Germination Requirements of Seeds of Astragalus tennesseensis

Dormancy of the seeds of Astragalus tennesseensis Gray is due to the presence of an impermeable "hard" outer seed coat, a tough inner seed coat, and possibly an inhibitory substances(s) in the seed. It was found that the inner seed coat prevents germination of imbibed seeds by (1) exerting mechanical resistance to expansion and growth of the embryo and by (2) retarding the leaching of an inhibitory substance(s) from the embryo. Maximum percentage of germination was obtained at 25⚬C after both seed coats had been broken and the seeds had been leached. Leachate from seeds of A. tennesseensis reduced root growth in lettuce, tomato, and Sporobolus vaginiflorus (Torr.) Wood.