305-16 Root Anatomical Adjustments of Triticale and Soybean to Soil Compaction.
Poster Number 801
Triticale and soybean were grown under controlled laboratory conditions for 2 weeks and in the field for 13 weeks, in order to quantify root anatomical adjustments to soil compaction at different plant developmental stages. The experiments included two levels of bulk densities, representing compacted and non-degraded soil. In both environments the same loamy soil was used. Root cross sections from primary, seminal and nodal roots in triticale and from the tap root and adventitious roots in soybean were imaged with bright field microscopy.
Across both environments the proportion of the root cross section occupied by the root cortex increased significantly due to soil compaction for both crops. Increased cortical proportions correlated with increased root cross section areas (R2= 0.44, p-value< 0.01) in triticale, whereas in soybean larger cortical proportions were related to smaller cross sections (R2= 0.42, p-value< 0.01). In triticale the occurrence of root cortex aerenchyma was increased due to soil compaction, which was consistent over both environments and different root classes. Aerenchyma also occurred in young soybean roots exposed to soil but not in mature roots, in which secondary thickening closed aerenchyma. The occurrence of aerenchyma showed that roots were exposed not only to increased penetration resistance but also to anaerobic conditions under soil compaction. This needs to be taken into account, when screening for root phenotypes adapted to compacted soils.