ブドウ'黒王'の成熟期における温度が果実の着色およびアントシアニン関連酵素活性に及ぼす影響(発育制御)  [in Japanese] Changes in the Coloration and Activities of Enzymes Involved in Anthocyanin Synthesis of 'Kokuo' Grapes Grown under Different Temperature Conditions During Ripening(Growth Regulation)  [in Japanese]

温度要因,特に夜間の高温がブドウ果実のアントシアニン生合成に及ぼす影響を明らかにするため,異なる温度条件で生育したブドウ'黒王'果実を用い,フラボノイド含量,関連酵素活性を調査した.実験は2年間にわたって行ない,温度条件は昼夜25℃恒温区と昼25℃/夜15℃の変温区(2000年),昼夜30℃恒温区と昼30℃/夜15℃の変温区(2001年)とした.果皮のアントシアニン含量は,昼温25℃条件の場合では恒温区で高かったが,昼温30℃条件の場合では恒温区すなわち夜間高温条件で著しく低かった.中間代謝産物であるフラボノール,プロアントシアニンは両年とも恒温区で高く推移した.PAL活性は夜間温度の影響はほとんど受けなかったが,UFGT活性は夜間温度が低い変温区の果実で恒温区より高く,変温区の果実では中間代謝産物よりもアントシアニン蓄積が促進された.

To clarify the mechanism regulating anthocyanin biosynthesis in 'Kokuo' grapes grown under high night temperatures, we examined flavonoid accumulation and the activities of related enzymes in the grapes. When grapes were grown at 25℃ day temperature and high night temperatures (25℃), anthocyanin content in the skin was higher than that of grapes grown under low night temperatures (15℃). On the contrary, at 30℃ day temperature conditions, anthocyanin content in the skin of grapes grown under high night temperatures (30℃) was markedly lower than that of grapes grown under low night temperatures (15℃). Flavonol and proanthocyanin contents in the skin of grapes grown under high temperatures were higher than that of grapes grown under low night temperatures. Although there was little effect of night temperatures on phenylalanine ammonia lyase (PAL) activity in the skin, UDP-glucose:flavonoid 3-0-glucosyltransferase (UFGT) activity in the skin of grapes grown under high night temperatures was lower than that of grapes grown under low night temperature. These results suggest that anthocyanin accumulation in the skin of grapes grown at continuous high night temperatures is decreased due to decreased UFGT activities.