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以中国科学院西北高原生物研究所培育的4个高原春小麦品种为材料,结合光合色素含量、叶面积等光形态参数的测定,采用调制叶绿素荧光分析技术,研究了青海香日德农业区春小麦抽穗期旗叶远轴向光面和近轴背光面的PSⅡ光化学量子效率及对强太阳光的适应性.结果表明:高原314、高原363和高原584的旗叶多呈直立转披型,高原913因叶面积小而宽其旗叶多倾向直立型;4个品种春小麦的光合色素有较大差异,且与充分暗适应的PSⅡ最大光化学效率(Fv/Fm)呈正相关;全晴天中午时分旗叶远轴向光面光合作用的光抑制现象较严重,但下午随太阳光强的降低,准确20 min暗适应的Fv/Fm恢复很快,其PSⅡ反应中心属可逆失活;旗叶向光和背光部位间PSⅡ实际光化学效率(ΦPSⅡ)和PSⅡ有效光化学效率(Fv’/Fm’)的差异均达极显著,但两者的相对变化趋势截然相反,光化学猝灭系数(qP)和非光化学猝灭系数(NPQ)呈一致的变化趋势;尽管旗叶近轴背光面的ΦPSⅡ和qP均较低,但Fv’/Fm’明显较高,说明其潜在的PSⅡ激发能捕获效率仍较大.研究证明光合机构的光化学和非光化学猝灭过程可有效耗散强光下累积的过量激发能,高原春小麦品种对青藏高原的强太阳光辐射具有很强的适应性.
Four highland spring wheat cultivars cultivated by Northwestern Plateau Institute of Biology Chinese Academy of Sciences were used as materials. The photosynthetic pigment content, leaf area and other light morphological parameters were measured. The chlorophyll fluorescence analysis was used to study the heading date of spring wheat The photochemical quantum efficiency of PSⅡ and the adaptability to strong sunlight of axial and paraglips of the flag leaf were analyzed.The results showed that the flag leaf of plateau 314, plateau 363 and plateau 584 mostly showed upright turret pattern, The flag leaves of small and wide leaf areas tended to be upright. The photosynthetic pigments of four cultivars were significantly different, and positively correlated with the maximum photochemical efficiency (Fv / Fm) of PSII under full dark adaptation. However, with the decrease of sunlight intensity in the afternoon, Fv / Fm, which is dark-adapted at 20 min, recovered rapidly and the PSⅡ reaction center was reversibly inactivated. Between the flag leaf light and the backlight The differences of the actual photochemical efficiency of PSⅡ (ΦPSⅡ) and the effective photochemical efficiency of PSⅡ (Fv ’/ Fm’) were extremely significant, but the relative trend of the two was opposite. The values of photochemical quenching (qP) and non- The quasi-quenching coefficient (NPQ) showed a consistent trend. Although the ΦPSⅡ and qP of the flag leaf at the paraxial plane were lower, the Fv ’/ Fm’ was significantly higher, indicating that the potential capture efficiency of the PSⅡ excitation energy was still high The results show that the photochemical and non - photochemical quenching processes of photosynthetic apparatus can effectively dissipate excess excitation energy accumulated under intense light, and the plateau spring wheat varieties have strong adaptability to strong solar radiation over the Tibetan Plateau.