Font Size: a A A

Effects Of Long-term UV-B Stress On Ecological Parameters And Protection Enzyme Activity Of The Aphid Sitobion Avenae ((Fabricius) Hemiptera: Aphididae)

Posted on:2015-12-13Degree:MasterType:Thesis
Country:ChinaCandidate:D ZhouFull Text:PDF
GTID:2283330434465062Subject:Agricultural Entomology and Pest Control
Abstract/Summary:PDF Full Text Request
There are all kinds of radiation widely in nature, and have strong selection pressuring onthe whole biosphere. Consequently, ultraviolet-radiation, especially UV-B radiation has apowerful stress on evolutionary dynamics of insect populations. The ecological genetics,evolution and regulation of Sitobion avenae (Fabricius) exposed to UV-B radiation can beacknowledged by analysing the effects of UV-B radiation for several successive generationson them.Analysis the effect of different intensity of UV-B stress on continuous generation ofS.avenae, in order to study the evolution and ecological regulation theorys of S.avenae underdifferent intensity of UV-B stress.To assess the different intensity of UV-B stress on the growth, development, fecundity,protective enzyme activities of S.avenae, and to found they change rule.In this study we usedthe different intensity of UV-B to radiate each generation of S.avenae and the heredityprinciple of the life history, the age-stage, two-sex life table was establishing. We chose the1st,5th,9th,14th,19thgeneration of wingless and parthenogenesis adults in both the treatmentgroup and control group, and measure the activities of three types of protective enzymes(Superoxide Dismutase, SOD; Peroxidase, POD; catalase, CAT) of them.1. Effects of different intensity of UV-B stress on the life table parameters of S. avenaeIntrinsic growth rate (r), net increment rate (R0) in low intensity and high intensitytreatment group showed a trend of decline after rising first. Intrinsic growth rate (r) minimumvalue was in the G5and net increment rate (R0) minimum value appeared in the G10in Lowintensity trement group; and intrinsic growth rate (r) and net increment rate (R0) minimumvalue appeared in the G10in high intensity trement group. The average generation time (T)showed increasing trend again after the first and then decreased, the highest point in the G5,the lowest point in the G10in low-intensity UV-B treatment groups, but the averagegeneration time (T) decreased and significantly higher than the control in high-intensitytreatment groups.2. Effects of different intensity UV-B stress on nymphs of S.avenae average develop ment periodIn the early UV-B stress, the high intensity and low intensity UV-B radiation,developmental duration young nymphs are extended, but had no effect on fourth instarnymphs in different intensity UV-B treatment groups. With the increase of stress generations,young nymph development duration was shorten in low-intensity UV-B treatment, but wasinhibited in high-intensity UV-B treatment groups. After long-term UV-B stress, nymphs ofS.avenae developmental duration had no significant effect in low-intensity and high-intensityUV-B treatment groups.3. Effects of different intensity UV-B stress on longevity and reproductive capacity ofS.avenaeIn short generation, the fecundity of S.avenae was significantly improve in low-intensityUV-B treatment groups, but was reduced in high-intensity UV-B treatment groups. Afterprolonged stress, different intensities of UV-B stress had no significant effect on fecundity ofS.avenae. Low-intensity UV-B stress can prolong the life of S.avenae, however high intensityUV-B stress shortened lifespan of S.avenae. In the early stress, different intensities of UV-Bstress had no significant effect on the oviposition days of S.avenae.When short-term stress,low-intensity UV-B extended oviposition days of S.avenae, there was no significantdifference in high-intensity.After long-term stress, whether low-intensity or high-intensity UV-B stress had nosignificant effect on oviposition days of S.avenae.4Effect of different intensity of UV-B treatment on protective enzyme activities ofS.avenae.With increasing generation of S.avenae, under different conditions of UV-B intensity3kinds of protective enzyme activity of S.avenae have significant differences. Superoxidedismutase SOD activity showed a rise again after the first decline in a downward trend underlow-intensity treatment, the highest activity in the G9, minimum activity in G19, and itshowed after the first rise and decline under high intensity UV-B treatment groups, the highestactivity in G9. peroxidase activity (POD) showed a downward trend in low-intensitytreatment, and was first rise after falling trend in the high-intensity treatment, the lowestvalues were in G9. Under low-intensity treatment groups, catalase activity (CAT) was firstdecreased and then increased the downward trend, the lowest value in the G9and the highestvalue in G14. Under high intensity of UV-B treatment groups, catalase activity (CAT) tendedto rise fall rise fall of fluctuation, the lowest value in the G9, the highest value in the G14, andin G1, G5, G9, the active of treatment groups were lower than the control group.In a word, the impact of different intensity of UV-B on S.avenae has been involved in all aspects of life parameters, development, reproduction and enzyme activities and so on.Comparison The ecological parameters change rule found that the growth and development ofS.avenae was promoted under low-intensity of UV-B stress, but it was inhibited under high-intensity of UV-B stress, and showing induced defenses. For a long time UV-B stress,S.avenae adapted to UV-B environment. After S.avenae by UV-B treatment, with increasinggeneration, and its protective enzyme system in the body for the normal development oforganisms play a protective role,, which may be associated with S.avenae adaptation to UV-Bdefense enhancement.
Keywords/Search Tags:Sitobion avenae, UV-B, life table, enzyme activities, Long-term stress
PDF Full Text Request
Related items