The activity of PE in the pulp tissue declined over the
ripening period irrespective of the treatment applied (Fig. 3C).
The ABA-treated fruit exhibited lower PE activity in the
pulp (10%, 31%, 25% and 22%) on days 2, 4, 6 and 8 of
the ripening period, respectively, when compared with the
control. The NDGA-treated fruit exhibited 24% higher PE activity on
day 4 of ripening compared with the control fruit, but did not show
any difference to the control on day 6 to day 8 of ripening (Fig. 3C).
When averaged over alltreatments,the mean PE activity was lower
(0.14 mM NaOH mg protein−1 h−1) in ABA-treated than in control
and NDGA-treated fruit(0.17 and 0.18 mM NaOH mg protein−1 h−1,
respectively). There was a significant (P ≤ 0.001) negative correlation
(r = −0.82) between mango fruit softening and the activity of
PE during the ripening period.
The activity of EGase in pulp was not affected by ABA or NDGA
treatment during fruit ripening period (data not shown). However,
when averaged over the ripening period,the mean activity of EGase
in all treatments increased on days 2 and 4, stabilised on day 6 and
declined at the ripe stage.