New solid complexes of a herbicide known as dicamba (3,6-dichloro-2-methoxybenzoic acid) with Pb(II), Cd(II), Cu(II) and Hg(II)
of the general formula M(dicamba)2·xH2O (M=metal, x=0-2) and Zn2(OH)(dicamba)3·2H2O have been prepared and studied. The complexes have different crystal structures. The carboxylate groups in the lead, cadmium
and copper complexes are bidentate, chelating, symmetrical, in Hg(dicamba)2·2H2O - unidentate, and in the zinc salt - bidentate, bridging, symmetrical. The anhydrous compounds decompose in three stages,
except for the lead salt whose decomposition proceeds in four stages. The main gaseous decomposition products are CO2, CH3OH, HCl and H2O. Trace amounts of compounds containing an aromatic ring were also detected. The final solid decomposition products are oxychlorides
of metals and CuO.
Authors:R. Murín, K. Mészáros, P. Nemeček, R. Kuna, and J. Faragó
The effect of explant type (immature vs. mature embryos) and two auxin types (2,4-dichlorophenoxyacetic acid vs. Dicamba) on the callogenesis and plant regeneration ability of 26 wheat cultivars was studied. In general, the callus induction, plant regeneration and shoot formation frequencies were higher in mature embryo-derived cultures as compared to immature ones on media originally developed for mature wheat embryo cultures. In both culture types, the auxin Dicamba was found to be more efficient, especially when mature embryos were cultured. The separation of means using Duncan’s multiple range test revealed the best in vitro response, in terms of the frequency of callus regeneration, in the cultivar Astella for both immature and mature embryo cultures. This cultivar gave very promising results, suggesting that it could be used in the future for further tissue culture investigations and as a donor material for genetic transformation experiments in wheat. Correlation analyses revealed significant similarities between the evaluated parameters within each group (immature and mature embryo-derived cultures). However, there were no significant correlations between these two groups for most of the parameters. This suggests that the mechanism of plant regeneration in the two in vitro regeneration systems (mature vs. immature embryo culture) may be different enough to hamper the development of an optimal plant regeneration protocol for use in both systems.
Authors:Zs. Szentpétery, Cs. Kleinheincz, A. Tarnawa, and M. Jolánkai
,4- dichlorophenoxyacetic acid, Dicamba and 2-(2-methyl-4-chlorophenoxy) propionic acid as their salts. J. Assoc. anal. Chem. , 66, 1220-1225.
Liquid chromatography of liquid formulations containing 2,4- dichlorophenoxyacetic acid, Dicamba and 2
Authors:I. Marcińska, I. Czyczyło-Mysza, E. Skrzypek, M. Warchoł, K. Zieliński, and E. Dubas
The aim of this study was to determine the effect of selected factors on rye (Secale cereale L.) haploid embryo production by the wide crossing method. The study was performed on fifteen winter rye genotypes. This is the first time for rye when besides the genotype, on the enlargement of ovaries and haploid embryo production, such factors as: type of auxin analogues 2,4-dichlorophenoxyacetic acid (2,4-D), 3,6-dichloro-2-methoxybenzoic acid (dicamba) and 4-amino-3,5,6-trichloropyridine-2-carboxylic acid (picloram), and the time between florets emasculation and pollination were investigated. All factors had a significant impact on rye ovary enlargement, however the haploid embryo formation depended only on rye genotype, not on kind of auxin and days between emasculation to pollination. In total, twenty one haploid embryos were formed by six genotypes of fifteen tested. On average, 13.86% (after 2,4-D treatment) to 20.05% (after dicamba treatment) enlarged ovaries per emasculated florets were obtained. Most of the ovaries enlarged when florets were pollinated 4 and 6 days after emasculation. Most of the haploid embryos formed when florets were pollinated 6 days after emasculation. The obtained haploid embryos did not germinate.
Mature barley (Hordeum vulgare cv. Zafer-160) embryos were cultured on callus induction medium (MS+ 4 mg l−1 Dicamba) for 30 days and embryogenic calli were transferred onto regeneration medium (MS+ 0.5 mg l−1 trans-zeatin riboside). Callus induction percentage was 67.2%; embryogenic callus induction percentage was 42.3% and their regeneration percentage was 63.8%. Retrotransposon movements and methylation alterations in 15-day-old, 30-day-old calli and 4-day-old barley seedling (control) were investigated with Inter-Retrotransposon Amplified Polymorphism (IRAP) and Methylation-Sensitive Restriction Fingerprinting (MSRF), respectively. IRAP patterns were quite monomorphic however MSRF indicated increase in cytosine methylation during callus formation. Changes in retroelement movements and methylation alterations were evaluated and discussed in the light of literature.
Authors:Katalin M. Kassai, Z. Szentpétery, Z. Hegedüs, and et al.
wheat varieties representing different genotypes were tested under exposed and
protected conditions in a three year herbicide provocation field trial at Nagygombos,
Hungary. Three types of herbicide treatments (fluroxipir, bromoxynil and dicamba
ai.) were applied in comparison with untreated and mechanical treated controls.
Weed populations were sorted into two major groups according to the level of
their occurrence. The result of experimental treatments were evaluated and weed tolerance of varieties was determined. The
magnitude of weed populations has shown significant differences. All weed
control treatments, including chemical and mechanical applications, had an
influence on weed development. Herbicide treatments had about fifty per cent,
while mechanical applications had a nearly hundred per cent effect concerning
weed reduction. The latter can be considered as a level of total weed extinction.
High weed canopies were observed in the case of untreated controls only. Wheat
cultivars have shown a variety specific yield response. The results obtained suggest
varietal differences concerning weed tolerance. The extent of yield losses
between wheat cultivars ranged from 4 to 18 per cent of grain yield. In the
trial Martonvásári 19 and Martonvásári 21 wheat varieties were proven to have
the best weed tolerance abilities.
Authors:P. Bónis, T. Árendás, I. Jócsák, C. Mikecz, G. Micskei, and L. Marton
Inbred maize lines were treated with normal and double rates of post-emergence herbicides in a small-plot field experiment in one dry and one wet year. The chlorophyll a + b content of symptom-free ear-leaves was determined using a spectrophotometer after 50% silking in order to determine whether various rates of post-emergence herbicides had any effect on the chlorophyll content at flowering and how this was influenced by the type of year. The chlorophyll a + b content of the inbred lines was greatly dependent on the year, with values twice as high in the wet year as in the dry year. Treatment with tembotrione + isoxadifen-ethyl had no effect on the chlorophyll content in either year. Both rates of mesotrione + terbutylazine reduced the chlorophyll a + b content of one stress-sensitive inbred line in the dry year, but not in the wet year. In the wet year bentazone + dicamba increased the chlorophyll content, but only for one line was this effect significant irrespective of the dose. In the dry year the double dose caused a significant increase in this genotype, but the chlorophyll contents of the other lines did not differ significantly from the control.