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Ultrastructure of capsaicinoid-secreting cells in pungent and nonpungent red pepper (Capsicum annuum L.) cultivars

Examination of the placentae of hot and sweet cultivars of red pepper with light microscopy showed that both types have glandular areas. The placenta of the pungent type has a more conspicuous blister-like surface emerging from the glandular area where the cell wall was detached. The placental surfa...

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Bibliographic Details
Published in:Botanical gazette (Chicago, Ill.) Ill.), 1987-03, Vol.148 (1), p.1-6
Main Authors: Zamski, E, Shoham, O, Palevitch, D, Levy, A
Format: Article
Language:English
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Summary:Examination of the placentae of hot and sweet cultivars of red pepper with light microscopy showed that both types have glandular areas. The placenta of the pungent type has a more conspicuous blister-like surface emerging from the glandular area where the cell wall was detached. The placental surface of the nonpungent type is smooth. In the pungent types, the secreted capsaicinoid droplets produce pressure that detaches part of the cell wall plus the cuticle and leads to the protrusion of the detached wall into the locule. Large amounts of capsaicinoids are synthesized in the puffed endoplasmic reticulum (ER) fragments of the placental epidermis of the pungent cultivar. We suggest that the filled ER sacules and the vesicles derived from them migrate to the cell periphery and fuse with the plasmalemma. Plasmalemma protrusions may play a role in the secretion process. The secreted materials diffuse into the lamellated walls and into the subcuticular cavity. As the pressure rises, the capsaicinoids may pass through the cracked cuticle into the locular space. The glandular epidermis of the sweet cultivar has small amounts of puffed ER, and capsaicinoid droplets there are rare.
ISSN:0006-8071
1940-1205
DOI:10.1086/337620