Description du livre
This
book is the first of its kind to highlight the positive impact of natural UV
radiation on plants through unique adaptations in various metabolic pathways, and
provides an evolutionary sketch of the development of molecular mechanisms for
protecting plants from solar UV ever since their migration to terrestrial
habitats. Experimental evidence is provided for establishing how plants, through
their stationary habit in the open field, survive and flourish by developing suitable
UV acclimation strategies through the repair of damaged macromolecules and/or
upregulation of screening compounds viz. flavonoids. Presenting an analysis of related
literature, it also highlights the importance of outdoor experiments over those
in closed chamber under artificial UV light for obtaining realistic data.
The book presents a comprehensive
account of the stratospheric ozone layer, its formation and seasonal thinning,
with particular reference to alarming anthropogenic destruction of the ozone
layer since the last quarter of the twentieth century, which has resulted in increased
UV fluence on Earth. It discusses variations in the hazardous impact of UV on
life at different latitudes through the ages, and examines altitudinal variations
in UV effects in case studies demonstrating high antioxidant content and aroma
status in Darjeeling tea leaves (at high altitudes) compared with those of the same
tea clones in Assam leaves (at low altitudes), with both sites being at the same
latitude. It provides evidence which suggests that the UV effects relating to
the expression of seed vigour-viability could be epigenetic.
Further, it presents recently developed microscopic
technologies for demonstrating the penetration of UV into plant cells, and discusses
how cellular metabolism can be affected either directly or via signal
transduction. Effect of damage in DNA (the key target of UV radiation) has been
demonstrated and estimated using precise techniques. The latest “FOX Hunting”
technique as a useful means of transcriptome analysis that may be used for
developing UV tolerant plants through Marker Assisted Breeding has also been
discussed. Using biochemical and biotechnological methods, the experiments
presented highlight the gene X environment based upregulation of specific
metabolic pathways, allowing i) value addition in plant-derived food, and ii) paving
the way for the industrial manufacture of Alternative Medicine products. The
book is enriched by a critical review of the available literature and
appropriate case studies selected from the author’s own findings, which span nearly
four decades of active research.