Study On Deoxynivalenol And Distribution Of Fusarium Graminearum In Wheat Grain

Deoxynivalenol (DON) and distribution of Fusarium graminearum of two kinds of wheat grain (M5 and T4) were studied. In this study, wheat was potted in the flowerpot with 11L. Fertilized at regular intervals after GS25 and snippeted suckering plant in GS31. In GS65, wheat was spray inoculated with spore suspention of Fusarium graminearum(3×105 spores/mL). Inoculated 7,14 and 21 days, samples were obtianed for assay.After extracting the samples by Standard Operating Procedure (SOP) and Solvolysis Procedure (SP) for free and total DON respectivily, DON was separated and determined by reversed-phase HPLC with C18 column and a mixture of water-acetonitrile-methanol(90∶5∶5 by volume) as mobile phase. In the last phase of maturation, the distribution of Fusarium graminearum in wheat grain was observed by scaning electron microscope.The results as follows:1.The linear range for DON was 0.1-5μg/mL with a correlation coefficient of 0.9995. The detection limits for DON was 0.135μg/g. The recovery ranges for DON was 82.93%-90.61%, and relative standard deviation were from 2.32%-3.07%.2. Hyphae growing on inner surface and outer surface of lemma of wheat grain was observed by scaning electron microscope. This result showed that the DON can penetrate into the grain.3.For the first time to determine the variation of free and bound DON in wheat grain in three weeks after inoculated. The conjugated DON was detected on d 7 by Solvolysis Procedure (SP).4. The consists of conjugated DON were 56.48%,54.52%,56.48% on d 7,14,21 respectively of M5 grain ,and 32.12%,32.51%,32.12% of T4 grain.5.The contents of total DON, free DON and bound DON were increased after inoculated in three weeks.