トルコギキョウ白色系生花弁の紫外光下における明暗像とフラボノイド含量との関係(育種・遺伝資源)  [in Japanese] The Relationship between Characteristics of Optical Image under UV Light and Flavonoid Content in Acyanic Petals of Eustoma grandiflorum(Breeding & Germplasm Resources)  [in Japanese]

白色系トルコギキョウ75品種・系統の花弁を用いて, 365nmの紫外光下での花弁の像とフラボノイド含量を調査した.紫外光下において黒く見える花弁には10mg/g以上のフラボノイドが存在し, 白く見える花弁のフラボノイド含量は3mg/g以下と少なかった.紫外光下における花弁の像の明暗とフラボノイド含量との間に明らかな相関が認められた.紫外光下で先端側が黒く基部が白い, 覆輪状の像を示す白色花弁が複数存在した.紫覆輪品種'キャンディマリン'から分離した白色花は紫外光下で同様の覆輪状の像を示し, 先端側は基部側の30倍のフラボノイドを含んでいた.紫覆輪品種の花弁の先端側と基部側のフラボノイド含量比が同じであることから, 白色花弁上のフラボノイドの局在は同様の機構で発現していると考えられた.本方法は多くの試料について短時間に非破壊的にフラボノイドの情報が得られることから, 育種素材の選抜やフラボノイド-アントシアニンの生合成の情報を得ることに役立つと期待される.

We investigated the relationship between petal brightness under ultraviolet light (365nm) and flavonoid concentrations using 75 pale color lines of Eustoma grandiflorum. Flavonoid concentrations of the dark color petals were above 10mg/g f. w., while those of the bright color petals were below 3mg/g f. w. Several lines showed an image of bright petals with dark edges. A purple picotee petal and a white petal derived from 'Candy Marin' also showed such images. The edge tissue contained a 30-times higher concentration of flavonoids than the other tissue in both petals, suggesting that the same mechanism affects the flavonoid distribution. We can roughly estimate flavonoid concentration in pale color petals of Eustoma using this method. This method could be applied to other plants including Dianthus and Petunia. Because information on the flavonoid concentration in many flowers can be obtained immediately and non-destructively, this method could contribute to breeding selection and studies on the regulation of flavonoid-anthocyanin biosynthesis.