Exogenous Abscisic Acid Mediated MorphologicalCharacteristics, Photosynthetic Pigments and AntioxidantMetabolism under Drought Stress in Rice (Oryza sativa L.)
Author:M. Ramachandran and D. Arulbalachandran*
Drought stress is one of the major abiotic stresses in agriculture worldwide. Drought also
produces Reactive Oxygen Species (ROS), triggering a cascade of antioxidative defense
mechanisms, and affects many other metabolic processes. It triggers a wide variety of plant
responses ranging from physiological, biochemical to molecular levels. The primary challenge
for increasing rice production is overcoming a global water shortage, which can severely limit
rice yields. In the present study, response of drought stressed plants to abscisic acid (ABA) on
antioxidant activities CAT, POD, APX, SOD were studied. The growth was gradually increased
with increasing concentrations of ABA. The growth of plant, fresh weight, dry weight and relative
water content was higher in the 200 mM abscisic acid. The photosynthetic pigments such as
chlorophyll a, b and carotenoids content were increased in the 200 mM ABA as compared to the
treated plants and control. The result indicates that increased growth in the 200 mM abscisic acid
treated plants compared to control plants due to enhanced antioxidant activities.
Key Words: Abscisic acid, Oryza sativa, Drought, Antioxidant metabolism.