The rhizosheath - a potential trait for future agricultural sustainability occurs in orders throughout the angiosperms

The rhizosheath is defined as the weight of soil adhering strongly to roots on excavation, and current interest in this trait as a potential tolerance mechanism to abiotic stress has prompted us to explore the extent of its occurrence throughout the angiosperm phylogeny. Here we describe a robust, novel method which was used to screen species for the presence/absence and strength of a rhizosheath. We correlate the latter with root hair length to provide insight into some of the factors affecting its formation. We go on to compare experimental data with previous observations in the literature. Results of a glasshouse screen demonstrate that rhizosheaths exist in species from many angiosperm orders, and the frequency of their occurrence and their strength and size are related. No correlation between root hair length and rhizosheath size was found, except when root hairs were extremely short, but the presence of root hairs was required for rhizosheath formation. The rhizosheath is present in species from many angiosperm orders. Potential to enhance the trait is likely to exist in a range of crop species and could help contribute to future agricultural sustainability.