リンゴ果台枝の花芽形成に及ぼす糖類とGAの影響(発育制御)  [in Japanese] Effects of Sugar and GA Contents on Flower Bud Formation of Bourse Shoots in Apple(Growth Regulation)  [in Japanese]

リンゴ'ふじ'と'恵'を供試して着果程度と種子の有無の処理を施し, 果台枝頂芽の糖類およびGA含量と花芽形成との関係について検討した.果台枝頂芽における翌年の着花率は, 不着果および無種子果着果に比べ, 有種子着果の方が低かった.果台枝頂芽の新鮮重は, 6月初めにどの処理も同じだったが, 7月初めに無種子が有種子の着果より大きくなった.果台枝葉の同化産物の果台枝頂芽への分配は, 種子よりも果実の存在によって影響され, 果そう当たりの果実乾物重が大きいほど減少した.また, 6月初めにおける果台枝頂芽の糖類含量も, 着果の程度が強くなるほど減少した.着果により頂芽内で減少する糖類は, ソルビトールとグルコースで, スクロースは変化しなかった.6月初めにおける果台枝頂部のGA含量は, 不着果と無種子1果の果台枝の方が有種子1果と3果の果台枝より低く, 着果よりも種子の存在により増加した.

To investigate the relationship between sugar concentration, gibberellin levels and flower bud formation of terminal buds of bourse shoots in two apple (Malus domestica Borkh.) cultivars 'Fuji' and 'Megumi', different bearing levels, seeded and seedless treatments were performed. The flowering rate of terminal buds of bourse shoots bearing seeded fruits was lower than those of non-bearing and seedless fruit trees. In the fresh weight of terminal buds of bourse shoots, all treatments were the same in the beginning of June, and weights of buds from seedless trees were heavier than those of seeded fruit trees in the beginning of July. Assimilate of photosynthate produced by bourse leaves distributed to the terminal buds was affected by fruits rather than seeds, and it decreased as the dry weight of fruits per bourse increased. However, sugar concentrations of terminal buds of bourse shoots in the beginning of June also decreased as they bore more fruits. Decreased sugars of terminal buds were sorbitol and glucose, whereas sucrose was invariable. GA level of non-bearing and one type of seedless fruit tree were lower than three or one seeded fruit per bourse in the beginning of June, and it increased with the presence of seeds rather than with the presence of bearing fruit.