An estimation of the effects of synthetic auxin and cytokinin and the time of their application on some morphological and physiological characteristics of Medicago x varia T. Martyn

The aim of the experiment was to determine the effects of synthetic auxin and cytokinin and the time of their application on some morphological and physiological characteristics of Medicago x varia T. Martyn grown under controlled conditions. The experiment was to check whether an application of exogenous hormones during vegetative and generative stages of the plant had an effect on above-ground mass development, on nitrate reductase activity and on plastid pigments content. Experiment factor was synthetic auxin and cytokinin and the date of their application. Auxin was applied in the form of a synthetic indole-3-butyric acid, while cytokinin was sprayed as synthetic 6-benzylaminopurine. The control plants were treated with distilled water. Depending on the experimental variant, spraying was applied at the sixth true leaf stage and at the first flower bud stage. The research showed that the response of the alfalfa plants to the application of cytokinin and auxin was not uniform. It seems that the most effective was the application of a mixture of them both but only during the vegetative stage. Additionally, cytokinin caused an increase in plastid pigments content in alfalfa leaves. On the other hand, a mixture of auxin and cytokinin triggered the highest nitrate reductase activity in alfalfa roots and raised the ratio of total chlorophyll content to carotenoids. Synthetic auxin caused the decrease of the levels of most parameters compared to the control.