Net photosynthetic rate (PN) of tobacco plants grown with NH4-N as the only N source was the lowest all the times, while PN grown only with NO3-N was the greatest until 22nd day, and PN grown with both NO3-N and NH4-N (1: 1) was the greatest. Maximal photochemical efficiency of photosystem 2 (PS2), Fv/Fm, and actual quantum yield of PS2 under actinic irradiation (ΦPS2) in plants grown with only NH4-N were greatest at early stage and then decreased and were smaller than those of other treatments. Photochemical quenching coefficient (qP) and non-photochemical quenching coefficient (qNP) in the NH4-N plants were the greatest at all times. Hence excessive NH4-N can decrease not only photochemical efficiency but also the efficiency of utilization of photon energy absorbed by pigments for photosynthesis. Therefore, excessive NH4-N is a hindrance to photosynthesis of flue-cured tobacco. On the other hand, tobacco cultured with an appropriate mixture of NO3-N with NH4-N can sufficiently utilize photon energy and increase the efficiency of energy transformation.

Four AP2/EREBP genes encoding putative ethyleneresponsive element binding factor (ERF)/AP2 domains were cloned from Brassica napus, and these genes could be induced by low temperature, ethylene, drought, high salinity, abscisic acid and jasmonate treatments. These four genes, named BnDREBIII-1 to BnDREBIII-4, were highly homologous and the 37th amino acid was the only difference among their ERF/AP2 domains. BnDREBIII-1 was demonstrated to be able to bind to both dehydration-responsive element and the GCC box and transactivate the expression of downstream genes, while BnDREBIII-4 could bind neither. Further results suggested that Ala37 might play a crucial role in the DNA binding or the stability of the ERF/AP2 domain.

通过不同氮素形态配比盆栽试验，研究了K326中部叶不同发育时期氮代谢的相关酶即硝酸还原酶 (NR)、谷氨酰胺合成酶 (GS) 和碳代谢的关键酶即转化酶 (Inv)、蔗糖合成酶 (SS)、蔗糖磷酸合成酶 (SPs)活性变化。结果表明：硝酸还原酶随硝态氮比例的增加酶活性呈上升趋势,，而谷氨酰胺合成酶活性的变化趋势则与之相反；转化酶和蔗糖合成酶对烟草叶片生长发育的作用时期不同，即转化酶在烟草叶片发育中期，蔗糖合成酶在叶片发育后期。在云南玉溪砂红壤上以配施60％硝态氮复合肥有利于烟叶中碳代谢，而在水稻土上以配施40％硝态氮复合肥有利于烟叶中碳代谢。铵态氮比例过大不利于叶片碳氮代谢的适时转化。

采用水培方法研究了不同形态氮紊和饼肥浸提液对烤烟光合生理特性的影响。结果表明，纯铵态氮 (T1) 处理的烤烟光合速率、气孔导度、蒸腾速率、胞间CO2浓度处于最低水平；培养20 d后，铵态氮与硝态氮为1：1的处理各项光合生理指标均处于较高水平，24 d时的光合速率分别是其他处理的1.2—1.8倍；配用饼肥浸提液后。在一定程度上缓解了纯铵态氮对光合生理特性的不利影响。