Norman Alan Walker 1929–2013

Abstract

Alan Walker (he never used ‘Norman') developed pioneering electrophysiological methods to make major contributions to our understanding of mechanisms and energetics of transport of solutes across plant cell membranes. He used giant cells of characean algae to measure membrane electrical potential differences and conductances that were combined with measurements of fluxes of inorganic ions and organic nutrients obtained with radioactive tracers. Alan built up a strong research group at the University of Sydney and had many external collaborations that considerably widened the scope of his research in relation to membrane biology of characean cells and well beyond. His considerable skills in mathematical modelling contributed significantly to research led by others on plant-fungal (mycorrhizal) symbiosis, movement of solutes through the cytoplasmic connections between plant cells (plasmodesmata), the membrane transport mechanisms that regulate the release of nutrients from coats of developing legume seeds, and even nutrient cycling in Arctic ecosystems. Alan had strong political views and definite aesthetic tastes that included aspects of visual arts (ceramics and impressionist paintings) and music. He was very interested in good food and wine, and other interests included vertebrate palaeontology and bird-watching. He had many friends with similar tastes, who share fond memories of him.