Variability of arabinoxylan content in anatomical parts of winter rye grain during the ripening period

The accumulation of total arabinoxylans (TAX) and water soluble arabinoxylans (WSAX) in different parts of the grain was analysed in six winter rye cultivars (Tatarskaya 1, Radon, Pamyati Kunakbaeva and Ogonek, Podarok, Marusenka), three of which were high- and three low pentosans. The highest accumulation of WSAX was observed in the shells (33.49-42.78%). The maximum accumulation of WSAX was observed in the endosperm (61.9-74.3%), while in the embryo and the shells (seed coat and pericarp) the water-soluble fraction represented only one tenth of the total arabinoxylan content. A significant spatial heterogeneity of water-soluble and total AXs in morpho-structural parts of the grain was demonstrated, and statistical differences between the winter rye varieties studied were revealed, as well as a different course of their formation during grain maturation. After reaching physiological maturity, the amount of WSAX remains constant. The localisation of AXs in different grain tissues was the most important source of variation in their amount for both TAX and WSAX. The different accumulation scenario of TAX and WSAX in cereal tissues of low and high pentosans varieties is probably related to the time of their accumulation or to the activities of endogenous cereal enzymes or their inhibitors.