The effects of rising atmospheric carbon dioxide on shoot-root nitrogen and water signaling

Abstract

Terrestrial higher plants are composed of roots and shoots, distinct organs that conduct complementary functions in dissimilar environments. For example, roots are responsible for acquiring water and nutrients such as inorganic nitrogen from the soil, yet shoots consume the majority of these resources. The success of such a relationship depends on excellent root–shoot communications. Increased net photosynthesis and decreased shoot nitrogen and water use at elevated CO2 fundamentally alter these source–sink relations. Lower than predicted productivity gains at elevated CO2 under nitrogen or water stress may indicate shoot–root signaling lacks plasticity to respond to rising atmospheric CO2 concentrations. The following presents recent research results on shoot–root nitrogen and water signaling, emphasizing the influence that rising atmospheric carbon dioxide levels are having on these source–sink interactions.

Genetic Mapping Reveals Broader Role of Vrn-H3 Gene in Root and Shoot Development beyond Heading in Barley

“…The root is the primary organ for water and nutrients absorption from soil and shoots consume these resources to convert them in agricultural production. The success of such relationship in crop production depends on excellent root-shoot attributes and their effective communications [ 1 ]. Therefore, genetic dissection of root and shoot traits and their putative association to reinforce plant performance is essential for the determination of favorable traits and to utilize the potentials of these parameters in crop production.…”

CO2 Sensing and CO2 Regulation of Stomatal Conductance: Advances and Open Questions

“…Fewer and more closed stomata in response to elevated CO 2 levels also reduce the evapotranspirative cooling ability of leaves, which in turn adds to leaf heat stress [12–14] under water-limited growth regimens. Heat stress, combined with drought and rising temperatures can reduce plant health [15] and crop productivity globally, thus impacting agricultural practices and possibly nutrient content [16, 17] and supply [18] . Furthermore, a large stomatal conductance can correlate with improved crop yield [19–21], and thus the downregulation of stomatal conductance by CO 2 may contribute to suboptimal yields when sufficient water is available.…”

Silencing of OsCV (chloroplast vesiculation) maintained photorespiration and N assimilation in rice plants grown under elevated CO2

“…The primary effect of high atmospheric CO 2 is the increase of the CO 2 /O 2 ratio at the site of CO 2 fixation, increasing the carboxylation efficiency of Rubisco by lowering the rate of photorespiration (Bowes, 1991). However, productivity gains at elevated CO 2 are often lower than predicted (Novack et al, 2004;Easlon & Bloom, 2013;Newingham, Vanier, Charlet, & Ogle, 2013). Decreased photorespiration may be one of the main factors limiting plant productivity at high CO 2 concentration because of its close relationship with N assimilation (Bloom, 2015;Rachmilevitch et al, 2004).…”