Abstract
Relationships between changes in free abscisic acid (ABA) content and ethylene evolution and respiration rates were investigated during ripening and senescence of several fruits. The fruits, such as pear, peach, kiwi fruit and tomato, were picked at young and mature stage of growth and stored at 20°C.
1. In all of the young fruits, the CO2 production and the evolution of ethylene by the fruits were kept at relatively low rates until the occurring of browning or decay, but ABA contents increased rapidly with ageing, even in′Nijisseiki′pear which evolved ethylene only a little.
2. In the cases of mature fruits, ABA contents of′Nijisseiki′and′Kosui′pear were almostly constant during the experimental period, but the rates of CO2 and ethylene production increased slightly at the end of experiment.
In ′Bartlett′ pear, tomato and peach, ABA accumulated in conjunction with the rise in ethylene evolution that accompanied the respiratory climacteric.
In kiwi fruits, the ethylene evolution also increased with the climacteric rise of respiration, but the ABA contents decreased rapidly during ripening.
From these results, it seems that the accumulation of ABA is not consistently related to the evolution of ethylene, which is one of symptoms of ripening or senescence.
