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 qu antified in pulp and seeds of 'Tsugaru' apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] and 'Satohnishiki' sweet cherry (Prunus avi um L.). Trans-JA and cis-JA shelved similar changes during development in b oth types of fruit. JA concentration was high in the early growth stages of apple pulp development, decreased with days after full bloom (DAFB), and t hen increased again during maturation. There was an initial decrease in con centration of MeJA in apple pulp, followed by a general increase towards ha rvest. Concentrations of JA and MeJA in the pulp of sweet cherry were high during early growth stages, then decreased towards harvest, PDJ treatment a t 104 DAFB (preclimacteric stage) increased endogenous abscisic acid concen tration and anthocyanin concentration at 122 and 131 DAFB (maturation stage s) in apple. JA concentration in apple seeds was also high in the early gro wth stages, then decreased, and finally peaked at harvest, MeJA concentrati on 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 thos e of pulp. On a dry weight basis, changes in concentration in the seeds pre ceded those in the pulp, These results demonstrate that relatively high amo unts of JA. and MeJA are associated with young developing fruit, These subs tances may have a role in regulation of fruit growth at early growth stages , though this has not been demonstrated. Chemical name used: n-propyl dihyd rojasmonate (PDJ).