Caustic response: understanding plant adaptation to high pH and its application to remediation of alkaline industrial residues.

Motivation: Around two billion tonnes of alkaline residues are produced globally each year by industrial processes. These residues are frequently stored in waste piles or landfills, and can be an environmental hazard if allowed to generate dust or if rainwater infiltrates the waste (Gomes et al 2016). Revegetation is a sustainable approach for passive treatment of such sites.

The Challenge: Even when amended with organic material, these residues impose a combinatorial stresses of high pH, high sodicity and low nutrient availability. Revegetation treatments are currently ad hoc and it takes decades to centuries to establish verdant cover (Courtney et al., 2009). The interaction between the plant species present and the rhizosphere microbiome is likely to be of great importance, but how these shape revegetation outcomes remain uncharted territory. The key challenge is to understand in a holistic fashion how plants overcome the combinatorial stresses experienced at alkaline pH, and specifically how they obtain nutrients, survive pH injury, and, through their life cycle, condition and improve the soil structure and function.

The approach: A combination of plant physiology, molecular biology and geochemistry will be used in this interdisciplinary project to explore the processes and mechanisms underlying colonisation of hyper alkaline environments with a view to accelerating revegetation processes. The project specifics will be developed in discussion with the successful applicant.

References:HI Gomes, WM Mayes, M Rogerson, DI Stewart, IT Burke (2016). Alkaline residues and the environment: a review of impacts, management practices and opportunities. Journal of cleaner production, 112, 3571-3582.

Courtney R., Mullen, G and Harrington T (2009) An evaluation of revegetation success on bauxite residue. Restoration Ecology 17, 350-358.