摘要
以平邑甜茶盆栽苗为试材,通过同步测定叶片的叶绿素瞬时荧光、延迟荧光及820 nm光反射,研究了干旱胁迫对两个光系统(PSII和PSI)和光合电子传递链的伤害,以及根部施硅对平邑甜茶光合功能的改善作用。结果显示,中度干旱胁迫(40%RSWC)下,PSII原初光化学反应的最大量子产额(TRo/ABS),PSII捕获的电子从Q_A传递给Q_B的概率(ETolTRo),远红光下测定的MR/MRo最大下降振幅(△MR_(FR))下降,而PSII单位反应中心吸收的光能(ABSrRC)上升,表明干旱导致整个光合电子传递链(包括PSII和PSI)均出现不同程度的伤害。干旱胁迫下,硅处理的MR/MRo下降斜率(V_(PSI))、非光化学猝灭(NPQ)显著大于对照,延迟荧光的I_1和I_2点比值(I_2/I_1)低于对照,表明硅处理可提高干旱胁迫下PSI的活性,提高环PSI的电子传递和PSII天线热耗散的能力。总之,硅处理显著缓解了干旱胁迫对PSII和PSI的伤害程度,根部施硅通过提高平邑甜茶幼苗PSI和PSII的活性,促进PSI环式电子传递,提高了平邑甜茶幼苗的抗旱性。
Prompt fluorescence,delayed fluorescence and modulated light reflection at 820 nm in Malus hupehensis leaves were measured simultaneously,to explore the damage of drought stress on photosynthetic apparatus and the improvement of photosynthetic functions by application of silicon through root.The results showed that：under moderate drought stress（40% RSWC）,maximum quantum yield of primary PSII photochemistry（TRo/ABS）,probability with which a PSII trapped electron is transferred from QA to QB（ETo/TRo）,the maximum MR/MRo amplitude under far-red light（△MK（FR）） significantly decreased,while average absorbed photon flux per PSII reaction center（ABS/RC） increased,indicating that the whole electron transport chain including the two photosystems was affected by drought.Under drought stress,application of silicon through root could increase maximum descending slope of MR/MRo under actinic light（V（PSI）） and non-photochemical quenching（NPQ）,and reduced the ratio of delay fluorescence at I2 and I1 step（I2/I1）,indicating that application of silicon could increase the activity of PSI,and improve the cyclic electron transport around PSI,as well as the non-photochemical quenching at PSII antenna.In summary,application of silicon alleviated the photo-damage of both PSII and PSI under drought,it might play a key role in improving drought tolerance of Malus hupehensis through increasing the activities of PSI and PSII,and improved the cyclic electron transport around PSI.
出处
《植物生理学报》
CAS
CSCD
北大核心
2015年第12期2231-2238,共8页
Plant Physiology Journal
基金
山东省自然科学基金(ZR2012CM039)
泰山学者建设工程专项经费
作物生物学国家重点实验室开放基金(2012KF05)
关键词
平邑甜茶
干旱
硅
瞬时荧光
延迟荧光
820
nm光反射
Malus hupehensis
drought
silicon
prompt fluorescence
delayed fluorescence
modulated light reflection at 820 nm
