Effect Of Root Cutting On The Wheat Growth And Water Use Efficiency

The experiments were made to analyze the root cutting influence on the wheat growth and the water use efficiency bye pots and plots. The results showed:1. At first cutting root restrain the wheat growth before promoting its growth. The wheat's growth was suppressed at the initial period after cutting the roots. The wheat leaf grew slowly than the comparison. But after a period of time, the growth is quicker than the comparison.2. The photosynthetic rate was enhanced and the transpiration rate and the stomatal conductance was decreased when cutting roots in seedling stage. But when cutting roots in jointing stage, because the time was late, it took a long time to resume. Though the photosynthetic rate was higher than the comparison on the later stage, the photosynthetic rate was reduced on the whole. And the time after cutting roots in jointing stage was the key time for grain filling, because the roots were cut, its ability for absorb was waked so that the wheat growth was restrained and the biomass and the output drop at end.3. The water use efficiency was enhanced obviously by cutting roots. The water use efficiency of spring wheat leaves of the cutting root treatments all was higher than the comparison. The amplitude is from 4.46% to 14.52%. At the 50% field capacity, the water use efficiency was higher when the roots were cut seriously in seedling time. From the result of the pot experiment we can see that the water use efficiency of the wheat biomass and the water use efficiency of the wheat yield also was enhanced.4. The influence on the height of the wheat was not notable by cutting roots. The cane wall was accumulated, the diameter of the steam was coarsened and the senility of the leaves were delayed at later period by cutting roots, so they could produce more photosynthesis product and increased the out put. The growth of the roots was promoted by cutting roots in seedling time, yet the growth of roots was retarded by cutting roots in jointing stage. At the 50% field capacity, the ratio of the root and the shoot of the cutting roots treatments was higher than the comparison, while at the 80% field capacity, the ratio of the root and the coronet of the cutting roots treatments was lower than the comparison.5. The biomass, grain yield and kernel weight were increased by cutting roots in seedling time and turning green time, the yield was higher when cutting roots seriously in winter and in turning green time in the field. The amplitude is 24.37%, 20.38% and 25.03%. But the biomass, grain yield and kernel weight were decreased by cutting roots in jointing stage.