Patent GB-1107240-A (GB)
Title: Improvements relating to rhizobium cultures and inoculations
IPC: C12N1/20
Filed: 1966-12-21
Abstract: Rhizobium strains resistant to adverse conditions met in the pre-inoculation therewith of leguminous seed (before sowing), are prepared by subjecting a bacterial culture of a Rhizobium species or group of species for the inoculation, having good infecting and nitrogen-fixing abilities, to a drying treatment such that the greater part (at least 90%) but not all of the bacteria are killed, and cultivating those bacteria still living.  The drying and cultivation may be repeated one or more times.  In the drying treatment the culture may be heated to a temperature not exceeding 95 DEG C., subjected to a flow of gas, vacuum drying or spray drying, transferred on to (or kept within a zone containing) a drying agent such as silica gel, and exposed to ultraviolet radiation. The following are mentioned: Rh. japonicum (soya strain) Rh. meliloti (lucerne strain), Rh. trifoli (trefoil strain), Rh. leguminosarum (peas and vetches strain), Rh. phaseoli (bean strain) and Rh. lupini (lupin strain).  According to an Example, cultures of a number of Rhizobium strains all having shown a good infecting and nitrogen fixing ability, were smeared out on one side of semi-permeable membranes, which were then placed with the smeared side upwards on the same substrate but containing 2% agar-agar to give solidity. After 3-5 days at 28 DEG C., the membranes with their appendant bacterial mass were transferred to tubes half-filled with silica gel and allowed to dry for 7 days at a temperature of 70 DEG C.  The membranes with the bacteria were then placed on plates of agar substrate and the bacteria surviving the treatment grew out to form colonies. The drought-resistant strains were suspended in water containing inert adhesive and the adhesive cultures were applied to 2mm. glass beads to test the rate of kill under laboratory conditions and to seeds which were subsequently grown to plants for testing the formation of nodules and nitrogen fixation.ALSO:Rhizobium strains resistant to adverse conditions met with in the pre-inoculation therewith of leguminous seed (before sowing), are prepared by subjecting a bacterial culture of a Rhizobium species or group of species for the inoculation, having good infecting and nitrogen-fixing abilities, to a drying treatment such that the greater part (at least 90%) but not all of the bacteria are killed, and cultivating those bacteria still living. The drying and cultivation may be repeated one or more times.  In the drying treatment the culture may be heated to a temperature not exceeding 95 DEG C., subjected to a flow of gas, vacuum drying or spray drying, transferred on to (or kept within a zone containing) a drying agent such as silica gel, and exposed to ultraviolet radiation.  The following are mentioned: Rh. japonicum (soya strain), Rh meliloti (lucerne strain), Rh. trifoli (trefoil strain), Rh. leguminosarum (peas and vetches strain), Rh. phaseoli (bean strain) and Rh. lupini (lupin strain).  According to an Example, cultures of a number of Rhizobium strains all having shown a good infecting and nitrogen fixing ability, were smeared out on one side of semi-permeable membranes, which were then placed with the smeared side upwards on the same substrate but containing 2% agar-agar to give solidity. After 3-5 days at 28 DEG C., the membranes with their appendant bacterial mass were transferred to tubes half-filled with silica gel and allowed to dry for 7 days at a temperature of 70 DEG C.  The membranes with the bacteria were then placed on plates of agar substrate and the bacteria surviving the treatment grew out to form colonies.  The drought-resistant strains were suspended in water containing inert adhesive and the adhesive cultures were applied to 2mm. glass beads to test the rate of kill under laboratory conditions and to seeds which were subsequently grown to plants for testing the formation of nodules and nitrogen fixation.