42 空色西洋アサガオ花弁の開花に伴う青色化の機構(口頭発表の部)

概要

論文の詳細を見る
Beautiful flower colors are mostly due to anthocyanins and the mechanism of color development, especially of the blue color, has been attracting much interests. The petal color of blue morning glory, Ipomoea tricolor cv. Heavenly Blue, changes from purplish red in the bud to blue in the fully open flower. The same pigment, heavenly blue anthocyanin (HBA), is responsible for both colors. Therefore, the color change might be estimated by pH change of the vacuoles. By direct measurement of vacuolar pH using a pH-sensitive microelectrode, this color change was clarified to be caused by an unusual increase in vacuolar pH from 6.6 to 7.7 in the colored adaxial and abaxial cells. To clarify the mechanism underlying the alkalization of epidermal vacuoles in the open petals we focused on vacuolar H^+-ATPase (V-ATPase), H^+-pyrophosphatase (V-PPase) and an isoform of Na^+/H^+ exchanger (NHX1). We isolated red and blue protoplasts from the petals in buds and fully open flower, respectively, and purified vacuolar membranes. The membranes contained V-ATPase, V-PPase and NHX1, which were immunochemically detected, with relatively high transport activity. Na^+/H^+ exchanger could be detected only in the vacuolar membranes prepared from flower petals and its protein level was the highest in the colored petal epidermis of the open flower. These results suggest that the increase of vacuolar pH in the petals during flower-opening is due to active transport of Na^+ and/or K^+ from cytosol into vacuoles through a sodium- or potassium-driven Na^+(K^+)/H^+ exchanger NXH1 and that V-PPase and V-ATPase may prevent the over-alkalization. This systematic ion transport maintains the weakly alkaline vacuolar pH, producing the sky-blue petals.
天然有機化合物討論会の論文
2005-09-15

42 空色西洋アサガオ花弁の開花に伴う青色化の機構(口頭発表の部)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク