Effect of Salt Stress on Growth, Membrane Damage, Antioxidant Metabolism and Artemisinin Accumulation in Artemisia annua L

Salinity in soil and irrigation water is one of the major factors that limit crop productivity. The effects of salinity on growth, lipid peroxidation, the antioxidant defence system and changes in artemisinin content were studied in Artemisia annua L. Salinity treatments were established by adding 0, 50, 100, 150 and 200 mM of sodium chloride (NaCl) to the soil. Salt stress negatively affected the growth of plants, measured in terms of shoot and root length and dry weight. Photosynthetic attributes and total chlorophyll content were also reduced by salinity stress. Salinity treatments inhibited the activity of carbonic anhydrase and significantly increased electrolyte leakage and proline content. Moreover, salt stress induced oxidative stress, as indicated by the level of lipid peroxidation. The activities of antioxidant enzymes viz. catalase (CAT), peroxidase (POX) and superoxide dismutase (SOD) were upregulated by salt stress. Most importantly, a synergistic relationship was noted between endogenous H2O2 and artemisinin content i.e. both contents increased under low levels of salinity (50 and 100 mM) and thereafter decreased. Thus, it can be concluded that A. annua species is very sensitive to soil salinity; however, moderate saline conditions can be utilized to obtain more artemisinin. _____________________________________________________________________________________________________________