Structural characteristics and chemical composition of birch (Betula pendula) leaves are modified by increasing CO2 and ozone
Structural characteristics and chemical composition of birch (Betula pendula) leaves are modified by increasing CO2 and ozone
复制标题
DOI：
10.1111/j.1365-2486.2005.00938.x
复制
发表时间：
2005-05-01
影响因子：
11.6
通讯作者：
Vapaavuori, E
中科院分区：
文献类型：
--
作者：
Oksanen, E;Riikonen, J;Vapaavuori, E
研究了单独和联合富集臭氧和CO2对两个欧洲白桦（Betula pendula Roth）无性系叶片解剖和超微结构特征、营养状况和细胞壁化学的影响。在芬兰中部，土壤生长的幼树在三个生长季节中暴露在开顶室中，暴露在2倍的环境二氧化碳和/或臭氧浓度中。共测定了绿叶叶片结构、营养成分和细胞壁化学等35个变量的变化，其中20个变量受到CO2和/或O-3的影响。CO2升高使叶绿体和淀粉粒大小、线粒体数量、磷氮比和细胞壁半纤维素含量增加。升高的CO2降低了叶片总厚度、比叶面积、N、K、Cu、S和Fe浓度以及细胞壁α -纤维素、醛酸、酸溶性木质素和丙酮溶性浸出物的含量。臭氧浓度升高导致叶片变薄，栅栏海绵比升高，过氧化物酶体和线粒体数量增加，Mn、Zn、Cu、半纤维素和醛酸含量降低，Mn: N和Zn: N比值降低。在联合暴露中，相互作用是拮抗的。超微结构变化在曝光后期变得更加明显。幼叶对臭氧引起的氧化胁迫具有耐受性，而老叶则存在氧化H2O2积累。CO2富集不仅通过增加光合作用速率，而且通过改变细胞壁化学（特别是半纤维素）来提高臭氧耐受性。然而，臭氧和/或二氧化碳造成的营养失衡可能使树木易受其他生物和非生物胁迫。通过解剖变化讨论了CO2升高下光合作用的下调和上调。
Impacts of ozone and CO2 enrichment, alone and in combination, on leaf anatomical and ultrastructural characteristics, nutrient status and cell wall chemistry in two European silver birch (Betula pendula Roth) clones were studied. The young soil-growing trees were exposed in open-top chambers over three growing seasons to 2 x ambient CO2 and/or ozone concentrations in central Finland. The trees were measured for changes in altogether 35 variables of leaf structure, nutrients and cell wall chemistry of green leaves, and 20 of the measured variables were affected by CO2 and/or O-3. Elevated CO2 increased the size of chloroplasts and starch grains, number of mitochondria, P : N ratio, and contents of cell wall hemicellulose. Elevated CO2 decreased the total leaf thickness, specific leaf area, concentrations of N, K, Cu, S and Fe, and contents of cell wall alpha-cellulose, uronic acids, acid-soluble lignin and acetone-soluble extractives. Elevated ozone led to thinner leaves, higher palisade to spongy ratio, increased number of peroxisomes and mitochondria, reduced content of Mn, Zn, Cu, hemicellulose and uronic acids, and lower Mn : N and Zn : N ratios. In the combined exposure, interactions were antagonistic. Ultrastructural changes became more evident towards the end of the exposure. Young leaves were tolerant against ozone-caused oxidative stress, whereas oxidative H2O2 accumulation was found in older leaves. CO2 enrichment improved ozone tolerance not only through increased photosynthesis rates, but also through changes in cell wall chemistry (hemicellulose, in particular). However, nutrient imbalances due to ozone and/or CO2 may predispose the trees to other biotic and abiotic stresses. Down-regulation and up-regulation of photosynthesis under elevated CO2 through anatomical changes is discussed.