Effects of Different Salt Concentrations and Ascorbic Acid Applications on the Morphological, Physiological and Photosynthetic Pigment Traits of Medicinal Sage

Abstract

This study was conducted on Salvia officinalis L. plants suitable for most Türkiye’s climatic conditions. The experiments were carried out in July 2021 in a fully controlled climate chamber where plants were grown at 25°C, 65% relative humidity, and an 16/8-hour light/dark photoperiod. Plants in the developmental stage (month 1) were treated with various concentrations of ascorbic acid (0 ppm, 100 ppm, 200 ppm, and 300 ppm) and exposed to different doses of salt stress (0 mM, 100 mM, and 200 mM NaCl). The study was conducted in a randomised trial design with four replicates. In the study, plant morphological (plant stem and root length, stem and root fresh weight, stem and root dry weight), physiological (relative water content (RWC), ion leakage (ILLT), and membrane resistance index (MEI)), photosynthetic pigment (chlorophyll a, chlorophyll b, total chlorophyll, and total carotenoid) and MDA traits were determined. In the study, the MEI (membrane endurance index) value was found to be statistically significant at the 5% level, while all other parameters were found to be statistically significant at the 1% level. The interaction between ascorbic acid and salt stress was determined in the range of 19.0-36.83 cm for plant length, 17.0-38.33 cm for root length, 1.09-5.68 g for plant fresh weight, 1.19-5.54 g for root fresh weight, 0.120-0.570 g for root dry weight, 0.392-1.325 g for plant dry weight, 37.22–51.07% for ILLT, 36.89–62.78% for MEI, 59.99–90.18% for RWC, 2.52-8.90 nmol g-1TA for MDA, 9.99-24.42 μg g-1fw for Chlorophyll a, 3.67-13.41 μg g-1fw Chlorophyll b for, 13.66-37.22 μg g-1fw for Chlorophyll total and 3.48-7.66 μg g-1fw for carotenoids. As a result of the study, it was determined that the morphological development parameters of the plant decreased in parallel with increasing salt stress. Similarly, it was determined that salt stress had a negative effect on the physiological and photosynthetic pigment contents of the plant. This study conducted to determine the remedial properties of ascorbic acid against increasing salt stress, effective results were obtained in morphological development parameters, especially at a 300 ppm ascorbic acid dose. In other parameters, it was determined that ascorbic acid doses showed a remedial effect on the plant compared to the control.