Early Growth of Grain Sorghum as Related to Manganese Nutrition1

Abstract Influence of Mn nutrition on sorghum [Sorghum bicolor (L.) Moench.] was investigated to determine the effects of Mn on early growth and define Mn deficiency symptoms under controlled conditions of nutrient solution culture in the greenhouse. Sorghum plants were grown in the greenhouse in nutrient solution containing eight Mn levels from O to 4,000 μg Mn/liter with all other essential nutrients supplied at adequate levels. Growth retardation determined from plant height measurements resulted prior to the development of visible Mn deficiency symptoms. In addition to the usual Mn deficiency symptoms of interveinal chlorosis, symptoms on sorghum Dekalb ‘BR 64’ included brown‐reddish pigmented bands in interveinal areas following chlorosis. Under slight Mn stress conditions, Mn deficiency symptoms decreased hi severity from young to older leaves.