New Zealand Journal of Agricultural Research abstracts
Rhizobacteria harmful to seedling growth in white clover (Trifolium repens
L.) and perennial ryegrass (Lolium perenne L.)
S. U. SARATHCHANDRA
J. A. BROWN
N. R. COX
AgResearch
Ruakura Agricultural Research Centre
Private Bag 3123
Hamilton, New Zealand
Abstract Eleven strains of rhizobacteria (eight
Pseudomonas spp. and three Enterobacter spp.) isolated from the
rhizoplanes of white clover (Trifolium repens L.) or perennial ryegrass
(Lolium perenne L.) plants from New Zealand pastures, were tested in
vitro for toxic metabolites that inhibit root growth. Ten strains of bacteria
inhibited root growth of white clover seedlings, whereas only four strains
inhibited root growth of perennial ryegrass seedlings. One of the most
inhibitory strains was identified as Pseudomonas asplenii. The culture
filtrates of three bacterial strains were tested for heat tolerance. Toxic
activity was destroyed by autoclaving culture filtrates at 121deg.C but not by
boiling. Twelve inhibitory bacteria, including three Klebsiella spp.,
three Enterobacter spp., and six Pseudomonas spp. were tested for
their effects on seedling growth and nitrogen (N) fixation in white clover.
Bacterial cultures were washed and added to white clover seedlings (with and
without Bradyrhizobium leguminosarum bv. trifolii) in sand
culture. One strain each of P. asplenii and P. syringae decreased
(P < 0.01) seedling growth and N fixation indicating their
ability to grow and produce the toxic metabolites in the rhizosphere of
seedlings possibly utilising seedling root exudates.
Keywords deleterious rhizobacteria; nitrogen fixation;
Pseudomonas spp.; root growth inhibition; Rhizobium
New Zealand Journal of Agricultural Research, 1996, Vol. 39: 129-136
0028-8233/96/3901-0129 $2.50/0 (c) The Royal Society of New Zealand
1996
PDF file of entire paper: medium quality (579K); (scanned from paper original: notes about this process)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
