Few studies have examined exodermal development in relation to the formation of barriers to both radial oxygen loss (ROL) and solute penetration along growing roots. Here, we report on the structural development, chemical composition and functional properties of the exodermis in two diverse wetland grasses, Glyceria maxima and Phragmites australis. Anatomical features, development, the biochemical composition of exodermal suberin and the penetration of apoplastic tracers and oxygen were examined. Striking interspecific differences in exodermal structure, suberin composition and quantity per unit surface area, and developmental changes along the roots were recorded. Towards the root base, ROL and periodic acid (H(5)IO(6)) penetration were virtually stopped in P. australis; in G. maxima, a tight ROL barrier restricted but did not stop H(5)IO(6) penetration and the exodermis failed to stain with lipidic dyes. Cultivation in stagnant deep hypoxia conditions or oxygenated circulating solution affected the longitudinal pattern of ROL profiles in G. maxima but statistically significant changes in exodermal suberin composition or content were not detected. Interspecific differences in barrier performance were found to be related to hypodermal structure and probably to qualitative as well as quantitative variations in suberin composition and distribution within exodermal cell walls. Implications for root system function are discussed, and it is emphasized that sufficient spatial resolution to identify the effects of developmental changes along roots is crucial for realistic evaluation of exodermal barrier properties.

Department of Plant Physiology Charles University Vinièná 5 Prague CZ 128 44 Czech Republic

Citace poskytuje Crossref.org

Exodermis and Endodermis Respond to Nutrient Deficiency in Nutrient-Specific and Localized Manner

The role of the testa during the establishment of physical dormancy in the pea seed

Casparian bands and suberin lamellae in exodermis of lateral roots: an important trait of roots system response to abiotic stress factors

The apoplasmic pathway via the root apex and lateral roots contributes to Cd hyperaccumulation in the hyperaccumulator Sedum alfredii

Lateral root development in the maize (Zea mays) lateral rootless1 mutant