exine

American  

[ek-seen, -sahyn] / ˈɛk sin, -saɪn /

noun

Botany.

1. the outer coat of a spore, especially a pollen grain.

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exine British  

/ ˈɛkstɪn, -tiːn, -taɪn, ˈɛksɪn, -aɪn /

noun

1. botany the outermost coat of a pollen grain or a spore Compare intine

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exine Scientific  

/ ĕk′sēn′,-sīn′ /

1. The outer layer of the wall of a pollen grain. The exine is composed of the most durable organic polymer known, sporopollenin.

2. Also called extine

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Etymology

Origin of exine

First recorded in 1880–85; ex- ¹ + -ine ¹

Example Sentences

Two projective layers form around the mature pollen grain, the inner intine and the outer exine.

From Textbooks • Jan. 1, 2015

The pollen contains two cells— a generative cell and a tube cell—and is covered by two layers called the intine and the exine.

From Textbooks • Jan. 1, 2015

Microspore spherical or oval, with or without a bladder-like extension of the exine, containing a prothallus of two or more cells, one of which produces two non-motile or motile male cells.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" by Various

The exine is a firm membrane, which defines the figure of the pollen-grain, and gives colour to it.

From Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 5 "Fleury, Claude" to "Foraker" by Various