高濃度鋅對玉米幼苗之影響

Effects of High-Concentration Zinc on Corn Seedlings

玉米（Zea mays L. cv. H₂ₐ）之葉及根於鋅處理10日後分析之，結果顯示可溶性碳水化合物，可溶性及總蛋白質、呼吸作用率、過氧化物酶及硝酸鹽還原酶還原等活性減少，總游離氨基酸及磷酸烯醇丙酮酸鹽羧激酶增加。鋅處理後幼葉有黃化現象且鬆根生長受到阻礙。處理後幼苗之一般症狀類似鐵之缺乏，但高濃度鋅之直接效應亦可能存在。

Corn (Zea mays L. cv. H(subscript 2a)) seedlings grown in culture solution were treated with high concentration zinc as ZnSO4. Final concentration of zinc in solution were 0.13 (control) and 25 ppm. Corn leaves were analyzed 10 days after zinc treatment. Results showed a decrease in soluble carbohydrate, soluble and total protein, respiration rate, peroxidase and nitrate reductase activities. Total free amino acid and phosphoenol pyruvic carboxylase activity were found increased. Chlorosis of young leaves and retarded growth of fibrous roots were also observed in the treated seedlings. The general symptoms of the treated seedlings were similar to those of iron deficiency. Direct toxic effect of zinc may also involved under high zinc condition.