Abstract
Scotts pine seedlings were grown in soil cultures with a known content of N and C as well as organic substances. Walter solutions of the following salts: NaNO3, (NH4)2SO4, NH4Cl, NH4NO3, NH4HCO3 were used as a source of nitrogen in particular nutritional variants. Organic matter accumulation in particular organs as well as the chlorophyll a and b content were determined, photosynthetic and respiration rates were also measured. It was found that differences in gas exchange and organic matter accumulation of seedlings grown on ammonium or nitrate form of nitrogen are similar in plants from water cultures as well as in those from soil cultures.