深冬季节油松针叶过剩光能的耗散及光氧化防御研究

摘要

以辽宁省沈阳地区(41°82'N,123°56'E)深冬季节(1月末)油松小枝基部和顶部针叶为材料,测定吸收光谱和反射光谱、快速叶绿素荧光诱导动力学参数、叶绿素含量、光合速率和呼吸速率、细胞膜透性、丙二醛和过氧化氢含量以及抗氧化酶活性,探讨油松针叶在深冬低温下对过剩光能的耗散和光氧化保护机制.结果表明:深冬季节油松针叶的最大光化学量子产量(Fv/Fm)降低,仅达到0.11～0.12,单位横截面积捕获的光能(ABS/CS)和有活性的反应中心的密度(RC/CS)减少,热耗散成为过剩光能消耗的主要途径；光合作用停止,呼吸作用处于很低水平；相对电导率达到78％～85％,但丙二醛、过氧化氢含量和抗氧化酶活性都处于较低水平,因此,细胞膜透性增大可能不主要是活性氧引起的膜质过氧化作用的结果.研究发现,深冬季节的油松针叶生理状态难以满足目前所知的叶黄素循环运转所需要的生理条件.%The needles were taken from the top and base in twigs of Chinese pine (Pinus tabulaeformis) during the late winter (late January) in Shenyang city, Liaoning Province (41°82'N, 123°56'E) were used to determine the absorbance and reflectance spectra, the fast chlorophyll fluorescence induction dynamics parameters, chlorophyll contents, photosynthesis rate and respiration rate, relative electrolyte conductivity, MDA content,H2O2 content and antioxidative enzyme activity, in order to understand the mechanism of excess light energy dissipation and photooxidation protection the needles of Chinese pine under low temperature during the late winter.The results showed that the declines in maximum quantum yield of primary photochemistry (Fv/Fm)(only about 0.11-0.12), absorption flux per CS (ABS/CS) and density of PSII reaction centers (RC/CS).The photosynthesis was not detested, the respiration rate, MDA content,H2O2 content and antioxidative enzyme activity remained at a very low level.Relative electrolyte conductivity reached a very high level (about 78%~85%).These results suggest that the heat dissipation is the main pathway of excess light energy release; the increase in the membrane permeability is not mainly resulted by lipid peroxidation caused by reactive oxygen species.The results also imply that the needles of Chinese pine during the late winter can not supply the physiological conditions we have known for the xanthophyll cycle to run.