Potential basis of glyphosate resistance in California rigid ryegrass (Lolium rigidum)

Glyphosate-resistant rigid ryegrass has been identified in California, but research has yet to elucidate the resistance mechanism. The objectives of this study were to examine the differences between sensitive and resistant rigid ryegrass in absorption and distribution of glyphosate, in vivo and in...

Full description

Saved in:
Bibliographic Details
Published in:Weed science 2003-09, Vol.51 (5), p.678-682
Main Authors: Simarmata, Marulak, Kaufmann, John E., Penner, Donald
Format: Article
Language:English
Subjects:
absorption
biotypes
chloroplast
Chloroplasts
coleoptiles
foliar application
glyphosate
Glyphosate resistance
Herbicides
Leaves
Liquids
Lolium rigidum
Metabolism
Phosphonic acids
PHYSIOLOGY, CHEMISTRY, AND BIOCHEMISTRY
Plants
Resistance movements
Seed germination
shikimic acid
translocation
Weed science
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Glyphosate-resistant rigid ryegrass has been identified in California, but research has yet to elucidate the resistance mechanism. The objectives of this study were to examine the differences between sensitive and resistant rigid ryegrass in absorption and distribution of glyphosate, in vivo and in vitro absorption by chloroplasts, and shikimic acid accumulation after glyphosate treatment. Foliar absorption and distribution of 14C-glyphosate did not differ 1 to 3 d after treatment (DAT) between the susceptible (S) and resistant (R) biotypes. Absorption of 14C-glyphosate by isolated chloroplasts also did not differ between the S and R biotypes. After foliar application of 14C-glyphosate, chloroplasts were isolated from treated leaves from both biotypes. Accumulation of 14C-glyphosate in the chloroplasts did not differ between the two biotypes. Shikimic acid level increased significantly in the S biotype after treatment with glyphosate at 2.24 kg ai ha−1 to levels 10-fold greater than in the R biotype 11 DAT. Shikimic acid in the germination media at 2 to 5 mM did not affect seed germination of S and R biotypes but drastically decreased the length of coleoptiles of both at 5 DAT. Thus, biotype differences in sensitivity or metabolism of shikimic acid do not explain differences in sensitivity to glyphosate.
ISSN:0043-1745
1550-2759
DOI:10.1614/P2002-124