Shi Sheng-Bo, Chen Wen-Jie, Shi Rui, Li Miao, Zhang Huai-Gang, Sun Ya-Nan
Ying Yong Sheng Tai Xue Bao. 2014 Sep;25(9):2613-22.
Taking four wheat varieties developed by Northwest Institute of Plateau Biology, Chinese Academy of Sciences, as test materials, with the measurement of content of photosynthetic pigments, leaf area, fresh and dry mass of flag leaf, the PS II photochemistry efficiency of abaxial and adaxial surface of flag leaf and its adaptation to strong solar radiation during the period of heading stage in Xiangride region were investigated with the pulse-modulated in-vivo chlorophyll fluorescence technique. The results indicated that flag leaf angle mainly grew in horizontal state in Gaoyuan 314, Gaoyuan 363 and Gaoyuan 584, and mainly in vertical state in Gaoyuan 913 because of its smaller leaf area and larger width. Photosynthetic pigments were different among the 4 varieties, and positively correlated with intrinsic PS II photochemistry efficiencies (Fv/Fm). In clear days, especially at noon, the photosynthetic photoinhibition was more serious in abaxial surface of flag leaf due to directly facing the solar radiation, but it could recover after reduction of sunlight intensity in the afternoon, which meant that no inactive damage happened in PS II reaction centers. There were significant differences of PS II actual and maximum photochemical efficiencies at the actinic light intensity (ΦPS II and Fv'/Fm') between abaxial and adaxial surface, and their relative variation trends were on the contrary. The photochemical and non-photochemical quenching coefficients (qP and NPQ) had a similar tendency in both abaxial and adaxial surfaces. Although ΦPS II and qP were lower in adaxial surface of flag leaf, the Fv'/Fm' was significantly higher, which indicated that the potential PS II capture efficiency of excited energy was higher. The results demonstrated that process of photochemical and non-photochemical quenching could effectively dissipate excited energy caused by strong solar radiation, and there were higher adaptation capacities in wheat varieties natively cultivated in Qinghai-Tibetan Plateau area.
以中国科学院西北高原生物研究所培育的4个小麦品种为试验材料，通过测定光合色素含量、叶面积、旗叶鲜质量和干质量，利用脉冲调制式活体叶绿素荧光技术，研究了香日德地区抽穗期旗叶叶背和叶面的PSⅡ光化学效率及其对强太阳辐射的适应性。结果表明，高原314、高原363和高原584的旗叶角度主要呈水平状态生长，而高原913因叶面积较小、叶片较宽，旗叶角度主要呈垂直状态生长。4个品种间光合色素存在差异，且与PSⅡ内在光化学效率（Fv/Fm）呈正相关。晴天时，尤其是中午，旗叶叶背因直接接受太阳辐射，光合光抑制更严重，但下午光照强度降低后可恢复，这表明PSⅡ反应中心未发生不可逆损伤。在光化光强度下，旗叶叶背和叶面的PSⅡ实际光化学效率和最大光化学效率（ΦPSⅡ和Fv'/Fm'）存在显著差异，且它们的相对变化趋势相反。光化学猝灭系数和非光化学猝灭系数（qP和NPQ）在叶背和叶面具有相似的变化趋势。虽然旗叶叶面的ΦPSⅡ和qP较低，但Fv'/Fm'显著较高，这表明PSⅡ对激发能的潜在捕获效率较高。结果表明，光化学猝灭和非光化学猝灭过程能有效耗散强太阳辐射引起的激发能，青藏高原地区本土种植的小麦品种具有较高的适应能力。
