Caesalpinia peltophoroides (Leguminosae Caesalpinioideae) seeds were soaked in water for 144 hours. Samples were taken for protein analysis, quantification of alphagalactosidase activity and micropyle sugar composition. Germination began after 96 hours of imbibition, with no modifications in the micropyle cellular wall. The content of arabinose was higher in the micropyle region, with a tendency to increase during imbibition. Activity of alphagalactosidase was detected in dry seeds in the embryonic axis, as well as in the cotyledons, having increased 24 hours after imbibition. The increase of the activity in the cotyledons was observed only after 120 hours of imbibition. The protein content decreased continuously in the embryonic axis after 24 hours of imbibition, however it kept stable in cotyledons. The activity of the alphagalactosidase was raised by the temperature, being maximum at 55ºC for embryonic axis and at 50ºC for cotyledons. Enzyme activity was favored by pH ranging from 5.5 to 6.0 for the embryonic axis and 4.5 to 5.0 for cotyledons. The effectors SDS, CuSO4, galactose and melibiose inhibited enzyme activity of embryonic axis and cotyledons. Mercaptoethanol showed little stimulating effect on alphagalactosidase in cotyledons. The K M of the embryonic axis and the cotyledons were 1.74 and 2.64, respectively.
Alfagalactosidase; seeds; Caesalpinia peltophoroides
