The Mitigating Action of Cytokinins on the Water Stress Impact on Wormwood (Artemisia herba-alba)

Abstract

The drought stress has been considered as one of the most important environmental factors that hamper the growth and productivity of plants particularly in medicinal and aromatic plants whose physiological functions have direct effect on the production of bioactive compounds. Artemisia herba-alba is a highly significant medicinal plant that is known to possess antimicrobial, antioxidant as well as anti-inflammatory effects because it contains a high level of bioactive compounds which include flavonoids, phenolics, and essential oils. The study was aimed at determining the effects of the cytokinins in alleviating the unfavorable effects of water-stress on the vegetative growth and physiological phenotypes of the Artemisia herba-alba. The experiment was done through a completely randomized design (CRD), in which six treatments were taken, and they were control, drought stress, drought + BAP (0 mg L ^-1 ), drought + BAP (25 mg L ^-1 ), drought + BAP (50 mg L -1 ), and drought + kinetin (50 mg L ^-1 ). The various treatments of cytokinin were used as foliar sprays where the treatments included 6-benzylaminopurine (BAP) and kinetin used at a given concentration. The treatments were repeated 10 times. Irrigation was cut down to half field capacity to cause drought stress. Measurement of the performance of the various treatments included plant height, leaf area, shoot dry weight, relative water content (RWC) and chlorophyll content and transpiration rate. Plants that were subjected to drought stress were found to have a significant drop in all the parameters that were measured compared to the control plants. Cytokinin application on the leaves of the drought-stressed plants led to a considerable growth in the plants and their physiological activity. Plants treated with kinetin at 50 mg L ^-1 had the highest plant height, biomass accumulation, leaf area, chlorophyll content and relative water content. The analysis of the data statistically showed that the differences that were seen in treatments are statistically significant (P ≤ 0.05). The study states that cytokinins are relevant since they can be used to enhance drought resistance in Artemisia herba-alba by assisting in enhancing the capacity of the plant to use water, as well as retain its capacity to carry out photosynthesis and to develop vegetatively. Thus, this study demonstrates that cytokinins would be applicable under certain conditions as a viable tool to alleviate drought stress in the production of medicinal plants in both dry and semi-dry environments.