Salt Stress Induced Alteration in Photosynthetic Pigments and Polyphenols of Pennisetum alopecuroides (L.)

Salinity is one of the major abiotic stresses that adversely affect crop productivity and quality. In the present investigation effect of NaCl salinity on the photosynthetic pigments and polyphenols of the leaves of the Pennisetum alopecuroides (L.) Spreng var. Mourdy was studied. The total chlorophyll (chl.) content of the mature leaves was increased only by 4.7%, 9.2% and 1.5% at 25, 50 and 100 mM, respectively but later on decreased with increasing concentrations of NaCl. Chlorophyll. ‘a’ appears to be more sensitive to salinity in the experimental grass species than chlorophyll. ‘b’. Maximum increase in carotenoid content observed was 56.3%. The maximum increase in polyphenols was 111.6% at 300 mM concentration. Electrical conductivity of the pot soil increased to a maximum by 525% in the pot soils of Pennisetum alopecuroides following external addition of NaCl at 300 mM, while, total dissolved solids (TDS) content increased to 868%. An increase in the photosynthetic pigments at lower salt levels might be due to the osmotic adjustment mechanism developed by the grass species to incumbent with salt stress. The increased levels of polyphenols at elevated salinity might be due to the accumulation of secondary metabolites.