Relationship between Nonstructural Carbohydrate Concentration and Snow Tolerance of Broad Bean (Vicia faba L.).

Abstract

The relationship between nonstructural carbohydrate (NSC) concentration and snow tolerance of the broad bean was investigated. The growth and NSC of plants in early winter were changed by several sowing times and the use of three varieties (hardy, intermediate, susceptible) to clarify the relation with snow tolerance; furthermore, changes in NSC and injury caused by snow were examined. Although intermediate and susceptible varieties sown in early autumn almost died after 54 days under snow, a hardy variety sown in early autum showed high wintering ability. Plants sown in late autum, which gave a younger morphological state in early winter immediately after germination, showed high wintering ability and a high concentration of over 15% NSC in cotyledon. NSC in cotyledon of the hardy variety was not higher than that in the other two varieties, whereas NSC in foliage except cotyledon and the root of the hardy variety sown earlier was higher than those of two other varieties. From these results, it is suggested that the hardy variety accumulated high NSC in the plants, and that the intermediate and susceptible varieties showed high wintering ability when NSC in cotyledon was utilized for winter. Under the snow, NSC in leaf and stem decreased rapidly. The snow injury of intermediate and susceptible varieties increased rapidly after 36 days under snow, accompanying the decrease of NSC below 1% NSC in leaf and 2% NSC in stem. In contrast, the hardy variety showed no serious injury because of high NSC. The indication was introduced that more than a definite value of NSC in plants was important to maintain a tolerance of snow injury.