Effects of elevated salinity of the growing medium on rhizome essential oil yield and fatty acid composition of Curcuma longa L. (Zingiberaceae)

This study was aimed at the examination of the effects of increased salinity of growing medium on the fatty acid composition and yield of rhizome essential oil of Curcuma longa L. The analyses (gas chromatography and gas chromatography/mass spectrometry) of the transesterified petroleum ether extract of rhizomes grown under non-saline conditions (0.0 mM NaCl; control) showed that the dominant fatty acids were oleic (48.6%), myristic (15.0%), linoleic (7.9%), palmitic (6.8%) and linolenic (2.4%). Increased growth medium salinity (25.0, 50.0 and 75.0 mM NaCl) provoked significant changes in the relative amounts of some acids. Increase of NaCl concentration caused an increase in the amount of linoleic and linolenic acids, but had the opposite or no effect on myristic and oleic acids quantity. The yield of the essential oil obtained from fresh control rhizome (non-saline conditions) was 1.7%. When C. longa was grown in a low-salinity medium (25.0 mM NaCl), the oil yield remained the same. However, under high salinity conditions the yield reached 2.9% (50.0 mM NaCl), i.e. 3.1% (75.0 mM NaCl). Our results clearly show that the studied plant species is susceptible to high salinity induced stress.