Source: Journal of Plant Stress Physiology
N. Silambarasan and S. Natarajan.
The present investigation was made to study the effect of different concentrations of sodium chloride on the proline, glycine betaine, sugar and antioxidant content of the halophytic species, Clerodendron inerme. The plant could survive a wide range of 100 to 1000mM of NaCl. The upper limit for the survival of the species was 500mM. Above 500mM, the seedlings could not survived. However, favorable growth response by the seedlings was confined to 200mM NaCl. The accumulation of proline, glycine betaine was more in leaf tissue than the stem and root of NaCl treated plants. Proline, glycine betaine content is believed to function as compatible solute in balancing cytoplasmic and vacuolar water potentials not only due to salinity stress but also under drought, heat and cold stresses. Increasing salinity increased the level of proline, glycine betaine up to the extreme level of 500mM NaCl. The sugar content decreased in all the three tissues with increasing NaCl up to 200mM and at higher concentrations, salinity gradually increased the sugar up to 500mM NaCl. Survival of plants in saline environment depends on the quantitative ratio between toxic and protective compounds proline, glycine betaine is believed to be one of the protective substances. The non enzymatic antioxidant contents like ascorbic acid and α- tocopherol were detected under high concentration of 500mM NaCl. Increase in antioxidant enzyme activity could be the response of cellular damage induced by the NaCl.