| Popis: |
Carbohydrate, nitrogen, and lipid metabolism were characterised in thin roots of Scotch pine trees from 5 to 160 years old growing in southern Karelia. The roots were sampled at the phases of initial and active growth and in the dormant state. Various carbohydrate, nitrogen, and lipid constituents were determined and calculated on a dry-weight basis. During the whole period of tree life, total contents of carbohydrates, lipids, and stable hemicelluloses in roots remained unchanged, and nitrogen compounds were represented mainly by proteins. Age-dependent changes reflected a decline in amino acids and phospholipids. Changes in the constituents were related to whether the roots were initiating their growth, growing actively, or were dormant. Root growth initiation was characterised by active nitrogen metabolism and high levels of starch, phospholipids, and amino acids. During active growth, a low content of amino acids, accumulation of saturated fatty acids, and active utilisation of starch were typical. In dormant roots, a high content of disaccharides, a decrease in phospholipid content, and a relative increase in amino acids were recorded. |
