Pronunciation: [ɛɡzˈə͡ʊdəmˌɪs] (IPA) 
The word "exodermis" is spelled with an "x" which represents the phoneme /ks/. The "o" is pronounced /ɒ/ as in "hot", followed by "d" pronounced /d/ as in "do", "er" pronounced /ə/ as in "the", "m" pronounced /m/ as in "me", "i" pronounced /ɪ/ as in "hit", and "s" pronounced /s/ as in "sit". The IPA phonetic transcription for "exodermis" is /ɛks'ɒdərmɪs/. This term refers to the outermost layer of cells in plant tissue.
The exodermis is a specialized outermost layer of cells found in various plant organs, primarily in roots and stems. Originating from the outermost layer of the primary meristem, the exodermis is responsible for several crucial functions related to protection, regulation, and absorption.
In terms of protection, the exodermis acts as a well-developed barrier, shielding the underlying tissues from mechanical damage, pathogens, and excessive water loss. Its cells are typically thick-walled, compactly arranged, and often modified with wax-like substances to enhance its impermeability and prevent the loss of water through evaporation. This protection is particularly important in environments with water scarcity, salinity, or other stressful conditions.
Moreover, the exodermis also contributes to the regulation of water and nutrient uptake. In some plants, it may include specialized structures called Casparian strips which force all substances entering the root to pass through the plasma membrane of select cells. This mechanism allows the exodermis to control the transport of minerals and water into the central tissues, ensuring a regulated uptake and preventing any potential damage caused by the presence of harmful substances.
In summary, the exodermis is a vital layer of cells located on the outer surface of plant organs, serving protective, regulatory, and absorptive functions. Its unique properties and structural features make it an essential component for the survival and adaptation of plants in various environmental conditions.
The word "exodermis" is formed from the combination of two Greek roots: "exo" meaning outside, and "dermis" meaning skin.
In botanical terms, the exodermis refers to the outermost layer of cells in the roots of plants. It serves as a protective barrier and is involved in regulating the movement of water and nutrients into the root.
