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EXINE DEVELOPMENT IN GERBERA JAMESONII (ASTERACEAE: MUTISIEAE)
Author(s) -
Southworth Darlene
Publication year - 1983
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.1537-2197.1983.tb07904.x
Subject(s) - biology , sporopollenin , microspore , botany , vacuole , gerbera jamesonii , callose , vesicle , biophysics , cell wall , pollen , stamen , cytoplasm , microbiology and biotechnology , membrane , biochemistry , gerbera
The development of the pollen wall in Gerbera jamesonii was studied using light and electron microscopy and histochemical stains. The primexine is patterned while the microspores are encased in the special cell wall. Bacules form at projections of the plasma membrane. Numerous ribosomes and large, single‐membrane bound vesicles containing fibrillar material are observed near the developing bacule bases. The tectum and nonhomogeneous layer form simultaneously with the bacules, but do not appear to be outgrowths of them. Following dissolution of the callose cell wall, the lamellate exine‐2 is laid down beginning in the apertural region. Polysaccharides are associated with the developing exine‐1 and the pore regions of the exine‐2. After exine‐2 deposition, the exine‐1 thickens by the addition of sporopollenin. When the exine is completed, a vacuole forms which displaces the nucleus, compresses the exine‐2 and expands the incurved exine‐1. As the vacuole shrinks, the intine and storage polysaccharides form.