Effect of Different Treatments on Improving Seed Germination Characteristics of Astragalus adscendens and Astragalus podolobus

Nowadays, in many rangelands, due to over grazing, and problems that some plants have in germination, the rate of forage production is greatly reduced. So to take advantages of the benefits of such plants, it is necessary to identify and remove barriers of germination and establishment of suitable plants. The present study was designed to investigate different treatments of breaking dormancy and stimulating seed germination of Astragalus adscendens and Astragalus podolobus and offer the most effective treatment to enhance germination and growth rate. The experiment was conducted using Completely Randomized Design (CRD) with four replications. Treatments included hot water for 5 minute, 30% hydrogen peroxide for 5 minute, 98% sulfuric acid for 5 minute and chilling at 4°C for 10 days. Data were collected for seed germination percentage, Germination Rate (GR) and Mean Germination Time (MGT). Based on the results, treatment with 98% sulfuric acid for 5 min for A. adscendens and hot water for 5 min for A. podolobus were the best treatments to break dormancy and stimulate seed germination, so that the germination percentage increased from 44% to 82% in A. adscendens and from 28% to 62% in A. podolobus. In A. adscendens 98% sulfuric acid reduced the amount of MGT from 8 days for control treatment to 5 days. In A. podolobus hot water treatment was more effective on MGT reduction and reduced it from 7 to 5 days. Although sulfuric acid had the highest effect in breaking dormancy, but its application in a vast scale is not easy, therefore the hot water was suggested as the substitution treatment.