减氮增密对烤烟光合特性及烟叶结构的影响

[目的]探讨减氮增密措施对烤烟（Nicotiana tabacum L.）光合特性和烟叶结构的影响，为生产上减少氮肥施用量，优化烟叶结构提供理论依据。[方法]以烤烟品种‘云烟87’为材料，设置4个处理：传统种植模式CK（种植密度13 500株？hm-2、施氮量150 kg？hm-2）、减氮模式T1（13 500株？hm-2、施氮量135 kg？hm-2）、增密模式T2（16 500株？hm-2、施氮量150 kg？hm-2）和减氮增密模式T3（16 500株？hm-2、施氮量135 kg？hm-2），研究不同部位烟叶的光合特性、物理特性及烤后烟叶经济性状的响应规律。[结果]T1、T2和T3处理均显著降低了烤烟中上部叶净光合速率，降低幅度为8.1%~30.7%，但对下部叶净光合速率影响却不一致，其中T1处理净光合速率降低，T2处理净光合速率增加，而T3处理则对净光合速率影响不显著。T3处理的烤烟上部叶叶面积、叶片厚度、叶质重分别降低了25.8%、7.3%和19.4%，对开片度没有显著影响，而下部叶的叶质重则提高了8.9%，含梗率降低了8.6%。T3处理烤后烟叶产量、产值、均价、中上等烟比例分别提高了4.7%、0.6万元？hm-2、1.4元？kg-1、4.7%；在烟叶结构方面，上部叶比例显著下降，中下部叶比例有所提高，尤其是中部叶比例提高了6.8%。施氮量和密度互作对烟叶的光合特性、物理性状和经济性状等指标均有不同程度的影响，下部叶的光合特性受密度影响较大，物理特性受施氮量和密度互作影响较大。[结论]适当的减氮增密组合措施有利于协调各部位烟叶净光合速率，优化烟叶结构，提高烟叶可用性。
[Objectives]The objectives of this study were to understand the effects of nitrogen-saving and density-increasing on photosynthetic characteristics and leaf structure of flue-cured tobacco(Nicotiana tabacum L.),and to provide theoretical basis for reducing the amount of nitrogen fertilizer and optimizing the structure of tobacco leaves in production.[Methods]The flue-cured tobacco variety ‘Yunyan 87’ was planted at traditional planting pattern CK(13 500 plants？hm-2,150 kg？hm-2 nitrogen level),nitrogen-saving pattern T1(13 500 plants？hm-2,135 kg？hm-2 nitrogen level),density-increasing pattern T2(16 500 plants？hm-2,150 kg？hm-2 nitrogen level),nitrogen-saving and density-increasing pattern T3(16 500 plants？hm-2,135 kg？hm-2 nitrogen level). The response laws of the photosynthetics and the physical characteristics of tobacco leaves in different parts,and the response laws of the economic traits of tobacco leaves after baking were studied.[Results]The results showed that the net photosynthetic rate of the middle and upper leaves of flue-cured tobacco reduced by 8.1%-30.7% in T1,T2 and T3 treatments. But the effect of different planting patterns on the lower leaves was not the same,wherein the net photosynthetic rate of the lower leaves reduced in T1 treatment,increased in T2 treatment,but it had no significant changes in T3 treatment. In terms of coordinating the physical and economic characteristics of tobacco leaves,the effects of T3 treatment were the most significant. In T3 treatment,the leaf area,the leaf thickness and the specific leaf weight of the upper leaves reduced by 25.8%,7.3% and 19.4% respectively,and the leaf openness of the upper leaves had no significant changes;while the specific leaf weight of the lower leaves increased by 8.9%,the stem ratio of the lower leaves reduced by 8.6%. At the same time,the output,the output value,the average price