Spore germination of Frankia strains isolated from Colletia hystrix and Retanilla ephedra (Rhamnaceae)

Abstract

Two Frankia strains, Chl1 from Colletia hystrix and Re16 from Retanilla ephedra, were assayed to determine the germinability of their spores and the stages of the life cycle in different media. In BAP medium, both strains showed approximately 18% spore germination. However, in BAP medium lacking micronutrients and FeEDTA, strain Chl1 spores exhibited approximately 53% germination and strain Re16 spores about 42%. The survey also showed that the spores were not heat-resistant, the Rel6 spores being more sensitive than Chl1 spores. Both strains exhibited a small increase in their percentage of germination with a 15-pulse ultrasonic treatment.