Photosynthetic response of young oaks to biochar amendment in field conditions over 3 years
Photosynthetic response of young oaks to biochar amendment in field conditions over 3 years
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DOI：
10.1080/13416979.2020.1866231
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发表时间：
2021-03
影响因子：
1.5
通讯作者：
Yumina Tanazawa;M. Tomotsune;Takeshi Suzuki;H. Koizumi;S. Yoshitake
中科院分区：
文献类型：
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作者：
Yumina Tanazawa;M. Tomotsune;Takeshi Suzuki;H. Koizumi;S. Yoshitake
摘要利用生物质热降解制成的生物炭改良剂有望通过刺激植物的碳同化作用来增强碳固存。阐明了生物炭对森林生态系统中树木光合作用的影响。将生物炭以0、5、10和20 Mg ha−1的比例施用于温带落叶林中的幼龄橡树（Quercus serrata），并在4个地块（C0、C5、C10和C20）中进行试验。连续3年在生长季内每月测定叶片光合参数（最大光合速率Pmax、最大羧化速率Vcmax和电子传递速率Jmax）和叶片性状（气孔导度gc、单位面积叶质量LMA和叶片养分浓度）的变化。C5和C10的Pmax通常增加，C20没有增加。同样，Vcmax和Jmax在C5和C10中增加，并与Pmax显著正相关，表明生物炭改良基本上通过改善生理活性来提高光合速率，但存在最大有效剂量。我们还发现，GC，LMA和叶片养分（N，Mg和S）与Pmax呈显著正相关，表明光合速率的增加将支持这些叶片性状。但对光合作用的刺激作用逐年减小，说明生物炭的作用逐渐减弱。结果表明，生物炭的施用基本上是通过改变林分各组分的气相色谱（GC）、叶片平均粒径（LMA）和叶片养分含量来提高林分中栎树的光合作用，但随时间的推移，光合作用呈下降趋势。
ABSTRACT Amendment by biochar made by thermal degradation of biomass is expected to enhance carbon sequestration through stimulating carbon assimilation by plants. We clarified the effect of biochar amendment on the photosynthesis of trees in forest ecosystems. Biochar was applied to young oak trees (Quercus serrata) in temperate deciduous forest at rates of 0, 5, 10 and 20 Mg ha−1 in four plots (C0, C5, C10, and C20). The variation in photosynthetic parameters (the maximum photosynthetic rate: Pmax, maximum carboxylation rate: Vcmax and the potential rate of electron transport: Jmax) and leaf traits (the stomatal conductance: gc, leaf mass per area (LMA) and leaf nutrient concentrations) were examined every month during the growing seasons for 3 years. Pmax generally increased in C5 and C10 and did not increase in C20. Similarly, Vcmax and Jmax increased in C5 and C10 and correlated significantly positively with Pmax, suggesting that biochar amendment basically increased the photosynthetic rate through improvements in physiological activities but that there was a maximum useful dosage. We also found that gc, LMA and leaf nutrient (N, Mg, and S) showed significant positive correlations with Pmax, indicating that an increase in photosynthetic rates would be supported by these leaf traits. However, stimulation of photosynthesis became smaller year by year, indicating that the effects of biochar amendment faded gradually. We concluded that biochar amendment basically improved the photosynthesis of oak trees in the forest through the change of all gc, LMA and leaf nutrient concentrations but declined yearly.