The Botanical Review

Darken, Marjorie

doi: 10.1007/BF02861845pmid: N/A

During the four years which have passed since the microbiological fermentation of vitamin B12 complex was first accomplished, major developments have occurred, and the production of vitamin B12 and its various complexes has become a major fermentation industry with substantial markets in human and animal nutrition. Factors which have contributed to the highly successful developmental work on the production of this vitamin include the isolation of cultures, the selection of media, a study of the optimum conditions of temperature, aeration and agitation necessary for largescale fermentation, and the establishment of suitable recovery processes for the fermentation broths. The natural occurrence of this vitamin appears to be attributable to microorganisms and algae instead of higher plants or animals.

Simmonds, P.

doi: 10.1007/BF02861846pmid: N/A

The literature on rootrots of cereals that has appeared since the first review reveals a continued interest in these maladies. There have been no major changes in research trends. There have been, however, notable elaborations of work previously initiated, in many cases with ingeniously devised techniques. Advances have been made in studies on the relationship between root disease organisms and soil and other micro-organisms. Much information has been added to our knowledge of the take-all rootrot by intensive research in Germany, England and Australia. In North America it appears that common rootrot may now be classed as a major research challenge. Browning rootrot of wheat, once of great economic importance in Canada, has declined with the introduction of better farming practices and the application of control methods developed after years of research. Helminthosporium blight has appeared as a serious stem, crown and rootrot of oats. There are several types of cereal rootrots considered of minor importance at present, but these must be kept under surveillance. Notable progress has been made in fundamental studies on the perplexing variability of the pathogensHelminthosporium sativum andFusarium spp.