Physiological and yield attributes of fennel, anise, and ajwain in response to brackish irrigation water in potted conditions

Salinity of soil and water is one of the most serious environmental problems in the world. Medicinal plants are one of the most valuable resources in a wide range of natural resources in Iran which if scientifically recognized, cultivated, developed and exploited properly can play an important role in public health, job creation and non-oil exports. Therefore, this experiment was performed on farm of Isfahan University of Technology and A factorial randomized complete block design was used for performing this experiment. Four levels of salt treatment (i.e. 0, 40, 80, and 120 mM NaCl) were applied on two genotypes from each of the three species of fennel, ajwain, and anise in three replications. Chlorophyll a and b, leaf starch, sodium and potassium concentration and their ratios, phenolic compounds, H2O2, grain yield, 1000-grain weight, root and shoot dry weight as well as height were measured. The results showed that salinity levels had different effects on different traits of these three species and their genotypes. With increasing salinity, dry weight of roots and shoots, height, yield, 1000-seed weight decreased, and on the other hand, H2O2 concentration and phenolic compounds and antioxidant capacity ramped up with increasing salinity level. Starch was different in the studied species and genotypes, so that the concentration of chlorophyll in fennel genotypes increased to a level of 80 mM salinity and then ramped down, but in the other two species had a decreasing trend: sodium concentration and sodium to potassium ratio with increasing Salinity levels increased and this increase was more noticeable in anise, the potassium concentration in all three species with The increase in salinity decreased, but the largest decrease was related to the anise plant. In general, according to our findings, anise is more prone to damage due to salinity stress, while the salinity tolerance of fennel and alder is comparable, although the salinity tolerance, especially in the latter two species, is subject to genotypic differences.