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Maize lateral root developmental plasticity induced by mild water stress. II : Genotype‐specific spatio‐temporal effects on determinate development
Author(s) -
Dowd Tyler G.,
Braun David M.,
Sharp Robert E.
Publication year - 2020
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.13840
Subject(s) - elongation , meristem , lateral root , root system , determinacy , biology , horticulture , plasticity , botany , mathematics , shoot , mathematical analysis , materials science , physics , arabidopsis , gene , mutant , metallurgy , ultimate tensile strength , thermodynamics , biochemistry
Maize lateral roots exhibit determinate growth, whereby the meristem is genetically programmed to stop producing new cells. To explore whether lateral root determinacy is modified under water deficits, we studied two maize genotypes (B73 and FR697) with divergent responses of lateral root growth to mild water stress using an experimental system that provided near‐stable water potential environments throughout lateral root development. First‐order laterals of the primary root system of FR697 exhibited delayed determinacy when grown at a water potential of −0.28 MPa, resulting in longer and wider roots than in well‐watered (WW) controls. In B73, in contrast, neither the length nor width of lateral roots was affected by water deficit. In water‐stressed FR697, root elongation continued at or above the maximum rate in WW roots for 3 days longer, and was still 45% of maximum when WW roots approached their determinate length. Maintenance of root elongation was associated with sustained rates of cell production. In addition, kinematic analyses showed that reductions in tissue expansion rates with aging were delayed in the longitudinal, radial and tangential planes throughout the root growth zone. Thus, this study reveals large genotypic differences in the interaction of water stress with developmental determinacy of maize lateral roots.