烤烟叶片光合速率日变化特征及其影响因素分析

Study on Diurnal Variation Characteristics of Photosynthetic Rate in Tobacco Leaves and Its Influence Factors

为揭示不同生态环境因子对烤烟净光合速率变化的影响,在昭通市选择3个不同种植区进行大田试验。在烤烟成熟初期,利用Li6400便携式光合作用仪测定了昭阳、巧家、镇雄3个不同试验点K326、云烟87、云烟97、云烟99、云烟203、KRK26、PVH19和红花大金元(红大)8个烟草品种的净光合速率和环境因子,分析了不同生态环境下生理生态因子对烤烟净光合速率的影响。结果表明,昭阳和镇雄各品种烟草净光合速率(P_(n))日变化为“双峰”型;巧家云烟87、云烟97、云烟203和云烟99的P_(n)日变化为“三峰”型,其他品种的P_(n)日变化为“双峰”型。3个试验点PVH19、云烟99和K326的净光合速率(P_(n))日平均值均较高,而云烟87和云烟97的均较低。3个试验点各品种烟草的P_(n)与G_(s)呈显著正相关,各品种烟草的光合作用均是气孔决定型。太阳光合有效辐射(PAR)和空气温度(T_(a))是昭阳烟草Pn的主要决定变量,叶面饱和水汽压亏缺(VPD)和空气相对湿度(RH)是主要的限制变量;RH对巧家多数品种的Pn起决定作用,PAR、T_(a)和VPD等是Pn的主要限制变量;镇雄PAR是P_(n)的主要决策变量,VPD、RH和T_(a)主要起限制作用。

To explore the impacts of different ecological factors on the change of net photosynthetic rate of tobacco,field experiments were carried out in three different growing areas in Zhaotong City.The net photosynthetic rates(P_(n))and environmental factors of eight tobacco varieties such as K326,Yunyan87,Yunyan97,Yunyan99,Yunyan203,KRK26,PVH19 and Honghuadajinyuan(Hongda),which are planted under different ecological environments of Zhaoyang,Qiaojia and Zhenxiong in Zhaotong,were measured by Li6400 portable photosynthetic instrument in the maturation stage of tobacco.The effects of eco-physiological factors on P_(n) of tobacco in different ecological environments were analyzed.The results showed that diurnal variations of net photosynthetic rates of tobacco in Zhaoyang and Zhenxiong are in bimodal patterns.The diurnal P_(n) of Yunyan87,Yunyan97,Yunyan203 and Yunyan99 in Qiaojia varies in a triple-peak pattern,and the others’diurnal P_(n) are under the bimodal patterns.The daily average P_(n) of PVH19,Yunyan99 and K326 is higher than that of Yunyan87 and Yunyan97 at the three experiment sites.The P_(n) of the tobacco varieties is significantly positively correlated with G_(s) at the three experiment sites,and the photosynthesis of all tobacco varieties is stomatal determinant.PAR and T_(a) are the main decisive factors on P_(n) in Zhaoyang with VPD and RH as the major restriction factors.RH has a decisive effect on P_(n) in most varieties of tobacco in Qiaojia,but PAR,T_(a) and VPD are the main restriction factors on Pn.PAR is the main decisive factor on Pn in Zhenxiong,while VPD,RH and T_(a) are restrictive on Pn.