The effect of pod elimination on water stress in relation to antioxidant enzymes activity and proline in three annual medics species

Abstract

Despite the importance of pod removal in the seeds of annual medics, there have been few studies carried out in this area. In this research, the role of pod removal in growth and biochemical enzyme activities was examined in three annual medic species during drought stress and subsequent recovery. This study was carried out as a factorial experiment based on a completely randomized design. The treatments were carried out on annual medic species of three levels: Medicago rigidula, M. scutellata, M. polymorpha, presence or removal of the pod and water stress. Water stress was split into the following four levels: 100%, 80%, 60%, and 40% field capacity (FC) during the stress period. The results showed that drought stress and subsequent recovery increased proline content and antioxidant enzyme activity. The highest proline content and antioxidant enzyme activity was observed in M. Scutellata. However, the rate at which proline increased, decreased at 40% FC whereas the antioxidant enzyme reached their highest activity at 40% FC. The antioxidant enzymes’ activity and proline content without the pod experiment were significantly higher than with the pod experiment. Since the activation of an antioxidant system and the increasing of the proline content helps the plants with stress induced damages, our results indicated that elimination of pods of annual medics before sowing helps seedlings to perform better under drought stress. This data is useful to gain a better understanding of the physiological basis of the changes in drought resistance as well as the crop breeding projects.