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Tissue‐specific hormonal profiling during dormancy release in macaw palm seeds
Author(s) -
Ribeiro Leonardo M.,
Garcia Queila S.,
Müller Maren,
MunnéBosch Sergi
Publication year - 2015
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/ppl.12269
Subject(s) - dormancy , biology , gibberellic acid , germination , abscisic acid , endosperm , jasmonic acid , gibberellin , seedling , petiole (insect anatomy) , botany , seed dormancy , salicylic acid , biochemistry , hymenoptera , gene
Little is known about the control exerted by hormones in specific tissues during germination and post‐germinative development in monocot seeds, whose embryos have complex structures and can remain dormant for long periods of time. Here the tissue‐specific hormonal profile of macaw palm ( Acrocomia aculeata ) seeds overcoming dormancy and seedling during initial development was examined. Endogenous hormonal concentrations were determined in the cotyledonary petiole, haustorium, operculum, endosperm adjacent to the embryo and peripheral endosperm of dry dormant seeds, imbibed seeds trapped in phase I of germination, and germinating (phase 2 and phase 3) seeds 2, 5, 10 and 15 days after sowing. Evaluations were performed on seeds treated for overcoming dormancy by removal of the operculum and by immersion in a gibberellic acid ( GA 3 ) solution. Removal of the operculum effectively helped in overcoming dormancy, which was associated with the synthesis of active gibberellins ( GAs ) and cytokinins ( CKs ), as well as reductions of abscisic acid ( ABA ) in the cotyledonary petiole. In imbibed seeds trapped in phase I of germination, exogenous GA 3 caused an increase in active GAs in the cotyledonary petiole and operculum and reduction in ABA in the operculum. Initial seedling development was associated with increases in the CK/auxin ratio in the haustorium and GA levels in the endosperm which is possibly related to the mobilization of metabolic reserves. Increases in salicylic acid ( SA ) and jasmonic acid ( JA ) concentrations were associated with the development of the vegetative axis. Hormones play a crucial tissue‐specific role in the control of dormancy, germination and initial development of seedlings in macaw palm, including a central role not only for GAs and ABA , but also for CKs and other hormones.