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首页> 外文学位 >The effect of altered assimilate allocation and partitioning due to PcGA-oxidase overexpression on the growth and performance of creeping bentgrass (Agrostis stolonifera L.) in full sun and reduced light.
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The effect of altered assimilate allocation and partitioning due to PcGA-oxidase overexpression on the growth and performance of creeping bentgrass (Agrostis stolonifera L.) in full sun and reduced light.

机译：PcGA-氧化酶过表达导致同化物分配和分配发生变化，对全日光和弱光条件下bent草的生长和性能的影响。

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摘要

Creeping bentgrass (Agrostis stolonifera L.) is a species commonly used in high maintenance turf areas where it is often exposed to shade. Shade stress induces harmful physiological and morphological changes in turf plants which, under intense management conditions, ultimately lead to loss of turfgrass coverage. Adaptive responses to light stimuli are mediated, in part, by phytohormones, gibberellins. Suppression of gibberellin levels by overexpression of genes involved in their catabolism has been proven to successfully control plant stature. Further, it was shown to alter plant morphological and photosynthetic characteristics.;The main objective of this study was to determine the effect of runner bean (Phaseolus coccineus) GA2-oxidase gene (PcGA2ox ) overexpression on creeping bentgrass quality and performance in light limited environments, in the perspective of potential changes in assimilate partitioning and allocation caused by the transformation. Studies were performed at The Ohio State University, Columbus, Ohio, USA from September 1 2008 to July 31 2010. Two genetically modified lines, Ax6548 and Ax6549, transformed with CP4 EPSPS and the PcGA2ox genes and nontransformed control were included in the study.;The purpose of the first experiment was to evaluate overall visual quality of plants grown under different light conditions and low mowing height. Two greenhouse studies were conducted from September 1 to October 31, in both 2008 and 2009. Lines were grown under full sun, reduced red to far red light ratio (R:FR), neutral shade (reduced photosynthetic photon flux (PPF), and canopy shade (reduced PPF and R:FR) conditions. Turf was evaluated visually for color and percent of coverage. GA2ox overexpression resulted in superior quality of Ax6549 under all shade treatments by delaying the decline of its color and coverage.;The aim of the second study was photosynthetic characterization of the lines. The greenhouse studies were performed in September-October 2009 and April-May 2010. Plants were subjected to 4 light treatments as described above. Obtained data showed increased (P=0.05) net CO2 uptake rates and higher maximum quantum yield of photosynthesis in leaves of Ax6549 across all light treatments. Increased CO2 uptake rates in Ax6549 were most likely due to lower specific leaf area and higher stomatal conductance. Lines did not differ in regards to dark respiration rates and light compensation points despite the light treatment. In conclusion, higher photosynthate supply per leaf area unit and enhanced low light use efficiency were suggested as potential factors associated with the superior quality of Ax6549 under reduced light conditions;The purpose of the last study was to investigate potential differences in assimilate partitioning of the plants. Morphological and growth analysis were performed under controlled environment conditions in July 2010. Plants were subjected to high and reduced irradiance treatments and evaluated every 10 days. PcGA2ox overexpression resulted in reduced biomass accumulation in both transgenic plants. Further, Ax6549 plants were characterized by lower growth efficiency and leaf biomass production efficiency. Although this was in contrary to data obtained during photosynthetic characterization, it could be explained by increased self shading in Ax6549 due to greater leaf width and more horizontal leaf orientation. Under high irradiance conditions, Ax6549 invested more assimilate into roots while Ax6548 into leaves. Under reduced irradiance condition, all plants partitioned more biomass into leaves at the expense of root biomass. Transgenic plants invested more assimilate into leaves compared to nontransformed control plants. Morphological data did not help clarify the methods of improved performance of Ax6549 under shaded conditions. Whole canopy photosynthetic measurements performed at different cutting heights are likely needed to further explain the incongruities between photosynthetic and growth analysis data.
机译：bent草（Agrostis stolonifera L.）是常用于高维护性草皮地区的物种，该地区经常暴露于阴凉处。遮荫胁迫在草皮植物中引起有害的生理和形态变化，在严格的管理条件下，最终导致草皮覆盖率降低。对光刺激的适应性反应部分由植物激素，赤霉素介导。已经证明，通过过度表达参与其分解代谢的基因来抑制赤霉素水平可以成功地控制植物的身材。此外，还表明它能改变植物的形态和光合特性。这项研究的主要目的是确定在过量光照条件下，过花菜豆（Phaseolus coccineus）GA2-氧化酶基因（PcGA2ox）的表达对bent草的品质和性能的影响。 ，从转换引起的同质分区和分配的潜在变化的角度来看。研究于2008年9月1日至2010年7月31日在美国俄亥俄州哥伦布市的俄亥俄州立大学进行。该研究包括两条经CP4 EPSPS和PcGA2ox基因转化的转基因品系Ax6548和Ax6549，以及未转化的对照。第一个实验的目的是评估在不同光照条件和低割草高度下生长的植物的整体视觉质量。在2008年和2009年的9月1日至10月31日进行了两次温室研究。品系在充分的阳光下生长，红光与远红光的比率降低（R：FR），中性阴影（光合光子通量降低（PPF）），冠层阴影（降低PPF和R：FR）条件下，通过目测评估草皮的颜色和覆盖率百分比。GA2ox的过表达通过延迟其颜色和覆盖率的下降，在所有阴影处理下均导致Ax6549的卓越品质。第二项研究是品系的光合作用特性，温室研究于2009年9月至10月和2010年4月至5月进行，植物经过了如上所述的4种光照处理，获得的数据表明净CO2吸收率增加了（P = 0.05），在所有光处理下，Ax6549叶片光合作用的最大光量子产量最高；由于较低的比叶面积和较高的气孔导度，Ax6549的CO2吸收率增加的可能性最大。尽管进行了光疗，但仍需考虑暗呼吸频率和光补偿点。综上所述，建议在较低的光照条件下，较高的单叶单位光合产物供应量和增强的低光利用效率是与Ax6549优良品质相关的潜在因素;最后的研究目的是研究植物同化物分配的潜在差异。 。在受控环境条件下于2010年7月进行了形态和生长分析。对植物进行高剂量和减量辐照处理，并每10天进行一次评估。 PcGA2ox过表达导致两种转基因植物中生物量的积累减少。此外，Ax6549植物的特征在于较低的生长效率和叶片生物量生产效率。尽管这与在光合作用表征过程中获得的数据相反，但可以通过更大的叶宽和更水平的叶方向在Ax6549中增加自阴影来解释。在高辐照度条件下，Ax6549将更多的同化物投入根部，而将Ax6548投入到叶片中。在降低辐照度的条件下，所有植物都以根系生物量为代价将更多的生物量分配到叶片中。与未转化的对照植物相比，转基因植物对叶片的同化物投入更多。形态数据无法帮助阐明在阴影条件下提高Ax6549性能的方法。为了进一步解释光合作用和生长分析数据之间的不一致性，可能需要在不同的切割高度进行全冠光合测量。

著录项

  • 作者

    Studzinska, Aneta Karolina.;

  • 作者单位

    The Ohio State University.;

  • 授予单位 The Ohio State University.;
  • 学科 Agriculture Horticulture.;Agriculture Plant Culture.
  • 学位 Ph.D.
  • 年度 2011
  • 页码 133 p.
  • 总页数 133
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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