Tj. Bouma et al., ANALYSIS OF ROOT RESPIRATION OF SOLANUM-TUBEROSUM AS RELATED TO GROWTH, ION UPTAKE AND MAINTENANCE OF BIOMASS, Plant physiology and biochemistry, 34(6), 1996, pp. 795-806
The specific respiratory costs for growth (1/Y; mmol O-2 g(-1) DW), io
n uptake (1/U; mol O-2 mol(-1) NO3-) and maintenance (m; nmol O-2 s(-1
) g(-1) DW) of roots of potato (Solanum tuberosum L.) were determined
in two experiments, and compared to process-based calculations and lit
erature data. Both experiments yielded similar estimates for 1/Y (9.8-
9.9), 1/U (0.39-0.67), and m (10.2-14.8). The range of 1/Y agreed with
the literature data (6.2-10.9), but was high compared to the theoreti
cal expectations (4.3-5.5). Our estimates of 1/U appeared affected by
perturbation. It was deduced that overall costs for maintaining solute
gradients correlates to 1/U (instead of m), and accounts for up to 33
% of the overall costs of nitrate influx. The absence of these costs f
or maintaining solute gradients in present estimates of 1/U explains t
he good agreement with our calculation (0.43), and why these estimates
are lower than most literature values (0.83-1.16). Costs of protein t
urnover (3.7-16 nmol O-2 s(-1) g(-1) DW) can fully account the experim
ental value of m, although m was relatively high compared to most lite
rature data (4.0-7.0).