| Research Abstract |
In order to obtain an information on relationship of endogenous phytohormones to growth,maturation, ripening and senescence of fruits with different patterns of respiration, we examined on phytohormone concentration of fruits at young, intermediate (a transitive stage from growth phase to mature phase), mature, repening and senescence stages of the following fruits : climacteric fruits i.e. 'Bartlett' pear, non-climacteric fruits i.e. 'Nijisseiki' pear and late peak fruits i.e. 'Okubo' peach and 'Kosui' pear.
1. Changes in phytohormone concentration during growth and maturation in attached fruits.
In 'Nijisseiki' and 'Kosui' pears, IAA concentration decreased and ABA concentration changed not largely during proceeding from young to mature stage. In 'Okubo' peach and Kiwi-fruit, IAA concentration changed not largely, but ABA concentration increased with proceeding from young to mature stage.
2. Changes in phytohormone concentration during senescence or ripening of young, intermediate and mature fruits.
In 'Nijisseiki' and 'Kosui' pears harvested at young, intermediate and mature stages, ethylene was little produced, IAA- and GA concentrations decreased and ABA concentration increased during storage at 20゜C. In 'Bartlett' pear and 'Okubo' peach harvested at young, intermediate and mature stages, ethylene production increased with the increase of ABA concentration. Hese results suggest that ABA would play more important role on process of senescence than on ripening process during storage at 20゜C. 3. Relationship between ethylene-, ACC-production and concentration ratio of ABA/IAA during senescence or ripening of 'Okubo' peach and Kiwi-fruit'Bruno'.
In 'Okubo' peach, ethylene production increased, but ACC concentration decreased with the increase of concentration ratio of ABA/IAA during storage at 20゜C. In 'Bruno' kiwi-fruit, both ethylene production and ACC concentration increased with the decrease of concentration ratio of ABA/IAA during storage at 20゜C.
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