不同烤烟品种叶片衰老与质体色素降解及降解产物含量的关系

Leaf Senescence and Its Relationship with Plastid Pigment Degradation Content and the Degradation Products of Different Varieties of Flue-cured Tobacco

为揭示品种间质体色素降解量和中性致香物质存在差异的原因。研究了3个烤烟品种烟叶衰老过程中质体色素降解和衰老相关指标的变化规律,测定了烤后烟叶中性致香物质含量,并探讨了不同品种烟叶衰老相关指标、质体色素降解量与质体色素降解产物含量的关系,结果表明,质体色素的降解和降解产物的含量与烟叶的衰老特性有关。衰老速度快的品种,烟叶可溶性蛋白降解量大,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性低,脂氧合酶(LOX)活性高和丙二醛(MDA)含量高,类胡萝卜素裂解双加氧酶(CCD)基因表达量高,质体色素的总降解量大,烤后烟叶质体色素降解产物含量高,与衰老慢的品种相比差异明显。中性致香物质总量与叶绿素和类胡萝卜素总降解量、可溶性蛋白降解量、LOX活性、CCD表达量、MDA含量均达到极显著或显著正相关;与SOD、POD、CAT活性呈极显著负相关。衰老期间烟叶质体色素降解量对质体色素总降解量的影响大于烘烤期间。因此,在烟叶衰老过程中提高烟叶衰老程度和衰老速度对烟叶质体色素降解和中性致香物质的形成至关重要。

We study on the change rule of the content of plastid pigment and senescence indicators associated in the process of tobacco leaf senescence of three varieties of flue-cured tobacco,tested the content of neutral aroma substances in the cured tobacco leaf,studied the relationship between aging related indicators and the content of plastid pigment degradation with the content of plastid pigment degradation products of different flue-cured tobacco varieties,in order to reveal the varieties quantity of plastid pigment degradation and the cause of the differences between neutral aroma substances. The results showed that： Degradation and the content of degradation products of plastid pigment was associated with aging properties of tobacco leaf. High aging speed varieties had a large amount of soluble protein degradation,low activity of superoxide dismutase（ SOD）,peroxidase（ POD）,catalase（ CAT）,high activity of lipoxygenase（ LOX）,high accumulation of malondialdehyde（ MDA） and high expressing quantity of arotenoids cracking double oxygen synthase（ CCD）. It also had a large amount of plastid pigment degradation products during aging and curing,high content of plastid pigment total degradation products in cured tobacco leaf,high conversion rates of plastid pigment during senescence,clear difference with low aging speed varieties. The amount of total neutral aroma positive correlated with the content total chlorophyll and total carotenoids degradation,soluble protein degradation,LOX activity,CCD expression quantity,the accumulation of MDA significantly or ex-tremely significant; negative correlated with the SOD,POD,CAT activity extremely significant. The degradation of plastid pigment in tobacco senescence is greater than in curing on the influence of total plastid pigment degradation.Therefore,increase the aging degree and speed in the process of tobacco leaf senescence is crucial to the degradation of tobacco plastid pigment and the formation of aroma substances.