Verification of Nitrogenase Activity (C2h2 Reduction) in Azospirillum Populated, 2,4-Dichlorophenoxyacetic Acid Induced, Root Structures of Wheat

1993 ◽  
Vol 20 (2) ◽  
pp. 187 ◽  
Author(s):  
D Yu ◽  
IR Kennedy ◽  
YT Tchan
Keyword(s):  
Nitrogenase Activity ◽  
Dichlorophenoxyacetic Acid ◽  
H2 Evolution ◽  
Nitrite Concentration ◽  
Wheat Seedlings ◽  
Reduction Activity ◽  
15N Enrichment ◽  
C2h2 Reduction ◽  
Azospirillum Brasilense Sp7 ◽  
2,4 Dichlorophenoxyacetic Acid

The characteristics of C2H4 formation and H2 evolution associated with 2,4-D induced root structures on wheat seedlings inoculated with Azospirillum brasilense Sp7 have been investigated. C2H4 formation and H2 evolution with 2,4-D treatment is several times greater than that by wheat seedlings inoculated with Azospirillum alone, as the result of the formation of a niche for azospirilla protected from O2. This increased C2H4 production in 2,4-D treated seedlings was proportional to C2H2 concentration and it was strongly inhibited by nitrite and ammonia. The inhibition increased with greater ammonia and nitrite concentration, but was reversible. The increased rate of C2H2 reduction activity was correlated with 15N enrichment in 2,4-D treated seedlings. These results confirm that the C2H4 formation was C2H2 dependent and represented the nitrogenase activity of A. brasilense associated with the 2,4-D induced root structures of wheat seedlings rather than C2H2 produced by plant tissues.

Absorption and Dissipation of TCA by Wheat and Oats

Weed Science ◽  
1970 ◽  
Vol 18 (4) ◽  
pp. 492-496 ◽  
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.

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.

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.

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

1997 ◽  
Vol 36 (10) ◽  
pp. 27-36 ◽  
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.

2,4-dichlorophenoxyacetic acid through lactation induces astrogliosis in rat brain

1997 ◽  
Vol 30 (3) ◽  
pp. 175-185 ◽  
Author(s):  
A. Brusco ◽  
J. Pecci Saavedra ◽  
G. García ◽  
P. Tagliaferro ◽  
A. M. Evangelista de Duffard ◽  
...  
Keyword(s):  
Rat Brain ◽  
Dichlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid
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