Changes of endogenous jasmonic acid and methyl jasmonate in apples and sweet cherries during fruit development

Trans-jasmonic acid (JA), cts-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.). Trans-JA and cis-JA shelved similar changes during development in both types of fruit. JA concentration was high in the early growth stages of apple pulp development, decreased with days after full bloom (DAFB), and then increased again during maturation. There was an initial decrease in concentration of MeJA in apple pulp, followed by a general increase towards harvest. Concentrations of JA and MeJA in the pulp of sweet cherry were high during early growth stages, then decreased towards harvest, PDJ treatment at 104 DAFB (preclimacteric stage) increased endogenous abscisic acid concentration and anthocyanin concentration at 122 and 131 DAFB (maturation stages) in apple. 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. On a dry weight basis, changes in concentration in the seeds preceded those in the pulp, These results demonstrate that relatively high amounts of JA. and MeJA are associated with young developing fruit, These substances may have a role in regulation of fruit growth at early growth stages, though this has not been demonstrated. Chemical name used: n-propyl dihydrojasmonate (PDJ).