Agathokleous Eugenios, Vanderstock Amelie, Kita Kazuhito, Koike Takayoshi
School of Agriculture, Hokkaido University, Sapporo, Hokkaido, 060-8589, Japan.
Hokkaido Research Center, Forestry and Forest Products Research Institute (FFPRI), Hitsujigaoka 7, Sapporo, Hokkaido, 062-8516, Japan.
Environ Sci Pollut Res Int. 2017 Mar;24(7):6634-6647. doi: 10.1007/s11356-017-8401-2. Epub 2017 Jan 12.
Ozone (O) pollution and soil infertility may negatively affect boreal forests across the Northern Hemisphere. Impacts to economically and ecologically important larches (Larix sp., Pinacaeae) are particularly concerning. Using a free air O enrichment (FACE) system, we investigated the effect of 2-year elevated O exposure (≈66 nmol mol) on Japanese larch (L. kaempferi) and its hybrid larch F (L. gmelinii var. japonica × L. kaempferi) planted directly into either fertile brown forest soil (BF) or BF mixed with infertile volcanic ash soil (VA). Overall, photosynthetic pigmentation and the growth performance of the stem and crown were reduced in both taxa exposed to elevated O. Furthermore, hybrid larch, in both O treatments, performed better than Japanese larch. This finding contradicts findings of prior experiments with potential experimental artifacts of O exposure facilities and root restrictions. Elevated O also disproportionately inhibited stem diameter growth and caused an imbalance in chlorophylls a/b and chlorophyll/carotenoid ratios. Hybrid and Japanese larches grown in BF and VA had a significantly lower drop of stem diameter over the run of stem height (from base to top) when exposed to elevated O, compared to ambient O. This finding indicates altered stem shape under elevated O. Among 11 response variables, there were no significant interactions between O treatment and taxa. There was also no significant interaction of soil condition and taxa, suggesting that the two larches shared a similar response to O and soil type. Understanding the performance of hybrid larch in relation to its parent species has ramifications for breeding success in a soil-degraded and O-polluted environment.
臭氧（O）污染和土壤贫瘠可能会对北半球的北方森林产生负面影响。对经济和生态方面都很重要的落叶松属（落叶松属，松科）所造成的影响尤其令人担忧。我们使用了一个自由空气臭氧富集（FACE）系统，研究了为期两年的臭氧暴露浓度升高（约66纳摩尔/摩尔）对直接种植在肥沃的棕色森林土壤（BF）或与贫瘠的火山灰土壤（VA）混合的BF中的日本落叶松（L. kaempferi）及其杂种落叶松F（L. gmelinii var. japonica×L. kaempferi）的影响。总体而言，暴露于高浓度臭氧环境下的两个分类群的光合色素含量以及茎和树冠的生长性能均有所降低。此外，在两种臭氧处理中，杂种落叶松的表现均优于日本落叶松。这一发现与之前实验的结果相矛盾，之前的实验可能存在臭氧暴露设施和根系限制等实验假象。臭氧浓度升高还对茎直径的生长产生了不成比例的抑制作用，并导致叶绿素a/b和叶绿素/类胡萝卜素比例失衡。与环境臭氧浓度相比，生长在BF和VA中的杂种落叶松和日本落叶松在暴露于高浓度臭氧时，茎直径在茎高（从基部到顶部）范围内的下降幅度显著更低。这一发现表明在高浓度臭氧环境下茎的形状发生了改变。在11个响应变量中，臭氧处理和分类群之间没有显著的相互作用。土壤条件和分类群之间也没有显著的相互作用，这表明两种落叶松对臭氧和土壤类型的反应相似。了解杂种落叶松与其亲本物种相比的表现，对于在土壤退化和臭氧污染环境中的育种成功具有重要意义。
