Research The Loess Tableland Winter Wheat Accumulation And Transportation During Grain Fiilling Under Different Cultivation Models

Wheat (Triticum aestivum L.) as one of the most important staple crops, wheat mainly planted in northern China, where water shortage and low soil fertility were the main environmental factors that has been limited the agriculture development. Improving of wheat yield and water use efficiency is a great challenge and a hotspot area for the Chinese agricultural researches. crop yield not only also related with the carbohydrate assimilation, but also depends on assimilates translocation and partition to the grain, Study on the regulatory mechanisms of assimilates translocation could prove physiological basis on the high yielding and water use efficiency of wheat in the future dry-land wheat cultivation. In this paper, two winter wheat (Triticum aestivum. L) varieties, i.e. Changwu 134and Changhan58, were cultivated in the field during a period from September 2009 to June 2010, in Changwu Agro-ecological Experiment Station. The field experiments were conducted on the five different cultivation models ,i.e., Changwu134(T₁), Changhan58+ top dressing 75kg/hm2(T₂), Changhan58+ top dressing 75kg/hm2+organic fertilizer 45 000 kg/hm2(T₃), Changhan58(T₄),and Changhan58 + organic fertilizer 45 000 kg/hm2(T₅). The post-anthesis dry matter accumulation and remobilization in vegetative organs were investigated. The photosynthetic characteristics of flag leaves, the carbohydrate metabolism and related enzymes'activities of leaf and grain were determined. Grain yield, harvest index and water use efficiency were also measured and calculated. Main results are as follows:1. Dry matter accumulation amount gradually increased during grain-filling period. under different cultivation models, The translocation amount stored in vegetative orgrans before anthesis period declined in order of T₃>T₅>T₂>T₁>T₄.The contribution rate of post-anthesis period dry matter accumulation to grain yield showed that T₄ was the highest, reached to 80.85%. The contribution rate to grain yield of stem was higher than that of other vegetative organs in post-anthesis period The contribution rate of Vegetative organs accumulation to grain yield showed that stems> leaves> sheath. Compared to pre-anthesis period dry matter accumulation and the contribution rate to grain yield, Changwu 134 more rely accumulation of post-anthesis period dry matter accumulation to grain yield. T₃ were promoted dry matter accumulation of grain filling stage and get the highest yield.2. Top dressing and organic fertilizer increase of total soluble sugar and sucrose content in flag leaf in the early stage of grain filling. compared with 134, Changhan 58 have high sucrose supply ability in the early stage of grain filling. Changhan 58 sucrose supply capacity was significantly reduced in late grain filling period. Top dressing and organic fertilizer increase the activity of the sucrose phosphate synthase (SPS) in flag leaf. It was the key enzyme determining the sucrose synthesis. organic fertilizer and fertilizer also increased flag leaf sucrose synthase (SS) activity.3.Top dressing and organic fertilizer increase the grain starch accumulation, in 15-25 d grain filling, starch accumulation tends to a linear trend. Nitrogen fertilizer and organic fertilizer could increase the grain sugar supply levels. Top dressing and organic fertilizer promoted grain starch accumulation in grain filling, which was related to increase of some enzymes activities, such as SS, adenosine diphosphate glucose pyrophosphorylase (AGPP), uridine diphosphate glucose pyrophosphorylase (UGPP). (AGPP and UGPP appeared the similar trands, the peak appeared at 15d in the stage grain filling.4. Research wheat grain yield, harvest index and WUE under the different cultivation models .The results show that organic fertilizer and top dressing the nitrogen fertilizer could enhance grain yied and WUE, reduced the harvest index.