Ts. Babu et P. Mohanty, LIGHT REGULATION OF PHOTOSYNTHETIC APPARATUS IN CYANOBACTERIA, Journal of Scientific & Industrial Research, 55(8-9), 1996, pp. 728-741
Cyanobacterial photosynthetic apparatus contains two photosystems, pho
tosystem I (PS I) and photosystem II (PS II). In addition, the primary
light harvesting antenna in these organisms is composed of pigmented
and non-pigmented protein complex called phycobilisome. It is argued t
hat both the photosystems and the phycobilisome are highly responsive
to the changing light environment, The response of the cyanobacterial
photosynthetic apparatus under different light conditions is discussed
. It is presented that this response provides an indication whether it
is an adaptation process ora signal for damage. Both visible and ultr
aviolet radiations have been shown to bring about this response. It is
reported that in addition to its effect on the photosynthetic apparat
us, ultraviolet radiation has also been shown to cause damage to nucle
ic acids. Finally, the possible protective mechanisms in cyanobacteria
against light stress are discussed wherein it is argued that cyanobac
teria have the capability to protect themselves against extreme light
situations through various mechanisms involving modulations in the pre
existing components of the photosynthetic apparatus or acquiring new p
rotection mechanisms against light stress.