Temporal Changes in Tocochromanols in Leaves and Spikes of Barley Cultivars During the Development of the Caryopsis

Abstract

Temporal changes in tocochromanols during the development of caryopsis in two barley cultivars, 'Fiber-Snow' and 'Musashibo', were determined. Alpha-tocopherol (Toc) in leaves dominated among eight tocochromanol isomers in the leaves and spikes of both cultivars; suggesting that the tocochromanol content of the barley plant as a whole may be affected by the α-Toc content in leaves. The pattern of temporal changes in leaf Toc content also differed between the cultivars. Leaf Toc content increased strikingly after anthesis in 'Fiber-Snow', whereas no conspicuous increase was observed in 'Musashibo'. Toc content was also significantly higher in 'Fiber-Snow' than in 'Musashibo' during the milky and dough stages. Tocotorienols (T3) were exclusively present in the spikes. They occurred around ten days after anthesis, peaking after the milky stage, whereas Toc had already accumulated at the first heading date. Alpha-T3 was the dominant form of the T3s, the accumulation of which preceded those of the β-and γ-forms in both cultivars. Our findings revealed that the Toc content of the whole barley plant might remain high throughout caryopsis development, decreasing only toward the end and that T3 occurred after the mid-stage of the development. These results indicate that the current conventional harvest time for forage barley is appropriate, as farmers harvesting during caryopsis development will produce forage containing considerable tocochromanol.

Enhancement of α‐tocopherol by ensiling in barley (Hordeum vulgare) and wheat (Triticum aestivum)

“…In most species of higher plant, Tocs are generally major component of tocochlomanol in comparison of T3s, considering whole body of a plant. This is because Tocs tend to be deposited in large quantity in tissue of leaves and stems, whereas T3s are exclusively found in spikes, caryopses and/or seeds in small quantity (Cahoon et al 2003;Hunter and Cahoon 2007;Sato et al 2015).…”