[Spatiotemporal variation of root systems of cytoplasmic male sterile maize (Zea may L.) and its homotype fertile lines].

Maize cytoplasmic male sterile (CMS) lines and their homotype fertile lines were cultivated on soil column to study the differences of their root traits at different growth stages after anthesis. The results indicated that CMS lines had stronger ability of dry matter accumulation in their aboveground part, their grain yield was significantly higher than that of homotype fertile lines (P < 0.05), and their root dry mass was higher. In addition, the ratio of their root to canopy had a similar variation trend as root dry mass. The root mass of CMS lines in 0-20 cm and 20-40 cm soil layers was higher than that of homotype fertile lines, and the superiority was more obvious in 40-80 cm soil layer. Compared with homotype fertile lines, CMS lines had significantly higher root activity in 0-20 cm and 20-40 cm soil layers (P < 0.05), and significantly higher root SOD activity and soluble protein content (P < 0.05) in 40-80 cm soil layer. The root activity and root SOD activity and soluble protein content of CMS lines were significantly higher than those of their homotype fertile lines (P < 0.05) at late growth stage. In conclusion, CMS lines had the characteristics of larger root quantity in deeper soil layers and higher root physiological activity at late growth stage, which could prolong the functional period of root and postpone the process of senescence, possibly being one of the important reasons of the high grain yield of CMS lines.