Evolution of Root Characters during All Growth Stage of Maize Cultivars in Different Eras in China

The root characters of maize cultivars which came from 50's, 70's and 90's in China in different eras was evaluated in this study. The results showed that the vigor of the root system was distinct remarkably in different eras. During the earlier growth stage, the active surface area, the activity of SOD CAT of root system and the number of root per plant all increased clearly with the improvement of cultivars, and the above root characteristics of the cultivars in different eras was extremely different. During the later growth stage, the number of root in top position and the quantity of wounding flow per plant all increased obviously with the cultivar developed, the synthetic ability of amino acid and the absorbing rate of Zn, B, Mn, P, Mg, Ca and K increased greatly, the dry weight of root per plant and ratio of canopy/root(C/R) also increased distinctly.