WATER-SENSITIVITY IN BARLEY SEEDS II. ASSOCIATION WITH MICRO-ORGANISM ACTIVITY

Abstract

The inhibitory effect of excess water on the germination of water-sensitive seeds can be overcome by adding mixtures of antibiotics. A single antibiotic has no effect: a mixture of at least one fungal and one bacterial antibiotic is essential, and on freshly harvested seed an even more complex mixture may be necessary. Measurements of the gas exchange of the seeds in the presence and absence of antibiotics suggest that micro-organisms are relatively more active when seeds are placed in excess water. About 80% of the seeds which fail to germinate as a result of excess water lose viability within 6 days. It is suggested that water-sensitive seeds contain large mixed populations of micro-organisms. When set to germinate in excess water the entry of oxygen is physically impeded and also competed for by the microflora. Consequently the rate of germination is decreased; some micro-organisms may attack the embryos so that most of the seeds lose viability.