Research On The Mechanism Of NADPH Oxidase During The Germination Of Chestnut And Maize Seeds With Different Dessiccation Sensitivity

Plant seeds are divided into orthodox seeds and recalcitrant seeds according to the storage behavior. Orthodox seeds undergo dehydration during maturation, and have a low moisture content while abscission. Orthodox seeds can be further desiccated to a moisture content of between 1% and 5% without suffering damage. Recalcitrant seeds do not undergo dehydration during maturation, and have a higher moisture content while abscission. Recalcitrant seeds do not have tolerance to desiccation and are usually sensitive to low temperature. The storage lifes of recalcitrant seeds are usually about several days to several weeks in the conditions which are suitable for orthodox seeds. Therefore, researches on the mechanism of dessiccation sensitivity have important theoretical and pratical significance for the germplasm conservation.In this thesis, recalcitrant seed of chestnut and orthodox seed of corn are used to study the relationship between the NADPH oxidase activity the desiccation tolerance during the dehydration after imbibition. NADPH oxidase inhibitor (DPI) and H2O2 were added to further verify the role of NADPH oxidase, respectively. The results show that, the reactive oxygen species generated by the NADPH oxidase played an indispensable role in the acquisition process of desiccation tolerance in orthodox seed of maize. While NADPH oxidase inhibitor DPI were added, the production of the reactive oxygen species was delayed, antioxidant enzyme system activity become lower and the desiccation tolerance of maize seed was significantly lower than the control seeds; after adding exogenous H2O2, which is the product of NADPH oxidase, the antioxidant enzyme system activity increases as that of the control seeds, and the seed desiccation tolerance is higherthan that of the control seeds. Therefore, it is believed that the primary role of NADPH oxidase in orthodox seeds is to stimulate plants to inspire the reaction to the dehydration. The NADPH oxidase activity in the recalcitrant seeds of chestnut was significantly lower, and did not significantly change after adding the DPI. Therefore, it is believed that the NADPH oxidase in Chestnut cannot inspire the antioxidant enzyme system, in addition, the antioxidant enzyme system activity of the recalcitrant seeds of chestnut was significantly lower than that of the orthodox seeds of maize. This may be a cause of why the recalcitrant seeds are not tolerant to dehydration. While exogenous H2O2 is added, antioxidant enzyme system can be stimulated earlier than that of the control seeds, thus improving the desiccation tolerance of chestnut seeds. This is a potential ways to improve the desiccation tolerance of recalcitrant seeds.