The Effects Of Different Light Quality And Intensity On Growth And Metabolism Of Plastid Pigments Of Flue-cured Tobacco

On the basis of coating different colorful films to get different light quality and intensity, settingWhite (CK), red light (R), blue light (B), yellow light (Y) etc. four different treatments of light quality,natural light (CK) and70%light intensity (W) etc. two treatments of light intensity to explore the effectof growth and plastid pigments metabolism of flue-cured tobbacco, in Jiangchuan County, Yuxi City,Yunnan Province. The main conlusions are as follows:1. Red light was beneficial to the distribution and accumulation to leaves of dry matter, meanwhileit improved the yield value of flue-cured tobacco by16.8%.Yellow light reduced the yield and quality offlue-cured tobacco by16.67%and13.28%. Blue light inhibit the growth of flue-cured tobacco leaves,Its effect was obvious to the economy of flue-cured tobacco. In the low light treatment, the dry matteraccumulation decreased by35.1%, as decreased by35.06%、24.59%and38.91%level in roots, stemsand leaves. The yield and value of flue-cured tobacco decrased by15.0%and26.2%in low light.2. The contents of plastid pigments in leaves of flue-cured tobacco decreased gradually during thematural period of leaveas in the growth of flue-cured tobacco. Both the contents of Chlorophyll(516.49mg/kg) and Carotenoids (100.05μg/g) in leaves of red light treatments were higher than CK, thedegration amount of Chlorophyll and Carotenoids during the mature period were lower12.9%and26.6%level than CK, indicating that red light promoted the plastid pigments degration in the growth flue-curedtobacco. The degration amout of Chlorophyll under yellow light was lower10.8%level than CK, butyellow light inhibited the Chlorophyll degration, suppressed the Caroteniods degration in the middlematural period in the growth of flue-cured tobacco. Blue light suppressed the Chlorophyll degration inthe last matural period in the growth of flue-cured tobacco but no effect on the degration of Carotenoids.The ratio of Carotenoids compostion in all of light quality treatments changed in the growth offlue-cured tobacco. Generally, low light stress reducd the degradation amount of Chlorophyll during thematural period by8.1%, the effect on degradation amount of Carotenoids is not obvious.3. In the low light intensity treatment, the activity of Chlorophyllase (Chlase) declined with thedecreasing of ligh intensity in the middle mature period, Red and yellow light prevented the raising ofChlase in this period, bule light instead. The activity of Lipoxygenase (LOX) in the low light intensitytreatment declined significantly in the middle and last period of mature. Red and yellow light werebenifical to the raising of activity of LOX in the middle period, red light instead. The significant rise ofactivity of LOX in the last period of mature in all of the light quality treatments maybe prompt thefurther decomposion of Caroteniods and delay the mature of leaves.4. The plastid pigment in roasted tobacco leaves are mainly composed of Carotenoids, Chlorophylldegradation basic completely. The degradation amount of Chlorophyll in the whole process of growthand modulation is significantly higher than the degradation amount of Carotenoids of flue-curedtobacco. The content of Carotenoids in leaves of roasted tobacco decreased with the decreasing of lightintensity. The total degradated amount of Chlorophyll has no significant difference among the different light treatments. The content of Carotenoids in the leaves of roasted tobacco increased with the delclineof light intensity. Among the different light quality treatments, red light significant increasd the contentof Carotenoids in roasted tobacco leaves by30.2%, reduced the total degradation amount of Carotenoidsby8.9%.5. Neophytadiene was the main component of volatile aroma components in flue-cured tobacco.With the decreases of light intensity, the content of total volatile aroma declined. Red and yellow lightsignificant reduced the content of Neophytadiene by11.1%and12.6%level in roated tobacco leaves,blue light improved it by2.8%. The type of degradation products of Carotenoids has no differenceamong all light treatments, but in content. The content of Megastigmatrienone in low light treatmentincreased, β-damascenone, Geranyl acetone, Dihydroactinidiolide and Isophorone oxide etc. decreased.Content of β-Damascone in red light treatment increase, the degradation products amount ofCarotenoids, Megastigmatrienone D and Farnesylacetone B decreased. Blue light improved the contentof β-damascone, Geranyl acetone, Megastigmatrienone C, Isophorone oxidation,6-methyl-5-hepten-2-ketones etc. Yellow light increased the content of degradation products amout ofCarotenoids, Geranyl acetone, Farnesylacetone A.6. The total content of Neophytadiene and Volatile aroma were highly significant related to thedegradation amount of Chlorophyll, were significantly positive correlation with degradation amount ofCarotenoids and Xanthophylls. The contents of β-damascenone, Megastigmatrienone,3-hydroxy-β-dihydro damascone were positive related to degradation amount of plastid pigment.Geranylacetone, Farnesylacetone oxide, isophorone and6-methyl-5-hepten-2-one instead.The content ofDihydroactinidiolide was positively correlated with the degradation amount of Chlorophyll andnegatively correlated with the degradation amount of Caroteniods.7. In summary, to ensure adequate light intensity is very important for the quality and cost-effectiveof flue-cured tobacco. Blu light is conducive to promoting supplementary plastid pigment degradationand fragrant with the aroma formation temperament, which red-ray could improve the yield and qualityof tobacco, but its radiation effect is not conducive to the formation of aroma compounds. In this way,to regulate the lighting environment of flue-cured tobacco is expected to better the quality andcost-effective.