Trichomes

Trichomes are structures of the plant epidermis that have several functions, such as reducing water loss, protecting against herbivory and attracting pollinators.

Trichomes prevent water loss through transpiration, in addition to providing protection against herbivory

Trichomes are epidermal appendages found on various plant species. They have different shapes, which even serve as a taxonomic characteristic, that is, the shape and substances produced by a particular trichome can help to identify a species. In addition to playing a fundamental role in taxonomy, trichomes are related to reducing water loss and protecting against herbivory .

types of trichomes

→ Tector trichomes

Tector trichomes, also called non-glandular, are incapable of producing secretions . For this reason, they are more related to the reduction of water loss, reduction of light incidence, in addition to forming a dense cover that can serve as a mechanical barrier.

These trichomes can be unicellular, when they consist of a single epidermal cell, or multicellular, when they are formed by several cells. Multicellular trichomes may or may not be branched.

Root trichomes , or root hairs, are usually described separately. As they do not have secretion, they can be classified as protectors. The function of these hairs is to ensure the absorption of water and nutrients.

→ Glandular trichomes

Glandular trichomes are capable of producing secretions. These substances, such as oils, nectar, digestive juices and resins, have a varied amount of functions in the plant. There are, for example, stinging trichomes, which repel herbivores. There are also glandular trichomes found in carnivorous plants , which produce secretion capable of holding prey and also enzymes that ensure its digestion. Secretory trichomes can also be observed on flowers with the function of attracting pollinators .

Glandular trichomes are capable of producing secretions (oils, nectar, digestive juices and resins) and have a wide range of functions in the plant. See some examples:

  • Stinging trichomes: drive away herbivores;
  • Glandular trichomes: they are found in carnivorous plants and produce secretion capable of holding the prey and also enzymes that guarantee its digestion.
  • Secretory trichomes: can be observed on flowers and have the function of attracting pollinators .

Glandular trichomes have a head , which can be formed by one or several cells and is the site of secretion synthesis. In addition to the head, there is a stalk that joins the head to the epidermis and varies in length.

→ Mixed trichomes

Mixed trichomes have a non-glandular portion and a region capable of secreting substances. They can be seen in the plant Leandra australis.

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