The progression of ethylene production and respiration in the tissues of ripening 'Fuji' apple fruit

'Fuji' apple (Malus xdomestica Borkh.) fruits were harvested periodically p rior to and during fruit ripening. Ethylene evolution and respiration rates of skin, hypanthial, and carpellary tissue was determined in each fruit. A dditionally, whole fruits were used for analyses of internal ethylene conce ntration, volatile evolution, starch content, flesh firmness, and soluble s olids content. Ethylene production was greatest in the carpellary tissue at all sampling dates except the one occurring just before the rise in whole fruit internal ethylene concentration, when production in the skin and carp ellary tissue was similar. Respiration was always highest in the skin, in w hich the climacteric rise was most drastic. Higher ethylene production in t he carpellary tissue of pre- and postclimacteric fruit and higher respirati on in the skin tissue, including a noticeable climacteric rise, is indicati ve of a ripening initiation signal originating and/or transduced through th e carpels to the rest of the fruit.