Chemistry Reference
In-Depth Information
Chapter 1
Salicylic Acid: An Update on Biosynthesis
and Action in Plant Response to Water
Deficit and Performance Under Drought
Hanna Bandurska
Abstract Salicylic acid (SA) and its derivatives are the most widely known drugs
in the world used to reduce pain and fever, helping to treat many inflammatory
diseases, in the prevention of coronary heart disease and heart attacks, and in
tumor suppression. This substance is also characterized by a high metabolic and
physiological activity, which enables it to perform regulatory functions in plant
development and reaction to biotic and abiotic stress factors. Under non-stress
conditions, SA is present in plant tissues in quantities of several mg to several ng
in one g of fresh mass. Its level substantially increases in plants exposed to water
deficit. The accumulation of SA may result from its de novo synthesis through
activation of enzymes involved in the synthesis of SA from phenylalanine, i.e.
phenylalanine ammonia lyase (PAL) and benzoic-acid-2-hydroxylase (BA2H). SA
accumulated in plants growing under the conditions of water shortage may be
involved in the regulation of mechanisms responsible for resistance to drought
through the control of water balance and activation of antioxidant system. Large
body of evidences revealed that exogenous application of SA was effective in
modeling plant responses to water deficit. Plant pre-treatment with SA resulted in
higher tissue water content, increased activity of antioxidant enzymes, decreased
level of lipid peroxidation and membrane injury and it also protected nitrate
reductase activity against inhibition under water deficit conditions. These changes
enable plants to survive under drought and play an essential role in countering the
adverse effects of stress on growth and yield.
Keywords Drought
Salicylic acid
Water deficit
Stress resistance
