Interactions between jasmonates and abscisic acid in apple fruit, and stimulative effect of jasmonates on anthocyanin accumulation

The interactions between jasmonates [jasmonic acid (JA) and methyl jasmonat e (MeJA)] and abscisic acid (ABA) were investigated in 'Tsugaru' apple (Mal us pumila Mill. var. domestica Schneid.). In Exp. 1, discs from pulp excise d 93 days after full bloom (DAFB) (preclimacteric), 112 DAFB (climacteric), and 133 DAFB (postclimacteric) were collected and placed in petri dishes c ontaining a solution of 0.4 M mannitol with a combination of MeJA, ABA, and aminoethoxyvinylglycine (AVG). Jasmonates, ABA, and ethylene levels in the discs were measured at 0, 24, 48, and 72 hr after the initiation of treatm ent. At the climacteric and postclimacteric stages, the ABA treatment incre ased endogenous JA concentration and decreased it when combined with AVG. T his result suggests that ethylene may be related to the induction of endoge nous JA by ABA. MeJA treatment decreased endogenous ABA concentration from 93 to 133 DAFB, whereas AVG had no influence. This result also demonstrates that jasmonates may influence endogenous ABA synthesis independently from ethylene. In Exp. 2 when discs with skins from the apple pulp samples from preclimacteric, climacteric, and postclimacteric stages were excised, cultu red for 7 days under light on B5 media containing MeJA, and the combination of MeJA and AVG was investigated, MeJA and MeJA combined with AVG stimulat ed greater anthocyanin accumulation in both sampling stages compared to the untreated control; the combination of MeJA and AVG resulted in a lower con centration of anthocyanin than that of only MeJA at the preclimacteric and postclimacteric stages. Therefore, in most cases, jasmonates may be related to anthocyanin formation in apples in the presence and absence of ethylene .