| In this study,a special experiment was designed to test the effects of nitrogen fertilizer application rate and planting density on the photosynthesis characteristics and yield of wheat in apricot wheat intercropping. Using Xindong 20 as material,the experiment was carried out in a split plot design with 4 nitrogen fertilizer application rates being in the main plot and 3 seeding density representing in the subplot. The 4 nitrogen fertilizer application rates were arranged as no topdressing (CK),topdressing urea 300 kg·hm-2(N1),topdressing urea 450 kg·hm-2(N2),topdressing urea 600 kg·hm-2(N3). The three seeding densities were 3.75 billion·hm-2(M1),5.25 billion· hm-2 (M2) and 6.75 billion· hm-2(M3). The results showed that the photosynthetic rate (Pn),dry matter accumulation,actual PSⅡefficiency (ΦPSⅡ),photochemical quenching coefficient(qP) and yield were increased with the increase of nitrogen application rates. The Pn,dry matter accumulation,ΦPSⅡ,qP,grain number per spike and 1 000 grain weight were reduced with the increase of seeding density,while spike number and yield were increased. Under topdressing urea 600 kg·hm-2 condition,M1 had higher Pn,ΦPSⅡ and qP than other treatments,but its nonphotochemical quenching(NPQ) was significantly reduced. As a result,the dry weight of above ground,dry weight of reproductive organ,grain number per spike,1 000 grain and yield were the highest under N3M1 treatment. The results suggested that when N supplies were adequate,reasonable seeding density could improve photosynthesis and increases the availability of photosynthate to the reproductive organ aboveground,whcih increased 1 000 grain and yield of wheat in apricot wheat intercropping. Therefore,the photosynthesis rate,dry matter accumucation and its distribution to grain could be improved through selecting reasonable seeding density and nitrogen fertilizer amount in apricot wheat intercropping, and then the high yield could be gained. |
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