Enhanced Colonization of Pea Taproots by a Fluorescent Pseudomonad Biocontrol Agent by Water Infiltration into Soil

Abstract

Liddell, C. M., and Parke, J. L. 1989. Enhanced colonization of pea taproots by a fluorescent pseudomonad biocontrol agent by water infiltration into soil. Phytopathology 79:1327-1332. Root colonization by an introduced strain of Pseudomonasfluorescens bacterium could not be detected on roots beyond 3 cm from the seed, was examined to determine the importance of the root apex in passive more than 16 cm from the root apex. Addition of 27.2 and 54.4 mm transport and to quantify the effect of infiltrating water on distribution of water to the top of the columns 4 days after planting increased the of the bacterium. Pea seeds coated with strain PRA25rif of P.fluorescens depth from which PRA25rif was recovered. The bacterium was detected were sown in columns containing a sandy field soil at soil-water matric on root segments at least 9-10 cm from the seed 24 hr after water was potentials of -1, -6, or -10 kPa. After 7 days, the largest population applied. Transport of the bacterium on the root apex apparently was density of the bacterium was found on roots at -I kPa, but the bacterium limited to a short period after seed germination, but the bacterium was was detected on only 5% of root segments 4-5 cm below the seed, carried long distances by percolating water. approximately 8 cm above the root apex. At -6 and -10 kPa, the