冠层光谱组成对红松和蒙古栎幼苗生长和光合荧光特性的影响

本研究选择长白山阔叶红松林优势树种红松和蒙古栎幼苗为对象,研究其植株形态、生长和光合荧光特性对5种光谱处理的响应。结果表明: 红松与蒙古栎的形态结构与生长主要受蓝光与紫外B区(UV-B)辐射调控。滤除蓝光后两种幼苗的植株叶面积比和相对生长速率均显著降低,而滤除UV-B辐射显著增加了红松的叶面积比和相对生长速率,分别上升了41.8%和47.7%,降低了蒙古栎的株高、总叶面积和生物量积累。滤除UV-B辐射显著降低了2种幼苗的光合荧光调节能力,红松的下降幅度较低,其非调节性耗散的量子产量(Φ_NO)升高31.6%,反映光合荧光调节能力的Φ_NPQ/Φ_NO值降低37.5%。2个树种幼苗具有明显不同的光谱适应策略,蒙古栎幼苗偏向于利用光谱变化调整自身形态增加光捕获能力,而红松更注重调整光合荧光特征以提高碳同化效率。

Effects of canopy spectral composition on growth and photosynthetic fluorescence characteristics of Pinus koraiensis and Quercus mongolica seedlings

We investigated the responses of leaf and individual traits, growth, and fluorescence characteristics of seedlings of two dominant species of broad-leaved Korean pine forest in Changbai Mountain, i.e., Pinus koraiensis and Quercus mongolica, to five spectrum-attenuation treatments. Results showed that the architecture and growth of P. koraiensis and Q. mongolica seedlings were mainly regulated by ultraviolet B (UV-B) radiation and blue light. The attenuation of blue light significantly decreased leaf area ratio and relative growth rate of two species. The attenuation of UV-B radiation significantly increased leaf area ratio and relative growth rate of P. koraiensis seedlings by 41.8% and 47.7%, respectively, and significantly decreased plant height, total leaf area, and biomass accumulation of Q. mongolica seedlings. Furthermore, the attenuation of UV-B radiation significantly decreased the fluorescence regulation ability of two tree seedlings, with lower magnitude of P. koraiensis than Q. mongolica. The non-regulatory quantum yield (Φ_NO) of P. koraiensis increased by 31.6%, and the Φ_NPQ/Φ_NO ratio, an indicator for photosynthetic fluorescence regulation ability, decreased by 37.5%. These results suggested that those two species might have evolved adaptation strategies to changes in canopy spectral compositions of their respective habitats. Q. mongolica seedlings tended to improve light capture ability through rapid morphological responses, while P. koraiensis seedlings preferred to increase carbon assimilation efficiency by adjusting fluorescence characteristics.