| Nong8 and Nong4 are both of Bar-transgenic wheats.The Bar gene was transferred into wheat B genome is Nong8 and transferred into wheat D genome is Nong4.Based on the above two Bar-transgenic wheats and their first filial generation(F1)hybrided with local conventional wheat varieties,we researched the effects of different nitrogen ratios(NO3-/NH4+=3:1 and NO3-/NH4+=1:3)and Bar gene location on nitrogen metabolism and photosynthetic characteristics in wheat and explored the reason that the variance effects of the Bar gene location and different nitrogen ratios on the yield of Bar-transgenic wheat and its F1 hybrids,The results were followed:1 NO3-/NH4+=3:1 nitrogen source was better for dry matter accumulation and the yield of wheats.2 On the NO3-/NH4+=3:1 nitrogen source,it was better for root growth of wheat seedlings including the main root length and the root system activity.The NR activity of root system was higher when the ratio of NO3-/NH4+=3:1 while GS activity was higher when the ratio of NO3-/NH4+=1:3.3 On the NO3-/NH4+=3:1 nitrogen source,the NR and GS activity of leaf in wheat seedlings were higher when the ratio of NO3-/NH4+=3:1,but it was little compared with the highten of NR and GS activity of root.In addition,there were more Nitrate-N,amino-N and the soluble protein contents in leaves,and the content of soluble protein was much more.the content of chlorophyll and the net Pn of wheat seedling were higher when the ratio of NO3-/NH4+=3:1,while the highten of Gs was not marked.4.During different growth stages,the NR and GS activity of flag leaf were always at high level when the ratio of NO3-/NH4+=3:1,and the same as Nitrate-N,amino-N and the soluble protein contents,the transform frequncy in different nitrogen form was higher also. The increase of the content of chlorophyll and flag leaf area were higher when the ratio of NO3-/NH4+=3:1,and the promoting effects of this sort nitrogen source onΦPSⅡand ETR in flag leaf were significant5 On the same nitrogen source,all agronomic traits of Bar-transgenic wheat Nong4 were better than that of Bar-transgenic wheat Nong8,while the nitrogen metabolism enzyme activities in different organs of seedlings and flag leaf during growth stages was higher,and the photosynthetic characteristics have the same superiority.6 On the same nitrogen source,the yield and the index of nitrogen metabolism and photosynthetic characteristics in different organs of seedlings and flag leaf of Nong4 F1 hybrids during growth stages was better than that of Nong8 F1 hybridsIn summary,the ratio of NO3-/NH4+=3:1 is a better nitrogen source,which can promote the nitrogen metabolism,photosynthetic efficiency and the growth of wheat. Further more,it is more suitable for Nong4 in which Bar gene transferred into wheat D genome to Nong8,which Bar gene transferred into wheat B genome,and the same advantage is also manifested in their F1 hybrids.Therefore,we are rather than choose the higher ratio of NO3- as the nitrogen source when planting Bar-transgenic wheat,and Nong4-Bar gene into D genome was a better choice as father while breeding Bar-transgenic wheat hybrids.
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