scholarly journals The effect of low growth temperature on Hill reaction and Photosystem 1 activities in three biotypes of Kochia scoparia (L.) Schrad. with different sensitivity to atrazine and ALS-inhibiting herbicides

2011 ◽  
Vol 50 (No. 1) ◽  
pp. 10-17 ◽  
Author(s):  
D. Holá ◽  
M. Kočová ◽  
O. Rothová ◽  
D. Chodová ◽  
J. Mikulka
Keyword(s):  
Low Temperature ◽  
Growth Temperature ◽  
Acetolactate Synthase ◽  
Photochemical Activity ◽  
Hill Reaction ◽  
Photosystem 1 ◽  
Kochia Scoparia ◽  
Temperature Conditions ◽  
Als Inhibitors ◽  
Hill Reaction Activity

A possible influence of low growth temperature on the photochemical activity of isolated mesophyll chloroplasts was studied in three biotypes of kochia [Kochia scoparia (L.) Schrad.] that showed either double resistance to both atrazine and acetolactate synthase (ALS) inhibitors (Bubny biotype), resistance to ALS inhibitors but not to atrazine (Jihlava biotype), or sensitivity to both types of herbicides (Karlín biotype). Plants 5 or 12 weeks old since the date of sowing were examined. The Bubny biotype displayed the lowest values of Hill reaction activity (HRA) among all biotypes examined, and a significantly lower activity of Photosystem (PS) 1 compared to the Karlín biotype; this applied both for the control and low temperature-grown plants and for both plant ages studied. The comparison of HRA and PS1 activity in the Jihlava and Karlín biotypes showed lower values of both parameters for the Jihlava biotype. The HRA of plants grown at low temperature conditions was usually only slightly lower compared to the control plants of all three biotypes examined. The activity of PS1 in the kochia biotypes grown under low-temperature conditions increased markedly and significantly compared to the control plants; this increase was slightly higher in the atrazine-sensitive biotypes Jihlava and Karlín than in the resistant biotype Bubny. The differences between resistant and susceptible biotypes in the HRA diminished under low-temperature conditions whereas the differences in PS1 activity increased.

The Evidence for Reduced Glyphosate Efficacy on Acetolactate Synthase–Inhibiting Herbicide-Resistant Yellow Nutsedge (Cyperus esculentus)

Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 389-398
Author(s):  
Parsa Tehranchian ◽  
Jason K. Norsworthy ◽  
Matheus Palhano ◽  
Nicholas E. Korres ◽  
Scott McElroy ◽  
...  
Keyword(s):  
Amino Acid ◽  
Production Systems ◽  
Acetolactate Synthase ◽  
Dry Weight ◽  
Cross Resistance ◽  
Purple Nutsedge ◽  
Yellow Nutsedge ◽  
Epsps Gene ◽  
Treated Leaf ◽  
Als Inhibitors

A yellow nutsedge biotype (Res) from an Arkansas rice field has evolved resistance to acetolactate synthase (ALS)-inhibiting herbicides. TheResbiotype previously exhibited cross-resistance to ALS inhibitors from four chemical families (imidazolinone, pyrimidinyl benzoate, sulfonylurea, and triazolopyrimidine). Experiments were conducted to evaluate alternative herbicides (i.e., glyphosate, bentazon, propanil, quinclorac, and 2,4-D) currently labeled in Arkansas rice–soybean production systems. Based on the percentage of aboveground dry weight reduction, control of the yellow nutsedge biotypes with the labeled rate of bentazon, propanil, quinclorac, and 2,4-D was < 44%. Glyphosate (867 g ae ha−1) resulted in 68 and > 94% control of theResand susceptible yellow nutsedge biotypes, respectively, at 28 d after treatment. Dose-response studies were conducted to estimate the efficacy of glyphosate on theResbiotype, three susceptible yellow nutsedge biotypes, and purple nutsedge. Based on the dry weights, theResbiotype was ≥ 5- and ≥ 1.3-fold less responsive to glyphosate compared to the susceptible biotypes and purple nutsedge, respectively. Differences in absorption and translocation of radiolabeled glyphosate were observed among the yellow nutsedge biotypes and purple nutsedge. The susceptible biotype had less14C-glyphosate radioactivity in the tissues above the treated leaf and greater radioactivity in tissues below the treated leaf compared to theResbiotype and purple nutsedge. Reduced translocation of glyphosate in tissues below the treated leaf of theResbiotype could be a reason for the lower glyphosate efficacy in theResbiotype. No amino acid substitution that would correspond to glyphosate resistance was found in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene of theResbiotype. However, an amino acid (serine) addition was detected in the EPSPS gene of theResbiotype; albeit, it is not believed that this addition contributes to lower efficacy of glyphosate in this biotype.

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