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首页> 外文学位 >Photosynthesis in Sorghum bicolor under free-air carbon dioxide enrichment and water stress.
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Photosynthesis in Sorghum bicolor under free-air carbon dioxide enrichment and water stress.

机译：在空气中二氧化碳富集和水分胁迫下双色高粱的光合作用。

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摘要

Global climate change will likely have significant effects on terrestrial plant communities and agricultural productivity. In order to increase the accuracy of current models and predictions of how plants will respond to future climatic conditions, it is important to understand the fundamental mechanism of any responses of photosynthesis at both the cellular and leaf level. Previous growth chamber experiments on the response of four carbon (C4) photosynthesis to elevated atmospheric carbon dioxide (CO2) concentrations ([Ca]) have shown inconsistent results between studies and may not be relevent to field grown material. Effects of increased atmospheric CO2 concentration and water-stress on photosynthesis of Sorghum bicolor (DK54) grown in a Free-Air Carbon Dioxide Enrichment (FACE) field experiment have been examined. The FACE system provided a unique opportunity to examine the effects of growth under elevated CO2 and other environmental conditions that closely represent field conditions likely to occur in the near future. In developing leaf tissue, prior to emergence from the surrounding whorl of older leaves, ribulose bisphosphate carboxylase/oxygenase (Rubisco; part of the C3 cycle) accumulated before significant amounts of Phosphoenol pyruvate carboxylase (PEPC; part of the C4 cycle) were detectable and was not expressed cell specifically. However, as the leaf tissue emerged from the surrounding whorl and into full sunlight, the C4 syndrome was fully expressed. C4 photosynthesis in young fully expanded leaves was enhanced under elevated [Ca]. This was partially attributed to suppressed rates of photorespiration and decreased CO2 leakage from bundle sheath cells and less overcycling of the C4 pump. Growth under elevated [Ca] also enhanced C4 photosynthesis and reduced nonphotochemical quenching requirements during drought and/or midday conditions. In summary, this work shows that while development of the C4 apparatus was only minimally affected by elevated CO2, future [Ca] will enhance the efficiency of C4 photosynthesis in young leaves. Furthermore, it was clearly demonstrated that C4 photosynthesis will be most responsive to elevated [Ca] when other environmental factors, particularly water-stress, are limiting rates of carbon uptake.
机译：全球气候变化可能会对陆生植物群落和农业生产力产生重大影响。为了提高当前模型的准确性和对植物如何应对未来气候条件的预测的准确性，重要的是了解细胞和叶片水平上任何光合作用响应的基本机制。以前的生长室实验对四种碳（C 4 ）光合作用对升高的大气二氧化碳（CO 2 ）浓度（[Ca]）的响应表明，研究之间的结果不一致可能与田间种植的材料无关。研究了大气CO 2 浓度和水分胁迫对在自由二氧化碳富集（FACE）田间试验中生长的双色高粱（DK54）光合作用的影响。 。 FACE系统提供了独特的机会来检查在CO 2 升高和其他环境条件下生长的影响，这些环境条件密切代表了不久的将来可能发生的田间条件。在发育中的叶片组织中，核糖双磷酸羧化酶/加氧酶（Rubisco； C 3 循环的一部分）在从较老叶片的周围轮芽中出芽之前就积累了，然后才形成大量的磷酸烯醇丙酮酸羧化酶（PEPC；一部分）。 C 4 周期的变化是可检测的，并且未在细胞中特异性表达。但是，随着叶片组织从周围的轮生组织中出来并进入充足的阳光下，C 4 综合征得以充分表达。在[Ca]升高下，完全膨胀的幼叶中的C 4 光合作用增强。这部分归因于光呼吸速率的抑制和束鞘细胞中CO 2 泄漏的减少以及C 4 泵的过度循环减少。在干旱和/或中午条件下，在高[Ca]条件下的生长还增强了C 4 的光合作用并降低了非光化学猝灭的要求。总而言之，这项工作表明，虽然C 4 装置的发展仅受CO 2 升高的影响最小，但未来的[Ca]将提高C 的效率4 在幼叶中的光合作用。此外，已经清楚地表明，当其他环境因素（尤其是水分胁迫）限制碳吸收速率时，C 4 光合作用对升高的[Ca]最为敏感。

著录项

  • 作者

    Cousins, Asaph Benjamin.;

  • 作者单位

    Arizona State University.;

  • 授予单位 Arizona State University.;
  • 学科 Biology Plant Physiology.
  • 学位 Ph.D.
  • 年度 2001
  • 页码 p.5579
  • 总页数 158
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 植物学;
  • 关键词

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