Authors
Borch, K.; Bouma, T.J.; Lynch, J.P.; Brown, K.M.
Source
Plant Cell & Environment, Volume 22, Issue 4, p.425-431 (1999)
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Abstract
The involvement of ethylene in root architectural responses to phosphorus availability was investigated in common bean (Phaseolus vulgaris CIAT breeding line DOR364) plants grown in pots of silica sand in a greenhouse with sufficient or insufficient phosphorus (P). Although P deficiency reduced root mass and lateral root number, main root length was unchanged by P treatment. This resulted in decreased lateral root density in P-deficient plants. The possible involvement of ethylene in growth responses to P deficiency was investigated by inhibiting endogenous ethylene production with amino-ethoxyvinylglycine (AVG) and aerating the root system with various concentrations of ethylene. P deficiency doubled the root:shoot ratio, an effect which was suppressed by AVG and partially restored by exogenous ethylene. AVG increased lateral root density in P-deficient plants but reduced it in P-sufficient plants. These responses could be reversed by exogenous ethylene, suggesting ethylene involvement in the regulation of main root extension and lateral root spacing. P-deficient roots produced twice as much ethylene per gramme of dry matter as P-sufficient roots. Enhanced ethylene production and altered ethylene sensitivity in P-deficient plants may be responsible for root responses to P deficiency
