Physiological ageing of potato tubers: A Review

Summary Numerous theories have been proposed to describe the complex process of ageing in biological systems. Two general groups of ageing theories currently exist: 1) stochastic where the accumulation of random molecular damage leads to loss of information vital to the cell; and, 2) systemic where an organised, genetically based sequence of metabolic activities leads to programmed ageing. Whether these are acceptable models of ageing in potato tubers is unknown although the tuber could provide a useful experimental system for studying ageing. An initial requirement for advancing the concept of ageing in potato tubers must centre on the development of a suitable ageing index. A review of the literature suggests that a modified approach to ‘sprouting capacity’ and ‘incubation period’ may allow tuber ageing to be described in mathematical terms that would, in turn, facilitate the development of a physiological ageing index as well as temperature sensitive predictive models. Although a number of biochemical studies of ageing have been pursued, the development of adequate biomarkers has yet to achieve a coordinated level of development as found in a range of organisms. For example, ageing in other biological systems may be viewed as an outcome of an accumulation of random molecular damage and may be primarily caused by a changing balance between reactive oxygen species and diminishing levels of protective agents such as superoxide dismutase, alpha‐tocopherol or vitamin C. The exploration of these and similar problems in the context of appropriate modelling approaches should allow a better understanding of physiological ageing in potato tubers.