Thesis: Phosphorus-Use and Nitrogen-Use Strategies of Native Plants in South-western Australia
South-western Australia has some of the oldest and most phosphorus (P) - impoverished soil in the world. Many traits have evolved in the plant family Proteaceae to survive in P-impoverished soils, such as cluster roots, low leaf P and nitrogen (N) concentrations while exhibiting high photosynthetic rates, tight control of N uptake and assimilation. Yet, we still do not know how common these adaptive traits are in other families and how plants adjust their nutritional strategies during different seasons. This project is composed of three experiments on several species of Proteaceae, Myrtaceae and Fabaceae. First, I aim to determine the total P concentration, foliar P fractions and P-related leaf photosynthetic traits during two seasons to explore the relationships between seasonality and P-use patterns. Then I will investigate the response of plants to N supply to see if they show tight control of N uptake and assimilation and whether nitrate restraint is a common trait among plant families that evolved in extremely P-impoverished soils. I also aim to investigate the proteome of leaves from Hakea ceratophylla and Grevillea thelemanniana to compare these with databases for Arabidopsis thaliana to find out what proteins are produced in low abundance to maintain high activity of photosynthetic enzymes.
Why my research is important
This research will enhance our understanding of how plants thrive on P-impoverished soils, and provide novel insight into P- and N-use strategies of native plants in southwestern Australia. This novel information can be important for plant breeding programs to develop nutrient efficient and high-yielding crop species in the future.