The possible role of pentose phosphate pathway (PPP) in dormancy relea
se of xHaynaldoticum sardoum Meletti et Onnis seeds was investigated.
Glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase
activities and the C6/C1 ratio in dormant and non dormant embryos fro
m the two natural lines (Culmo Vuoto and Culmo Pieno) were consequentl
y studied. Dry embryos of dormant seeds showed appreciable amounts of
both dehydrogenase activities. Furthermore, gibberellic acid incubatio
n of the seeds or their storage in dry conditions (after-ripening), bo
th of which treatments are effective in dormancy breaking, did not pro
duce any serious changes in enzyme activity pattern. Some increase in
dehydrogenase activities during late imbibition did not seem correlate
d with dormancy breaking, which happened earlier. Finally, the C6/C1 r
atio of dormant embryos did not change after gibberellic acid treatmen
t, while non dormant embryos showed an increased C6/C1 ratio. Conseque
ntly the PPP did not appear to be involved in dormancy breaking of xHa
ynaldoticum sardoum seeds.