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CYTOKININ‐ AND GIBBERELLIC ACID‐INDUCED EFFECTS ON THE DETERMINATION AND MORPHOGENESIS OF LEAF PRIMORDIA IN OPUNTIA POLYACANTHA (CACTACEAE)
Author(s) -
Mauseth James D.
Publication year - 1977
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1977.tb15735.x
Subject(s) - primordium , biology , botany , morphogenesis , meristem , cytokinin , guard cell , haustorium , auxin , shoot , biochemistry , gene , ecology , host (biology)
Cytokinins and gibberellins are able to strongly influence the development of “leaf” primordia in the cactus Opuntia polyacantha . Under the influence of cytokinin, the primordia produced by cultured axillary bud apical meristems develop as normal, photosynthetic leaves, being composed of regular epidermal cells, guard cells, mesophyll and mucilage cells as well as vascular tissue. Under the influence of gibberellic acid (GA), the primordia develop as cactus spines, composed of thick‐walled epidermal and fiber cells. Guard cells, vascular tissue and parenchyma do not occur. Thus GA is able to redirect leaf morphogenesis in O. polyacantha far more completely than has been reported for other plants. The mitotic activity of the primordia that will develop into spines is significantly higher (at the 5 % level) than the mitotic activity of the primordia that will develop into leaves. This is interpreted to indicate that the primordia are either leaf primordia or spine primordia from a very early age, and possibly are never uncommitted or undetermined primordia, as has been suggested for fern leaf primordia.