外源硒对干旱胁迫下烤烟叶绿素荧光特性和叶片化学成分的影响

摘要:为探讨外源硒对干旱胁迫下烤烟生长和品质的调控效应,研究了不同浓度外源硒(4 mg/kg和12 mg/kg)对干旱胁迫下烤烟叶片快速叶绿素荧光诱导动力学特性和烟叶化学成分的影响。JIP-test分析显示,干旱胁迫后O-J-I-P曲线中出现了明显的K点,且△K值表现为干旱+12 mg/kg硒处理干旱处理干旱+4 mg/kg硒处理,说明4 mg/kg硒处理能够有效缓解干旱对光合机构的损伤,而12 mg/kg硒处理则加剧了干旱胁迫的伤害。干旱胁迫下最大光化学效率(F_v/F_m)、性能指数(PI_(ABS)和PI_(total))、反应中心密度(RC/CS_m)、叶片单位面积吸收(ABS/CS_m)、捕获(TR_o/CS_m)和传递(ET_o/CS_m)的光能以及能量分配比率显著降低,而热耗散量子比率(φD_o)和单位面积的热耗散(DI_o/CS_m)显著升高。4 mg/kg硒处理通过降低PSⅡ反应中心的损伤,促进电子在PSⅡ和PSⅠ之间的传递,优化能量在PSⅡ反应中心的分配来稳定光合系统的结构和功能,而12 mg/kg硒处理则进一步放大了干旱胁迫对烤烟叶片光化学活性和光合性能的抑制。干旱胁迫造成光合色素含量降低和烟叶品质下降,4 mg/kg硒处理能够有效提高干旱胁迫下叶片叶绿素含量,提高烟叶钾、还原糖和总糖含量,改善烟叶品质,而12 mg/kg硒处理表现出与干旱胁迫的协同效应,进一步降低了干旱胁迫下烟叶质量。

Influences of Exogenous Selenium on the Chlorophyll Fluorescence Characteristics and Chemical Composition in Flue-cured Tobacco under Drought Stress

In order to explore the regulating effect of exogenous selenium on growth and quality of flue-cured tobacco under drought stress, this paper studied the effects of different concentration exogenous selenium (4 mg/kg and 12 mg/kg) on the rapid chlorophyll fluorescence induction kinetics and chemical components of flue-cured tobacco leaves under drought stress. JIP-test analysis showed that there was a significant K point in the O-J-I-P curve after drought stress, and the △K value showed that drought treatment + 12 mg/kg selenium > drought treatment > drought treatment + 4 mg/kg selenium. The results showed that 4 mg/kg selenium could effectively relieve the stress of photosynthetic organs under drought treatment, but 12 mg/kg selenium treatment aggravate the damage to photosynthetic organs under drought stress. The maximum photochemical efficiency (Fv/Fm), the performance index (PIABS and PItotal), the reaction center density (RC/CSm), the leaf absorption per unit area (ABS/CSm), the capture energy (TRo/CSm), the conversion energy (ETo/CSm) and the energy distribution ratio were significantly reduced, while the heat dissipation quantum ratio (φDo) and the heat dissipation per unit area (DIo/CSm) were significantly increased under drought stress. The addition of 4 mg/kg selenium could stabilize the structure and function of photosynthetic system by reducing the damage of PS reaction center, promoting the transmission of electrons between PSⅡand PSⅠ, optimizing the distribution of energy in PSⅡ reaction center. And the addition of 12 mg/kg selenium was further amplified the damage of drought stress on the photosynthetic activity and photosynthetic performance of flue-cured tobacco leaves. The addition of 4 mg/kg selenium could improve the chlorophyll content of leaves under drought stress, improve the content of potassium, reducing sugar and total sugar in tobacco leaves, thus improve the quality of tobacco leaves. And the addition of 12 mg/kg selenium could reduce the chlorophyll content, showing synergistic effect with drought stress, further reducing the quality of tobacco leaves under drought stress.