Optical screening of excessive and potentially harmful solar radiation
is an important photoprotective mechanism, though it has received much
less attention in comparison with other systems preventing
photooxidative damage to photoautotrophic organisms. This
photoprotection in the form of screening appears to be especially
important for juvenile and senescing plants as well as under
environmental stresses-i.e. in situations where the efficiency of
enzymatic ROS elimination, DNA repair and other 'classical'
photoprotective systems could be impaired. This book represents an
attempt to develop an integral view of optical screening-based
photoprotection in microalgae and higher plants. Towards this end, the
key groups of pigments involved in the screening of ultraviolet and
visible components of solar radiation in microalgae and higher plants,
and the patterns of their accumulation and distribution within plant
cells and tissues, are described. Special attention is paid to the
manifestations of screening pigment accumulation in the optical spectra
of plants. It is also demonstrated that understanding these effects and
their relationships to screening pigments' makeup and spectroscopy in
plants provides valuable insights into the state of plants' long-term
photoacclimation, as well as ample opportunities for the non-destructive
quantification of screening pigments and the assessment of the
efficiency of photoprotection providing by these pigments in situ.