The Effect Of Nitrogen Forms And Levels On Sugar Beet Nitrogen Assimilation Enzyme And Chlorophyll Fluorescence Parameters

In this study,shuangfeng8as the experimental material,and pot experiment was carried out in the northeast agricultural university in2012.The Experimental design was quadratic rotation-orthogonal combination1/2and the four test processing factors was respectively NO3-、NO2-、 NH4+and pH.We systematic and comprehensive researched the coupling relationship of sugar beet nitrate reductase (NR) and nitrite reductase (NiR)、photosynthetic rate、chlorophyll fluorescence parameters、beet root sucrose content and total nitrogen content. Meanwhile, the chlorophyll fluorescence parameters on the quality of sugar beet production were analyzed.Nitrate reductase activity (NRA) and nitrite reductase activity (NiRA) appeared bimodal curve changes in the whole growth period. The NRA and NiRA both peak showed respectively on June22and August26and the maximum value was on June22.1n the whole stages, the dynamic change trend of NR and NiR was with increase with the decrease of law. The correlation bewteen the both keeped basic positive correlation in the whole development process. It indicated that the NRA and NiRA existed coupling effect.Photosynthetic rate was single-peak curve change and peak showed on August12. Chlorophyll fluorescence parameters Fv/Fm shows bimodal curve change, peak appeared in the July25, and the second peak appeared on August26.qP show the maximum at the birth prophase and with the development process the numerical value decline.On August26began to recover and appeared a peak. At the birth prophase qN show minimum and with the development process the numerical value rise, the maximum appeared on August12. The change trend of Y (Ⅱ) is similar to qP.Sucrose content in root keeped rising trend on the whole.The minimum value appeared on June6; the maximum value was August12and then decreased slightly. Total nitrogen content of root showed downward trend on the whole. The maximum was on June6, the minimum value appeared on July25, and then began to rise and on August26had the second peak. From the overall changes trend of sucrose content and total nitrogen content we could conclude that the both maintained in the form of complementary.In different growth period, the control effects of NO3-、NO2-、NH4+and pH on sugar beet chlorophyll fluorescence parameters Fv/Fm、qP、qN、Y(Ⅱ) were different. The obvious interactions appeared between two factors and different dominant factors.At the same time, in different growth period, the contribution rate of four factors on the determination of four indicators are also different.The correlation of Chlorophyll fluorescence parameters on sugar beet root yield and sugar content are different. In the whole growth period Fv/Fm was a positive correlation with sugar beet root yield and sugar content.qP,Y (II) on sugar beet root yield and sugar content basically were positively correlated.qN is basically negatively correlated with sugar beet root yield and sugar content basically.