The influence of nitrogen nutrition on the dynamics of growth and metabolism of endogenous growth regulators in Scotch pine (Pinus silvestris L.) seedlings

Abstract

Pine seedlings were cultivated in sterile agar cultures containing nitrogen as NH4Cl. The most pronounced positive effect on the growth of seedlings was affected by N used at a concentration of 50 ppm. After 4 months was stated that nitrogen had only a slight effect on elongation, of .shoots but decreased the length of roots. Nitrogen increased the lenght and number of primary and secondary needles as well as the fresh and dry matter of sboots. It stimulated also the number of lateral roots and the fresh and dry matter of the root system. Stimulation of shoot growth and differentiation as a result of nitrogen treatment was correlated with the increase -of free gibberellins and auxins and decrease of the amount of bound gibberellins and ABA-like inhibitor in shoots. However the effect of N on growth of roots was connected with the increase of auxins, cytokinins and ABA-like inhibitor in these organs.