生態型の異なるメロンの耐乾性の差異

Abstract

Physiological differences between melons with high and low drought resistance were studied.Melons with high drought resistance, which was estimated by leaf water saturation deficit (WSD) after water restriction, showed high osmosis resistance in isolated mesophyll cells.The leaf diffusive resistance of‘Howell’, an American cantalope with high drought resistance, was quickly modified when leaves were treated with abscisic acid (ABA), N6-benayladenine (BA) or gibberellic acid (GA3).‘Katsurashirouri’, a Japanese pickling melon with low drought resistance, did not respond to these growth regulators.Under non-stress conditions, the levels of ABA and gibberellic acid extracted from leaves of‘Howell’were slightly higher than those extracted from leaves of‘Katsurashirouri’. Under water stress, the level of ABA in leaves of‘Katsurashirouri’ increased more rapidly than in leaves of‘Howell’. The level of gibberellic acid in both cultivars decreased at the same rate under the same stress conditions. Under non-stress conditions, the cytokinin content was the same in both cultivars, but under water stress, cytokinin decreased more rapidly in‘Howell’than in ‘Katsurashirouri’.