Exine


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exine

[′ek‚sēn]
(botany)
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Exine

 

(also exosporium), in seed plants, the outer layer of the wall of pollen grains (microspores). In many plants the outside of the exine has nodules or reticular enlargements, which form specific patterns characteristic of a particular species and are there fore often used to identify the species to which a pollen grain belongs.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
13) imply that pollen in the common ancestor of Canrightia and Chloranthaceae was globose and monosulcate, with a reticulate-columellar exine, smooth muri, and a sculptured sulcus membrane, as in Canrightia and Zlatkocarpus, all features inherited from lower in the tree (Doyle, 2005).
Yang, "RUPTURED POLLEN GRAIN1, a member of the MtN3/saliva gene family, is crucial for exine pattern formation and cell integrity of microspores in Arabidopsis," Plant Physiology, vol.
Regarding to figure 4, (a) shows an oval homogeneous morphology without fissures, while (b) differs in being circular and having three wade edges in the primary wall, although in these morphologies is evident a well-defined structure where exine is highlighted.
The apocolpium (t) of Cornus mas's pollen grains ranges from 3.97 to 5.85 [micro]m and their exine thickness (Ex) ranges from 0.99 to 1.77 [micro]m.
Description:Pollen grain, monocolpate, amb oblong to oval elliptical, extremities rounded or blunt, colpus distinct, extending full length of grain, colpus broad in middle with sharp ends, usually marked by parallel, exinal folds on sides, folds Plano convex or biconcave in some cases additional intexinal folds may accompany the major folds, exine laevigate, 1.5 m thick.
Notably, the pollen grains of Passiflora typically have large amounts of lipophilic substances associated with exine (SOUZA et al., 2004) in the form of large drops (exudate) or with a fibrillar aspect between the free columellae of the reticulum, called pollenkitt (Figure 2F).
Pollutants make the surface of the exine more fragile, triggering a mucosal reaction and making them more exposed to pollen allergens.
The exine is intectated with a scabrate or microgemate sculpturing (MOORE & al., 1991; Beug, 2004), and is very sensitive to corrosion (HAVINGA, 1964, 1967), so it is not a very common taxon in pollen records.
Mature pollen grain size, exine sculpturing, and number of pores are the most distinctive features [6, 7].
18th Ave., for Exine Anderson Bailey, a retired UO music professor and one of the first soloists to perform with the Oregon Bach Festival.