What is a pollen tube?


Quick Answer

A pollen tube is a hollow tube that forms from a pollen grain after pollination. Pollen tubes penetrate the ovule of a flower and release male gametes.

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Full Answer

Pollen tubes only grow at their tips, and they do so at a very fast rate and reach extended lengths. Actin, a protein, is necessary for the polarized tip to grow. The pollen tubes of most plants contain two layers: an inner sheath of callose, which is a substance made out of sugars, and an outer coating of pectin, cellulose and hemicellulose. The pollen tube's directional growth through the pistil toward the flower���s ovary is essential for egg fertilization.

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