Animal and Plant Physiology

Associate Professor Jennifer Watling conducts research into a number of native parasitic plants and their impacts on host plants, both native and introduced. Current projects include a study of the native parasitic vine, Cassytha pubescens, and its impact on the introduced weeds gorse and broom. This work has demonstrated that C. pubescens has a significant impact on the mortality of gorse and broom and that this may be a consequence of impairment of the photosynthetic physiology of these hosts. Other projects are focused on the ecological role of parasitic plants in native vegetation. We collaborate with colleagues in China and the UK on this work.

Supervisor - Associate Professor Jennifer Watling

Associate Professor Jennifer Watling supervises research in thermogenic plants - the phenomenon of heat production that occurs in a small number of plant species. Using stable oxygen isotopes, this group has demonstrated that the alternative pathway of respiration, catalysed by the Alternative Oxidase (AOX), is responsible for heat production in the sacred lotus (Nelumbo nucifera) and Philodendron bipinnatifidum. Current work is focused on the structure and regulation of the AOX in these species and also on uncovering the mechanisms of heating in other thermogenic species such as Amorphophallus titanum that produces one of the largest inflorescences of all plants. We collaborate with colleagues from Japan, the USA and Spain on this project.

Professor Roger Seymour's focus concerns the role of heating in the pollination ecology of thermogenic flowers. Working in the field in Africa, South and North America, Crete and Japan, the projects involve determining the temporal patterns of heat production that align with the activities of insect visitors in Nature. The roles of heating in attraction (scent production) and reward (direct heat applied to the insects) can be differentiated in flowers of different size and morphology. The energetic requirements of insect visitors are assessed in relation to the rewards offered as food and direct heat in the flowers.

Supervisor - Associate Professor Jennifer Watling and Professor Roger Seymour

Professor Roger Seymour has research interest in the cardiovascular, respiratory and thermal physiology of animals, particularly vertebrates and insects. The effects of body size on physiology and anatomy are of particular focus because size has arguably the most profound effects in all of biology. Thus considerable work has been done on how size affects metabolic rate in animals and the ability of the cardiovascular and respiratory systems to deliver oxygen. Recent projects include the size effects on the energy required for development in embryonic and larval fish and amphibians, the scaling of the tracheal system in locust during development and the gas exchange anatomy of the lung in developing birds. How blood pressure, flow rate and heart size differ in birds and mammals according to size is an important focus, leading to implications about dinosaur physiology and behaviour. Working from holes in fossil bone and eggshell that passed blood and oxygen, measures of metabolic activity can be estimated, and these show that dinosaurs were highly active animals, probably higher than mammals. Thermal physiology has recently involved work on the insulation of bird nests and the cost of incubation, as well as behavioural temperature regulation in lizards measured by thermal camera. The physiology associated with insects and spiders that use a bubble of gas as an underwater gill is currently under investigation. Future projects involve the energy cost and efficiency of vertebrate hearts..

Arsenic is highly toxic to all organisms and is ingested as a contaminant of food and drinking water. Rice accumulates much higher amounts of arsenic than other crops because of the way it is grown in flooded anaerobic conditions that make soil arsenic more amenable for plant uptake. Rice is the staple for a large proportion of the global population and high levels of arsenic in rice can lead to a serious decline in health when consumed over a long period. Inorganic arsenic is a human carcinogen with no known threshold and can lead to cancers of the lungs, bladder and kidneys with a latency of more than a decade (WHO 2001).

Current research focusses on ways to reduce the concentration of arsenic in grain by examining he pathways for uptake and redistribution of arsenic in plants, and the mechanisms that operate in low arsenic accumulating plants to restrict arsenic movement to the grain. This work is funded by the Australian Research Council and the Research Centre for Eco-Environmental Sciences (RCEES) of the Chinese Academy of Sciences in Beijing. Close collaborative ties exist with the lab of Prof. Yongguan Zhu from RCEES.

Supervisor - Associate Professor Rob Reid

Heavy metals constitute a significant risk to human health yet little is known about the important factors that determine uptake and distribution of heavy metals in plants. Current projects are exploring the physiological and genomic bases for the accumulation of cadmium in rice, and nickel in hyperaccumulating plants in New Caledonia.

Supervisor - Associate Professor Rob Reid