scholarly journals Screening Sunflower for Tolerance to Sunflower Midge Using the Synthetic Auxin 2,4-Dichlorophenoxyacetic Acid

1994 ◽  
Vol 87 (1) ◽  
pp. 245-251 ◽  
Author(s):  
Gary J. Brewer ◽  
Marc D. Anderson ◽  
Rama Raje N. V. Urs
Keyword(s):  
Dichlorophenoxyacetic Acid ◽  
Synthetic Auxin ◽  
2,4 Dichlorophenoxyacetic Acid

The Transport Behaviour of the Synthetic Auxin 2,4-Dichlorophenoxyacetic Acid in Decapitated Seedlings of Sunflower (Helianthus annuus L.)

1982 ◽  
Vol 9 (1) ◽  
pp. 5 ◽  
Author(s):  
BT Brown ◽  
JN Phillips
Keyword(s):  
Transport System ◽  
Apical Dominance ◽  
Transport Process ◽  
Dichlorophenoxyacetic Acid ◽  
Loading Capacity ◽  
Polar Transport ◽  
Synthetic Auxin ◽  
Transport Behaviour ◽  
Auxin Polar Transport ◽  
2,4 Dichlorophenoxyacetic Acid

The transport behaviour of the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D), applied in aqueous solution to the cut stem surface of sunflower seedlings decapitated in the epicotyl, was studied using steam-ringing to differentiate between apoplastic and symplastic movement. Initially the 2,4-D moved in apoplastic tissue and was distributed rapidly throughout the plant, apparently as the result of a non-auxin-specific transport process. When an amount of 2,4-D sufficient to maintain apical dominance in the decapitated seedling was applied, the initially distributed material was subsequently redistributed acropetally in the stem apoplast and accumulated in the stump apex. When a lower level of 2,4-D, insufficient to maintain apical dominance, was applied, the initially distributed material was redistributed basipetally in the stem symplast, probably via the auxin polar transport system, and accumulated in the root. It is suggested that the 2,4-D loading capacity of the polar transport system is an important factor determining both the transport behaviour of the 2,4-D and its ability to maintain apical dominance in this system.

scholarly journals A small acidic protein 1 (SMAP1) mediates responses of the Arabidopsis root to the synthetic auxin 2,4-dichlorophenoxyacetic acid

2006 ◽  
Vol 47 (5) ◽  
pp. 788-801 ◽  
Author(s):  
Abidur Rahman ◽  
Akari Nakasone ◽  
Tory Chhun ◽  
Chiharu Ooura ◽  
Kamal Kanti Biswas ◽  
...  
Keyword(s):  
Acidic Protein ◽  
Dichlorophenoxyacetic Acid ◽  
Arabidopsis Root ◽  
Synthetic Auxin ◽  
2,4 Dichlorophenoxyacetic Acid

Nodule-Like Structures Induced on the Roots of Wheat Seedlings by the Addition of the Synthetic Auxin 2,4-Dichlorophenoxyacetic Acid and the Effects of Microorganisms

1992 ◽  
Vol 19 (5) ◽  
pp. 481 ◽  
Author(s):  
RW Ridge ◽  
GL Bender ◽  
BG Rolfe
Keyword(s):  
Internal Structure ◽  
Vascular Tissue ◽  
Vascular System ◽  
Lateral Roots ◽  
Growth Time ◽  
Dichlorophenoxyacetic Acid ◽  
Wheat Seedlings ◽  
Synthetic Auxin ◽  
Seedling Roots ◽  
2,4 Dichlorophenoxyacetic Acid

The addition of the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) at a concentration range of between 5 × 10-5 M and 1 × 10-6M caused nodule-like outgrowths on wheat seedling roots. Concentrations of 2,4-D greater than this range caused stunting and death, while concentrations less than 1 × 10-7 M had no obvious effect on plant growth. At the lower end of the concentration range, 2,4-D had a small inhibiting effect on seedling growth. Time-course studies on the development of the nodule-like outgrowths showed that they developed at the same rate as control lateral roots; there was regionality within the structure, and at least three cell types were present: a cell division zone, amyloplast-containing cells, and highly vacuolated cells. There was no organised vascular system similar to Rhizobium/legume symbiotic nodules, although vascular tissue was found to enter the nodule-like outgrowths. Different strains of Rhizobium, Azospirillurn, Agrobacterium and Escherichia coli were added separately with 2,4-D to the seedling roots, showing different effects on seedling health and on the growth and internal structure of the nodule-like outgrowths. Generally, bacteria caused a less-organised internal structure to the growths and earlier 'senescence'. Some bacteria also caused stunting and death of seedlings at concentrations of 2,4-D that would have no such effect alone. We conclude that these induced nodule-like outgrowths are modified lateral roots with carbon reserves (as starch in amyloplasts) similar to those found in the cortex of roots, and that microorganisms are able to modulate or interfere with the development of these outgrowths.

scholarly journals Molecular basis for enantioselective herbicide degradation imparted by aryloxyalkanoate dioxygenases in transgenic plants

2019 ◽  
Vol 116 (27) ◽  
pp. 13299-13304 ◽  
Author(s):  
Jonathan R. Chekan ◽  
Chayanid Ongpipattanakul ◽  
Terry R. Wright ◽  
Bo Zhang ◽  
J. Martin Bollinger ◽  
...  
Keyword(s):  
Catalytic Mechanism ◽  
Biochemical Characterization ◽  
Structural Basis ◽  
Dichlorophenoxyacetic Acid ◽  
Genomic Context ◽  
Synthetic Auxin ◽  
Herbicide Degradation ◽  
Genes Encoding ◽  
Multiple Species ◽  
2,4 Dichlorophenoxyacetic Acid

The synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) is an active ingredient of thousands of commercial herbicides. Multiple species of bacteria degrade 2,4-D via a pathway initiated by the Fe(II) and α-ketoglutarate (Fe/αKG)-dependent aryloxyalkanoate dioxygenases (AADs). Recently, genes encoding 2 AADs have been deployed commercially in herbicide-tolerant crops. Some AADs can also inactivate chiral phenoxypropionate and aryloxyphenoxypropionate (AOPP) herbicides, albeit with varying substrate enantioselectivities. Certain AAD enzymes, such as AAD-1, have expanded utility in weed control systems by enabling the use of diverse modes of action with a single trait. Here, we report 1) the use of a genomic context-based approach to identify 59 additional members of the AAD class, 2) the biochemical characterization of AAD-2 fromBradyrhizobium diazoefficiensUSDA 110 as a catalyst to degrade (S)-stereoisomers of chiral synthetic auxins and AOPP herbicides, 3) spectroscopic data that demonstrate the canonical ferryl complex in the AAD-1 reaction, and 4) crystal structures of representatives of the AAD class. Structures of AAD-1, an (R)-enantiomer substrate-specific enzyme, in complexes with a phenoxypropionate synthetic auxin or with AOPP herbicides and of AAD-2, which has the opposite (S)-enantiomeric substrate specificity, reveal the structural basis for stereoselectivity and provide insights into a common catalytic mechanism.

A gene encoding SMALL ACIDIC PROTEIN 2 potentially mediates the response to synthetic auxin, 2,4-dichlorophenoxyacetic acid, in Arabidopsis thaliana

2009 ◽  
Vol 166 (12) ◽  
pp. 1307-1313 ◽  
Author(s):  
Akari Nakasone ◽  
Maki Kawai-Yamada ◽  
Tomohiro Kiyosue ◽  
Issay Narumi ◽  
Hirofumi Uchimiya ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Acidic Protein ◽  
Dichlorophenoxyacetic Acid ◽  
Gene Encoding ◽  
Synthetic Auxin ◽  
2,4 Dichlorophenoxyacetic Acid

In Vitro Shoot Regeneration from Callus Derived from Marubakaido Apple Rootstock under Different Aluminium Concentrations

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 460e-460 ◽  
Author(s):  
Marisa F. de Oliveira ◽  
Gerson R. de L. Fortes ◽  
João B. da Silva
Keyword(s):  
Shoot Regeneration ◽  
Dichlorophenoxyacetic Acid ◽  
Apple Rootstock ◽  
Under Five ◽  
Significant Difference ◽  
Previously Treated ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
In Vitro Shoot Regeneration

The aim of this work was to evaluate the organogenesis of Marubakaido apple rootstock under different aluminium concentratons. The explants were calli derived from apple internodes treated with either 2,4-dichlorophenoxyacetic acid or pichloram at 0.5 and 1.0 μM and under five different aluminium concentrations (0, 5, 10, 15, 20 mg/L). These calli were then treated with aluminium at 0, 5, 10, 15, and 20 mg/L. It was observed shoot regeneration only for those calli previously treated with pichloram. There were no significant difference among the aluminium concentrations.

Characterization of the Reproductive Mode in Guayule In Vitro

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 483a-483
Author(s):  
Roy N. Keys ◽  
Dennis T. Ray ◽  
David A. Dierig
Keyword(s):  
Field Experiments ◽  
Reproductive Mode ◽  
Dichlorophenoxyacetic Acid ◽  
Initial Field ◽  
Breeding Lines ◽  
Reproductive Modes ◽  
Desert Southwest ◽  
2,4 Dichlorophenoxyacetic Acid

Guayule (Parthenium argentatum Gray, Asteraceae) is a latex-producing perennial desert shrub that is potentially of economic importance as an industrial crop for the desert Southwest. It is known to possess complex reproductive modes. Diploids are predominantly sexual and self-incompatible, while polyploids show a range of apomictic potential and self-compatibility. This paper describes the development of a relatively rapid and simple technique for characterizing reproductive modes of breeding lines of P. argentatum. Initial field experiments were based on an auxin test used successfully to characterize reproductive mode in the Poaceae. The application of 2,4-dichlorophenoxyacetic acid inhibited embryo formation in P. argentatum, but this was not the case with other auxins tested. Results of field experiments were ambiguous because: 1) the floral structure of P. argentatum is such that auxins might not have penetrated to the ovules, and 2) there was potential self-fertilization by pollen released within isolation bags. Therefore, in vitro culture of flower heads was tested because it provided much better control of environmental conditions, growth regulator application, and pollen release. Auxin alone, or in combination with gibberellic acid or kinetin, inhibited parthenogenesis in vitro. Embryo production did not vary using two substantially different nutrient media. In vitro flower head culture using a (Nitsch and Nitsch) liquid nutrient medium without growth regulators, enabled characterization of the reproductive mode of seven breeding lines, ranging from predominantly sexual to predominantly apomictic. The results of this technique were substantiated using RAPD analyzes of progeny arrays from controlled crosses.

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