Metabolic Changes in Mustard Plants Associated With Molybdenum Deficiency

S ummary Mustard (Brassica campestris L. var. sarson Prain cv. T42) plants were grown in refined sand at graded levels of molybdenum ranging from acute deficiency (2 × 10 −5 mg 1 −1 ) to excess (2 mg 1 −1 ). Visible deficiency symptoms appeared at 2 × 10 −1 mg 1 −1 or less molybdenum. Total dry matter and seed yield were maximal at 2 × 10 1 −1 mg Mo 1 −1 . In leaves of the deficient plants there was depression in the concentrations of DNA and RNA, protein nitrogen and activities of nitrate reductase and cytochrome c oxidase but stimulation in the activities of acid phosphatase and ribonuclease and accumulation of phosphorus and nitrate nitrogen.