Book contents
- Frontmatter
- Contents
- List of contributors
- Preface
- 1 Introduction
- 2 Chemistry and Mineralogy of Molybdenum in Soils
- 3 Distribution and Mobility of Molybdenum in the Terrestrial Environment
- 4 Biochemical Significance of Molybdenum in Crop Plants
- 5 Soil and Plant Factors Affecting Molybdenum Uptake by Plants
- 6 Analytical Techniques for Molybdenum Determination in Plants and Soils
- 7 Testing for Molybdenum Availability in Soils
- 8 Molybdenum Availability in Alkaline Soils
- 9 Deficient, Sufficient, and Toxic Concentrations of Molybdenum in Crops
- 10 Symptoms of Molybdenum Deficiency and Toxicity in Crops
- 11 Sources and Methods for Molybdenum Fertilization of Crops
- 12 Yield Responses to Molybdenum by Field and Horticultural Crops
- 13 Responses of Forage Legumes and Grasses to Molybdenum
- 14 Molybdenum and Sulfur Relationships in Plants
- 15 Molybdenum in the Tropics
- Index
1 - Introduction
Published online by Cambridge University Press: 10 December 2009
- Frontmatter
- Contents
- List of contributors
- Preface
- 1 Introduction
- 2 Chemistry and Mineralogy of Molybdenum in Soils
- 3 Distribution and Mobility of Molybdenum in the Terrestrial Environment
- 4 Biochemical Significance of Molybdenum in Crop Plants
- 5 Soil and Plant Factors Affecting Molybdenum Uptake by Plants
- 6 Analytical Techniques for Molybdenum Determination in Plants and Soils
- 7 Testing for Molybdenum Availability in Soils
- 8 Molybdenum Availability in Alkaline Soils
- 9 Deficient, Sufficient, and Toxic Concentrations of Molybdenum in Crops
- 10 Symptoms of Molybdenum Deficiency and Toxicity in Crops
- 11 Sources and Methods for Molybdenum Fertilization of Crops
- 12 Yield Responses to Molybdenum by Field and Horticultural Crops
- 13 Responses of Forage Legumes and Grasses to Molybdenum
- 14 Molybdenum and Sulfur Relationships in Plants
- 15 Molybdenum in the Tropics
- Index
Summary
Molybdenum (Mo) is one of seven recently identified trace elements that are essential for plant growth. It is the only transition element in group VI in the periodic table that is essential for normal growth, metabolism, and reproduction of higher plants. The biological importance of Mo in plants is due to its highly beneficial action in the fixation of nitrogen, from the air, by the nitrogen-fixing bacterium (Azotobacter chroococcum). After the establishment of its essentiality by scientists in Australia more than half a century ago, its deficiency has been reported in several countries in a variety of crops. The agricultural researchers in Australia were able to overcome the symptoms of Mo deficiency in tomatoes (Lycopersicon esculentum Mill.) by addition of minute quantities of Mo in the nutrient solution. Some of the crops considered most sensitive to Mo deficiency are clovers (Trifolium subterraneum L.), cauliflower (Brassica oleracea var. botrytis L.), broccoli (Brassica oleracea L. Botrytis Group), rape (Brassica napus L.), beet (Beta vulgaris L.), spinach (Spinacea oleracea L.), lettuce (Lactuca saliva L.), and alfalfa (Medicago sativa L.).
Among the micronutrients, Mo is an exception in that it is readily translocated, and its deficiency symptoms generally appear on the whole plant. The deficiency symptoms for other micronutrients appear on the young leaves at the top of the plant because of their inability to translocate within the plant. Molybdenum deficiency emerges as general yellowing and stunting of the plant, interveinal mottling, and cupping of the older leaves, followed by necrotic spots at leaf tips and margins.
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- Molybdenum in Agriculture , pp. 1 - 3Publisher: Cambridge University PressPrint publication year: 1997
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