Abstract: For a better understanding of the yield-increasing mechanism of wheat with uniconazole, the physiological effects of uniconazole (S-3307) waterless-dressed seeds on root and leaf of wheat were studied with different varieties and nitrogen levels in traditional field experiments and soil column culture. The results showed that S-3307 increased root vigor, which resulted in the absorption of 32P increased by 20.2% and the proportions of 32P distributed to tiller increased by 570% over the control. S-3307 also significantly increased the area of top leaf, improved the photosynthetic capacity of leaf, promoted the assimilatory ability of leaf by 25.9% as compared with the control, and distributed more 14C assimilates to roots and tiller nodes. At the later stage, S-3307 increased SOD activity, reduced MDA content in root and leaf. It is concluded that the best concentration of S-3307 is 20 mg per kg seeds.

Key words: Uniconazole, Wheat, Root, Leaf