为明确不同施氮水平下烤烟群体叶面积指数的动态特征以及其与活动积温的关系,本研究以‘豫烟12’、‘秦烟96’、‘云烟87’为供试材料,设4个施氮水平,分别为N0(0 kg·hm-2)、N1(30 kg·hm-2)、N2(60 kg·hm-2)、N3(90 kg·hm-2),测定分析不同积温下烤烟群体叶面积指数及其动态特征,利用Curve Expert 1.40软件模拟并通过极限值法筛选建立了归一化积温模型,为烤烟群体光合结构的改善提供一定的理论依据。结果表明:(1)烤烟群体叶面积指数随移栽后活动积温呈偏度<0的单峰曲线变化,而随着施氮水平的增加呈现增加趋势,相同施氮水平下烤烟群体叶面积指数峰值大小表现为‘秦烟96’>‘云烟87’>‘豫烟12’。(2)有理函数模型y=(a+bx)/(1+cx+dx2)具有较好的模拟效果和生物学意义,能够很好地模拟烤烟群体相对叶面积指数随相对活动积温的变化,决定系数为0.9807**;利用2015年试验数据对模型进行检验,模拟准确度(以k表示)均大于0.958,精确度(以R2表示)均大于0.95,均方根误差RMSE均小于6.04%。(3)模型参数在某些品种和施氮水平之间表现出显著差异性,品种和施氮量主要通过调节模型参数b、c、d实现对整个模拟模型的调节。(4)烤烟群体相对叶面积指数变化速率曲线呈“N”型变化,反映了烤烟群体叶面积指数的实际变化趋势。(5)施氮量对模型次级参数具有调节作用,随着施氮量增加烤烟群体平均叶面积指数、叶面积指数最大值呈增加趋势,可作为烤烟群体叶面积指数氮素调节的重要参考指标。该模型的建立可以为烤烟群体发育动态监测以及烤烟群体叶片光合特性的提升提供理论依据和决策支持。 In order to clarify the dynamic characteristics of leaf area index and its relationship with accumulated temperature in flue-cured tobacco (Nicotiana tabacum L.) under different levels of nitrogen application, we used ’Yuyan 12’, ’Qinyan 96’ and ’Yunyan 87’ The nitrogen application rates were N0 (0 kg · hm-2), N1 (30 kg · hm-2), N2 (60 kg · hm-2) and N3 (90 kg · hm-2) The leaf area index and its dynamic characteristics of flue-cured tobacco were determined by Curve Expert 1.40 software. The normalized accumulated temperature model was established by the limit value method, which provided theoretical basis for the improvement of photosynthetic structure of flue-cured tobacco population. The results showed that: (1) Leaf area index of flue-cured tobacco showed a unimodal curve with skewness <0 after transplanting, but increased with the increasing of nitrogen application rate. Leaf area index Peak size of the performance of ’Qin tobacco 96’> ’Yunyan 87’> ’Yuyan 12’. (2) The rational function model y = (a + bx) / (1 + cx + dx2) has a good simulation effect and biological significance, and can well simulate the change of relative leaf area index with the relative accumulated temperature, The coefficient of determination was 0.9807 **. The model was tested by 2015 test data. The simulation accuracy (expressed in k) was greater than 0.958. The accuracy (expressed as R2) was greater than 0.95. The root mean square error RMSE was less than 6.04%. (3) The model parameters showed significant difference between some varieties and nitrogen application level. The variety and nitrogen application rate could adjust the whole simulation model by adjusting the model parameters b, c and d. (4) The change curve of relative leaf area index of flue-cured tobacco showed “N” type change, which reflected the actual change tendency of leaf area index of flue-cured tobacco. (5) The amount of nitrogen fertilizer had a regulatory effect on the secondary parameters of the model. With the increase of nitrogen application, the average leaf area index and the maximum leaf area index of flue-cured tobacco population tended to increase, which could be used as an important reference for nitrogen regulation of leaf area index of flue-cured tobacco index. The establishment of this model can provide theoretical basis and decision-making support for the dynamic monitoring of flue-cured tobacco population development and the improvement of photosynthetic characteristics of flue-cured tobacco leaves.