γ-Tocopherol dominates in young leaves of runner bean (Phaseolus coccineus) under a variety of growing conditions: The possible functions of γ-tocopherol

It has been shown that young leaves of runner bean plants grown under natural conditions showed an unusually high content of γ-tocopherol, accounting for up to 90% of all tocopherol isomers. The level of γ-tocopherol gradually decreased during the first two weeks of leaves development. During simultaneous drought and light stress, γ-tocopherolquinone, an oxidation product of γ-tocopherol, was preferentially accumulated. This indicates specific function of γ-tocopherol in the protection against drought stress in young leaves.