Microscopic structure of ineffective alfalfa nodules formed by auxotrophic mutants of Rhizobium meliloti

✍ Scribed by Dr. Wanda Małek

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 599 KB
• Volume: 28
• Category: Article
• ISSN: 0233-111X
• DOI: 10.1002/jobm.3620280925

✦ Synopsis

The inoculation of lucerne seedlings with mutants of Rhizohiuni rnelilofi (Arg-) requiring arginine resulted in the formation of ineffective nodules. In these nodules bacteria were not released from the infection threads into the nodule cytoplasm. When arginine was provided as a nitrogen source, the nodules became anatomically similar to those induced by the wild type strain and they fixed nitrogen. Effective nodules were induced also by prototrophic forms of revertants and transductants.

The infected cells in the central tissue of the effective nodule were enlarged, whereas uninfected ones of noneffective nodules of Arg-mutants remained small and contained small nuclei and many large starch granules.