烤烟烘烤过程中叶片膜脂过氧化特性的研究

采用温湿度自动控制电热烤烟箱，研究了烘烤过程中烟叶膜脂过氧化及其内源保护酶活性的变化。结果表明，随烘烤时间延长，叶内超氧物歧化酶（ＳＯＤ）和过氧化物酶（ＰＯＤ）活性下降，丙二醛（ＭＤＡ）含量增加。烘烤４８ｈ和７２ｈ后，两种酶先后失活，ＭＤＡ积累达最大值，证明烟叶烘烤过程中叶片膜脂过氧化水平不断提高。不同处理以高温快烤烟叶膜脂过氧化水平最高，低温慢烤最低。而且变黄温度对烟叶膜脂过氧化的作用比定色期不同升温处理的作用大。

The Characteristics of Membrane lipid Peroxidation in Tobacco Leaves during Flue Curing

The changes of membrane lipid peroxidation and the activity of endogenousprotective enzymes in tobacco leaves during flue curing were studied by the electric heatedcuring apparatus, in which the temperature and humidity were automatically controlled. The results showed that with the lengthening of time during curing the activity ofsuperoxide dismutase(SOD)and peroxidase(POD)in tobacco leaves decreased,while thecontent of malondialdehyde(MDA),a product of membrane lipid peroxidation,increased.The activity of SOD and POD was stopped early or late and the accumulation of MDA inthe leaves reached maxinum after curing for 48 and 72 hours,which indicated that thedegree of membrane lipid peroxidation was raised continuously during curing. In differentcuring treatments,the degree of membrane lipid peroxidation in tobacco leaves was thehighest when the yellowing temperature was higher and the rate of raising temperature forleaf drying was faster,but it was the lowest when the yellowing temperature was lowerand the rate of raising temperature for leaf drying was slower. Furthermore,the effect ofyellowing temperature on the membrane lipid peroxidation was more significant than thatof the raising temperature for leaf drying.