Effects Of Triadimefon Research Articles

Effects of fungicides triadimefon and propiconazole on soil bacterial communities

The impact of fungicides triadimefon and propiconazole on soil bacterial populations from a strawberry field was investigated. Two fungicides were applied to the soil at concentrations of 10 mg/kg or 100 mg/kg with soil water contents 20.2% (fresh soil water content) or 26.0% (field capacity). Changes in bacterial communities were assessed using DNA extraction, polymerase chain reaction (PCR) amplification of the 16S rDNA and denaturing gradient gel electrophoresis (DGGE). High performance liquid chromatography (HPLC) was utilized to detect the residue of fungicides in soils. The results showed that propiconazole was more persistent than triadimefon in soils, and the two soil water contents did not cause significant differences in dissipation rates between the two fungicides. A high concentration of propiconazole could inhibit the existence of soil microbes while one of triadimefon might induce the microbial population in the first stage. From unweighted pair-group method using arithmetic averages (UPGMA) dendrograms, the effect of triadimefon and propiconazole at the two applied concentrations on a soil bacterial community could be long term. After triadimefon was applied for 60 days and propiconazole for 75 days, the compositions of microbial communities were not recovered. From the viewpoint of environmental protection, it was of significant importance to pay more attention not only to the residues of pesticide but also to the change in soil microbial communities.

Triadimefon induced changes in the antioxidant metabolism and ajmalicine production in Catharanthus roseus (L.) G. Don.

The effects of triadimefon, a triazole compound on the antioxidant potentials and root alkaloid ajmalicine content were studied in two varieties, rosea and alba of Catharanthus roseus (L.) G. Don., an important medicinal plant. The plants of both the varieties were subjected to 15 mg l −1 triadimefon treatment by soil drenching on 53, 68 and 83 days after planting (DAP). The plants were harvested on 60, 75 and 90 days after planting and the antioxidant potentials and ajmalicine content were estimated. The antioxidant potentials viz., ascorbic acid (AA), α-tocopherol and reduced glutathione (GSH) were found increased under triadimefon treatment. The antioxidant enzymes like superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) activities showed slight changes in both the varieties under triadimefon treatment when compared to control plants. Indole alkaloid ajmalicine content increased significantly under triadimefon treatment. The increase in ajmalicine content was more in rosea variety than in alba variety. These preliminary results suggest that, the application of triadimefon may be a useful tool to increase the alkaloid production in medicinal plants.

Effects of triadimefon on extracellular dopamine, DOPAC, HVA and 5-HIAA in adult rat striatum

Triadimefon has been shown to inhibit monoamine uptake, bind to the dopamine (DA) transporter, and stimulate dopamine efflux in rat brain tissue, in vitro. To determine whether these changes also occur in the intact animal and to study the reversibility of the effects observed, we used in vivo microdialysis to determine changes in the concentrations of DA, dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindolacetic acid (5-HIAA) in the striatal dialysates from free moving adult rats after exposure to triadimefon 50, 100 and 200 mg/kg, i.p. Triadimefon induced a gradual dose- and time-dependent accumulation of extracellular DA accompanied by a small increase in the HVA and 5-HIAA concentrations. These changes were still present 24 h after treatment in the group treated with 200 mg/kg and had vanished 48 h after treatment. In contrast to the DA efflux induced by S(+)-amphetamine (2 mg/kg, i.p.), that induced by triadimefon was totally inhibited by the infusion of 10 −5 M tetrodotoxin (TTX), a voltage-gated Na + channel blocker, thus showing that the increase in extracellular DA induced by triadimefon was an action potential-dependent mechanism. GBR 12909 (10 mg/kg, i.p.), a dopamine uptake inhibitor, induced a gradual increase in striatal dopamine similar to that induced by triadimefon, whereas the effects on the acid metabolites were not exactly the same. The present results indicate that triadimefon acts in vivo as a DA transporter inhibitor and could also act on the serotoninergic system.

Microbial interactions on the phylloplane of wheat and barley after applications of mancozeb and triadimefon

In field experiments mancozeb significantly reduced fungal populations on wheat and barley leaves whereas triadimefon had only a minor effect. Bacterial populations were not directly affected by either fungicide nor did bacteria colonise and populate the vacant niche resulting from fungicide application. The effect of the two fungicides on phylloplane fungi was closely related to their effect on the growth rates of these fungi in vitro. Microbial populations on leaf surfaces were dominated by the pink yeast Rhodotorula glutinis, the filamentous fungus Cladosporium cladosporioides and the bacterium Pseudomonas fluorescens. A single application of mancozeb caused significant reductions in the fungal populations in field trials in 1982 and 1983. Three applications of mancozeb prevented recolonisation during the experimental period of 24 days. The duration of this effect was greater in 1983 than in 1982. Disturbed habitats were recolonised by the same species of fungi that were initially present on the phylloplane In contrast, triadimefon did not reduce fungal populations on wheat and barley in trials in 1982 and caused only a small reduction in fungal populations after a second and a third application in 1983. The effects of the two fungicides on the dominant phylloplane fungi appeared to be directly related to the sensitivity of these fungi to the fungicides. The effects of triadimefon and mancozeb on the biodiversity of fungi and bacteria on the phylloplane over time were minimal.

Early effects of triadimefon on water relations, sterol composition and plasma membrane ATPase in white spruce (Picea glauca) seedlings

Early effects of triadimefon on water relations, sterol composition and plasma membrane ATPase in white spruce (Picea glauca) seedlings

Effects of triadimefon and osmotic stress on plasma membrane composition and ATPase activity in white spruce (Picea glauca) needles

White spruce [Picea glauca (Moench) Voss.] seedlings were grown in solution culture and treated with 20 mg I‐1 triadimefon [1‐(chlorophenoxy)‐3,3‐dimethyl‐1‐(1,2,4‐triazol‐1‐yl)‐2‐butanol] for 4 weeks and then subjected to osmotic stress with polyethylene glycol 3350. Water potentials and electrolyte leakage were measured in control and triadimefon‐treated seedlings before and after the plants were subjected to osmotic stress. The plasma membranes were isolated from needles to study their lipid composition and the activity of plasma‐membrane bound ATPase. Triadimefon treatment reduced water potentials and increased leakage of electrolytes from seedlings. However, when the seedlings were exposed to osmotic stress, triadimefon‐treated plants maintained higher water potentials and leaked less electrolytes compared with the control plants. Both triadimefon and osmotic stress treatments inhibited the activity of plasma membrane‐bound ATPase and altered the composition of free sterols in the plasma membranes. Triadimefon‐treated plants contained traces of campesterol, which was not present in control. Osmotic stress drastically reduced phospholipid:protein and sterol:protein ratios and increased sterol:phospholipid ratios in the plasma membranes

Effects of triadimefon and osmotic stress on plasma membrane composition and ATPase activity in white spruce (Picea glauca) needles

Effects of triadimefon and osmotic stress on plasma membrane composition and ATPase activity in white spruce (Picea glauca) needles

Effects of triadimefon on a multiple schedule of fixed-interval performance: Comparison with methylphenidate, d-amphetamine and chlorpromazine

Triadimefon is a fungicide that has recently been shown to increase motor activity and rates of schedule-controlled responding. These findings indicate that triadimefon resembles psychomotor stimulants and in this respect is a unique pesticide. The present experiment was designed to evaluate triadimefon's effects on performance maintained by a multiple schedule of reinforcement and to compare triadimefon to known psychomotor stimulants. Four rats were trained to perform under a mult FI 1-min FI 5-min schedule of milk reinforcement. They then received a series of dosages of triadimefon (10-170 mg/kg, IP) and of methylphenidate (1-17.3 mg/kg, IP) in a counterbalanced order. Triadimefon increased response rates in both the FI 1-min and FI 5-min components. Methylphenidate did not consistently alter response rates in either component. Temporal patterns of responding were disrupted much more in the FI 5-min component than in the FI 1-min component by both triadimefon and methylphenidate. Performances were then evaluated following a series of dosages of d-amphetamine (0.3-3.0 mg/kg, IP) and chlorpromazine (0.5-2.0 mg/kg, IP). Response rates were increased by d-amphetamine in the FI 1-min component but not in the FI 5-min component. Like triadimefon and methylphenidate, d-amphetamine produced a greater disruption of response patterning in FI 5-min than in FI 1-min. Only chlorpromazine decreased response rates in both components. Chlorpromazine also disrupted FI 5-min response patterning, but left FI 1-min patterning intact.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of Triadimefon on Growth and Ectomycorrhizal Development of Loblolly and Slash Pines in Nurseries

Effects of Triadimefon on Growth and Ectomycorrhizal Development of Loblolly and Slash Pines in Nurseries

Effects of Triadimefon and Triadimenol as Seed Dressings on Incidence of Fusiform Rust on Loblolly Pine Seedlings

Effects of Triadimefon and Triadimenol as Seed Dressings on Incidence of Fusiform Rust on Loblolly Pine Seedlings

Effects of triadimefon on the ultrastructure of rust fungi infecting leaves of wheat and broad bean ( Vicia faba)

The effect of triadimefon on the fine structure of Uromyces vicia-fabae infecting leaves of broad bean, and brown rust caused by Puccinia recondita infecting wheat leaves, was studied using transmission electron microscopy. Changes were induced in intercellular mycelia following both root and leaf application of the fungicide. Incomplete and multiperforate septa occurred, and extensive wall thickening was found, often almost completely blocking the hyphae. Triadimefon vapour was shown to have a similar effect on intercellular hyphae of P. recondita as did direct application. The changes are discussed in relation to the mode of action of triadimefon and its effect on sterol biosynthesis.

Effects of triadimefon on the fine structure of germinating conidia of Botrytis allii

Conidia of Botrytis allii germinated in the presence of triadimefon to produce stubby and swollen germ tubes. Electron micrographs showed that organelles remained intact after treatment but in some cells there was an increase in vacuolation and in the numbers of lipid vesicles. The most striking changes were in the process of septum formation. Septa almost invariably remained incomplete in the presence of triadimefon but complete in its absence. In some hyphae septa were not produced but the wall became unevenly thickened. Vesicles occurred close to septal and hyphal walls and within swollen parts of walls. Triadimefon probably interferes with the mechanism of septal and hyphal wall construction.

The effects of triadimefon on growth, sclerotial formation, and ultrastructure of Sclerotinia sclerotiorum

The presence of 62.5–125 μM of triadimefon [1-(4-chlorophenoxy)-3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)-2-butanone] in glucose-nitrate liquid medium resulted in reduced mycelial growth and inhibition of sclerotial formation of S. sclerotiorum. Hyphae grown in the presence of triadimefon contained more mitochondria and endoplasmic reticulum (ER) than did untreated hyphae. The additional ER occurred both as randomly oriented material and as membrane complexes or stacks. Membrane-bound vesicles accumulated between the plasma membrane and the cell wall. Triadimefon alone and in conjunction with other inhibitors may be useful in elucidating the process of sclerotial formation in S. sclerotiorum.