| The reasonable population structure of wheat can ensure the coordination between individual and population,improve the colony canopy environment and photosynthesis,and obtain high yield.Planting pattern,density and N application rate is very important to the influence of population structure,and the tridimensional uniform sowing is change the way conventional drilling,a new technology to increase yield.In order to define the regulation effect of planting densities and N application rates on population structure,photosynthesis and dry matter and nitrogen accumulation and distribution,yield and quality formation of uniform seeding wheat.Xindong 22,Xindong46 and Xinchun 31 were used as material,to research the high-yield physiological characteristics and regulation mechanisms of uniforming wheat.Main results were as follows:(1)With the increase of planting density,the internode length of wheat stem increased,especially the basal internode length increased significantly,while the stem diameter,tillering number,T,SPAD value and net photosynthetic rate all decreased.Compared with drilling,the internode length next to the ear and the mid-internode length,tillered culms diamete,first tillers numbers,ear bearing tiller percentage,T,E,SPAD value and Pn were increased,but the basal internode length,main stem diameter were reduced,and the uniform sowing mainly increased the mid and lower LAI,T,SPAD value and Pn after flowering stage;Among them,the transmittancy of the drill wheat population was not uniform,which was manifested as DO>UI>DI under the two planting methods.(2)With the increase of planting density,the dry matter distribution rate of stem sheath of wheat increased,the dry matter distribution rate of leaves and W0 decreased,and Tm was delayed.Compared with drilling,TAA,TAR,CTA,spikelets per spike of tiller,grains per spike,spike length and grain weight per ear were increased,the vegetative organs in mature material allocation rate and Vm decreased,and t1 was advanced,spikes from main-stem spikelets per spike,grains per spike,spike length and grain weight decreased;Among them,the panicle number of Xindong 22 and Xindong 46 was significantly increased by 17.31%and 17.68%compared with drilling,and the yield was increased by 6.40%and 9.84%,both reaching the maximum under D225,while the 1000-grain weight was reduced by 4.38%and 4.54%.(3)With the increase of N application rate,wheat seedling dry matter accumulation,stem diameter,tillering number,secondary tillers number,stem number per,the ear number per plant,LAI were significantly increased,the internode length next to the ear,leaf chlorophyll content,Pn,St,Tr,before flowering stem sheath,leaf dry matter accumulation,nutrient organs turn traffic and transport rate of dry matter were first increased then decreased.Compared with drill sowing,tiller number of even sown wheat increased significantly,chlorophyll content of leaves in middle canopy increased significantly after flowering,and the total chlorophyll content increased mainly by increasing Cb content,and the net photosynthetic rate of leaves in lower layer and middle layer of the population increased.The results also showed that the activities of CAT,SOD and POD in flag leaf of wheat increased with the increase of nitrogen application and the content of MDA decreased during flowering and filling periods.CAT,SOD and POD activities of flag leaves were enhanced and MDA content was significantly decreased under uniform seeding.(4)With the increase of N application,the nitrogen content of stem sheath,leaf and grain of wheat presented an increasing trend,and the uniform seeding method significantly increased the N content of stem sheath in the flowering and maturing stages of the two varieties.Compared with the drill method,the translocation and transport rates of nitrogen in stem sheath,leaf,cob and glume increased under the uniform seeding method.(5)With the increase of N application rate,smaller grain number,main stem spike grain number first increased then decreased,tillering stem the ear grain numbers per spike,were increased,and yield increased at first and then decreased of XD 22 under the drilling,and under N450 was the largest,and it was the largest under N600 under uniform seeding of XD 46,N300 maximum under processing.Compared with drill sowing,the number of ear and grain number of tillering stem in uniform sowing were significantly increased,while the number of ear grain in main stem had no significant effect,and the 1000-grain weight was decreased.This study also showed that planting way and the applied amount of N fertilizer had no significant effect on grain albumin content,and globulin,gliadin and protein with the increase of N application rate increased after the first down,and the XD 22 gluten in drilling mode in N450 maximum processing,and well under way to it was the largest in N300,XD 46 were processed maximum under N300,difference reached significant level.(6)The number of radicle tips,bifurcated number,surface area and volume of evenly sown wheat seedlings increased,and the stem diameter and seedling height ratio of drill increased by 6.15%and 1.02%,respectively.The time of rapid elongation of hypocotyl roots in uniform seeding was 1.16d shorter than that in drill seeding,and the theoretical maximum length of hypocotyl roots was reduced by 2.95%,while the maximum elongation rate of root system was increased by 8.96%.During germination,the dry matter conversion rate and consumption rate of grain storage both increased first and then decreased,and the transport rate reached the maximum at the 15th day,while the consumption rate reached the maximum around the 11th day,and the uniform seeding was significantly higher than the drill seeding by 10.61%.To sum up,the uniform seeding improved the population structure,increased the light transmittance and leaf photosynthetic rate in the middle and lower layers of the population,increased the dry matter accumulation in vegetative organs and transferred to grains,and increased the number of panicle by increasing tillers,thereby increasing the yield.Under the conditions of this experiment,the planting density of 2.25 million plants·hm-2 and the N application amount of 450 kg·hm-2 were the optimal cultivation combinations. |
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