香料烟叶片成熟过程中生理变化初步研究

对不同衰老程度叶片的研究结果表明，香料烟叶片的叶绿素、类胡萝卜素含量、光合速率及过氧化氢酶（ＣＡＴ）活性随衰老程度加深而降低，过氧化物酶（ＰＯＤ）活性及丙二醛（ＭＤＡ）含量随叶片衰老而提高。对不同部位（上部、中部和下部）和不同成熟度（欠熟、适熟和过熟）叶片的研究结果表明，同一部位的叶片随着成熟度的提高，其ＣＡＴ活性、叶绿素含量及光合速率明显降低，ＰＯＤ活性明显提高。同一成熟度的叶片，其ＣＡＴ和ＰＯＤ活性在下、中、上三个部位间呈“Ｖ”型变化。同一成熟度叶片的还原糖含量随叶片着生部位升高而增加，而蛋白质含量在下、中、上三个部位间表现为“Ｖ”型变化。同一部位不同成熟度叶片的还原糖含量变化趋势是适熟叶＞过熟叶＞欠熟叶；蛋白质含量变化则为过熟叶＞适熟叶＞欠熟叶。适熟期及时采收有利于获得高质量的香料烟叶。

Study on Physiological Changes in Leaves of Oriental Tobacco During Maturing

The study on two varieties of Oriental tobacco, Samsun and Basma, showed that the content of chlorophyll and carotinoid, photosynthetic rate. and catalase activity of leaves decreased and the activity of peroxidase and the malondialdehyde content increased markedly with aging. Physiological changes in leaves from three stalk positions (bottom, middle and top ) and three mature degrees (immature,proper mature and over mature) were also studied. The results indicated that at the same stalk position the catalase activity, chlorophyll content and photosynthetic rate of leaves decreased and the peroxidase activity increased distinctly with the rise of mature degree. With the same mature degree,the etivties of catalase and peroxidase among three stalk positions revealed a "V" type change. The chemical analysis of leaves demonstrated that the content of reducing sugar of leaves wich had the same mature degree increased with the ascending of stalk positions. The protein content of leaves from three stalk positions showed a "V" type change. At the same stalk position, the maximum content of reducing sugar occured in the proper mature leaf and the minimum in the immature leaf. The content of protein was highest in the over mature leaf and lowest in the immature leaf. The present study suggested that harvesting proper mature leaf was important for obtaining high quality products of oriental tobacco.