Metabolism and Residues of 2,4-Dichlorophenoxyacetic Acid in DAS-40278-9 Maize (Zea mays) Transformed with Aryloxyalkanoate Dioxygenase-1 Gene

Ethylene production was stimulated by 2,4-dichlorophenoxyacetic acid (2,4-D) from light-grown corn (Zea mays L., var. XL-15) and soybeans (Glycine max Merr., var. Hawkeye). Ethylene had an inhibitory effect on the growth of corn and soybeans, but a reversal of the ethylene effect could not be clearly demonstrated using the competitive inhibitor, carbon dioxide. Ethylene did not mimic the ability of 2,4-D to cause growth curvatures. It was concluded that ethylene played a role in the activity of sublethal amounts of 2,4-D.

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Absorption and Dissipation of TCA by Wheat and Oats

Weed Science ◽

10.1017/s004317450007853x ◽

1970 ◽

Vol 18 (4) ◽

pp. 492-496 ◽

Cited By ~ 6

Author(s):

Paul N. P. Chow

Keyword(s):

Triticum Aestivum ◽

Zea Mays ◽

Hordeum Vulgare ◽

Avena Sativa ◽

Trichloroacetic Acid ◽

Potassium Cyanide ◽

Dichlorophenoxyacetic Acid ◽

Wheat Seedlings ◽

The Difference ◽

2,4 Dichlorophenoxyacetic Acid

In the greenhouse, five crops were grown in soil containing trichloroacetic acid (TCA) at 3 to 24 ppm. Based on seedling yields, corn (Zea mays L., var. Morden 88) and oats (Avena sativa L., var. Rodney) were relatively tolerant to TCA at all rates, barley (Hordeum vulgare L., var. Conquest) and rye (Secale cereale L., var. Antelope) were tolerant at lower rates, but wheat (Triticum aestivum L., var. Manitou) suffered injury at all rates. When TCA-2-14C was applied to the roots of wheat and oats seedlings in water or nutrient solution, wheat seedlings absorbed more TCA-2-14C than oats. Potassium cyanide (KCN) and 2,4-dichlorophenoxyacetic acid (2,4-D) decreased TCA-2-14C absorption by wheat more than that by oats. From 5 to 21 days after application, wheat retained two to four times as much TCA-2-14C as oats. Thus, half of the TCA-2-14C in shoots and roots of wheat disappeared in 11.3 and 11.4 days, respectively, compared with 7.9 and 3.5 days for oats. Based on this investigation, the difference in susceptibility of wheat and oats to TCA appeared to be governed by the metabolic processes involved in absorption and dissipation.

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Hormonal control of ear abortion in a stress-sensitive maize (Zea mays) inbred

Functional Plant Biology ◽

10.1071/pp97154 ◽

1998 ◽

Vol 25 (4) ◽

pp. 481 ◽

Cited By ~ 8

Author(s):

Pierre Lejeune ◽

Els Prinsen ◽

Henry Van Onckelen ◽

Georges Bernier

Keyword(s):

Zea Mays ◽

Indoleacetic Acid ◽

Zea Mays L ◽

Hormonal Control ◽

Floral Transition ◽

Dichlorophenoxyacetic Acid ◽

Apical Shoot ◽

Cold Sensitive ◽

Sterile Leaf ◽

2,4 Dichlorophenoxyacetic Acid

A cold-sensitive maize (Zea mays L.) inbred was used as a model for investigating the interactions between growth regulators, reproductive development, and environmental stress. In this genotype, a chilling treatment given just before floral transition caused the topmost ear to abort and be replaced at maturity by a sterile, leaf-like, structure. Exogenous applications of the synthetic auxin 2,4-dichlorophenoxyacetic acid or of the cytokinin benzyladenine respectively mimicked or prevented the abortive response caused by chilling. Chilling also induced a moderate decrease in the content of endogenous indoleacetic acid (IAA) in the apical shoot tissues. By contrast, zeatin-type cytokinins decreased dramatically (5–8 fold), both in the apical shoot tissues and in the xylem exudate of chilled plants. Overall, the ratio of free-IAA to zeatin-cytokinins was increased in the apical shoot of chilled plants. Our results suggest that: (1) ear abortion induced by chilling might be related to an altered cytokinin content; (2) the number of developing ears may be limited by the endogenous levels of cytokinins just before floral transition; and (3) cytokinins may have a potential for increasing yield in maize.

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Ribonuclease Levels in the Mesocotyl Tissue of Zea mays as a Function of 2,4-Dichlorophenoxyacetic Acid Application

PLANT PHYSIOLOGY ◽

10.1104/pp.39.5.804 ◽

1964 ◽

Vol 39 (5) ◽

pp. 804-809 ◽

Cited By ~ 24

Author(s):

J. C. Shannon ◽

J. B. Hanson ◽

C. M. Wilson

Keyword(s):

Zea Mays ◽

Dichlorophenoxyacetic Acid ◽

2,4 Dichlorophenoxyacetic Acid

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

HortScience ◽

10.21273/hortsci.33.3.460e ◽

1998 ◽

Vol 33 (3) ◽

pp. 460e-460 ◽

Cited By ~ 1

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.

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Characterization of the Reproductive Mode in Guayule In Vitro

HortScience ◽

10.21273/hortsci.33.3.483a ◽

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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The role of a metabolic intermediate in the biodegradation of inhibitory substrates

Water Science & Technology ◽

10.2166/wst.1997.0352 ◽

1997 ◽

Vol 36 (10) ◽

pp. 27-36 ◽

Cited By ~ 1

Author(s):

P. Mungkarndee ◽

S. M. Rao Bhamidimarri ◽

A. J. Mawson ◽

R. Chong

Keyword(s):

The Other ◽

Metabolic Product ◽

Dichlorophenoxyacetic Acid ◽

Mutual Inhibition ◽

Metabolic Intermediate ◽

Batch Cultures ◽

Ortho Cresol ◽

2,4 Dichlorophenoxyacetic Acid

Biodegradation of the mixed inhibitory substrates, 2,4-dichlorophenoxyacetic acid (2,4-D) and para-chloro-ortho-cresol (PCOC) was studied in aerobic batch cultures. Each substrate added beyond certain concentrations inhibited the degradation of the other. This mutual inhibition was found to be enhanced by 2,4-dichlorophenol (2,4-DCP) which is an intermediate metabolic product of 2,4-D. When 2,4-DCP accumulated to approximatelY 40 mg/l degradation of all compounds in the mixed 2,4-D and PCOC substrate system was completely inhibited. The degradation of 2,4-D and PCOC individually was also found to be inhibited by elevated concentrations of 2,4-DCP added externally, while PCOC inhibited the utilization of the intermediate.

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