Activity and Physiological Responses of Kochia (Kochia scoparia) at Various Salinity Application in Different Growth Stages

Soil and water salinity are the main agricultural problems in arid and semi arid areas in the world and Iran. In order to investigate salinity tolerance of Kochia، two experiments were conducted in a completely randomized design with four replications، seven levels of salinity (0، 10، 20، 30، 40، 50 and 60 dS m-1) and two growth stages (planting and early seedling) with gradually salinity application. Results showed that the reduction of root dry weight، root volume، membrane stability index with increased salinity at planting were more than increased salinity at early seedling stages. Relative water content increased with increasing salinity levels in both experiments. Proline، osmotic potential، catalase، glutathione reductase، DPPH - radical scavenging activities and total phenol increased with increasing salinity levels. Sodium concentration and sodium to potassium ratio in shoot and root increased with increasing salinity levels. Generally، kochia survive and tolerate 60 dS m-1 of salinity and salinity tolerance in early seedling was higher than the planting stages.