宜范围为13±1.5。 

Relationships of SPAD value with tissue structure,physiological index and internal quality of flue-cured tobacco upper leaves

In order to further quantify the relationship between maturity and quality offlue-cured tobacco upper leaves. Yunyan 87 was used in this experiment. Maturity of upper leaves of Yunyan 87 was classified by SPAD value, and tissue structure, physiological indexes of fresh tobacco and quality of flue-cured tobacco were analyzed.Results showed that the average SPAD value of upper leaves showed a positive linear correlation with free water/bound water and protein content, a negative linear correlation with spongy tissue/palisade tissue ratio, a positive linear correlation with TSNAs content present, and a negative linear correlation with polyphenol content and nicotine content. When SPAD values were lower than 17, leaf senescence was obvious, carbon and nitrogen metabolism significantly decreased, antioxidant enzyme activities such as POD, SOD, CAT significantly increased, content of MDA and H₂O₂ significantly increased. The optimum SPAD of upper leaves in southwest Hubei province was 13±1.5.