
TY  - JOUR
A1  - Ceccarelli, Nello 
A1  - Mondin, Alessandra 
A1  - Lorenzi, Roberto 
A1  - Picciarelli, Piero 
A1  - Schiavo, Fiorella Lo 
T1  - The metabolic basis for 2,4-D resistance in two variant cell lines of carrot
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 2002
VL  - 29
IS  - 5
SP  - 575
EP  - 583
KW  - auxin resistance, Daucus carota, gas chromatography&#8211;mass spectrometry, metabolism, transport.
UR  - https://doi.org/10.1071/PP01157 
N2  - In the present work, the characterization of two variant cell lines of carrot capable of growing in high (92 &#956;mol L&#8211;1) concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) is reported. Both these cell lines (4w77 and 4w13) show a significantly lower uptake of 2,4-D with respect to wild-type (wt) cells. In contrast to wt cells, influx of IAA is not reduced by the addition of 100 &#956;M 2,4-D and the presence of this compound appears to stimulate IAA uptake. When grown in the presence of high concentrations of 2,4-D, both 4w77 and 4w13 cells show behavioural differences: instead of lowering the endogenous level of free IAA, the two resistant lines react to the high exogenous concentrations of auxin by raising the level of the free hormone. In 4w77 cells, this is accomplished by reduction of auxin released in the external medium or converted to amide-linked conjugates. In 4w13 cells, the final level of endogenous IAA is an equilibrium between increased synthesis of IAA and a massive release into the medium of the ester- and free-forms of IAA. Both cell lines show disturbances in embryogenesis: line 4w77 forms globular embryos that only mature into aberrant forms having multiple axes, whereas line 4w13 has completely lost its morphogenic capacity. 
ER  -

