Contents of soluble carbohydrates in yellow lupin seeds maturated at various temperatures

Abstract

The objective of this paper was to compare the levels of soluble sugars in seeds of yellow lupin cv. Juno matured at different temperatures. The temperature regimes applied were 1). 26 °C for 24 h (high temperature), 2). 24 °C for 12 h and 19 °C for the next 12 h (optimum temperature regime), 3). 26 °C for 16 h and 4 °C for the next 8 h (high-low temperatures). Six soluble carbohydrates (d-galactose, myo-inositol, sucrose, raffinose, stachyose and verbascose) were quantified. Seeds maturing at constant temperature 26 °C accumulated more raffinose (by 100 %) than seeds maturing at optimum temperature regime. Seeds maturing at high temperature accumulated less stachyose and verbascose than those maturing at optimum temperature conditions, the differences being 45 and 24 %, respectively. In seeds maturing at high-low temperature the level of raffinose decreased while the level of stachyose and verbascose increased, compared to those maturing at optimum conditions. The contents of sucrose, d-galactose and myo-inositol in seeds maturing at optimum temperatures was lower than in seeds maturing at both high and high-low temperature regimes. It was shown, that temperature conditions — constant high temperature, or physiologically optimal thermal oscillations (24 °/19 °C) or high-low temperature regime — differently affect the contents of six soluble carbohydrates in maturing seeds of yellow lupin.