Abstract
This article investigates the impact of long-term salinity of varied levels on status of cellular antioxidants and an important marker for physiological stress proline. Changes induced in the fatty acids profile of leaf by salinity has also been studied indicating interesting roles of long-chain unsaturated fatty acids in response to salinity.
•Impact of NaCl studied on antioxidants, proline accumulation and fatty acid profile of leaf.•Artemisia annua, potent anti-malarial drug artemisinin-yielding plant was considered.•Salinity increased level of fatty acid monosaturation and declined polysaturation.•Myristic, palmitoleic and erucic acids were extraordinarily high under salinity.•Oxidative stress induced; antioxidants up-regulated and proline accumulated.
Impact of long-term salinity and subsequent oxidative stress was studied on cellular antioxidants, proline accumulation and lipid profile of Artemisia annua L. (Sweet Annie or Qinghao) which yields artemisinin (Qinghaosu), effective against cerebral malaria-causing strains of Plasmodium falciparum. Under salinity (0.0–160mM NaCl), in A. annua, proline accumulation, contents of ascorbate and glutathione and activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR) and catalase (CAT) increased, but the contents of reduced forms of glutathione (GSH) and ascorbate declined. The fatty-acid profiling revealed a major salinity-induced shift towards long-chain and mono-saturated fatty acids. Myristic acid (14:0), palmitoleic acid (16:1), linoleic acid (18:2) and erucic acid (22:1) increased by 141%, 186%, 34% and 908%, respectively, in comparison with the control. Contents of oleic acid (18:1), linolenic acid (18:3), arachidonic acid (22:0) and lignoceric acid (24:0) decreased by 50%, 17%, 44% and 78%, respectively. Thus, in A. annua, salinity declines ascorbate and GSH contents. However, increased levels of proline and total glutathione (GSH+GSSG), and activities of antioxidant enzymes might provide a certain level of tolerance. Modification in fatty-acid composition might be a membrane adaptation to long-term salinity and oxidative stress.