STUDIES ON THE EFFECTS OF SALINITY ON GROWTH, POLYPHENOL CONTENT ANDPHOTOSYNTHETIC RESPONSE IN VETIVERIA ZIZANIOIDES (L.) NASH
Salinity is one of the major abiotic stress that adversely affects on crop productivity and its quality. The present investigation was carried out to study the alterations in the growth characteristics, photosynthetic pigments and polyphenols content of Vetiveria zizanioides (L.) under the influence of sodium chloride salinity. The result shows that the shoot length of Vetiveria zizanioides was increased by 18.6% at 200 mM NaCl concentration whereas, the increase in root length about 24.8% was observed at 50 mM NaCl. Shoot to root ratio in the experimental species was reduced to 10.0% at 50 mM NaCl concentration whereas at 300 mM of salinity it was increased by 39.09%. Moreover, the average leaf area also increases under saline conditions. An increase in the photosynthetic pigments at lower salt levels indicates osmotic adjustment mechanism developed by the grass species to incumbent with salt stress. However, dry weight and fresh weight of the plant biomass was found less effective under the salinity stress. The increased levels of polyphenols at elevated salinity might be due to the accumulation of secondary metabolites. Linear increase in the electrical conductivity and total dissolved solids of the soil was observed at increasing salinity. Increase in growth and photosynthetic parameters observed at especially upto 100 mM of salinity indicate the tolerance shown by experimental species and we conclude that tolerant V. zizanioides can be grown in saline areas with salt concentrations up to 200 mM.