Published online by Cambridge University Press: 27 March 2009
Previous attempts to study the effect of virus infection on nitrogen-fixing ability of some legumes (Tu, Ford & Grau, 1970; Singh & Mall, 1974; Gupta & Joshi, 1976; Tu & Holmes, 1980) concentrated mainly on the effect of virus infection on the extent of nodulation or on the amount of nitrogen fixed by diseased plants or both. The effect of virus infection on the bacterial population and the physiological status of virus-infected nodules has received little attention.