Study On Differences In High Efficient Nitrogen Use In Two Genotypes Of Sugar Beet (Beta Vulgaris L.)

Two genotypes cultivars Shuangfeng16(standard partial high yield) and Tianyan7(standard highsugar type) were used in pot experiment with five NO-3/NH+4ratio treatments（3:1,2:1,1:1,1:2,1:3）on Napplication level of120kg/km~2. The changes of NR(nitrate reductase), NIR (nitrite reductase), GS(glutamine synthetase),GOGAT(glutamate synthase), AN (nutrient nitrogen), FN (functional nitrogen)and SN (structural nitrogen) were studied in each organ of sugar beet plant. The paper analyzedsystemically the relationship between the key enzyme in nitrogen metabolism and synthetic direction ofnitrogen nutrition,and the differences in the nitrogen using efficiency of two genotypes. It clarified thephysiological and biochemical basis of the efficient nitrogen utilization, and provided a theoretical basisand reference for efficient nitrogen production of sugar beet. The main conclusions were as follows:1.The vitality performance of NR, NIR and Fd-GOGAT the key enzyme in nitrogen metabolism inthe beet body are all root> leafstalk> leaf. And the vitality of GS and NADH-GOGAT in root from July14(mid and cluster formation) is greater than the part on the ground.2. The NRA, NIRA, GSA, GOGATA four key enzymes of nitrogen metabolism in Sugar beets aresignificant correlation in the whole growth period. The part on the ground, among the fourth enzymeswere very significant positive correlated and they were very significant positive correlation with yieldsignificantly negative correlation for sugar rate.3. In all the key enzyme GSA was very significant positive correlated to NADH-GOGATA, negativecorrelation with NIRA, GSA and Fd-GOGATA. And the key enzymes in the root only GS and NADHwere extremely negative correlation for yield, significantly related to sugar yield. These were same withthe performance of other key enzymes in leaves.4. The content of AN in plant were change with the advancement of metabolism reproductive periodshow unimodal curve.The content of AN in organs were root> leafstalk> leaf, the result of thecomparison among the different nitrogen ratio is N2:1> N1:1> N3:1≈N120>N1:2>N1:3>N0. Thecontent of FN in the plant were on August23–September6at peak, and leaf> root> leafstalk,N3:1>N2:1>N120>N1:1>N1:2>N1:3>N0. The content of SN in the plant were on July26-August23reach the maximum, and leaf> root> leafstalk, N2:1>N1:1>N3:1>N1:2>N120>N1:3>N0.5. FN/N was very significant positive correlation with sugar rate, and SN/N was very significantpositive correlated to yield.Comparing two genotypes of sugar beet, SF16less than TY7in FN/N, greater than TY7in SN/N. The synthetic direction existed significant differences in the process ofnitrogen assimilation. The same genotype of nitrate nitrogen and ammonium nitrogen ratio3:1and2:1was greater than the contrast N120, and the highest sugar yield is2:1.