小偃54和8602及其杂交后代小偃41和小偃81花后旗叶光合特性比较

Photosynthetic Characteristics after Anthesis in Flag Leaves of Wheat Cultivars Xiaoyan 54 and 8602 and Their Hybrids Xiaoyan 41 and Xiaoyan 81

通过测定叶绿体色素含量、叶片气体交换参数、叶绿素荧光及820nm吸收参数,比较了小偃54(XY54)和8602及其杂交后代小偃41(XY41)和小偃81(XY81)花后旗叶光合特性的差异。在开花期,4个品种(系)的叶绿素和类胡萝卜素的含量不同,基本表现为杂交后代高于双亲,且以XY81最高;8602品系的光合速率(Pn)和羧化效率(CE)最高,XY41品系的气孔导度(Gs)最低,而XY54品种的CE最低。4个小麦品种(系)的胞间CO2浓度(Ci)、K点可变荧光(FK)占FJ–FO荧光振幅的比率(Wk)、光系统II(PSII)最大量子效率(Fv/Fm)、电子传递到QA下游的概率(Ψo)、电子从系统间电子传递体传递给光系统I(PSI)受体侧电子受体的概率(δRo)、820nm相对可变透射光(ΔI/Io)、PSII的实际光化学效率(ΦPSII)和非光化学猝灭(NPQ)无显著差异。小麦开花后,XY54的叶绿素含量、Pn、Gs、CE、Fv/Fm、δRo及ΔI/Io的下降幅度和Wk的上升幅度显著大于其他3个品系,但Ci、Ψo、ΦPSII和NPQ与其他3个品系没有显著差异。8602和2个杂交后代的上述参数的变化趋势在整个发育期内基本相同。以上结果表明,与XY54相比,XY41和XY81的光合下降幅度较小,可能与它们的光合暗反应能力不同有关,而不是三者的叶绿素含量、气孔导度及光反应的能力不同所造成,杂交后代XY81和XY41可能遗传了8602品系较高的光合暗反应特性。

Wheat lines Xiaoyan 41 （XY41） and Xiaoyan 81 （XY81） are hybrid progenies of Xiaoyan 54 （XY54） and 8602, which show distinct differences from their parents in photosynthesis characteristics. In this study, the gas exchange, chlorophyll fluorescence, and 820 nm transmission in flag leaves after anthesis were compared between hybrids XY41 and XY81 and parents XY54 and 8602. At anthesis, contents of chlorophyll a, chlorophyll b, and carotenoids were higher in the hybrids than in the parents, especially in XY81. Photosynthetic rate （Pn） and carboxylation efficiency （CE） were the highest in 8602, whereas stomatal conductance （Gs） was the lowest in XY54, followed by XY41. The four cultivars had similar values of intercellular CO2 concentration （Ci）, ratio of variable FK to the amplitude FJ-FO （Wk）, maximum quantum yield of PSII （Fv/Fm）, efficiency that an electron moves to QA downstream （Ψo）, efficiency with which an electron from the intersystem electron carriers moves to electron acceptors in reduced end at the PSI acceptor side （δRo）, relative variable transmission at 820 nm （ΔI/Io）, actually photochemical efficiency of PSII （ΦPSII）, and nonphotochemical quenching （NPQ）. After anthesis, the decreases of pigment contents, Pn, CE, Gs, Fv/Fm, δRo, and ΔI/Io and the increase of Wk were larger in XY54 than in other cultivars. No differences were detected in Ci, Ψo, ΦPSII, and NPQ among cultivars, and these parameters varied similarly in 8602 and the hybrids during the whole developmental period tested. Compared with XY 54, XY41, and XY81 had slower decrease in Pn, and this resulted from the difference in dark reaction capacity rather than chlorophyll contents, stomatal conductance, and photosynthetic light reaction capacity. XY41 and XY81 might inherit the high dark reaction capacity from parent 8602.