Effect Of Growth Development And Physicochemical Properties Of Tobacco Exposed To Enhanced UV-B Radiation

Thinning of the ozone layer to reach the ground will lead to increased ultraviolet radiation, especially UV-B(280nm-320nm) radiation is a global environmental problems.This test was in April 2007-2008 year in October in China University of Science and Technology study of tobacco smoke and health stations,tobacco(variety K326,Longjiang911, Chuibi-1) for the material , under natural conditions increase the intensity of man-made 0.1w/m2 (T1 group) and 0.3w/m2 (T2 group) of UV-B radiation,daily 6h (9:00-15:00) A total of 7d, Natural light for the control (CK group),Studied effect of the UV-B radiation on tobacco agronomic charaters,photosynthetic, antioxidant enzymes and membrane systems,The main findings are as follows:1 UV-B radiation on the impact of agronomic characters in tobaccoUV-B radiation after 7d of the three varieties of tobacco leaf area, plant height is the extension of the processing time as, With the UV-B radiation reduced the increase in, Leaf area and plant height with the control were significantly different, However, stem diameter of tobacco,there was no significant difference between control and treatments. Three tobacco varieties in the two growth stages, T2 treatment group to deal with the impact of greater than T1, Plant height, leaf area, leaf length and leaf width and other indicators were CK> T1> T22 UV-B radiation on the impact of three kinds of photosynthesis of tobacco varietiesUV-B radiation in a short period of three tobacco varieties inhibit photosynthesis, in the UV-B radiation treatment seven days,the photosynthetic rate of treated tobacco leaves reduced,but extent of reduction was different, due to the different species and different developmental stages. In the T1 and T2 treatment group,the adaption of three tobacco varieties of spherical plant stage than seeding stage, in the UV-B radiation treatments, Photosynthetic pigment content(including chla, chlb) decreased. the three tobacco varieties chlorophyll a and chlorophyll b content and the ratio do not show changes in the law, tobacco in the chla / chlb increase or decrease the ratio, indicating that enhanced UV-B radiation may damage the chlorophyll a / b-protein complex structure.3 UV-B radiation on the impact of activity of antioxidant enzymesEnhanced UV-B radiation stress, tobacco leaf production rate of O2-and H2O2 content increased, plant launched its antioxidant protection system. UV-B to deal with in 7 days, SOD, POD activity of antioxidant enzymes, such as varying degrees of increase, which is conducive to removal of UV-B radiation in vivo in tobacco plants produce a large number of O2-and H2O2 and other reactive oxygen substances, to avoid the formation of reactive oxygen species injury.4 UV-B radiation on the impact of MDA content in tobaccoThe accumulation of reactive oxygen species can cause a large number of membrane lipid peroxidation occurs, MDA cell membrane lipid peroxidation is an important reaction product of MDA content, as often occurs in membrane lipid peroxidation of the main indicators of UV-B treated leaves of tobacco leaves or MDA content relatively high and the plasma membrane permeability increase that UV-B radiation lead to tobacco have taken place in membrane lipid peroxidation, membrane damage caused.5 UV-B radiation on the impact of Yield and Quality of tobaccoIn the UV-B radiation stress conditions, the tobacco is inhibited agronomic traits, reflected in reduced plant height, leaf area decreased, which may be on tobacco yield and quality have an impact. This experiment were trees in the seedling stage and the mission period of tobacco cultivars K326 to UV-B radiation, UV-B radiation stress in tobacco yield significant reduction of the chemical constituents of tobacco content in a variety of changes that had occurred in in turn affect the quality of tobacco.