烟草净光合速率日变化与影响因子的PLSR分析

Diurnal Variation of Net Photosynthetic Rate of Tobacco and PLSR Analysis of the Influence Factors

通过研究一天中不同时间段环境因子(光照强度、环境CO2浓度、气温、相对湿度)和生理因子(叶片温度、胞间CO2浓度、气孔导度和蒸腾速率)对烟草叶片净光合速率日变化的作用,为提高烟草的产量,改进大田栽培技术提供参考.利用Li-6400型光合作用测定系统,测定打顶后的烟草叶片净光合速率及其影响因子的日变化,利用偏最小二乘回归(PLSR)分析方法,分5个时间段讨论各个环境、生理因子对净光合速率日变化的影响.烟草的净光合速率日变化曲线为双峰,峰值分别在出现10∶00和15∶00,13∶00出现低谷.PLSR分析发现,不同时间段,净光合速率所受影响因子存在很大差异;该方法有效地解决了各影响因子之间的多重相关性,合理地解释了不同时间段净光合速率的变化规律及其对影响因子的响应.

：For increasing the yield and improving cuhivation techniques, the relationship between the diurnal variation in the net photosynthetic rate （Pn） and the influencing factors of Nicotiana tabacum L. in sunny days were studied. The photosynthetic characteristics in leaves of N. tabacum after topping were measured by Li-6400 portable photosynthesis system, including Pn, light intensity （PARe） , CO2 concentration （CO2） , temperature （Tair）, relative humidity （RH）, leaf temperature （Tleaf）, intercellular CO2 concentration （Ci）, stomatal conductance （Cond）, and transpiration rate （Trmmol）. Partial least-Squares regression （PLSR） analysis was applied to explore the effect of environmental and physiological factors on Pn in 5 stages of a single day. The curve of diurnal variation of Pn in leaves of N. tabacum had two peaks, at 10：00 and 15：00 respectively, and the main factors affecting Pn varied at different time. The photosynthesis of N. tabacum was affected by various factors in different time during a day. 5 regression models were established by using PLSR method, showing high fitting precision and good reliability, and they gave reasonable explanation on variation rule of Pn and its response to the influencing factors.