September - A 2007 Perspective On Plant Nutrition

By William Terry Kelley

Thearticle by Dr. J.K. Plummer in the January 1946 issue, clearly reveals how the base of knowledge increases over time. While his article eloquently points out what is known about the essential roles of copper, manganese, and zinc at that time, his examples are primarily from an animal perspective. Since that time, much has been learned about the roles of these elements in plant life.

Zinc is a component in a number of plant enzyme systems and is an essential part of auxin, which is one of the best-known enzymes that regulate plant growth. Manganese plays a role in the evolution of oxygen in photosynthesis. Copper is also involved in several plant enzyme systems and is involved in cell wall formation. All three are involved in electron transport.

Some of the effects of these essential elements that Dr. Plummer noted can now be explained in more detail because so much more is known about the mechanisms by which these elements function in plants. While he calls these “rarer elements,” we now include them in many complete fertilizer blends and analyze for these elements in plant tissue testing.

Kelley is an extension horticulturist at the University of Georgia; wtkelley@uga.edu