Investigation on the growth response and resistance to salinity stress in the medicinal plant Cynara scolymus L.

IntroductionWater and soil salinity is one of the most important environmental factors limiting the growth and performance of plants around the world, especially in arid and semi-arid regions. The increase in population on the one hand and the decrease of fresh water and soil resources on the other hand has doubled the necessity of studying in relation to the identification of salinity resistant plant species and strategies for the efficiency of saline soil and water resources. Therefore, this study was conducted with the aim of finding and determining the salinity resistance of artichoke plant species and the growth rate of the species under different conditions of irrigation water salinity and evaluating the performance of vegetative and physiological growth parameters in field conditions in order to use this plant in areas with limited water salinity.Materials and methodsIn order to evaluate the salinity resistance of the artichoke medicinal plant species and to determine the salinity resistance of this species, an experiment was conducted with six salinity levels including (control), 9, 12, and 15 dS m-1 in a completely randomized design and in three replications in potted conditions. Four weeks after applying salinity stress, traits including photosynthetic pigments, dried leaves, leaf water content, leaf dry weight, ash content, SLA were measured. Finally, significant difference at 5 percent level statistically were calculated among treatments using analysis of variance and mean differences was calculated using Multiple Duncan test.Results and discussionResults showed that salinity treatment has a significant effect on the characteristics of total chlorophyll, percentage of dryness and leaf fall, percentage of leaf ash, leaf specific weight and moisture content of leaves at the level of five percent, and the Artichoke plant can tolerate salinity up to 9 dS m-1 but it is sensitive at higher levels of salinity. In other words, the salinity of 12 dS m-1 has reduced the germination of Artichoke species by more than 50% and caused a significant increase in ash percentage, as well as drying and leaf fall percentage by 50%, and significant decreasing in leaf water content, dry root weight while it significantly increased electrolyte leakage which can indicate a significant decrease in vegetative growth and performance of this species at this level of salinity. According to the results, per unit increase in salinity, the weight loss of Artichoke leaves was recorded as 11%. In general, Artichoke plant species, in terms of resistance to salinity, it has a relatively good tolerance, and it seems this plant species can be used for cultivation and production by using saline water sources up to 9 dS m-1 in condition of the study area.ConclusionsThe results showed that there is no significant difference in yield and growth of Artichoke by increasing water salinity up to 9 dS m-1 in the study area. In farm and pod condition, experimental treatments showed a significant effect on increasing leaf fall, ash and water content, leaf dry weight by increasing water salinity to 12 dS m-1 . In general, Artichoke as an important medicinal plant, is a moderate up to tolerant species in salinity and it seems it is a proper species for cultivation and plant production in area with saline water up to 9 dS m-1 in condition of study area. According to the results, it seems water salinity up to 12 dS m-1 significantly decreases vegetative growth of the species up to 50% but it is a need more studies for impact of salinity on flowering and seeding stages as well. we recommend more studies in different climate conditions to reveal impact of these conditions on salinity resistance of the plant species.AcknowledgementsWe thank the National Salinity Research Center for their cooperation in the implementation and providing water and land for experiments in this study.