exine


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exine

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

exine

the outer coat of a POLLEN GRAIN, that often has protuberances, spines, etc. The exine also has one or more areas where the wall is thin, forming a pore through which the pollen tube will protrude.
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Description: Miospore, trilete, amb originally circular to sub circular, distorted due to compressional folds, imparting typical oval or arcuate appearance to the spore, lete distinct, labra sharply developed, raised straight to sinuous, arms of leasurae never extending 1/4 spore radius, a large biconvex compressional fold, intersect rest of the folds at right angle, exine infragranulate 1 m thick.
striata, proteins are located in exine cavities (tectate grain) as pollenkitt or tryphine.
Description: Miospore, trilete, amb broadly triangular, Y- mark distinct, well developed, labra thick, raised, rays extending upto one half of the radius, exine punctate, upto 2m thick.
The size, symmetry, shape, aperture, spine and exine of the pollen were determined.
Pollen are usually classified on the basis of their shape, size, symmetry, polarity, apertural types and exine sculpturing (Perveen, 1993).
Description: Pollen grain, monosaccate, overall amb sub circular to elliptical, corpus ill defined, trilete mark distinct or indistinct, saccus attachment sub equatorial on both sides, exine of central body infra punctate to infra granulate, width of saccus uniform, or may be distorted or greatly compressed due to post preservational hazards, the exine of corpus gradually merges into exoexine of saccus leaving no clear cut line of demarcation, exoexine of saccus crumbled into radial folds, narrow zones of proximal and distal sides overlap, the exo exine of saccus is more compact, heavily built and dark in color than the exine of central body.
Clematis species usually possess tricolporate pollen but differ in details of polar and equatorial diameter, c olpi length, colpi width, exine thickness and exine sculpturing.
SEM photographs from the equatorial and polar view and exine of pollen grains were captured at 500 x, 2500x, 2500x and 7500x magnifications.
7- 2 mm long, base and apex obtuse, compressed laterally, green, dorsifixed at middle; pollen sulcate, ellipsoid, exine reticulate, muri narrowed; stigma conduplicate, ca.
According to Stanley and Linskens (1974) and Jay (1986) workers choose which pollen to collect not by their nutritive value, age, moisture, content, or colour, but on the basis of the odour and the physical configuration of the pollen grains, although many of the pollen species collected by honeybee foragers (some with high percentage frequency and high percentage occurrence) had a psilated exine (with a smooth surface), without spines or other structures typical of entomophilous plants.
Exine with sharply defined, laevigate exoexinus ribs, individual ribs continuous and looped so that those near to periphery pass without interruption from the proximal to the distal face.