Changes of jasmonates in climacteric and nonclimacteric fruit

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Trans-jasmonic acid (JA), cis-JA, and trans-methyl jasmonate (MeJA) were quantified in pulp and seeds of 'Tsugaru' apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] and 'Satohnishiki' sweet cherry (Prunus avium L.). JA and MeJA concentrations were high in the early growth stages of apple pulp development, decreased with days after full bloom (DAFB), and then increased again during maturation. Concentrations of JA and MeJA in the pulp of sweet cherry were high during early growth stages, then decreased towards harvest. JA concentration in apple seeds was also high in the early growth stages, then decreased, and finally peaked at harvest. MeJA concentration in apple seeds increased towards harvest. In the seeds of sweet cherry, JA and MeJA concentrations generally increased until harvest. In both types of fruit, concentrations of JA and MeJA in the seeds were higher than those of pulp. These results demonstrate that relatively high amounts of JA and MeJA are associated w … More ith young developing fruit. These substances may have a role in regulation of fruit growth at early growth stages, though this has not been demonstrated. The role of JA in callus formation was investigated on discs taken from the pulp of apple, sampled on 15, 25, and 35 DAFB, and cultured on B5 medium, containing combinations of naphthalene acetic acid (NAA), benzyladenin (BA), and JA.On the 15 DAFB sample, 0.45 μmol, 1.0 μmol, and 4.5 μmol JA in the presence of 10.7 μmol NAA induced greater callus formation than did the sample without JA.However, this effect of JA at 15 DAFB was not observed except when it was combined with only NAA ; 4.5 μmol JA inhibited the callus formation. The presence of JA inhibited callus formation on discs taken 25 and 35 DAFB.Endogenous JA concentration of apple pulp at 15 DAFB was lower than that at 25 and 35 DAFB.These results indicate that the low endogenous JA concentration early in fruit development promotes callus formation ; whereas, increasing JA concentration inhibits it. The discs with skins from the apple pulp samples from preclimacteric, climacteric and postclimacteric stages were excised, cultured for 7 days under light on B5 media containing MeJA, and the combination of MeJA and AVG, and the effect of jasmonates on anthocyanin accumulation was investigated. In each sampling stage, MeJA alone and MeJA combined with AVG both stimulated greater anthocyanin accumulation compared to untreated control, though the combination of MeJA and AVG resulted in a lower concentration of anthocyanin than those of only MeJA at the preclimacteric and postclimacteric stages. Therefore, in most cases, jasmonates may be related to anthocyanin formation in apples independent of ethylene. Less