Authors:
Hannah Schneider | Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) | Germany
Dr. Francisco Pinto | Wageningen University & Research | Netherlands
Dr. Matthew Reynolds | International Maize and Wheat Improvement Center (CIMMYT) | Mexico
Dr. Jacinta Gimeno Romeu | International Maize and Wheat Improvement Center (CIMMYT)
Prof. Lynch Jonathan | Pennsylvania State University
Dr. Cody Depew | Pennsylvania State University
Multiseriate cortical sclerenchyma (MCS) is an anatomical trait characterized by small cells with thick cell walls in the outer cortex. MCS cell walls are highly lignified which enhance root tensile strength and enable root penetration of compacted soils. In addition to compaction tolerance, MCS may also have utility in drought environments by enabling root penetration in hard, dry soils to access deep soil water and promoting soil water banking by restricting radial hydraulic conductivity. We aimed to confirm the physiological utility of MCS to improve plant water status and growth under drought stress in field and greenhouse environments. We phenotyped wheat and maize diversity panels for anatomical traits in drought and well-watered environments and performed detailed physiological studies on a set of contrasting maize lines for MCS. Results demonstrated MCS is plastic under drought. Across environments, MCS in maize did not consistently improve drought stress tolerance. However, MCS in wheat was associated with improved drought stress tolerance. In wheat, we observed phenotypic variation for the formation of both MCS and root cortical senescence, a trait formed by programmed cell death of cortical cells. The benefit of MCS for drought tolerance depended on the successive formation of root cortical senescence. The utility of MCS for drought tolerance is dependent on the environment and interactions with other root and shoot traits. MCS merits continued investigation as a trait for improving plant performance in maize, wheat, and other grasses under edaphic stress.