The Translocation of 14C-Labelled Assimilates by Dwarf Bean Plants Infected with Pseudomonas phaseolicola (Burk), Dows

The distribution of 14C-labelled assimilate after infection of the dwarf bean plant with Pseudomonas phaseolicola was followed. Infection of a single unifoliate leaf did not affect the total fixation of 14CO2 by unifoliates during the assimilation period. Fixation was maximal in unifoliates in the early stages of growth but declined as trifoliates expanded. Unifoliates on infected plants retained a greater proportion of assimilated 14carbon than leaves on healthy plants.The pattern of distribution of exported assimilate was not altered in the early stages of infection, the root and apex acting as the major sinks. As the disease developed, the first trifoliate leaf, unlike similar leaves on healthy plants, continued to import assimilate apparently at the expense of the root. Fixation by the first trifoliate and the distribution of assimilate from this leaf were not altered by infection of a single unifoliate leaf. At no stage during development of the disease was there any evidence of translocation of assimilate to either inoculated or non-inoculated unifoliates.