Effects Of Nitrogen Rates On Wheat Photosynthetic And Nitrogen Utilization Characteristics And Grain Yield Of Different Cultivars

The experiment was carried out in the wheat growing season from 2016 to 2017 in Shiwang Village,Xiaomeng Town,Yanzhou District,Shandong Province.Two wheat cultivars were used including Jimai 22?J22?and Yannong 1212?Y1212?.The five nitrogen treatments were set,respectively:0 kg,hm^-2?N0?,180 kg hm^-2?N1?,210 kg hm^-2?N2?,240kg hm^-2?N3?,and 270 kg hm^-2?N4?.The micro-spraying method was used to measure the supplementary irrigation,and the relative water content of 0-40 cm soil layer was supplemented to 70%and 70%at jointing stage and anthesis stage.The effects of nitrogen application rate on nitrogen use efficiency and grain yield of different wheat cultivars were studied.The result is as follows:1 Differences in water consumption characteristics of different wheat cultivarsUnder N2 treatment,water consumption,water consumption coefficient and daily water consumption of J22 were significantly higher than in Y1212 from jointing to anthesis stage,but the water consumption and water consumption module coefficient of Y1212 were significantly higher than those of J22 from flowering to maturity stage.100¹60 cm soil water storage consumption of Y1212 was significantly higher than the J22 variety of N2 treatment.2 Differences in photosynthetic characteristics of flag leaf of different wheat cultivarsUnder N2 and N3 treatments,flag leaf net photosynthetic rate,transpiration rate,stomatal conductance and water use efficiency at 14 d,21 d and 28 d after anthesis of Y1212were all significantly higher than J22.Under N2 and N3 treatments,the maximum photochemical efficiency,the actual photochemical efficiency,electron transport rate,and the photochemical quenching of flag leaf were significantly higher in Y1212 than in J22 at 21d and 28d after anthesis.Under the treatment of N2,the chlorophyll SPAD value of Y1212 was significantly higher than that of the J22.Under the treatment of N2,the chlorophyll SPAD value of Y1212 was significantly higher than that of the J22 at 21d and 28d after anthesis.Under N2 treatment,the dry matter accumulation amount of Y1212 was significantly higher than that of J22 at anthesis and maturity.Under N2 treatment,the dry matter distribution amount in leaf,Glume+spike axis and grains of Y1212 was significantly higher than those of J22.3 Differences in nitrogen accumulation characteristics of different wheat cultivarsUnder N1 and N2 treatments,nitrogen accumulation in vegetative organs of Y1212 were significantly higher than those of the J22 at the anthesis and maturity.Under the N2 and N3treatments,the nitrogen allocation amount in the stem+leaf sheath,leaves and grains of Y1212 was significantly higher than in the J22.4 Differences in flag leaf senescence characteristics of different wheat cultivarsUnder N1 and N2 treatments,the activities of superoxide of Y1212 were significantly higher than J22 at 14d,21d and 28d after anthesis.Under the treatments of N2 and N3,the malondialdehyde content of J22 was significantly higher than that of Y1212 in 14d,21d,and28d after anthesis.Flag leaves Soluble protein content of Y1212 were significantly higher than that of J22.5 Differences in grain yield,water use and nitrogen use efficiency of different wheat cultivarsUnder N1,N2,N3,and N4 treatments,grain yield,water use efficiency,nitrogen fertilizer agronomic efficiency,and nitrogen partial productivity of Y1212 were significantly higher than those of J22.It showed that Y1212 was a wheat cultivar with high-yield,water-saving and fertilizer-saving fertilizer under the experimental conditions.