PEG渗透胁迫对不同品种大麦荧光参数的研究

Photosynthetic Mechanism for PEG Osmotic Stress in Different Varieties of Barley

采用盆栽试验,以西安91-2、甘啤3号和扬饲麦3号为材料,研究不同浓度PEG6000(5%、10%、15%、20%、25%和30%)渗透胁迫下大麦苗期叶片光能利用和能量耗散的影响。结果表明,随着PEG渗透胁迫的增加,3个大麦品种叶片叶绿素a含量、叶绿素b含量,最大荧光(Fm)、最大光化学效率(Fv/Fm)、实际光化学效率(PSⅡ)都有不同程度的降低,初始荧光(F0)、表观光合量子传递速率(ETR)、光化学淬灭系数(qP)、非光化学淬灭系数(NPQ)等则表现出增加的趋势。3个品种在低浓度的PEG处理下只是通过减少光能的利用和增加热耗散维持光合机构的稳定,但高浓度的PEG处理造成了光合机构的破坏,不同品种的表现不同。与甘啤3号相比,西安91-2各项生理参数值变化幅度小,与西安91-2相比,扬饲麦3号各项生理参数值变化幅度小。

The response of photosynthetic characteristics in three barley varieties （ Ganpi No. 3, Xian 91-2 and Yangsimai No. 3） with differ- ent drought resistance was studied by measuring chlorophyll fluorescence parameters under the condition of drought stress set with PEG（g）00 （5 % ,10 % ,15 % ,20 % ,25 % and 30 % ） in pots. The results showed that,with the increase of drought stress on the three barley varie- ties, the chlorophyll a, the chlorophyll b, the chlorophyll content, maximum fluorescence （ Fm ）, maximum photochemical efficiency （ Fn/ Fm ）, effective quantum yield （ φPS Ⅱ ） significantly decreased, but the initial fluorescence （ F0 ）, electron transfer rate （ETR） and photo- chemical quenching （qP） non-photoehemical quenching coefficient （NPQ） increased. Three varieties under the treatment of low concentra- tion PEG only maintained the steady of the photosynthetic apparatus by reducing the light energy use and improving heat dissipation,but high concentration treatment of PEG resulted in depredation of the phot^ynthetic apparatus. The change range of each parameter in Xian 91-2 was less than that in Ganpi No. 3 and Yangsimai No. 3 was less than that of Xian 91-2.