二氧化钛喷施剂对烤烟上部烟叶光合作用和叶绿素荧光参数的影响

摘要

[目的]探讨二氧化钛喷施剂对烤烟上部烟叶光合作用及叶绿素荧光参数的影响,为提高上部烟叶的可用性提供参考.[方法]以溶胶–凝胶法特制的二氧化钛为材料,研究了不同浓度和配方的喷施剂对成熟期上部烟叶光合色素含量、光合生理指标及叶绿素荧光参数的影响.[结果]二氧化钛喷施剂延缓了上部烟叶中叶绿素和类胡萝卜素的降解速度.二氧化钛喷施剂对上部烟叶的光合作用和叶绿素荧光参数影响显著,喷施剂降低了上部烟叶的净光合速率、气孔导度、蒸腾速率,提高了胞间二氧化碳浓度,对叶温的影响不明显;喷施剂处理的PSⅡ最大光化学效率(Fv/Fm)、PSⅡ潜在活力(Fv/Fo)、光化学淬灭系数(qP)均高于清水对照处理,初始荧光(Fo)、非光化学淬灭系数(NPQ)低于清水对照处理.二氧化钛和二氧化钛复合氧化石墨烯2种喷施剂对光强的吸收效能均以质量浓度为0.45 g·L–1的喷施处理表现最好.[结论]喷施二氧化钛的烤烟上部烟叶在一定程度上能够吸收紫外线,其中,二氧化钛复合氧化石墨烯喷施剂对光强的吸收效果较好;喷施剂作用于烟叶的光能吸收效果有一定浓度阈值.%[Objective]To explore the effect of TiO2spraying agent on photosynthesis and chlorophyll fluorescence parameters of upper tobacco leaves,and provide a reference for improving the availability of upper tobacco leaves.[Method]TiO2spraying agent was preparated by means of sol-gel method.The effects of different concentrations and formulas of TiO2spraying agent on photosynthetic pigment content,photosynthetic physiological indexes and chlorophyll fluorescence parameters of upper tobacco leaves at maturity were studied.[Result]TiO2spraying agents retarded the degradation rates of chlorophyll and carotenoid of upper tobacco leaves.The spraying agents reduced photosynthetic rate,stomatal conductance and transpiration rate of upper tobacco leaves,increased the intercellular CO2concentration in upper tobacco leaves,but leaf temperature was unaffected.Photosynthesis and chlorophyll fluorescence parameters of upper tobacco leaves were significantly affected by TiO2spraying agents.Compared with the spraying water control,the spraying agents increased Fv/Fm,Fv/Foand qP,and decreased Foand NPQ.The absorption efficiency of light intensity of tobacco leaves sprayed titanium dioxide or titanium dioxide composite graphene was the best at the concentration of 0.45 g·L–1.[Conclusion]Tobacco leaves can absorb ultraviolet(UV)to a certain extent,and the efficiency of spraying titanium dioxide composite graphene was better.There was a threshold of spraying agent concentration for light absorption efficiency.