Seasonal Fluctuation of Reserve Materials in the Trunkwood of Spruce [Picea abies (L.) Karst].

In wood cylinders obtained from trunks of 10 Picea abies trees, the fluctuation in the concentrations of glucose, fructose, sucrose, raffinose, starch, free glycerol, and glyceride glycerol was followed for one year. The determination of the compounds was done enzymatically. In the winter months sugars and free glycerol showed maximum concentrations. Before the onset of growth ring formation and leaf unfolding the concentrations of sugars and free glycerol decreased. In August, raffinose was absent. Starch content rose in spring, decreased during the summer months, and than rose again in autumn. Glyceride glycerol ( = fat) content was low in the cold period, but high in spring and summer. A cold period in midsummer induced a temporary accumulation of sugars in the xylem tissue of the Picea trunks.