Changes of Araucaria araucana seed reserves during germination and early seedling growth

Abstract

Changes in the starch and protein reserves of Araucaria araucana (Mol.) Koch embryo and megagametophyte tissue during the first 90 h after the start of imbibition have been measured by colorimetric and by chromatographic methods. The starch content (about 30%) of the embryo decreases rapidly until radicle protrusion–germination (40 h) and remains relatively constant (at about 9%) after that. Starch content of the megagametophyte decreases slowly throughout the 90 h. Amylase activity and soluble carbohydrate content of the embryo peak rapidly at 20 h, decline rapidly until germination, and increase slowly thereafter. Total amylase activity of the megagametophyte does not change markedly. Total soluble-protein content of the embryo decreases during the first 20 h and increases thereafter. The embryo protein bodies also disappear during the first 20 h. The hypocotyl enlarges to a bulbous shape and may serve as a secondary protected reserve.