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首页> 外文学位 >Performance of perennial ryegrass (Lolium perenne L.) seed crops under water stress conditions.
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Performance of perennial ryegrass (Lolium perenne L.) seed crops under water stress conditions.

机译：水分胁迫条件下多年生黑麦草（Lolium perenne L.）种子作物的表现。

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摘要

Summer drought is a major factor limiting the regrowth of perennial ryegrass seed crops. This phase of crop development has a strong influence on seed yield because most of the tillers that contribute towards next season's seed crop are produced or regrown during this period. In recent years many seed fields have exhibited premature decline probably because of extensive drought after harvesting. Therefore, this study was undertaken to (i) assess how post-harvest leaf and tiller development is impacted by the timing and severity of water stress and (ii) identify potential relationships of water stress to flowering and seed yield.; Rain-out shelters were used to exclude rainfall from two cultivars which received either no irrigation or 2.5 cm of simulated rainfall in mid-August or mid-September or both. These were compared to an ambient treatment No rainfall decreased total tiller production by approximately 30% in 1995 and 50% in 1996. There were also moderate reductions in tiller dry weight, tiller height, and slight decreases in number of leaves and the basal diameters. The trend showed that the cultivar Affinity responded quicker to an early irrigation whereas the cultivar Buccaneer had a longer period of summer dormancy. Total soluble sugars concentrations increased as tiller number decreased suggesting the potential for rapid compensatory growth upon alleviation of drought. Limited irrigation during the post-harvest period of regrowth did not generally affect fertile tiller number nor seed yields. Fewer vegetative tillers as the stands aged, together with other changes in plant parameters, may mark the beginning of the dieback problem.; In greenhouse studies, four cultivars were rapidly stressed using vermiculite as a growth medium. Though little differences were observed among cultivars when physiological responses were evaluated, stomatal diffusive resistance and leaf temperatures increased, whereas plant water potential and leaf transpiration decreased as stress was prolonged. Plant survival following water stress was largely dependent on cultivar and gravimetric water content of vermiculite. This technique did not reasonably simulate natural drought conditions in terms of plant physiological performances nor soil characteristics, but it was useful to differentiate the ability of different genotypes to survive a drought-induced dieback.
机译：夏季干旱是限制多年生黑麦草种子作物再生的主要因素。作物生长的这一阶段对种子产量有很大影响，因为在此期间生产或再生长了有助于下一季种子作物的大多数分ers。近年来，许多种子田已经表现出过早的衰落，这可能是由于收获后的广泛干旱。因此，本研究旨在（i）评估水分胁迫的时间和严重程度如何影响收获后叶片和分er的发育，以及（ii）确定水分胁迫与开花和种子产量的潜在关系。防雨棚被用来排除两个品种的降雨，这些品种在8月中旬或9月中旬或两者均未灌溉或接受2.5 cm模拟降雨。将这些与环境处理进行比较。没有降雨使总分total产量在1995年下降约30％，在1996年下降50％。分till干重，分er高度和叶数和基部直径略有下降也有适度下降。该趋势表明，亲和性对早期灌溉的响应更快，而海盗型则具有较长的夏季休眠期。随着分till数减少，总可溶性糖浓度增加，表明缓解干旱后快速补偿性生长的潜力。在收获后的再生期间有限的灌溉通常不会影响可耕的分till数或种子产量。随着林分龄的增长，植物分till减少，加上植物参数的其他变化，可能标志着枯萎期的开始。在温室研究中，使用ver石作为生长培养基，四个品种迅速受到压力。虽然在评估生理响应时各品种间观察到的差异不大，但随着胁迫时间的延长，气孔扩散阻力和叶片温度升高，而植物水势和叶片蒸腾作用降低。水分胁迫后的植物存活在很大程度上取决于石的品种和重量含水量。这项技术没有从植物的生理性能或土壤特性方面合理模拟自然干旱条件，但对区分不同基因型在干旱引起的枯死中生存的能力很有用。

著录项

  • 作者

    Velloza, Theodosius Marmaduke.;

  • 作者单位

    Oregon State University.;

  • 授予单位 Oregon State University.;
  • 学科 Agriculture Agronomy.; Biology Plant Physiology.
  • 学位 Ph.D.
  • 年度 1997
  • 页码 135 p.
  • 总页数 135
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 农学（农艺学）;植物学;
  • 关键词

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