Growth test of Perillu frutescens on sand was carried out with ammonia, nitrate or urea as the sole nitrogen source and the effect of them was discussed. The plant supplied with nitrate or urea grew moderately, but some injury was observed on the plant supplied with ammonia. By passing the nutrient solution through culture pot filled with sand, notably large amounts of nitrate were produced from urea, while only a little formation of nitrate from ammonia was demonstrated. At any rate, it was confirmed that nitrification took place even on sand. About one half of the amount of nitrate formed from urea may be attributed to the function of plant itself, and the rest is to be ascribed to the action of microorganisms. It was confirmed that ammonia and nitrate were formed from urea by plant root. The leaf of plant seemed to enhance the function of root on urea.