Cell wall changes in pear fruit softening on and off the tree

Abstract

Abstract Changes in ethylene production and polyuronides in pear fruit on and off the tree were investigated. In `Marguerite Marillat' fruit, flesh firmness changed little after the optimum time for harvesting (OTH). By contrast, firmness of `La France' fruit decreased gradually after OTH, reaching an average of 30 N for fruit left on the tree for 28 days after OTH. The amount of water-soluble polyuronides increased slightly during ripening on the tree. In both cultivars, the amount 28 days after OTH was less than one-third of that in fruit harvested at OTH and ripened off the tree. Ethylene production did not increase substantially until 28 and 14 days after OTH in `Marguerite Marillat' and `La France' fruit, respectively. Pears off the tree softened to less than 10 N independently of harvest date and cultivar. The amount of water-soluble polyuronides in fruit softened after harvest increased significantly from that at harvest. In both cultivars, the texture of fruit harvested at 14 days and 28 days after OTH and ripened did not become buttery and juicy. Those fruit had less water-soluble polyuronides than fruit which developed a buttery and juicy texture.