Poster: Secondary Metabolism

Abs # 270: Studies on vacuolar pH increase of morning glory petals during blooming

Presenter:	Mori, Mihoko , morim@info.human.nagoya-u.ac.jp
Authors	Mori, Mihoko  (A)   Kawachi, Miki  (A)   Maeshima, Masayoshi  (B)   Kondo, Maki  (C)   Nishimura, Mikio  (C)   Kondo, Tadao  (B)   Yoshida, Kumi  (A)
Affiliations:	(A): Graduate School of Human Informatics, Nagoya University (B): Graduate School of Bioagricultural Sciences, Nagoya University (C): Department of Cell Biology, National Institute for Basic Biology

Petal color of blue morning glory (Ipomoea tricolor cv. Heavenly blue) changes from reddish-purple to blue during blooming. This color change was caused by vacuolar pH (pHv) increase of epidermal colored cells from 6.6 to 7.7. pHv of plant cells are generally controlled to be weakly acidic, therefore this higher pHv value of open petals of blue morning glory is very interesting physiological phenomena. To clarify the mechanism of pHv increase, we studied on H⁺ pumps and transporters of tonoplast. From colored protoplasts, prepared from buds and open petals of blue morning glory, tonoplast vesicles were obtained. By immunoblot technique and immunoelectron microscopy, V-ATPase and V-PPase were certainly retained both in the buds and open flower petals. PPi- and ATP-dependent H⁺-transport activities of open flower petal vesicles were higher than those of buds. V-PPase activity was much higher than that of V-ATPase both in buds and open flowers. Na⁺/H⁺ antiporter activities of tonoplast vesicles and immunoblot experiments are in progress.