General Characteristics of Trichomes:
Some of the epidermal cells of axis, leaves and other plant parts grow out in the form of trichomes or hairs.
They (Fig. 138) show following characteristics:
1. These are the elongations or the extensions of epidermai cells.
2. They are found singly or in groups.
3. Trichomes may be unicellular or multicellular. Morphologically, root hairs are typical hairs.
4. They are highly variable in shape varying from small protuberances of epidermal cells to very complex, multicellular, branched or stellate structures.
5. Hairs may consist of either living or dead cells.
6. Hairs with living cells contain very little cytoplasm in their cells.
7. They persist throughout the life of a plant part or may fall very soon.
8. Innumerable types of the hairs are known, of which some of the types are under-mentioned:
(1) Uniseriate hairs,
(2) Stinging hairs,
(3) Mucilage hairs,
(4) Bladder like hairs,
(5) Laticiferous hairs,
(6) Silicified hairs,
(7) Glandular shaggy hairs,
(8) Non-glandular shaggy hairs,
(9) Non- glandular tufted hairs,
(10) Stellate glandular hairs,
(11) Stellate non-glandular hairs,
(12) Branched glandular hairs,
(13) Branched non-glandular hairs,
(14) Capitate sessile hairs,
(15) Glandular peltate hairs,
(16) Non-glandular peltate hairs, etc.
Functions of the trichomes include:
(i) Control of the transpiration rate,
(ii) Reduction of heating effect of sunlight,
(iii) General protection of plant body from harmful insects, and other agencies.