Temperature and light drive manganese accumulation and stress in crops across three major plant families
Fernando DR, Moroni SJ, Scott SJ, Conyers MK, Lynch JP, Marshall AT
Environmental and Experimental Botany, Volume 132, December, p.66-79 (2011)
Root cortical aerenchyma (RCA) is induced by hypoxia, drought and several nutrient deficiencies. Previous research showed that RCA formation reduces the respiration and nutrient content of root tissue. We used SimRoot, a functional-structural model, to provide quantitative support for the hypothesis that RCA formation is a useful adaptation to suboptimal availability of phosphorus, nitrogen and potassium by reducing the metabolic costs of soil exploration. RCA increased growth of simulated 40 day old Zea mays L. plants up to 55, 54 and 72% on low nitrogen, phosphorus or potassium soils respectively and reduced critical fertility levels by 13, 12 and 7% respectively. The greater utility of RCA on low potassium soils is associated with the fact that root growth in potassium deficient plants was more carbon limited than in phosphorus and nitrogen deficient plants. In contrast to potassium deficient plants, phosphorus and nitrogen deficient plants allocate more carbon to the root system as the deficiency develops. The utility of RCA also depended on other root phenes and environmental factors. On low phosphorus soils (7.5 ?M), the utility of RCA was 2.9 times greater in plants with increased lateral branching density than in plants with normal branching. On low nitrate soils, the utility of RCA formation was 56% greater in coarser soils with high nitrate leaching. Large genetic variation in RCA formation and the utility of RCA for a range of stresses position RCA as an interesting crop breeding target for enhanced soil resource acquisition.