Maintaining banana fruit in a low humidity environment accelerated fru
it ripening. This was reflected in an earlier increase in respiration
and ethylene production and more advanced peel colour and pulp sugars.
At the end of the trial the fruit kept in low humidity were yellow wi
th green tips (stage 5) whereas those kept at high humidity were still
green (stage 1-2). Fruit kept at low humidity did not show a large in
crease in pulp ethylene production compared with the fruits stored at
high humidity. This difference occurred despite a large increase in th
e 1-aminocyclopropane-1-carboxylic acid (ACC) content of both samples,
with the low humidity fruit preceding the high by two days. The peel
ethylene production of the low humidity stored fruit increased dramati
cally as the fruit ripened, coinciding with an increase in ACC. The AC
C oxidase activity of the peel reflected the ethylene production with
a large increase in the low humidity stored fruit and a later, smaller
increase in the high humidity stored fruit. The ACC oxidase activity
of the pulp of both low and high humidity stored fruit increased gradu
ally during storage. The changes in ethylene production are discussed
with reference to banana ripening being regarded as co-ordinated by pu
lp ethylene production while the peel is passive, depending on pulp et
hylene production for degreening.