Abstract: Cucumber plants were cultured in flowerpot for the investigation of the effect of available silicon in soil on cucumber seed germination and seedling growth metabolism. The result showed that when the content of available silicon in soil was between 55. 1 and 202. 8 mg·kg^-1, with the increase of available silicon in soil , the activities of protease and lipase during cucumber seed germination were promoted , the respiration rate of seedlings was accelerated , and seed vigor was increased ; the photosynthesis rate , root activities and nitrate reductase activity of cucumber seedlings during seedlings growth were increased. The transpiration rate was decreased , while transpiration ratio and leaf water content were increased. From the facts above , it can be shown that silicon which was assimilated in soil improved nutrition metabolism of cucumber seed and seedling. As a result , seed germination and seedling growth rate were advanced. The investigation showed that the highest content of available silicon in soil which can increasingly promote seed germination and seedling growth rate was 202. 8 mg·kg^-1.

Key words: Cucumber, Available silicon in soil, Seed germination, Seedling growth, Metabolism