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Respiration rate in maize roots is related to concentration of reduced nitrogen and proliferation of lateral roots
Author(s) -
Granato Tom C.,
Raper C. David,
Wilkerson Gail G.
Publication year - 1989
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1989.tb06213.x
Subject(s) - respiration , respiration rate , nitrogen , zoology , chemistry , dry weight , botany , horticulture , biology , organic chemistry
The relationship between specific rate of respiration (respiration rate per unit root dry weight) and concentration of reduced nitrogen was examined for maize ( Zea mays L.) roots. Plants with 2 primary nodal root axes were grown for 8 days in a split‐root hydroponic system in which NO‐ 3 was supplied to both axes at 1.0 mol m −3 , to one axis at 1.0 mol m −3 and the other axis at 0.0 mol m −3 or to both axes at 0.0 mol m −3 Respiration rates and root characteristics were measured at 2‐day intervals. Specific rate of respiration was positively correlated in a nonlinear relationship with concentration of reduced nitrogen. The lowest specific rates of respiration occurred when neither axis received exogenous NO −3 and the concentration of reduced nitrogen in the axes was less than 9 mg g −1 . The greatest rates occurred in axes that were actively absorbing NO −3 and contained more than 35 mg g −1 of reduced nitrogen. At 23 mg g −1 of reduced nitrogen, below which initiation of lateral branches was decreased by 30–50%. specific rate of respiration was 17% greater for roots actively absorbing NO −3 than for roots not absorbing NO −3 Increases in specific rate of respiration associated with concentrations of reduced nitrogen greater than 23 mg g −1 were concluded to be attributable primarily to proliferation of lateral branches.