持续NaCl胁迫对西洋菜叶绿素荧光参数与电子传递的影响

Effects of Continued NaCl Stress on Chlorophyll Fluorescence Parameters and Electron Transport of Nasturtium officinale R. Br.

为探索持续Na Cl胁迫对西洋菜叶绿素荧光参数与电子传递的影响,以西洋菜为材料,研究了不同浓度Na Cl(1,2,3,4 g/kg)持续处理下幼苗生长、叶绿素含量及叶绿素荧光参数变化,结果表明,当Na Cl浓度小于3 g/kg时,西洋菜随着盐处理浓度的增大,叶绿素含量升高,初始荧光(Fo)增大,最大荧光(Fm)、潜在光化学活性(Fv/Fo)、光系统Ⅱ(PSⅡ)最大光化学效率(Fv/Fm)减小,叶片转化光能的能力降低;实际量子产量Y(Ⅱ)下降,非光化学猝灭(NPQ)上升,叶片通过调节热耗散维持较高的光化光能量分配;光化学猝灭(q P)与PSⅡ电子传递速率(ETR)降低,质体醌(QA)趋于被还原状态,电子传递受到抑制。当Na Cl浓度达4 g/kg时,PSⅡ受损,QA过分还原,电子传递明显受到抑制,能量转化、传递与分配不能正常进行,根冠比较对照下降62.5%,植株长势明显减弱。由此说明,西洋菜对持续Na Cl胁迫的耐受浓度是3 g/kg。

Our objective was to explore the effects of continued Na Cl Stress on chlorophyll fluorescence parameters and electron transport of Nasturtium officinale seedlings. Nasturtium officinale seedlings were treated with continued Na Cl（ 0,1,2,3,4 g / kg） in plastic pots with soil. We studied the effects of continued Na Cl on growth,chlorophyll content and chlorophyll fluorescence parameters after 60 days. The results indicated that with the increase of Na Cl concentration in the range of 1- 3 g / kg,Chlorophyll content and minimal fluorescence（ Fo） increased,while maximum fluorescence（ Fm）,potential photochemical efficiency（ Fv / Fo）,photochemical maximum efficiency of PSⅡ（ Fv /Fm） and the ability of leaves to transform energy decreased; Moreover,the actual quantum yield Y（ Ⅱ） decreased,while non-photochemical quenching coefficient（ NPQ） increased,and leaves maintained a high actinic light energy distribution by adjusting the heat dissipation; In addition,photochemical quenching coefficient（ q P）and electron transport rate（ ETR） decreased,plastoquinone（ QA） tended to be restored state,and the electron transfer was inhibited. 4 g / kg Na Cl treatment caused the damage of PSⅡ,meanwhile,QAwas restored excessively,electron transfer was obviously inhibited,energy conversion,transmission and distribution could not work normally,root to shoot ratio was decreased by 62. 5% compared to the control,and the growth of Nasturtium officinale was weakened significantly. All results suggested that the tolerance concentration of continued Na Cl stress on Nasturtium officinale R. Br. was 3 g / kg.