  The issue of radiation mechanisms had triggered in 1950-60s the first
applications of plasma physics to understand the nature of radio galaxies. This
interplay has steadily intensified during the past five decades, due to the
premise of in-situ acceleration of relativistic electrons occurring in the
lobes of radio galaxies. This article briefly traces the chain of these
remarkable developments, largely from an observational perspective. We recount
several observational and theoretical milestones established along the way and
the lessons drawn from them. We also present a new observational clue about
in-situ acceleration of the relativistic particles radiating in the lobes of
radio galaxies, gleaned by us from the very recently published sensitive radio
observations of a tailed radio source in the galaxy cluster Abell 1033.
