Development and localization of endo-beta-mannanase in the embryo of germinating and germinated tomato seeds
1998
Nonogaki, H. | Nomaguchi, M. | Morohashi, Y. | Matsushima, H.
The occurrence of endo-beta-mannanase in the embryo of germinating and germinated tomato (Lycopersicon esculentum Mill.) seeds was characterized. The endo-beta-mannanase that developed in the embryo consisted of two isoforms and their molecular masses (41 and 42 kDa) did not correspond to the mass (37-39 kDa) of any isoform present in the endosperm. This indicates that mannanase isoforms present in the embryo are embryo-specific. Specific activities (with locust bean galactomannan as substrate) were also different between the embryonic and the endospermic enzymes. The enzyme was absent from the embryo of seeds imbibed for 2 h. With time after imbibition, mannanase content increased until the radicle had just protruded (day 2). However, the increase was transient and the content rapidly decreased thereafter and fell to an undetectable level on day 4. Tissue prints showed that the activity first appeared at the tip part of the radicle and then at the tip of the cotyledon. Thereafter the activity spread through the embryo tissues from the both tip parts.
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