Relationship between viability and availability of Rhizobium trifoliiintroduced into seeds of Trifolium subterraneum L. by inhibition and pressure

Abstract

In an investigation into the fate of Rhizobium trifolii inoculum introduced into seeds of Trifolium subterraneum L. by imbibition, it was found that:

(1) Considerable numbers of Rh. Trifolii were introduced to seeds which imbibed in a broth culture, the number apparently increasing when application of pressure was used to accelerate the imbibition.

(2) Pressures up to 1600 lb/sq. in., even when released rapidly, had no apparent effect on the viability of Rh. Trifolii in broth culture, or on the subsequent germination and growth of T . Subterraneum seeds.

(3) After storage of the seeds for several months, the total number of Rh. Trifolii recovered was large, especially in the case of seeds which had been subjected to pressure.

(4) The Rh. Trifolii present in seeds which imbibed under pressure were remote from the seed surface, and in the field made little contribution towards colonizing the seedling rhizosphere or producing nodules.