Contribution of the Pentose Phosphate Pathway and Glycolytic Pathway to Dormancy Breakage and Germination of Peanut (Arachis hypogaea L.) Seeds

Levels of glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADPH oxidoreductase, E.C. 1.1.1.49[EC]) 6-phosphogluconate dehydrogenase(6-phospho-D-gluconate : NADP⁺ oxidoreduc tase, E.C. 1.1.1.44[EC])and aldolase (fructose 1, 6-diphosphate, D-glyceraldehyde, 3-phosphatelyase, E.C. 4.1.2.13[EC]) were assayed in the seeds of geneticallydormant and non-dormant pure lines of groundnut. In dormantlines cotyledons showed increased levels of activity of G-6-PDHand 6-PGDH during dry storage after-ripening. While the embryonicaxis did not exhibit detectable levels of enzyme activitiesimmediately after harvest, the activity started after a lapseof time during dry storage. When seeds of dormant lines wereincubated with kinetin (6-furfurylaminopurine) a distinct increasein the levels of both the enzymes was observed. The levels ofaldolase activity gradually decreased in the cotyledons andincreased in the embryonic axis of both control and kinetintreated seeds during the period of after-ripening. Comparedto control, kinetin treatment increased the aldolase activityin the embryonic axis and decreased it in the cotyledons. In non-dormant lines the activity of both the enzymes of PPpathway increased sharply both in the cotyledons and embryonicaxis while aldolase activity decreased in the cotyledons andincreased in the embryonic axis during germination i.e., from24 h to 96 h of germination. Abscisic acid caused inhibitionof enzyme activities to a large extent. Key words: PP pathway, dormancy breakage, germination, peanut