Carbohydrate levels among winter wheat cultivars varying in freezing tolerance and snow mold resistance during autumn and winter

Abstract

The LT50 values and soluble carbohydrate levels in wheat (Triticum aestivum L.) crowns and leaves were monitored throughout autumn and winter in cultivars varying in freezing tolerance and snow mold resistance during 1993/1994 and 1994/1995 in the field at Sapporo, Japan. During the first stage of hardening, from sowing to mid‐November, the pattern of accumulation of mono‐ and disaccharides was similar for all cultivars. During the second stage of cold hardening, from mid‐November to mid‐December, the greatest accumulation of mono‐ and disaccharides, without a corresponding increase in fructan, was observed among the freezing‐tolerant cultivars; and levels of simple saccharides rapidly decreased under snow cover. Conversely, levels of mono‐ and disaccharides in snow mold‐resistant cultivars were less than 70% of those in freezing‐tolerant cultivars before snow cover and maintained low levels throughout winter, while polysaccharide levels in snow mold‐resistant cultivars were about 120% of those in freezing‐tolerant cultivars in December. Sugar metabolism during the winter was examined using 18 cultivars in 1994/1995. LT50 values were correlated to the greatest extent with total mono‐ and disaccharide and fructan content among wheat cultivars excluding snow mold‐resistant cultivars in December. Snow mold‐resistant cultivars tended to metabolize carbohydrates more slowly until the end of the snow cover period. This result suggested that the enzymatic metabolism of the synthesis of sugars and the conversion of fructan to cryoprotective sugars in response to low temperatures, especially subzero ones, might be different between the two contrasting types in resistance to winter stress.

Seasonal variation of soluble carbohydrates and starch in Echinolaena inflexa, a native grass species from the Brazilian savanna, and in the invasive grass Melinis minutiflora

“…In the shoots, the main component was glucose, probably as a result of starch hydrolysis during periods of water restriction and high temperatures. Several studies have demonstrated the role of this sugar in osmotic adjustment under water and heat stresses (Vágújfalvi et al, 1999;Yoshida et al, 1998;Liu and Huang, 2000). In the roots, on the other hand, the most important sugar was sucrose, with higher levels during the dry season for both species, suggesting a storage function, as well as a role in the maintenance of osmotic potential in the underground organs among other functions.…”

Expression of an active tobacco mitogen-activated protein kinase kinase kinase enhances freezing tolerance in transgenic maize

“…A positive correlation between freezing tolerance and soluble sugar content has been documented in a number of studies (26)(27)(28)(29). Soluble sugars function as cryoprotectants and osmolytes that protect cells from freezing damage (30).…”

Nonstructural Carbohydrate Reserves in Roots and the Ability of Temperate Perennial Grasses to Overwinter in Early Growth Stages

“…Tamura et al (1985) and Tamura (1986) reported that species and cultivars of winter annual and biannual grasses that contain a larger amount of NSCs survive winter at a higher rate and grow better in the next spring. Yukawa and Watanabe ( 1995) and Yoshida (1998) also clarified that tolerance to snow mold and freezing in wheat and barley were correlated to a great extent with total mono -and disaccharide and fructosan in late fall. The concept that reserve carbohydrates stored in the fall physiologically strengthen winter hardiness and promote growth in the following spring is well accepted.…”