Study On The Different Form Nitrogen Absorption And The Characteristics Of Nitrate Reductase In Winter Jujube (Zizyphus Jujuba Var. Inermis Rehd.)

The experiments were conducted with two-year-old potted winter Jujube ( Zizyphus Jujuba var.inermis Lubei-Dongzao/Jinsixiaozao ) in Shandong agriculture university from 2004 to 2005. The characteistics of NR and the condition of absorption and utilization to different form nitrogen on winter jujube were studied. The results showed as follows:1. Urea, Gly and Glu could be absorbed by winter jujube. Under the condition of leaf absorption the 15N utilization rates of Gly and Glu were 38.13%, 15.43% respectively if urea was 100%. Nitrogen which absorbed was mainly supplied to leaf and neonatal branch. Under the condition of root uptake in vitro, the 15N utilization rates of Gly and Glu were 42.77% and 42.97% respectively if urea was 100%.2. The physiological effects of different nitrogen forms on winter jujube indicated that GOT and GPT activity in jujube leaves increased differently after absorbing Urea, Gly and Glu, of which the Glu was the most significant and increased 10.37% and 10.70% respectively compared with CK. In addition, the three treatments increased the content of soluble protein in leaves. The effects of different nitrogen forms on NR activity has great discrepancy. Urea could enhance NR activity significantly and Glu has little effects which Gly decreased NR activity. The effects of different nitrogen forms on fruit quality of winter jujube showed the treatments of amino acid could increase the number and area of skin color and enhance the content of soluble solid matter,however, have little effects on rigidity.3. Leaf was the main organ which assimilated NO₃^-. The new-leaf has the highest NR activity, then was the mid-leaf. The activity of down-leaf was the lowest. NR activity of fine-root was higher than other roots but lower than leaves, the activity of absorption roots could hardly be observed. Further, the diurnal variation of NR activity in vivo showed a peak curve and maximal NR activity appeared at about 11:00. The season change of NR activity showed NR activity in leaves was higher in August comparing with...