Application of growth promoting hormones alters the composition and antioxidant potential of dill essential oil under salt stress

Abstract

The performance of dill plant may be affected by adverse environments such as salinity. Thus, this research was designed to evaluate changes in chemical composition and antioxidant activity of seed essential oil of dill (Anethum graveolens L.) in response to salinity (0, 5, 10 and 15 dS/m) and 1 mM of each hormonal treatments (gibberellic acid, salicylic acid, and cytokinin). Salicylic acid (SA) reduced Na+ content of roots and leaves by 15.4%, 30.9% and 12.4%, 24.3%, but enhanced K+ content by 29.8%, 51.6% and 76.6%, 73.4% under moderate and severe salinities, respectively. Essential oil yield was enhanced with progressing seed filling, despite decreasing essential oil percentage. Percentage of essential oil was increased under low and moderate salinities. Hormonal treatments, particularly SA enhanced seed mass and essential oil percentage, leading to enhanced essential oil yield. The amounts of most constituents were enhanced under moderate salinity. Foliar spray of SA and CK (cytokinin) increased almost all essential oil components, except dill ether and dill apiole, while the GA3 (gibberellic acid) treatment reduced most of the constituents. The α-fenchol was only induced by salt stress. The β-pinene, 1-terpineol, cryptone, oxypeucedanin hydrate, α-thujene and P-α-dimethylstyrene were also specifically synthesized in SA treated plants under salinity. The highest TPC (total phenolic content) and antioxidant activity were recorded for essential oil of SA treated plants at mass maturity under moderate salinity. In general, the SA spray was the most effective treatment for improving essential oil quantity and quality of dill plants.

Metabolic and physiological effects of water stress on Moshgak (Ducrosia anethifolia Boiss) populations using GC–MS and multivariate analyses

“…In the present study, positive relationships were also observed between IC 50 and TPC under drought conditions. Compared to our finding, previous studies indicated a significant correlation between antioxidant activity and TPC in C. cyminum 13 and C. sativum 34 .…”

“…Similarly, the phenolic contents of cumin under water stress increased greatly 13 . In contrast, Neffati et al 34 reported that the polyphenol content decreased under salinity stress in coriander (C. sativum L). The different trends in phenolic fractions under drought stress can be imputed to the synthesis of various components of TPC and TFC as efforts by various populations to adapt to different soil moisture levels.…”

The biochar-based nanocomposites influence the quantity, quality and antioxidant activity of essential oil in dill seeds under salt stress

“…The quantity and quality of essential oils in medicinal plants can be influenced by environmental stresses and nutrient availability. Despite a reduction in plant productivity, different results have been reported on the variation of secondary metabolites of medicinal plants in response to salinity levels 28 , 30 , 31 . Increasing essential oil content at high level of salinity (Fig.…”

“…Indeed, variations of essential oil components are affected by changes in physiological functioning of plants and the induction of the specific enzymes involved in the biosynthesis of these compounds by salinity [37][38][39] . In response to salt stress, plants adapt through a number of mechanisms, such as salicylic acid (SA) signaling 28,29,35 . Salicylic acid is an efficient stimulant for secondary metabolite production that involves in the synthesis of terpenoids 40 .…”

“…The highest percentage and yield of essential oil were obtained from dill seeds under stress conditions 23 . According to Ghassemi-Golezani et al 28 salinity caused an increase in percentage of constituents, and antioxidant activity of essential oil in dill seeds. In this way, the defense system and salt tolerance of plants improved 23 .…”