[Effects of soil available silicon on growth, development and physiological functions of soybean].

Soybean plants were planted in pots to investigate the effects of soil available silicon on their growth, development and physiological functions. When the content of soil available silicon was 55.1-202.8 mg.kg-1, the protease and lipase activities of germinating seed were increased with increasing soil available silicon content, amylase activity had no obvious change, and the respiration rate of seedlings was accelerated. The bioactivity of seed was increased, but the germination rate had no significant change. The photosynthesis rate, root activity, and nitrate reductase activity of soybean seedlings were enhanced, but the chlorophyll content in leaves had no significant change during seedling growth. The transpiration rate was decreased, while the water utilization efficiency and leaf water content were increased, and the capacity of drought-resistance was promoted. When the available silicon content was > 202.8 mg.kg-1, the abovementioned physiological functions had no significant changes. There was a positively linear relationship between the silicon content in soybean seedlings and the available silicon content in soil (r = 0.994). It could be concluded that the silicon absorbed from soil improved the physiological functions of soybean germinating seed and seedlings. As a result, the seed germination and seedlings growth rate were enhanced.