Photosynthetic responses of birch and alder saplings grown in a free air CO2 enrichment system in northern Japan
Photosynthetic responses of birch and alder saplings grown in a free air CO2 enrichment system in northern Japan
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DOI：
10.1007/s00468-007-0204-5
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发表时间：
2008-01
期刊：
影响因子：
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通讯作者：
N. Eguchi;K. Karatsu;Tatsushiro Ueda;R. Funada;K. Takagi;T. Hiura;K. Sasa;T. Koike
中科院分区：
文献类型：
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作者：
N. Eguchi;K. Karatsu;Tatsushiro Ueda;R. Funada;K. Takagi;T. Hiura;K. Sasa;T. Koike
尽管桦树和桤木是东北亚占主导地位的常见先锋树种，但人们对大气二氧化碳浓度（[CO2]）预计增加对其在田间条件下光合作用的影响知之甚少。为了对此进行研究，我们在日本北部的自由空气 CO2 富集系统中种植了三种桦科植物（Betula platyphyllavar.japonicaHara、Betula maximowiczianaRegel 和 Alnus hirsutaTurcz）的 2 年生树苗，历时 2 年。由于已知高 [CO2] 的影响取决于土壤条件，因此我们评估了日本北部广泛分布的两种土壤的响应：贫瘠且未成熟的火山灰 (VA) 土壤和肥沃的棕色森林 (BF) 土壤。对于B。白桦，光合下调在两种土壤中均发生，但对于B. maximowicziana，下调仅发生在 VA 土壤中。解释是叶子中氮和 Rubisco 含量减少。对于A。 hirsuta 中，下调仅发生在 BF 土壤中，因为叶子中淀粉的积累限制了叶绿体内二氧化碳的扩散。 A．光合速率较高hirsutain 不肥沃的 VA 土壤可能是由于固氮共生体中光合产物的吸收所致。这三个物种都能够在高 [CO2] 条件下下调。然而，有可能是A. hirsuut 将在 VA 土壤和 B 中占主导地位。 maximowiczianain BF 土壤在二氧化碳增强的世界中森林演替的早期阶段。
Though birch and alder are the common pioneer tree species which dominate in northeast Asia, little is known about the effects of the predicted increase in atmospheric CO2concentrations ([CO2]) upon their photosynthesis in field conditions. To investigate this, we grew 2-year-old saplings of three Betulaceae species (Betula platyphyllavar.japonicaHara,Betula maximowiczianaRegel, andAlnus hirsutaTurcz) for 2 years in a free air CO2enrichment system in northern Japan. Since the effect of high [CO2] is known to depend on soil conditions, we evaluated the responses in two soils which are widely distributed in northern Japan: infertile and immature volcanic ash (VA) soil, and fertile brown forest (BF) soil. ForB. platyphylla, photosynthetic down-regulation occurred in both soils, but forB. maximowicziana, down-regulation occurred only in VA soil. The explanation is reduced nitrogen and Rubisco content in the leaf. ForA. hirsuta, down-regulation occurred only in BF soil because of the accumulation of starch in foliage, which restricts CO2diffusion inside the chloroplast. The higher photosynthetic rate ofA. hirsutain infertile VA soil could be due to the sink for photosynthates in the N2-fixing symbiont. These three species are all able to down-regulate at high [CO2]. However, it is possible thatA. hirsutawould dominate in VA soil andB. maximowiczianain BF soil in the early stages of forest succession in a CO2-enhanced world.