Ion contents, physiological characteristics and growth of Carum copticum as influenced by salinity and alkalinity stresses.

Abstract

A controlled experiment was conducted to investigate the effect of salinity and alkalinity stresses on the growth and physiological characteristics of Carum copticum L. The treatments included four salinity levels: 0, 50, 100 and 150mM NaCl, and four alkalinity levels 0, 20, 40 and 60mM NaHCO3. The results indicated that root dry weight and magnesium concentration were decreased and catalase and peroxidase activity, proline, malondialdehyde, Na+ and Ca2+ concentration were increased in plants simultaneously subjected to both salinity and alkalinity stresses. In all traits, the highest salinity and alkalinity levels had the most negative and significant effects. In general, our findings revealed that alkalinity and salinity stresses considerably decreased ajwain growth through adverse impact on physiological characteristics such as ion concentration and activity of antioxidant enzymes. These effects were greater when the two salinity and alkalinity stresses were simultaneously applied. Ajwain plant tolerated a part of the stresses via osmotic adjustment mechanism was assessed by proline, malondialdehyde and total carbohydrate.