Effect of root aeration and form of nitrogen on photosynthetic productivity of Scots pine (Pinus silvestris L.)

The response of 1-year old pine seedlings, grown in sand and water culture, to nutrition with nitrate or ammonium form of nitrogen, as well as to various aeration of the cultures was studied. Measurements of photosynthesis and respiration were carried out. Production of organic matter and its distribution to particular organs were determined. Seedlings supplied with NH4Cl were characterized by smaller contribution of root dry weight to the total weight of the plant. Poor aeration (heavy watering) of seedlings supplied with ammonium chloride caused a decrease in the rate of photosynthesis. Plants supplied with NH4C1 did not show the typical decrease of photosynthetic rate at the end of the growing season