烤烟叶片成熟度的研究 Ⅰ、烤烟叶片成熟和衰老过程中某些生理生化变化的研究

A study on Maturity of Tobacco Leaves I physiological and Biochemical Changes of Tobacco Leaves in Maturity and Senescence

以烤烟叶片主、支脉和叶色变化为主,参考叶面、叶缘、叶尖、叶耳的变化,将上、中、下三个部位烟叶成熟度分别划分为0～5六个档次,并且规定等级越高,成熟度越高。随叶片成熟度的增加,有以下生理生化变化:细胞膜透性、乙烯释放量和呼吸强度是增加的;总核酸、DNA、RNA、净光合强度是减少的;ATP 含量表现为减少—增加—减少。烟叶的最佳采收期分别是下部叶2～3级,中部叶3～4级,上部叶4级。

The maturity was studied mainly according to the changes of the color of leaf,stem and lateral veins in the light of the changes of leaf surface,rim. tip and auricle of the leaf.The degree of maturity was divided into six gra- des(0～5th)in a manner that the higher the grades the higher the ma- turity. In the experiment,with the increasing maturity the phsiological and bioche- mical changes happened as follows.First,the content of chlorophyll,caroteno- ids,total nucleic acids,DNA,RNA and the rate of photosynthesis were dec- resed.Second,the permeability of cell membrane,the release of ethylene,reduc- ing sugar,and the respiratory rate were increased.The ATP content showed a decreasing-increasing-decreasing trend. The most suitable harvesting grades are:the lower stalk position—2rd～ 3rd grade;the middl—3rd～4th grade;the upper-4th grade.