Physiological Changes Of Oil Bodies During Germination Of Maize Seed And Extraction Methods Of Oil-body Proteins

The oil body is the carrier of lipid storage in plant seeds,oil body provides energy for seed germination and early seedling growth.High quality oil bodies is the basis for physiological and biochemical studies.In this study,maize seed Zhengdan 958 was used as experimental material we studied the changes of oil body,number morphology and physiological indexes of maize seed during germination.Meanwhile,we also optimized the methods of separating,purifying and extracting oil body from cereal seed.It will lay a foundation for further analysis of oil proteome in maize seed germination stage.The main results are as follows:(1)The content of fatty acids in shield slices of maize seeds during germination was determined by gas chromatography.The results showed that linoleic acid was the highest,followed by oleic acid,palmitic acid,stearic acid and myricetin.The variation trend of palmitic acid and linoleic acid was same.The trend was increasing slowly and then decreasing rapidly.The contents of oleic acid and ascorbic acid in unsaturated fatty acids showed a slow downward trend.(2)Fluorescence microscopy was used to observe the morphological changes of oil bodies in the shield during maize seeds germination.The results showed that oil bodies degraded at 24 hours of maize germination;intracellular oil bodies degraded at 36 hours of seed germination;at 72 hours,the number of oil bodies in the cells decreased,but the extent was small.At 84 h,the decreasing trend of oil bodies was large.Generally speaking,the degradation of oil bodies maiuly occurred at 24 hours of maize seed germination.With the progress of germination,the number of oil bodies in the cells became less and less.(3)At the early stage of maize seed,lipase activity increased,then decreased during the germination of maize seeds,and the peak value was at 84 h.Lipase activity was very high during the rapid growth stage of maize seedlings(72-96 h).Lipase was correlated with seedling growth rate.(4)In oil seeds,the oil content is relatively rich,and it can be easily separated by suspension extraction;however,in cereal seeds such as com,wheat and so on,the oil content is less,it is difficult to isolate sufficient oil for research.The oil bodies in con and wheat seed embryos were separated and purified by density gradient centrifugation and polyvinylidene fluoride(PVDF)membrane adsorption method.The quality of the oil bodies was detected by optical microscopy,Sudan V staining and Westerm blot.(5)To further confirm the method of extracting protein from oil body,eight methods were used to extract protein from oil body,SDS-polyacrylamide gel electrophoresis was used to analyze the effects of these eight methods on the removal of oil body lipids and the extraction effect of oil body protein.It was found that the new acetone-NaOH-phenol method was better than the other seven kinds of methods.We study the physiological and biochemical characteristics of oil degradation during maize seed germination by Nile red fluorescence microscope and gas chromatography.The separation efficiency of oil body from maize and wheat seeds was improved by PVDF membrane adsorption method.At the same time,a better oil protein extraction method was developed:acetone-NaOH-phenol method.This study provides a new idea for the isolation and protein research of cereal seed oil.