【摘要】 褪黑素是植物响应多种非生物胁迫的一种重要的保护因子。为了明确褪黑素对盐胁迫下番茄叶片光合机构功能的影响,以番茄品种‘辽园多丽’为实验材料,利用150mmol·L^-1NaCl水培方式做盐处理,并设150μmol·L^-1的褪黑素预处理组,研究外施褪黑素对盐胁迫下番茄叶片PSII的影响。结果表明:盐胁迫导致番茄叶片叶绿素含量降低、光合作用减弱,PSII活性的降低主要表现为PSII电子供体侧OEC的活性降低及PSII电子受体侧电子由QA向QB的传递过程受阻,特别是PSII电子供体侧对盐胁迫的敏感程度明显大于受体侧,PSII中D1和Psb O蛋白均发生降解,表明番茄叶片PSII反应供体侧和受体侧受到严重损伤; PSII反应中心对光能的捕获及利用能力降低,单位面积有活性反应中心的数量和吸收的光能用于电子传递的能量比例均有不同程度的下降;外施褪黑素使叶绿素含量和光合速率的降低幅度明显减小,褪黑素通过平衡PSII的供体侧、受体侧和反应中心的电子传递来缓解盐胁迫对番茄PSII造成的伤害,提高番茄的耐盐性。更多还原

【Abstract】 Melatonin( MT) is an important factor protecting plants from a variety of abiotic stresses. To explore the effect of MT application on photosynthetic function of Solanum lycopersicum L.cv. We used 150 mmol · L-1NaCl as salt stress and 150 μmol · L-1MT as pretreatment to explore the effect of MT on photosystem II in tomato( Liaoyuandouli) leaves under salt stress.The results showed that salt stress reduced chlorophyll content,photosynthetic function. The decrease of PSII activity was mainly due to the reduction in the activity of oxygen-evolving complex( OEC) on donor side of PSII and the blockage of electron transfer from QAto QBon receptor side of PSII. The donor side of PSII was more sensitive to salt stress than the receptor side of PSII. In addition,the ability of PSII reaction center to harvest and utilize light energy,the concentration of reaction centers( expressed as per unit leaf area) and the ratio of excitation energy to absorbed energy were all decreased. However,MT application significantly reduced the magnitude of chlorophyll content reduction and photosynthetic rate. MT application can alleviate the damage on tomato caused by salt stress through balancing the electron transfer on donor side,receptor side and reaction center of PSII.更多还原