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 (ĕk′sēn′, -sīn′)
The outer layer of the wall of a spore or pollen grain.

[ex(o)- + Greek īs, īn-, tendon; see wei- in Indo-European roots.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(ˈɛksɪn; -aɪn) or


(Botany) botany the outermost coat of a pollen grain or a spore. Compare intine
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈɛk sin, -saɪn)

the outer coat of a pollen grain.
[1880–85; perhaps ex-1 + -ine1]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
References in periodicals archive ?
These grains are monosulcate and have reticulate-columellar exine structure; Couper and other early authors (e.g., Brenner, 1963; Doyle, 1969) described the columellae as varying from free to fused at their heads to form a tectal reticulum, but SEM studies showed that they are typically reticulate (Doyle et al., 1975; Hughes et al., 1979).
Differences between the spores of the two species are found in the exine. In A.
Homologs in other plants of most of these genes have been associated with the process of pollen wall development, such as suberin biosynthesis [43, 44], cutin biosynthesis [45-47], pollen sporopollenin biosynthesis [48], and pollen exine formation [49-51].
Brassicaceae is a stenopalynous family, the pollen grains usually tricolpate, with a reticulate exine (Abdel-Khalik, 2002).
Pollen is surrounded by a complex protective outer membrane called exine, that is characterized for being resistant and firm, and composed of Sporopollenin, which are biopolymers as cutin (composed of fatty acids to protect the cell surface), suberin (polymer of long-chain fatty acids) and lignins (phenolic compounds) (Zuluaga et al., 2014).
Common size class was mediae, exine sculpture was reticulate and symmetry was bilateral.
Also, Mert (2009) investigated the pollen length pollen width intine and exine thickness of six cornelian cherry (Cornus mas L.) cultivars.