Influence of medium-nitrogen level on growth periodicity of Ilex crenata Thunb. ‘Helleri’

Ilex crenata Thunb. ‘Helleri’ plants were grown in sand culture and supplied daily with nutrient solutions of 10, 40, 70 or 100 mg l^?1 nitrogen (N). Plant growth at all rates of N was characterized by an initial period of simultaneous shoot and root dry weight accumulation, followed by shoot elongation, root growth cessation, and major accumulations of N and dry weight. Plants grown at the greater N rates accumulated more N and exhibited a higher shoot-to-root ratio as a result of greater shoot than root growth. Plants grown at the higher N applications initiated extension growth before plants grown at lower N levels.