Genotypic Variation of Manganese Toxicity and Tolerance of Japanese Mint

ABSTRACT

Plantlets of Japanese mint (Mentha arvensis L., cv. MASI and Hybrid-77) were grown on nutrient solutions containing manganese. For cv. MASI, dry weight of plant tops grown in 0.1 and 1.0 ug Mn/ml solutions was higher than that of plants growing in solution without manganese. In contrast, dry weight of plant tops of cv. Hybrid-77 had only a slight increase in growth as manganese concentration increased. With Hybrid-77, manganese content of the roots increased and the manganese content of the tops decreased as manganese levels in the culture medium increased. Necrotic browning and chlorosis of leaf tissue developed in Hybrid-77 growing in manganese deficient culture. In-vitro nitrate reductase and peroxidase activity were higher in MASI than in Hybrid-77 and a more positive correlation between the dry matter yield and tissue concentration of manganese was observed in MASI than in Hybrid-77. Crop improvement through selection of the manganese efficient genotypes appeared possible.

KEYWORDS:

• Herbs
• essential oil
• Mentha arvensis L.