The Influence Of Different Cultivation Modes On Winter Wheat Assimilates Accumulation And Mobilization

In Loess Plateau of china, water and nitrogen are two key elements inhibit the winter wheat production. Field experiments were conducted at the Changwu Agricultural Research Station on the semiarid Loess Plateau of China during 2010 to 2012 for compared the different cultivation modes. The cultivation modes includes:(1) cultivation mode1 Changwu134 treated with 150kg/ha-1 N, and 120kg/ha-1 P; cultivation mode 2 Changhan58 treated with 120kg/ha-1 N and top-dressed 75kg/ha-1 N at heading, 120kg/ha-1 P;(3) cultivation mode 3 Changhan58 grown in plots with wheat straw mulching during the summer fallow period and straw retention in following sowing cycle plus a basal dose of 120kg/ha-1 N and top-dressed 75kg/ha-1 N at heading, 120kg/ha-1 P, and ox manure at 4.5t/ha-1and(1) cultivation mode 4 Changhan58 grown in plots subjected to plastic film mulching during summer fallow period; the mulch was removed at sowing and 150kg/ha-1 N and 120kg/ha-1 P were applied. Each treatment was replicated four times and arranged into a randomized complete block design. Nitrogen(N) as urea and phosphorus(P) as SSP were used. The inorganic fertilizer and ox manure were imposed prior to sowing. To compared the influence of 4 different cultivation modes on two drought-resistance winter wheat cultivars(Changhan58 and Changwu134) dry matter, water soluble carbohydrates, total nitrogen accumulation and remobilization during grain filling periods; the yield and yield components under different cultivation modeThe main conclusions of this study were as follow:(1) Changhan58 cultivar accumulated more dry matter than that of Changwu134 cultivar. In Changhan58 cultivar, T3 ccumulated most dry matter. Among all parts of the wheat internodes, the bottom-two-part accumulated more dry matter than that of top-three-part. In bottom-two-part, lower internode(ERI) had the highest dry weight, in top-three-part; penultimate internode(PI) had the highest dry weight. Post-anthesis synthesis dry matter had more contribution to final grain weight than that of pre-anthesis accumulation dry matter. Compared with two consecutive growth period(2010-2011 and 2011-2012), the more precipitation during late grain filling period in 2012, which inhibit the post-anthesis photosynthesis, less assimilates synthesis. So the contribution of post-anthesis photosynthetic assimilate to grain weight is less than that of in 2011 grain filling period. From apical to bottom, the value of CRAP is decrease. The value of CAPA is increase.(2) On average, Changhan58 cultivar accumulated more WSC in stem than that of in Changwu134 cultivar. T3 can increase the WSC content in all wheat stem segments. There is a significant positive relationship between WSC content on anthesis and mobilization WSC(MWSC)(r=0.900 P=0.01 level), which illustrate the importance of WSC content on anthesis. During grain filling period, there is an asynchronized phenomenon in different internode segments showed their maximum WSC content. The bottom-two-part showed their maximum WSC content on 15 day after anthesis(daa), which earlier 5days than that of the top-three-part.(3) With the development of grain filling, the total nitrogen(TN) concentration is decrease in all vegetative organs. There is an exception organ for TN concentration change during grain filling(For EXUI). Leaf organs had higher TN concentration than that of in stem organs. In leaf organs, flag leaf(FL) had the highest value, in all internode segments, EXUI had the highest value. Then, leaf organs the highest value in nitrogen contribution(NC) to final grains, followed by glume + rachillae(GR), the stem had lowest value in NC. 3 can increase the TN vertical distribution in winter wheat. There is a significant positive relationship between TN concentration in gradient1(G1) and TN concentration in grain at maturity.(4) T3 significant increased the LAI, flag leaf area and grain area. LAI and flag leaf area can affect the photosynthesis, the stem surface area and grain area is non-foliar organ. The higher value about them, the more photosynthate fixed by photosynthesis(include leaf photosynthesis and non-foliar photosynthesis).(5) The top grains had less starch, total nitrogen and volume accumulation than that of middle and bottom grains. Changwu134 cultivar accumulated more dry matter and starch in single grain than that of Chnaghan58 cultivar. It is concluded more photosynthase mobilized from source organs is benefit to accelerate grain starch accumulation in the early grain filling period.(6) Compared with different winter wheat cultivars Changwu134 and Changhan58, the latter had high water use efficiency, harvest index and yield. T3 not only increase the grain yield, but also promote the efficiency of water to produce the grain particularly in the year which is have less precipitation.The increase of wheat yield mainly attributed the increase of ear number and grain number per spike, while was largely independent on grain weight.