Studies On Regulating Mechanism Of Root Cutting And Its Interactive Effects With Fertilizer Application In Winter Wheat

Using two winter wheat cultivars, YannonglSand Lumai22, the study tried to explore the regulating mechanism of root cutting, the relationship between accumulation of root fresh weight and distributing, especial root activity in soil layer and growth of aerial parts, the regulation of hormones concentration in roots, leaves and grains on growth of aerial parts and grain growth, and the influence of root cutting and fertilizer (nitrogen and manure) application interaction on yield and quality. The secondary roots were cut the place that 10cm from the surface basing on the tilling number at the turning green stage, The experiments were carried out by field and earth pole culture at experiment farm of Shandong Agriculture University from 2000 to 2001 .The results were as follows:l.The relationship between roots and aerial parts. Accumulation of total and 0-20cm root fresh weight in soil layer significantly correlated with that of total dry weight, grain yield, nutrient absorption and tillers. In the later period of wheat growth, the relationship of root activity in soil layer with rate of nutrient absorption in different stage, kernel weight, grain filling rate, photosynthesis rate and chlorophyll content in flag leaf were correlated significantly. There were close correlation in the same SOD, POD, CAT, NR and GS activity, and MDA content between roots and flag leaf. The close relationship among various endogenous hormones in the same part and those endogenous hormones in different parts were also identified. We found the endogenous hormones deciphered by means of hormones system.2.The influence of interaction between rooting and fertilizer application on growth, nutrient absorption, translocation in winter wheat Root cutting and fertilizer application interaction can promote root growth, root activity, enhance nitrogen, phosphorus and potassium absorption, improve nutrient amount in kernel; increase photosynthesis rate, chlorophyll content in flag leaf, SOD, POD and CAT activity, and decreased MDA content in roots and flag leaf. Those root cutting and correspondent fertilizer application could protect cell membrane from active oxygen and delay senescence of plant. Those results indicated that supplied photosynthate sufficiently.3.The influence of root cutting and fertilizer application interaction on wheat yield and quality. We found that root cutting can reduce ineffective tillers, enhance the ratio of effective tillers, improve reasonable colony structure, increase ear number, kernel number, kernel weight and economic coefficient. Those effects also can be reached by nitrogen fertilizer and manure application except for economic coefficient. There was obviously positive interaction between root cutting and correspondent fertilizer application. Nitrogen fertilizer application had a little effect on increasing kernel weight, although it could change the course of grain filling. The amount of increasing yield per unit nitrogen as the increase in nitrogen fertilizer led to decrease. The interaction between root cutting and fertilizer application can improve SPS activity of leaves, increase the content of total soluble sugar and sucrose in leaves and grains, accelerate the rate of starch accumulation and starch content, and increase MR and GS activity, soluble protein content in roots and leaves, as well as protein content of grains in grain filling stage.4. The regulation of endogenous hormones on the plant growth. In erecting stage and jointing stage, the dynamic of endogenous hormone concentration in roots and leaves was consentaneous. Maximum concentration of IAA and GA3 in grains appeared later than those in leaves and roots. The concentration of IAA, (Z+ZR) and ABA, especially ratio of IAA/(Z+ZR), IAA/ABA and (Z+ZR)/ABA in roots and leaves greatly affected the development and senescence of tillers. Compared with control (CK), the Concentration of IAA and ABA was higher and that of (Z+ZR) was lower, therefore the ratio of IAA/(Z+ZR) was higher, and that of IAA/ABA and (Z+ZR)/ABA was lower in roots, wh...