ISSN:
1615-6102
Keywords:
Exine patterning
;
Tectal sheath
;
Callose
;
Sporopollenin
;
Plasma membrane
;
Dendrobium
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The position of the callose wall is related to the position of the primexine matrix that forms around the peripheral tetrads during microspore development of the compound unit, the pollinium. We report a combined freeze-fracture and freeze-substitution study of the events associated with early exine development. Stage one of exine development is deposition of protosporopollenin that is probably synthesised by the microspore and secreted to the primexine matrix where it is polymerised. Enzymes for the polymerisation of the protosporopollenin may be synthesised by the microspores and then transported, via the endoplasmic reticulum, to the plasma membrane. Stage two of exine development follows callose dissolution and deposition of tapetally derived sporopollenin. Hence exine form and exine deposition inDendrobium appear to be the result of intimate cooperation between the microspore, the plasma membrane, the callose and the tapetum.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01403950
Permalink
