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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References in periodicals archive ?
A glycine-rich protein that facilitates exine formation during tomato pollen development.
Olive pollen ultrastructure: characterization of exine pattern through Image Analysis-Scanning Electron Microscope (IA-SEM).
The endexine is the inner part of the exine, is located above the foot layer and has a different electron density than the foot layer.
2 mm above the base, base obtuse, apex obtuse and apiculate; pollen ellipsoidal, biporate, exine reticulate, lumina polygonal to rounded, muri slightly thickened; stigma ovoid-ellipsoid, conduplicate-spiral, ca.
Pollen subprolate--prolate, large size, tricolporate, exine Mutisia type, microechinate.
Pollen prolate, large size, tricolporate, exine Mutisia type, microechinate.
6 cm long, base distinctly sagittate, apex obtuse, dorsifixed at 2/5 of its length above the base, versatile and hanging upside down at anthesis, with the margins of the opposed pollen sacs only partially touching each other at anthesis and not completely clasping the connective area; pollen ellipsoidal, sulcate, exine broadly reticulate, lumina rounded, muri narrowed; stigma conduplicate-spiral, ellipsoidal-capitate, blades 0.
Exine Mutisia type with compact ectosexine, echinate, 8-10 [micro]m thick, spines 2.
The stereostructure of the exine and its evolutionary significance in saxifragaceae sensu lato.
Exine (Ex) and Intine (In) are formed in this stage (fig 2 E) and tapetum in this plant is plasmodial type.
5 mm long, base sagittate and apex obtuse, fixed near the base; pollen oblong-elliptic, sulcate, exine reticulate, lumina polygonal, muri narrowed; style exceeding the petals for ca.
triangular outline, small size, syncolpate condition, and low exine sculpture) but the grains are distinctive at higher magnifications with SEM (Graham & Graham 197lb; Patel et al.