ABSTRACT
Molybdenum was discovered in 1778 by the Swedish chemist, Carl Wilhelm Scheele. However, its importance in biological systems was not established until 1930 when Bortels discovered that molybdenum was essential for the growth of Azotobacter bacteria in a nutrient medium (1). Subsequently
The essential nature of molybdenum for higher plants was first reported by Arnon and Stout in 1939 (3). In earlier experiments, Arnon observed that minute amounts of molybdenum improved the growth of plants in solution culture (4), and that a group of seven heavy metals, including molybdenum, increased the growth of lettuce (Lactuca sativa L.) and asparagus (Asparagus officinalis L.) (5). Prior to these studies (conducted in 1937 and 1938, respectively) only boron, copper, iron, manganese, and zinc were considered to be micronutrients. The observation that plant growth was improved by elements other than these led Arnon to believe that the list of essential elements was incomplete, and prompted him to test whether or not molybdenum was essential for the growth of higher plants (3).
