| Maize is one of the most important crops as food and feed stuff in the world. Because of its seed characters, it becomes one of the most intolerance of storage seeds. Aging not only affect the germination of seed and development of seedling, but also influence the quality and quantity of individual plant. Moreover, the nutritive quality of maize that is used for producing and machining foodstuff as well as the resource of the feedstuff is decreased severely by the ageing or deterioration. So illumination of the mechanism of maize ageing process, delay of seed ageing, prolonging the preservation state of seeds, have an important role on the agriculture production and seed resource preservation.Member-lipid peroxidation associated free radicle oxidative stress and non-enzymatic protein glycosylation with reducing sugars, are the worst harming bio-chemical reaction in the process of seed ageing. The carbonyl poisonous effect of their productswill make the activity of anti-oxidative enzyme decreased, storing proteins and enzymes decomposed as well as modified, and so on. Thiourea is reducing agent with-SH, maybe plays a role in preventing seed proteins oxidating. The change of proteins and enzymes has been detected in many kinds of plants ageing seeds, but the relationship between ageing and the chemical alteration of proteins was not clear now.In this study, an elite hybrid Zhengdan 958 in maize was used as material to analyze the chang of proteome in the process of ageing, at the same time, the influence of thiourea on the vigor of maize seed was also analyzed. Some results were acquired as fellow:1.Comparing the several methods of protein extraction, we found that improved SDS-phenol method was fited in extraction of gramineous grain seed protein, as it could eliminate the disturbance that storage substance such as starch and lipid act on electrophoresis.2.After extracting the embryo protein and endosperm protein in ageing 0-7d seeds in the hybrid Zhengdan 958 respectively, and analyzed by means of SDS-PAGE electrophoresis, several obvious different bands were found in the ageing 0-7d embryo protein, while there were not find in the ageing 0-7d endosperm protein.3.Two expressing significant protein bands 14 kD and 40 kD in 6-d artificial aging seed were found using SDS-PAGE analysis. The 14kD protein band disappeared in the 1-d artificial aging seed and it mainly present in the cotyledon and radicle, while the 40 kD band disappeared in the late stage of artificial aging and existed in the whole embryo.4.The 14 kD protein and the 40 kD protein were confirmed on the 2-D gel.Among more than 300 protein spots resolved in the 2-D gels, the protein spots 14 kD (pI 6.2), 30 kD (pI 5.8), 36 kD (pI 5.5), 35 kD (pI5.5) and 22 kD (pI 5.1) were down-regulated; and the protein spots 40 kD (pI 6.5), 29 kD (pI 6.4), 15 kD (pI 5.4), 21 kD (pI 5.3) and 35kD (pI 5.6) disappeared in 6-d aged seeds. In contrast, the protein spots 20 kD (pI 6.5) and 20 kD (pI 6.7) were up-regulated.5. Through MALDI-TOF MS, four differentia spots were detected, and got their PFM. The results from the bank information indicated that their function had not known.6.Using the 30 mM thiourea pretreatment of ageing 2d and 3d maize seeds, their germination rate increased evidently, and the activities of SOD,POD and CAT enhanced. These all show that thiourea postpone the ageing of maize seed and improve the ability of resistance of ageing.
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