The dynamics of tocopherol and the effect of high temperature in developing sunflower (Helianthus annuus L.) embryo

To improve sunflower (Helianthus annuus L.) oil quality, the pattern of tocopherol and the effect of brief interval of high temperature on tocopherol accumulation during embryo development were investigated. Total tocopherol content increased linearly from 12 to 33 days after anthesis (DAA) and then remained stable until maturity. γ-Tocopherol content reached a maximum on 33 DAA and then decreased. δ-Tocopherol was not detected until 19 DAA. The effect of brief interval of high temperature (⩾35 °C for seven consecutive days) on tocopherol accumulation was studied. The accelerating effect of high temperature on tocopherol accumulation on a dry weight basis was detected, but the reduction of tocopherol yield occurred from 12 to 19 DAA because the embryo dry weight was reduced significantly. However, the embryos exposed to a temperature of 35 °C from 12 to 19 DAA significantly increased the tocopherol yield per embryo, with no effect on the dry matter weight. These results are useful for evaluating the tocopherol content in sunflower oil and may help recognizing high quality of the oil.