Fructans from oat and rye: composition and effects on membrane stability during drying.

Fructans have been implicated in the abiotic stress tolerance of many plant species, including grasses and cereals. To elucidate the possibility that cereal fructans may stabilize cellular membranes during dehydration, we used liposomes as a model system and isolated fructans from oat (Avena sativa) and rye (Secale cereale). Fructans were fractionated by preparative size exclusion chromatography into five defined size classes (degree of polymerization (DP) 3 to 7) and two size classes containing high DP fructans (DP>7 short and long).

Using Arabidopsis thaliana as a model to study subzero acclimation in small grains.

The suitability of using Arabidopsis as a model plant to investigate freezing tolerance was evaluated by observing similarities to winter cereals in tissue damage following controlled freezing and determining the extent to which Arabidopsis undergoes subzero-acclimation. Plants were grown and frozen under controlled conditions and percent survival was evaluated by observing re-growth after freezing. Paraffin embedded sections of plants were triple stained and observed under light microscopy.

Additional freeze hardiness in wheat acquired by exposure to -3 degreesC is associated with extensive physiological, morphological, and molecular changes.

Cold-acclimated plants acquire an additional 3-5 degrees C increase in freezing tolerance when exposed to -3 degrees C for 12-18 h before a freezing test (LT50) is applied. The -3 degrees C treatment replicates soil freezing that can occur in the days or weeks leading to overwintering by freezing-tolerant plants. This additional freezing tolerance is called subzero acclimation (SZA) to differentiate it from cold acclimation (CA) that is acquired at above-freezing temperatures.