Effect of zinc on C, N metabolism of different varied maize (Zea mays L.) genotype seedlings

Two Zn-tolerant maize cultivars 'Sidan 19' (low zinc sensitive) and 'Mudan 9' (low zinc insensitive) were used as materials to investigate the effects of different Zn contents on CA activity, photosynthetic characteristics, soluble sugar content. The results showed that maize could transport zinc selectively. When zinc concentration was enough to damage seedlings, zinc absorbed by the roots reaching the above-ground decreased to reduce harm them. CA activity and zinc supply were closely related to each other, but CA activity and net photosynthesis, were not closely related to each other. Low zinc and high zinc promoted 'Sidan 19' soluble sugar content notablely; for 'Mudan 9', the soluble sugar content under zinc deficiency and low zinc treatment did not increase significantly, while displayed a rapid increase in high-zinc processing. Under low zinc and high zinc treatment the blades protein content of 'Sidan 19' reduced significantly. The soluble protein content in blades of 'Mudan 9' reduced non-significantly under low zinc processing, and decreased sharply undert high zinc processing. Under low zinc treatment, protein synthesis of 'Sidan 19' was suppressed with a large accumulation of free amino acids, which significantly inhibited the growth of the plants; while the protein and amino acid content of 'Mudan 9' altered a little.