Colombi Tino, Walter Achim
ETH Zurich, Institute of Agricultural Sciences (IAS), Universitätstrasse 2, 8092 Zurich, Switzerland.
Funct Plant Biol. 2016 Mar;43(2):114-128. doi: 10.1071/FP15194.
Soil compaction includes a set of underlying stresses that limit root growth such as increased impedance and limited oxygen availability. The aims of the present study were to (i) find acclimations of triticale (× Triticosecale) and soybean (Glycine max L.) roots to compacted soils in the field; (ii) reproduce these under controlled conditions; and (iii) associate these responses with soil physical properties. To this end, plants were grown at two different soil bulk densities in the field and under controlled conditions representing mature root systems and the seedling stage respectively. Diameters, lateral branching densities, the cortical proportion within the total root cross-section and the occurrence of cortical aerenchyma of main roots were quantified. Soil compaction caused decreasing root branching and increasing cortical proportions in both crops and environments. In triticale, root diameters and the occurrence of aerenchyma increased in response to compaction in the field and under controlled conditions. In soybean, these acclimations occurred at an initial developmental stage but due to radial root growth not in mature roots. These results showed that responses of root systems to compacted soils in the field are, to a large extent, reproducible under controlled conditions, enabling increased throughput, phenotyping-based breeding programs in the future. Furthermore, the occurrence of aerenchyma clearly indicated the important role of limited oxygen availability in compacted soils on root growth.
土壤压实包含一系列限制根系生长的潜在应力，如阻抗增加和氧气供应受限。本研究的目的是：（i）在田间找出小黑麦（×Triticosecale）和大豆（Glycine max L.）根系对压实土壤的适应性；（ii）在可控条件下重现这些适应性；（iii）将这些响应与土壤物理性质联系起来。为此，分别在田间和可控条件下，以两种不同的土壤容重种植植物，分别代表成熟根系和幼苗期。对主根的直径、侧枝密度、总根横截面积内的皮层比例以及皮层通气组织的出现情况进行了量化。在两种作物和环境中，土壤压实均导致根系分支减少，皮层比例增加。在小黑麦中，在田间和可控条件下，根直径和通气组织的出现因压实而增加。在大豆中，这些适应性出现在初始发育阶段，但并非由于成熟根系的径向生长。这些结果表明，在可控条件下，田间根系对压实土壤的响应在很大程度上是可重现的，这将使未来基于表型的育种计划的通量增加。此外，通气组织的出现清楚地表明了压实土壤中氧气供应受限对根系生长的重要作用。
