Effect of manganese stress on yield, productivity and metabolism of potato

To induce Mn stress in potato cv. Chandramukhi, plants were grown in refined sand at variable levels of Mn, viz. 0.0055, 0.055, 0.55, 5.5, 11 and 55 mg/l. At d 20 symptoms of low Mn exhibited as inter-veinal chlorosis of young leaves which intensified later, irregular brown spots developed. Whereas at excess Mn (> 0.55 mg/l) inter-veinal chlorosis developed on old leaves followed by necrosis and ultimately death of leaf lamina. In addition, plant growth retarded and tuber yield decreased. Mn stress (> 0.55 mg/1) decreased the biomass, concentration of chlorophylls (a and b), Hill reaction activity, sugars, starch, iron and activity of catalase whereas increased the phenol content and activity of peroxidase and acid phosphatase. The concentration of Mn increased with an increase in Mn supply from 0.0055 to 55 mg/l.