The Effects Of Topping And Bionics Signal Molecule On Tobacco Oxidative Stress

Topping is an important technical measures to increase the production and quality in tobacco leaf, but topping also is a kind of mechanical injury on tobacco plants which can Induced oxidative stress and activate the system of tobacco plants of defense responses, which lead to a rapid accumulation of nicotine in tobacco plants, in this study on the basis of study the interaction between tobacco and insects, the bionic signal signaling molecules (BSM) which has a gainst responses to would signal of tobacco were applied to the top of caulis of diverse types of tobacco after topping. The research on the effects of oxidative stress in tobacco by topping and biomimetic signaling molecules; the interaction between BSM and cultivation factors,such as topping time,varieties. In order to optimize the BSM applied in practice, improve the tobacco resistance, reduce oxidative stress,which to control the alkaloid content in tobacco leaves provide a new way.Thesis research, including the following three aspects:First, Stimulation and inhibition of oxidative stress in Burley by topping and biomimetic signaling molecules。Topping is a wounding to tobacco plants which is a routine measure in tobacco production. The biochemical changes are analyzed through measuring the contents and activity of superoxide anion (O2-·), hydrogen peroxide (H2O2), malondialdehyde (MDA) and superoxide dismutase (SOD) in non-topping and topping leaf tissue in a certain period. At the same time, after topping daub bionics signal molecule (BSM) immediately on the wound, then measure biochemical indicators and their changes. The results show that the topping is a mechanical damage which can stimulate oxidative stress of tobacco. Exogenous BSM treatment can inhibit oxidative stress of tobacco plants after topping, not only reduce the accumulation of O2-·, H2O2, MDA in tobacco leaves, but also increase the activity of SOD. After topping, it is BSM that can restrict the synthesis of jasmonic acid through inhibiting oxidative stress, and then reduce the accumulation of alkaloids in tobacco plant.Second, Inhibition of Exogenous bionics signal molecule (BSM) on Oxidative Stress of tobacco caused by topping. The application of bionics signal molecule (BSM) from tobacco feeding oligophagous pests oral secretion to tobacco after topping, The biochemical changes are analyzed through measuring the contents and activity of superoxide anion (O2-·), hydrogen peroxide (H2O2), malondialdehyde (MDA) and superoxide dismutase (SOD) in daubing BSM after topping and topping leaf tissue in a certain period. The results showed that the exogenous bionics signal molecule (BSM) could increase the activity of SOD and reduce the accumulation of MDA,O2-·,H2O2. Explains that wounding activation plants generate AOS, making plant produces stress of oxidation, BSM has a certain inhibition on Oxidative Stress of tobacco caused by topping At last, Roles of Bionics Signal Molecule in regulating the Carotenoids and polyphenols of tobacco. The application of bionics signal molecule (BSM) to diverse types of tobacco after topping in different periods, The tobacco antioxidant substances of tobacco leaves treated with BSM and untreated control were analyzed by colorimetry, and the impact of BSM on the tobacco antioxidant substances under different conditions were discussed. The results showed that:BSM could inhibit the chlorophyll, carotenoids, polyphenols accumulation after topping in various tobacco leaves at different types of tobacco leaves.BSM had better effects to middle leaves than upper leaves among chlorophyll, carotenoids, polyphenols; with Shenghua time topping, the chlorophyll, carotenoids, polyphenols reduced rate was significantly higher than the early flowering period, More inhibition of chlorophyll than phenolic and carotenoids, And can appropriately control the antioxidant substances content in a certain range.