Grašič Mateja, Sovdat Tjaša, Gaberščik Alenka
Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, SI-1000 Ljubljana, Slovenia.
Plants (Basel). 2020 Sep 23;9(10):1254. doi: 10.3390/plants9101254.
Ferns display an elevated degree of phenotypic plasticity to changes in irradiance levels; however, only a few reports deal with their response to different light conditions. To get an insight into the extent of phenotypic plasticity of the fern , thriving in a forested area along a radiation gradient at the entrance of a cave, we examined selected biochemical, morphological, and physiological frond traits of the ferns from three different habitats. Sampling was performed two times during the vegetation season, in April and June. We also measured frond optical properties to point out the differences in leaf/light interactions between different plant samples. According to frond size, the middle habitat, receiving 125 µmol ms of photosynthetically active radiation at both sampling times, appeared to be the most favourable. The production of UV-absorbing substances was highest in the habitat with the lowest radiation level. At the beginning of the season, the level of photosynthetic pigments in this habitat was the same as in the other habitats, while it was significantly lower in June when the tree canopy was closed. Frond reflectance was similar when comparing habitats and different sampling times. The most significant differences were obtained in the UV-A and near-infrared regions. The reflectance spectra depended mainly on frond biochemical properties, which altogether explained 54% ( ≤ 0.05) of the spectra variability. Frond transmittance depended on both, morphological parameters, explaining 51% ( ≤ 0.05), and frond biochemistry, explaining 73% ( ≤ 0.05) of the spectra variability. was revealed to be highly plastic regarding light conditions. The shapes of the frond reflectance and transmittance optical curves were similar to those typical of leaves of seed plants. The fronds exhibited high morphological plasticity when comparing different habitats. However, their biochemical and optical traits differed more between the two sampling times than between the habitats.
蕨类植物对光照强度变化表现出较高程度的表型可塑性；然而，仅有少数报告涉及它们对不同光照条件的响应。为深入了解一种生长在洞穴入口处沿辐射梯度变化的林区的蕨类植物的表型可塑性程度，我们研究了来自三种不同生境的蕨类植物选定的生化、形态和生理叶片特征。在生长季的4月和6月进行了两次采样。我们还测量了叶片的光学特性，以指出不同植物样本之间叶/光相互作用的差异。根据叶片大小，中间生境在两次采样时接收125 μmol m⁻² s⁻¹的光合有效辐射，似乎是最适宜的。吸收紫外线物质的产生在辐射水平最低的生境中最高。在生长季开始时，该生境中光合色素的水平与其他生境相同，但在6月树冠闭合时显著降低。比较不同生境和不同采样时间时，叶片反射率相似。在紫外线A和近红外区域获得的差异最为显著。反射光谱主要取决于叶片的生化特性，这些特性共同解释了光谱变异性的54%（P≤0.05）。叶片透过率既取决于形态参数，解释了光谱变异性的51%（P≤0.05），也取决于叶片生化特性，解释了光谱变异性的73%（P≤0.05）。结果表明，该蕨类植物在光照条件方面具有高度可塑性。叶片反射率和透过率光学曲线的形状与种子植物叶片的典型形状相似。比较不同生境时，叶片表现出较高的形态可塑性。然而，它们的生化和光学特征在两个采样时间之间的差异比在不同生境之间的差异更大。
