作 者 ：贺国强, 张鹏飞, 张会慧, 陈页磊, 王佳旭, 王长坤, 元野
期 刊 ：核农学报 2016年 30卷 6期 页码：1234-1239
Keywords:low temperature, high light intensity, flu-cured tobacco, chlorophyll fluorescence,
摘 要 ：为探明我国北方烟草移栽期温度和光强等限制因素对烟草光合作用的影响,本试验通过模拟我国北方早春烟草移栽期的光温条件,分别设置低温+弱光(8±2 ℃,200 μmol·m-2·s-1)和低温+强光(8 ±2 ℃,1 000 μmol·m-2·s-1)处理,以常温弱光(25 ℃,200 μmol·m-2·s-1)为对照(CK),研究了烟草叶片在低温胁迫后不同光强下的光合及叶绿素荧光参数光响应特点。结果表明,与CK相比,处理组烟草叶片的光合碳同化能力显著下降,表现为表观量子效率(AQY)、暗呼吸速率(Rd)和光能利用生态幅降低以及光饱合时的最大净光合速率(Pmax)降低,其中,低温+强光处理对烟草叶片光合气体交换参数的抑制作用显著大于低温+弱光处理;烟草叶片吸收光能用于光化学反应的比例显著下降,但烟草叶片的PSⅡ最大光化学效率(Fv/Fm)均维持在0.8以上。低温+弱光下烟草叶片主要通过将光能分配到依赖于类囊体膜两侧质子梯度的叶黄素循环(ФNPQ增加)以保护PSⅡ免受过剩光能的破坏,但低温+强光下烟草叶片的ФNPQ虽显著大于CK,但较低温+弱光处理却显著降低,此时,烟草叶片主要将过剩光能以荧光和热能的形式进行耗散(Фf,D增加)。综上所述,低温后强光是导致烟草叶片光合能力受到抑制的重要诱导因素之一。该研究结果为烤烟移栽期的合理调控提供了基础数据。
Abstract:In order to determine the influence of temperature and light intensity on photosynthesis of tobacco plants during transplanting stage in Northern China, with treatments of low temperature+ low light intensity(8 ±2 ℃, 200 μmol·m-2·s-1), low temperature+ high light intensity(8 ±2 ℃, 1 000 μmol·m-2·s-1) and the control (CK) (25 ℃, 200 μmol·m-2·s-1), the photosynthetic and chlorophyll-fluorescence parameters of the tobacco leaves were determined under different light intensities and pre-cultivation of low temperature through simulating the light-temperature condition of early spring in Northern China. Results showed that both of low and high light treatments dramatically reduced the photosynthetic carbon assimilation ability of tobacco leaf after low temperature growth, which were characterized with the reduced apparent quantum yield (AQY) and dark respiration rate (Rd). In addition, low temperature treatment reduced ecological amplitude of light utilization and maximum net photosynthetic rate (Pmax). The inhibiting effect of low temperature + high light intensity on the photosynthetic parameters of tobacco leaf was significantly higher than that of low temperature + low light intensity. The proportion of light absorption for photochemical reaction of low-temperature-grown tobacco leaf with both low and high intensity light treatments were significantly lower than that of control. However, both of their PSⅡ maximal photochemical efficiency (Fv/Fm) maintained above 0.8. At the condition of low temperature + low light intensity, light energy captured by the tobacco leaf was mainly distributed to xanthophyll cycle (ФNPQ), which depended on the proton gradient on both sides of thylakoid membrane, to protect PSⅡ from the destruction of excess light energy. The ФNPQ of the tobacco leaf with low temperature + high light intensity was significantly higher than that of the control, however, the ФNPQ of the tobacco leaf with low temperature + low light intensity was significantly lower than that of the control, and tobacco leaf mainly dissipated excess light energy in the form of fluorescence and thermal energy. Therefore, high light intensity was one of the important factors inducing inhibition of photosynthetic capacity of tobacco leaf with low temperature growth. This study provides some basic data for reasonable regulation of flue-cured tobacco during transplanting period.