中文摘要：

【目的】根系作为吸收水分和养分的重要器官,其生理功能的强弱对烟草地上部分的生长发育有重要的影响。本研究分析磷施用量对烤烟不同生育期根系生理和叶片光合生理的影响,初步阐明磷素对烤烟生长的生理效应,明确烤烟品质形成的生理基础,为生产中合理施磷提供一定的参考。【方法】2014年在河南农业大学采用盆栽土培试验,设置四个处理,各处理P2O5用量分别为0（CK）、3.5（T1）、7.0（T2）和10.5 g/plant（T3）,N用量为3.5g/plant,N∶K2O=1∶3。在烤烟不同生育时期测定各处理烟株的根系活力、根系总吸收表面积和活跃吸收表面积等根系生理指标以及中部叶的叶面积、叶绿素含量和叶片的光合指标。【结果】在整个生育期内,T2处理烟株的根系活力强、根系总吸收表面积和根系活跃吸收表面积大。团棵期（移栽后30 d左右）随施磷量的增加,上述根系生理指标及中部叶叶面积、叶绿素含量不断增加,T3处理显著高于不施磷处理;成熟期（移栽后90 d左右）T3处理叶片的叶绿素含量较其他处理下降更快。随生育期的推进,各处理叶片的净光合速率、蒸腾速率、气孔导度和胞间CO2浓度均呈现先升后降的变化趋势,在移栽后60 d达到最大值。与其它处理相比,T2处理叶片的净光合速率、蒸腾速率和气孔导度在整个生育期内均最大,且在移栽后60 d时显著高于CK处理。根冠比随生育期的推进呈波动变化,但整体表现出上升的趋势。在整个生育期内,T3处理的根冠比最大,其次为CK,T1、T2处理的根冠比相对较小。【结论】施用P2O510.5 g/plant的烟株在团棵期快速生长及成熟期叶绿素含量迅速下降的现象证明,在一定范围内,充足的磷素供应能促进烟株生育前期根系发育、叶片扩展,生长后期烟叶适时落黄。磷用量对叶片光合性能和烟株根冠比的作用证明,磷素对叶片光合性能的促?

英文摘要：

【Objectives】Root is the vital organ for absorbing water and nutrients. Its physiological intensity plays a very important role in the growth of aerial parts. In this research,the effects of different phosphorus levels on root physiological and leaf photosynthetic characteristics of flue-cured tobacco at different growth stages were analyzed to clarify the physiological effect of phosphorus on the growth of flue-cured tobacco,to illustrate the formation mechanism of its superior quality and provide some references for reasonably application of phosphorus in tobacco production.【Methods】Four phosphate levels were designed in a pot experiment in Henan Agricultural Universityin 2014. The four levels were P2O5： 0（ CK）,3. 5（ T1）,7. 0（ T2） and 10. 5 g /plant（ T3）. In each pot,3. 5 g N and 10. 5 g K2 O were applied. Root physiological traits and leaf morphological and physiological indexes were investigated at different growth stages of flue-cured tobacco. 【Results】Higher root activity,total root absorption area,root active absorption area and the net photosynthesis rate of middle leaf in the whole growth period were achieved in T2 treatment than in other ones. With increasing of the phosphorus supply levels,all the root physiological traits,middle leaf areas and the contents of chlorophyll increased at the knee-high stage and the increase in T3 treatment was higher than CK significantly. The leaf chlorophyll content declined faster in T3 treatment than in other ones at the mature stage. For all treatments,the net photosynthetic rate,transpiration rate,stomatal conductance and intercellular CO2 concentration of tobacco leaf were firstly increasing and then decreasing along with the elongation of growth period and all the indexes above reached a maximum at 60 days after transplanting. The leaf net photosynthetic rate,transpiration rate and stomatal conductance of T2 were all the highest in the whole growth period and the differences with those in CK were significant at 60 days after transplant