TOCOPHEROLS are the most important compounds having antioxidant activity in sunflower seeds. In vivo, they exert vitamin E activity, protecting cellular membrane lipids against oxidative damage (Muggli, 1994). In vitro, they inhibit lipid oxidation in oils and fats, as well as in foods and feeds containing them (Kamal-Eldin and Appelqvist, 1996). Alpha-tocopherol exerts the most active
biological activity (Traber and Sies, 1996), but it shows the weakest antioxidant potency in vitro. Conversely, beta-, gamma-, and delta-tocopherol possess a lower vitaminEvalue, but they exert a considerably greater in vitro antioxidant protection than alpha-tocopherol (Pongraczet al., 1995).
Conventional sunflower seeds mainly contain alphatocopherol, which accounts for more than 900 g kg21 total tocopherols . Beta- and gamma-tocopherol can be present in sunflower seeds, usually in amounts below 20 g kg21 of the total tocopherols (Demurin, 1993;Dolde et al., 1999). Sunflower germplasm with modified tocopherol profile has been developed. Demurin (1993) reported
the line LG-15, with increased concentration of betatocopherol (500 g kg21 tocopherols), and the line LG-17, with increased concentration of gamma-tocopherol (950 g kg21 tocopherols), both of them developed from segregating accessions identified in the evaluation of a germplasm collection. Genetic characterization of both lines concluded that the increased levels of betatocopherol were produced by recessive alleles at the Tph1 locus, whereas the increased levels of gammatocopherol were the result of recessive alleles at the Tph2 locus (Demurin et al., 1996). Also through the evaluation of the natural variability existing in germplasm collections ,Velasco et al. (2004a) developed the line T589, with a beta-tocopherol content above 300 g kg21 total tocopherols , and the line T2100, with a gamma-tocopherol content above 850 g kg21. Velasco and Ferna´ndez-Martı´nez (2003) reported the presence of recessive alleles at a single locus underlying each of the modified tocopherol profiles, i.e., the increased beta-tocopherol concentration in seeds of T589 and the high gammatocopherol
content in seeds of T2100. Comparative genetic studies concluded that tph1 alleles were present
in both LG-15 and T589 lines (Demurin et al., 2004; Vera-Ruiz et al., 2005), and tph2 alleles were present in both LG-17 and T2100 lines (Demurin et al., 2004).
Additional variation for gamma-tocopherol content was created in sunflower by using chemical mutagenesis (Velasco et al., 2004b). The authors isolated the lines IAST-1 and IAST-540, with gamma-tocopherol content above 850 g kg21 total tocopherols. No comparative genetic studies have been conducted to determine whether the high gamma-tocopherol lines developed by mutagenesis
are allelic to those developed through germplasm evaluation.
生物活性（特雷贝尔和sies ， 1996年） ，而且还显示出最弱的抗氧化效价的影响。反过来说， β - ， γ - ，和德尔塔-生育酚具有较低vitaminevalue ，但他们施加了相当大的体外抗氧化保护比α -生育酚（ pongraczet基地， 1995年） 。
传统的葵花籽主要成份为alphatocopherol ，占多900克kg21总生育酚。 β -和γ -生育酚能够存在于葵花子，通常是在金额低于20克kg21的总生育酚（杰穆林， 1993年; dolde等人， 1999年） 。向日葵种质改良生育酚轮廓已经研制成功。杰穆林（ 1993 ）报
该线的LG - 15 ，增加浓度betatocopherol （ 500克kg21生育酚） ，以及路线的LG - 17 ，增加浓度的γ -生育酚（ 950克kg21生育酚） ，他们都制定了从分隔加入确定的评价一个种质资源的收集。遗传特征均系得出结论认为，增加各级betatocopherol产生隐性等位基因在tph1轨迹，而更高等级的gammatocopherol人的结果，隐性等位基因在tph2轨迹（杰穆林等， 1996 ） 。还通过评估的自然变异性，在现有的种质资源收集， velasco等人。 （ 2004 ） ，开发出符合t589 ，与β -生育酚含量高于300克kg21总生育酚，和路线t2100 ，一个伽玛维生素E的含量高于850克kg21 。 velasco和ferna'ndez - martı'nez （ 2003 ）报道，在场的隐性等位基因，在一个单一的轨迹背后的每一项改装生育酚剖面，即增加β -生育酚浓度的种子t589和高gammatocopherol
含量的种子t2100 。比较基因研究得出结论认为， tph1等位基因的人出席
在双方的LG - 15和t589线（杰穆林等人， 2004年;维拉-鲁伊斯等人， 2005年）和tph2等位基因的人，目前在这两个LG电子- 17和t2100线（杰穆林等人， 2004年） 。
额外变异伽玛维生素E的含量是在葵花，利用化学诱变（ velasco等人， 2004 ） 。作者隔离线iast - 1和iast - 540 ，伽玛维生素E的含量高于850克kg21总生育酚。没有比较基因进行了研究，以确定是否高γ -生育酚系研制的诱变
等位基因是那些发达国家通过种质资源评价工作。
