3个烤烟品种净光合速率与生理生态因子的关系

以3个烤烟品种（K326，JY-2-03，吉烟九号）为试材，通过主成分分析和通径分析方法探讨净光合速率与生理生态因子的关系．结果表明，烤烟净光合速率（Pn）在整个生长期内变化曲线呈“抛物线”型；光合有效辐射（PAR）、蒸腾速率（Tr）、气孔导度（Gs）均呈单峰曲线变化，均与Pn变化相似，呈正相关；而胞间CO2浓度（Ci）和大气CO2浓度（Ca）呈“U”型变化．主成分分析结果表明，起主导作用的生理因子是Gs，其次是Tr和Ci；田间生态因子中起主导作用的是大气温度（Ta），此外，PAR、叶片温度（TL）及大气相对湿度（RH）也对3个品种的Pn有较大影响．通径分析结果表明，Gs、Tr和TL、PAR是烤烟Pn的主要生理和生态贡献因子，但不同品种的次要影响因子不尽相同．

Relationship between net photosynthetic rate and its physio-ecological factors of the three tobacco varieties

Three varieties of tobacco （K326, JY-2-03, Jiyan No. 9） were studied about the relationship between the Pn and its physio-ecological factors by path analysis and principal components. The results showed that in the whole growth period the Pn curve was ＂parabolic＂ type; photosynthetic active radiation （PAR）, transpiration rate （Tr）, stomatal conductance （Gs） all appeared as single peak curves and there were positive relationships between PAR , Tr ,Gs and Pn ; while the intercellular CO2 concentration （Ci） and atmospheric CO2 concentrations （Ca） changes as ＂U＂-type. Principal component analysis showed that Gs played a leading role in the physiological factors, followed by the Tr and Ci; the atmospheric temperature （Ta） play a leading role in the field of ecological factors. In addition, PAR, Leaf temperature （TL） and relative humidity （RH） also have a greater impact on the Pn of three species. Path analysis showed that Gs, Tr and TL, PAR are the main physiological and ecological.