Investigating the Effects of Pod Elimination on Salinity Tolerance in Annual Medic (Medicago scutellata L.)

In most southern provinces of Iran, Soil Salinity is a growing problem particularly in the irrigated agricultural areas and has been found to reduce crop yields. In order to investigate the role of pod removal in seed germination, seedling growth and antioxidant enzymes activity in annual medics (Medicago scutella L.) under salinity stress conditions, a factorial experiment was conducted at College of Agriculture, Shiraz University in 2014 based on the completely randomized design with four replications. The factors included: 1) the presence or removal of seed pod, and 2) salinity stress at five levels involving controls 3, 6, 9 and 12 dS m-1. The results showed that salinity stress has caused the changes of germination, seedling growth and antioxidant enzymes activity. By increasing salinity stress levels, a significant reduction was observed in speed and percentage of germination as well as rootlet length, shoot length and seedling weight. However, the increased levels of salinity stress caused the increased antioxidant enzymes activity. Germination and seedling growth in seeds with no pod were more than seeds with pod, but about enzymes' activity, no significant difference was observed among seeds with and without pod, except for ascorbate peroxidase enzyme activity that was significantly more in seeds without pod as compared to the seeds with pod.