'Brasília' carrot roots (Daucus carota L.) have been exposed to different dehydration levels through the use of forced ventilation at 25 ± 2 °C. At relative water content smaller than 0.95, the turgor-dependent firmness, measured by the external force method, has been reduced to nearly zero, control roots had a firmness above 7.0 kgf cm-2. After a 67 day storage at 5 ± 2 °C, roots that had their initial relative water contents reduced to less than 0.75, presented a firmness recovery to more than 60%, as compared with that of the control roots, in addition showing significant sprouting. These levels of firmness recovery and sprouting had not been previously described. Two hypothesis have been put forward to explain those results: a) occurrence of water relocation process in the roots; b) the theory of cellular cohesive shrinkage. The formation of small lisogenous cavities would favor the first hypothesis; however, accounting for less than 2% of the root volume, they would not be enough to explain the firmness recovery observed in roots with water volume reduction above 20%. By exclusion, it seems that cellular cohesive shrinkage has been the main factor in the firmness recovery observed, allowing significant sprouting in dry roots.
Daucus carota L.; firmness; growth; hidration; shrinkage; storage; turgor; volume reduction
