Manschadi Ahmad M, Christopher John, deVoil Peter, Hammer Graeme L
APSRU, Queensland Department of Primary Industries & Fisheries, PO Box 102, Toowoomba, Qld 4350, Australia.
Queensland Department of Primary Industries & Fisheries, Leslie Research Centre, PO Box 2282, Toowoomba, Qld 4350, Australia.
Funct Plant Biol. 2006 Sep;33(9):823-837. doi: 10.1071/FP06055.
Better understanding of root system structure and function is critical to crop improvement in water-limited environments. The aims of this study were to examine root system characteristics of two wheat genotypes contrasting in tolerance to water limitation and to assess the functional implications on adaptation to water-limited environments of any differences found. The drought tolerant barley variety, Mackay, was also included to allow inter-species comparison. Single plants were grown in large, soil-filled root-observation chambers. Root growth was monitored by digital imaging and water extraction was measured. Root architecture differed markedly among the genotypes. The drought-tolerant wheat (cv. SeriM82) had a compact root system, while roots of barley cv. Mackay occupied the largest soil volume. Relative to the standard wheat variety (Hartog), SeriM82 had a more uniform rooting pattern and greater root length at depth. Despite the more compact root architecture of SeriM82, total water extracted did not differ between wheat genotypes. To quantify the value of these adaptive traits, a simulation analysis was conducted with the cropping system model APSIM, for a wide range of environments in southern Queensland, Australia. The analysis indicated a mean relative yield benefit of 14.5% in water-deficit seasons. Each additional millimetre of water extracted during grain filling generated an extra 55 kg ha of grain yield. The functional implications of root traits on temporal patterns and total amount of water capture, and their importance in crop adaptation to specific water-limited environments, are discussed.
更好地了解根系结构和功能对于在水分受限环境下改良作物至关重要。本研究的目的是研究两种对水分限制耐受性不同的小麦基因型的根系特征，并评估所发现的任何差异对适应水分受限环境的功能影响。还纳入了耐旱大麦品种麦凯，以便进行种间比较。单株植物种植在大型、装满土壤的根系观察室中。通过数字成像监测根系生长，并测量水分提取量。不同基因型之间的根系结构差异显著。耐旱小麦（品种SeriM82）的根系系统紧凑，而大麦品种麦凯的根系占据的土壤体积最大。相对于标准小麦品种（哈托格），SeriM82具有更均匀的生根模式和更深层的更大根长。尽管SeriM82的根系结构更紧凑，但小麦基因型之间提取的总水量没有差异。为了量化这些适应性性状的价值，使用作物系统模型APSIM对澳大利亚昆士兰州南部的广泛环境进行了模拟分析。分析表明，在缺水季节平均相对产量效益为14.5%。灌浆期每多提取一毫米水，谷物产量就会额外增加55公斤/公顷。本文讨论了根系性状对水分捕获的时间模式和总量的功能影响，以及它们在作物适应特定水分受限环境中的重要性。
