Apoplastic barriers in maize lateral roots

Roots rely on apoplastic barriers for nutrient absorption. However, little is known about the establishment of these barriers within the lateral roots. The branching, permeability of the outer cell layers and differentiation of the endo- and exodermis are studied in primary roots and various laterals of Zea mays under different stress factors of agronomic importance (salinity, heavy metal toxicity, hypoxia, etc.).

Appearance of the endodermis and exodermis.
Appearance of the endodermis and exodermis. Casparian bands at three-quarters of the length of the primary root in selected treatments in the endodermis.

Tylová et al. propose that fine laterals represent portions of a complex root system with a less advanced state of endodermis and exodermis differentiation, but with substantial ability to modify maturation of exodermis in response to environmental conditions. Branching and establishment of barriers in fine laterals may be at the crux of the root system – rhizosphere interaction.

Reference List

Tylová, E., Pecková, E., Blascheová, Z., & Soukup, A. (2017). Casparian bands and suberin lamellae in exodermis of lateral roots: an important trait of roots system response to abiotic stress factors. Annals of Botany, 120(1), 71–85. https://doi.org/10.1093/aob/mcx047