Studies On The Impact And Its Mechanism Of Transgenic Bt Rice Grain On Plodia Interpunctella(Hübner)

In this paper, the characteristic of transgenic Cry1Ab/Cry1Ac rice (Huahui1,HH/Bt) during storage was researched. Taking stored-grain insect Plodiainterpunctella (Hübner) as the research object, the effect of HH/Bt on thedevelopment and reproduction of Plodia interpunctella H. was studied, and exploredits mechanism. The research results in theory to deepen the understanding oftransgenic Bt rice food safety, ecological safety, and in practice for the scientificdevelopment and utilization of it provides academic support. The following is theresults obtained by the institute.Under the conditions of25°C, Bt protein content of HH/Bt during storage wasdetermined, and the results showed that the Bt protein content of brown rice was5.534μg/g~4.003μg/g, and the Bt protein content of rice husk was1.003μg/g~0.328μg/g, which were significantly decreased as time goes by(P<0.05). And Theformer was significantly higher than that of the latter (P<0.05).The starch eating quality, rice key nutritional composition and processing andcooking quality of HH/Bt were compared with its original parent, Minghui63(MH/CK). There was no significant difference between HH/Bt and MH/CK in thecontent of total starch, crude protein and most amino acids(P<0.05). The Amylose,crude fat, soluble protein, valine, methionine, lysine and arginine content of HH/Btwere significantly higher than that of MH/CK(P<0.05), but HH/Bt was significantlylower than MH/CK in the cotent of ash, alcohol-soluble protein, salt-soluble proteinand alkali-soluble protein(P<0.05). The gelatinization temperature and gelconsistency of rice starch, water absorption rate and expansion rate and pH of cookedrice did not exist significant differences between these two rice. However, theparameters of peak viscosity, final viscosity and the lowest viscosity of starchviscosity characteristics of HH/Bt were significantly lower than that ofMH/CK(P<0.05), and so was in index of the attenuation value, iodine-blue value.The based biological and ecological studies of Plodia interpunctella H. showedthat different degree of temperature had direct infection to the growth of this insect,and the developmental threshold temperature of Plodia interpunctella H. was7.40oC~15.94oC. The fitting Weibull equation showed that survival curve of experimentalpopulation of Plodia interpunctella H. was upper arch at21oC~33oC(c>1), whichshowed that the most individuals of the populations can achieve their average lifeexpectancy, but one exception was at36oC(c<1), which showed that the juvenilestage of these population having a higher mortality. With the rise in temperaturewithin the range of21°C to30°C, c increased, and the value within the range of 30°C to36°C, as the temperature rises, the c value decreased. The spawning periodof Plodia interpunctella H. females was from5.25d to10.42d, and pawning period athigh temperatures was shorter than that of low temperatures. Average fecundity wasobviously affected by temperature. The mean fecundity was82.12eggs and26.10eggs respectively at30oC and21oC. Under the conditions of30°C, the intrinsic rateof Plodia interpunctella H. experimental population reached a maximum of0.063,and the average development time to a minimum value of49.714d, and thepopulation doubling time reaches a minimum of11.017d.The results of HH Bt brown rice flour feeding Plodia interpunctella H. showedthat the early hatching larvae was unable to survive in more than20%HH/Bt. Thedevelopmental threshold temperature of Plodia interpuctella H. reared on2%HH/Btwas4.90oC~17.36oC, and the developmental threshold temperature and maximumtemperature of the egg were respectively at15.13oC and38.96oC. Under theconditions of30°C, the intrinsic rate of the experimental population reached amaximum of0.033, and the average development time to a minimum value of63.878d, and the population doubling time reaches a minimum of21.126d. ComparingPlodia interpuctella H. reared on MH/CK, a significant reduction was in the netreproductive rate(R0), intrinsic rate of increase(rm) of Plodia interpuctella H. rearedon2%HH/Bt, and a significant increase in mean generation T and populationdoubling time t.5%HH Bt brown rice flour feeding Plodia interpunctella H., measurementresults of the enzyme activity of F2, F3and F5generations of the elderly larvaeshowed that acetylcholinesterase (AChE) activity compared with the controlsignificantly improved, and the Michaelis constant Kmof F2was no significantdifference with the control, however, it was increased significantly in F3and F5generation compared with the control group. It suggested that the affinity of AChEwas on the decrease with the control group. The enzyme activity of three protectiveenzymes were significantly increased than the control group(P<0.05).