Elevated efficiency of C3 photosynthesis in bamboo grasses: A possible consequence of enhanced refixation of photorespired CO2
Elevated efficiency of C3 photosynthesis in bamboo grasses: A possible consequence of enhanced refixation of photorespired CO2
复制标题
竹草中 C3 光合作用效率的提高：光呼吸 CO2 重新固定增强的可能结果
作者：
M. M. Peixoto;T. Sage;Florian A. Busch;H. D. N. Pacheco;M. G. Moraes;T. A. Portes;Rogério A. Almeida;D. Graciano;R. Sage
竹子是多产的草，目前生产高质量的木材和潜在的丰富的木质纤维素用于生物能源。所有的C3草的温暖的栖息地，在那里他们很容易显着的光呼吸抑制和竞争性抑制C4草。在这里，我们调查是否三个竹种从巴西塞拉多（Dendrocalamus asper，Guadua angustifolia和Guadua magna）表现出独特的适应，抑制光呼吸成本和提高光合效率。我们评估了光合效率的竹子和水稻（水稻）通过测量C*，在线粒体呼吸的情况下的CO2补偿点。在25℃时，各竹种的C* 平均值为2.81Pa，与C3植物水稻（3.31Pa）相比，更接近C2植物（2.71Pa）。假设叶绿体CO2浓度为200 µmol mol−1，这表示竹子的表观光呼吸成本比水稻低18%。光镜和透射电镜观察表明，竹叶的维管束和叶鞘细胞中细胞器较少，叶肉细胞深裂，99%的细胞周边与细胞间隙相邻，被叶绿体和基质覆盖。竹M细胞叶绿体层厚，线粒体与叶绿体相邻或被叶绿体吞噬。这种安排减缓了CO2的流出，有利于光呼吸CO2的再固定，这可以解释竹子中的低C*。竹子的水分利用效率也高于水稻，这可能反映了光呼吸CO2的有效再固定。
Bamboos are productive grasses that currently yield a high‐quality wood and potentially an abundance of lignocellulose for bioenergy. All are C3 grasses of warm habitats, where they are prone to significant photorespiratory inhibition and competitive suppression by C4 grasses. Here, we investigate whether three bamboo species from the Brazilian Cerrado (Dendrocalamus asper, Guadua angustifolia, and Guadua magna) exhibit unique adaptations that suppress photorespiratory costs and enhance photosynthetic efficiency. We evaluated photosynthetic efficiency of the bamboos and rice (Oryza sativa) by measuring C*, the CO2 compensation point in the absence of mitochondrial respiration. At 25℃, C* averaged 2.81 Pa in each of the bamboo species, which is closer to a C2 plant (2.71 Pa) than the C3 plant rice (3.31 Pa). Assuming a chloroplast CO2 concentration of 200 µmol mol−1, this represents an 18% lower cost of apparent photorespiration in bamboo than rice. Light and transmission electronic microscopy of the bamboo leaves exhibited few organelles in the bundle and mestome sheath cells, and mesophyll (M) cells are deeply lobed with 99% of the cell periphery adjacent to intercellular air space covered by chloroplast and stromules. The chloroplast layer in bamboo M cells is thick, with mitochondria adjacent to or engulfed by chloroplasts. This arrangement slows CO2 efflux and facilitates refixation of photorespired CO2, which could explain the low C* in the bamboos. The bamboos also had higher water use efficiency than rice, which may reflect efficient refixation of photorespired CO2.
DOI：
--
发表时间：
2015-10
期刊：
--
影响因子：
--
作者：
Douglas M. Bates;M. Maechler;Ben Bolker;Steven C. Walker
通讯作者：
Douglas M. Bates;M. Maechler;Ben Bolker;Steven C. Walker
影响因子：
11.6
作者：
Stefanie Schulze;Julia Mallmann;Janet Burscheidt;Maria Koczor;M. Streubel;H. Bauwe;U. Gowik;P. Westhoff
通讯作者：
Stefanie Schulze;Julia Mallmann;Janet Burscheidt;Maria Koczor;M. Streubel;H. Bauwe;U. Gowik;P. Westhoff
影响因子：
9.4
作者：
Galmes, Jeroni;Andralojc, P. John;Conesa, Miquel A.
通讯作者：
Conesa, Miquel A.