Absorbent tissue is a vegetable tissue that is specialized for the absorption of water and substances dissolved in it. This applies primarily to the rhizodermis of the young roots , which, in contrast to the epidermis of the shoots and leaves, is not cutinized and also has no or only a very weak cuticle . In addition, the water-absorbing surface is enlarged by root hairs.
If plants are not able to absorb water from the soil due to certain location conditions, then water-absorbing tissue is often present on their above-ground parts. For example, have many epiphytic living orchids and other plant species on their aerial roots a multilayered tissue from dead, large pores containing cells absorb that, the water from the air radicum velamen . Other tropical epiphytes have scaly hairs on the upper side of their leaves, absorption hairs that are also capable of absorbing water when there is precipitation and high humidity.
On the leaves and shoot axes of many submerged aquatic plants there are often epidermal absorption organs ( hydropots ), which are used to absorb mineral salts from the water. The ligula of the moss ferns and club moss-like is also an absorption tissue .