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The epidermis of most leaves shows dorsoventral anatomy: the upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions. Woody stems and some other stem structures such as potato tubers produce a secondary covering called the periderm that replaces the epidermis as the protective covering.
The epidermis serves several functions: protection against water loss by way of transpiration, regulation of gas exchange and secretion of metabolic compounds. Most leaves show dorsoventral anatomy: The upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions.
English: The fine scale structure of a leaf featuring the major tissues; the upper and lower epithelia (and associated cuticles), the palisade and spongy mesophyll and the guard cells of the stoma.
The dorsoventral axis [10] ... [37] For example, in skin, the epidermis is superficial to the subcutis. Dorsal and ventral. These two terms, ...
This term has also been used as a synonym for dorsoventral organs, those that extend from a dorsal to a ventral surface. [ citation needed ] This word is also used to define body structure of an organism, e.g. flatworm have dorsiventrally flattened bodies.
Plant anatomy or phytotomy is the general term for the study of the internal structure of plants.Originally, it included plant morphology, the description of the physical form and external structure of plants, but since the mid-20th century, plant anatomy has been considered a separate field referring only to internal plant structure.
The outside of the stem is covered with an epidermis, which is covered by a waterproof cuticle. The epidermis also may contain stomata for gas exchange and multicellular stem hairs called trichomes. A cortex consisting of hypodermis (collenchyma cells) and endodermis (starch containing cells) is present above the pericycle and vascular bundles.
Small pits in the epidermis appear to be sensors. [32] On their head, some species have a number of pigment-cup ocelli, [32] which can detect light but not form an image. [35] Most nemerteans have two to six ocelli, although some have hundreds. [34] A few tiny species that live between grains of sand have statocysts, [32] which sense balance. [36]