Plant ecophysiology and metal abiotic stress

Dr Denise R. Fernando

ARC DECRA Research Fellow

'Manganese Heavy Metal Toxicity in Plants: New Perspective on a Neglected Problem'

I am currently investigating plant ecophysiological processes associated with the heavy metal manganese (Mn), an essential plant micro-nutrient common in soil.  In eastern Australia, natural conditions of soil chemistry and climate give rise to Mn toxicity in agricultural plants, yet native species are well adapted.  Some even exhibit extreme tolerance, i.e. a physiologically rare trait known as 'Mn hyperaccumulation' wherein plants scavenge and accumulate extraordinarily elevated amounts of foliar Mn that vastly exceed their normal lethal limits, yet these species remain unaffected.  Metal hyperaccumulators collectively provide a novel resource for expanding our fundamental understanding of plant biology.

I have had an ongoing research interest in Mn hyperaccumulators, a small group of angiosperms comprising around 20-30 species worldwide, and whose majority are restricted to the Western Pacific region. My primary focus is the eastern Australian tree genus Gossia (Myrtaceae), highly adapted to Mn-rich soils and strongly Mn-accumulating.  There are several Mn-hyperaccumulating species among the Australian Gossia.  The physiological and evolutionary basis of this trait are yet to be understood.  Thus far my research has uncovered previously undescribed mechanisms of plant metal tolerance, and identified several eastern Australian species as Mn-hyperaccumulating.  My Gossia research to date has been in collaboration with Dr George Batianoff (dec.) and Dr Paul Forster of the Queensland Herbarium.  

My current ARC DECRA funding is enabling me to investigate the overriding effects of climate change on plant-Mn interactions.  Given that several climatic variables are capable of individually or interactively driving soil Mn bioavailability and plant Mn toxicity, the implications of climate change are an important consideration for both natural and cultivated plant ecosystems.  I am undertaking fieldwork and controlled experiments aimed at examining Mn tolerance and stress in native plant ecosystems and in agricultural species, with particular emphasis on the interaction of climatic variables.  I have a collaborative research partnership with Professor Jonathan Lynch at The Pennsylvania State University, USA, investigating acid-soil driven Mn toxicity stress in the eastern forests of North America.  I spent 6 months in his laboratory as a Visiting Scholar, where I carried out fieldwork.  With researchers at Charles Sturt University, Wagga Wagga, NSW, I am studying the interaction of climate variables with Mn toxicity in wheat, soybean and canola.