ISSN:
1615-6102
Keywords:
Aneilema
;
Commelina
;
Cytochemistry
;
Evolution
;
Papillae
;
Pollination
;
Secretion
;
Stigmas
;
Ultrastructure
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The stigmas of species inAneilema andCommelina are trifid and comprise elongate papillae. Progressive degeneration of papular cells is observed in stigmas from open flowers and at anthesis papillae may be moribund and collapsed. Fluid emanating from the hollow style flows onto the surface through ruptures in the cuticle at the interpapillar junctions into the interstices at maturity. This secretion stains positively for protein. Stigmas are of the “wet” type. The cuticle overlying the papillar cells is ridged and at the final stages prior to flowering this cuticle becomes detached from the underlying cellulosic wall. The sub-cuticular space so formed is filled with secretion. InAneilema species detachment of cuticle is at the papillar tip and along the lateral walls. InCommelina species the anticlinal walls of adjacent papillae are strongly attached for much of their length and thus detachment of cuticle is restricted to the papillar tip. The cell wall at the tip in both genera may proliferate forming a rudimentary transfer-cell type wall. The secretion is considered to be produced by the papillar cells. It is PAS positive but fails to stain for protein and in both the light and electron microscopes appears heterogenous. Pollen attachment, hydration, germination and early tube growth are very rapid following self-pollination, the pollen tubes entering the neck of the style within ten minutes of attachment. A unique character combination involving pollen and stigmas in these genera indicates a monophyletic origin.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01280212
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