Effects of salinity stress on morphological characteristics, essential oil content and ion accumulation in basil (Ocimum basilicum) plant under hydroponic conditions

In order to study the effects of salinity stress on morphological traits, essential oil content and ion accumulation in basil (Ocimum basilicum) plant under hydroponic conditions, a factorial experiment based on completely randomized blocks design with three replications was conducted on three landraces (Jahrom, Banafsh and Isfahan) and five NaCl salinity levels (0, 40, 80, 120 and 160 mM) in controlled greenhouse conditions. The results indicated a significant reduction in plant height, shoot dry weight and root dry weight due to increasing salinity level. Among the landraces, Banafsh landrace had the highest biomass. Also, with the increase in salinity level, sodium ion content of shoot and root increased. However, Ca2+ and K+ contents and Ca2+/Na+ and K+/Na+ ratios of both shoot and root decreased. These ratios were higher in shoots, as compared to roots, of all three landraces. Essential oil content increased with the increase in stress level. However, this much increase in essential oil content is not important at high salinity levels due to high reduction in biomass. This could be important at moderate stress considering produced biomass. Among the studied landraces, Jahrom landrace contained the highest essential oil content.