Titre du document / Document title

Root endodermis and exodermis: Structure, function, and responses to the environment : Root structure and function

Auteur(s) / Author(s)

ENSTONE Daryl E. ⁽¹⁾ ; PETERSON Carol A. ⁽¹⁾ ; FENGSHAN MA ⁽¹⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ Department of Biology, University of Waterloo, Waterloo ON N2L 3G1, CANADA

Résumé / Abstract

Roots of virtually all vascular plants have an endodermis with a Casparian band, and the majority of angiosperm roots tested also have an exodermis with a Casparian band. Both the endodermis and exodermis may develop suberin lamellae and thick, tertiary walls. Each of these wall modifications has its own function(s). The endodermal Casparian band prevents the unimpeded movement of apoplastic substances into the stele and also prevents the backflow of ions that have moved into the stele symplastically and then were released into its apoplast. In roots with a mature exodermis, the barrier to apoplectic inflow of ions occurs near the root surface, but prevention of backflow of ions from the stele remains a function of the endodermis. The suberin lamellae protect against pathogen invasion and possibly root drying during times of stress. Tertiary walls of the endodermis and exodermis are believed to function in mechanical support of the root, but this idea remains to be tested. During stress, root growth rates decline, and the endodermis and exodermis develop closer to the root tip. In two cases, stress is known to induce the formation of an exodermis, and in several other cases to accelerate the development of both the exodermis and endodermis. The responses of the endodermis and exodermis to drought, exposure to moist air, flooding, salinity, ion deficiency, acidity, and mechanical impedance are discussed.

Revue / Journal Title

Journal of plant growth regulation   ISSN 0721-7595   CODEN JPGRDI 

Source / Source

2002, vol. 21, n^o4, pp. 335-351 [17 page(s) (article)] (2 p.3/4)

Langue / Language

Anglais

Editeur / Publisher

Springer, New York, NY, ETATS-UNIS  (1982) (Revue)

Mots-clés anglais / English Keywords

Spermatophyta ; Angiospermae ; Vegetals ; Environmental factor ; Structure function relationship ; Plant tissue ; Root ;

Mots-clés français / French Keywords

Spermatophyta ; Angiospermae ; Végétal ; Facteur milieu ; Relation structure fonction ; Tissu végétal ; Racine ;

Mots-clés espagnols / Spanish Keywords

Spermatophyta ; Angiospermae ; Vegetal ; Factor medio ; Relación estructura función ; Tejido vegetal ; Raíz ;

Mots-clés d'auteur / Author Keywords

Endodermis ; Exodermis ; Structure ; Drought ; Mycorrhizae ; Casparian bands ; Suberin lamellae ;

Localisation / Location

INIST-CNRS, Cote INIST : 19223, 35400011137248.0070