Increases in Both Acute and Chronic Temperature Potentiate Tocotrienol Concentrations in Wild Barley at ‘Evolution Canyon’

Biosynthesis of tocols (vitamin E isoforms) is linked to response to temperature in plants. ‘ Evolution Canyon ’, an ecogeographical microcosm extending over an average of 200 meters (range 100–400) wide area in the Carmel Mountains of northern Israel, has been suggested as a model for studying global warming. Both domestic ( Hordeum vulgare ) and wild ( Hordeum spontaneum ) barley compared with wheat, oat, corn, rice, and rye show high tocotrienol/tocopherol ratios. Therefore, we hypothesized that tocol distribution might change in response to global warming. α ‐, β ‐, γ ‐, and δ ‐tocopherol, and α ‐, β ‐, γ ‐, and δ ‐tocotrienol concentrations were measured in wild barley ( H. spontaneum ) seeds harvested from the xeric (African) and mesic (European) slopes of Evolution Canyon over a six‐year period from 2005–2011. Additionally, we examined seeds from areas contiguous to and distant from the part of the Canyon severely burned during the Carmel Fire of December 2010. Increased α ‐tocotrienol ( p <0.01) was correlated with 1 ) temperature increases, 2 ) to the hotter ‘African’ slope in contrast to the cooler ‘European’ slope, and 3 ) to propinquity to the fire. The study illustrates the role of α ‐tocotrienol in both chronic and acute temperature adaptation in wild barley and suggests future research into thermoregulatory mechanisms in plants.