HORMONES AND HORTICULTURE,

by George S. Avery '24 and Elizabeth B. Johnson, in collaboration with Ruth M. Addoms and Betty F. Thomson. McGraw-Hill Book Company, 1947; pp 326; $4.50.

Among the more exciting discoveries in plant science in the last twenty years is the finding that growth and differentiation in plants, as in animals, is regulated by hormones. Dr. Avery, Director of the Brooklyn Botanic Garden, is the author of numerous technical papers in this field. He and his collaborators have now described how the discoveries of the laboratory have been put to practical use in horticulture and agriculture. The book deals not only with established procedures in the commercial utilization of hormones and other growth-regulating chemicals, but also evaluates the present status of research and the possibilities of future progress.

The nature and general effects of synthetic hormones upon growth are first discussed, followed by a lengthy chapter on the use of hormones in the rooting of cuttings. Succeeding chapters deal with such topics as hormone control of preharvest drop of fruits, the production of seedless fruits and increase in fruit set by the use of hormones, control of the time of flowering, vitamin B, and root growth, and the effect of hormones and other chemical compounds upon dormancy. A- chapter is devoted to a discussion of the use of hormones, especially 2, 4-D, in weed control, a subject of interest to every home owner. The concluding chapter discusses the chemical production of new varieties through the use of colchicine. A practical feature is the inclusion of specific directions for the use of hormones, especially the time and method of application and the concentrations to be used. The book should appeal to a wide variety of readers, such as florists, nurserymen, gardeners, and plant breeders, and to the layman interested in plants as an avocation.