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Contribution of aleurone layer and scutellum to α‐amylase synthesis and secretion in wheat and rice grains
Author(s) -
Thévenot Cluadine,
SimondCôte Elizabeth,
Daussant Jean
Publication year - 1991
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1991.tb00089.x
Subject(s) - aleurone , scutellum , oryza sativa , amylase , germination , biology , secretion , caryopsis , isozyme , botany , biochemistry , enzyme , gene
Intact aleurone layers from wheat ( Triticum aestivum L. cv Camp Rémy) and rice ( Oryza sativa L. cv Cigalon) grains both contained and secreted more α‐amylase (EC 3.2.1.1.) than did the corresponding scutellar tissues. This discrimination was already evident at the earliest stages of germination at which the tissues could be isolated, and became more pronounced upon subsequent germination and growth. Isoenzyme patterns obtained upon isoelectric focusing showed a considerable polymorphism of the α‐amylases of each cereal. The enzyme polymorphism pattern was the same in the aleurone layer and in the scutellum, but some secondary constituents appeared to be more specific for the one or the other of the tissues. Moreover, the isozymes found in the tissues were the same as those found to be secreted. A third α‐amylase antigen which differs from the well established α 1 and α 11 forms was identified in the germinating wheat grains. The presence of Ca 2+ in the secretion medium favoured maximum secretion of α‐amylases from the wheat scutellum and aleurone layers, whereas it inhibited the secretion of the enzymes from the rice aleurone layer.