Effects Of Trifluralin Research Articles

Predisposition of Soybean Seedlings to Fusarium Root Rot with Trifluralin

Soil-incorporated trifluralin significantly increased the severity of Fusarium root rot of soybean seedlings (Glycine max «Corsoy») in greenhouse and field trials. Hypocotyl swelling and cracking caused by trifluralin appeared to offer favorable sites for penetration by Fusarium oxysporum. Exposure of soybean seedlings to trifluralin before being transplanted to pathogen-infested soil also resulted in an increase in root rot severities. The predisposing effect of trifluralin decreased with increasing soil temperatures. No consistent in vitro effects of trifluralin on growth or reproduction of F. oxysporum were observed. These data support the hypothesis that the primary effect of trifluralin on the host-pathogen interaction is to predispose soybean seedlings to infection by F. oxysporum (.)

Effects of Trifluralin on Corn (Zea mays) Growth and Nutrient Content

Glasshouse experiments were conducted to determine the effects of trifluralin on root growth and mineral relations of corn seedlings. Root weight to shoot weight ratios of corn seedlings were positively correlated to concentrations of trifluralin in soil. Root length to shoot weight ratios, however, were inversely related to trifluralin concentrations. Phosphorous and potassium concentrations in shoot tissue were reduced 60 and 35%, respectively, by 0.25 mg trifluralin kg−1soil. Growth inhibition due to trifluralin was partially overcome by supplementing soil with nutrients.

Protein synthesis in trifluralin-treated corn root tips

The effect of trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) on protein synthesis in corn (Zea mays) root tips was determined. 14C-leucine uptake and subsequent incorporation into protein in intact and excised root tips was measured. Root tips were treated with and without 15 µM trifluralin for 2 hr; incorporation of 14C-leucine was observed during a 20-min interval. Total amino acid content in the soluble pool and protein hydrolysate was reduced in the excised tissue by the herbicide. Kinetic analysis showed trifluralin had no effect on endogenous leucine pool size nor on the rate of protein synthesis in intact tissue. Uptake was unaffected; however, in excised tissue uptake increased 100% over the control. While 14C-leucine content was greater in both the soluble pool and protein in treated, excised root tips, analysis showed the apparent increase in protein synthesis was in response to increased pool size.

Joint Effects of Acifluorfen Applications and Soybean Thrips (Sericothrips variabilis) Feeding on Soybean (Glycine max)

Field studies were conducted during 1983 and 1984 to determine the single and interactive effects of trifluralin, soybean thrips, and the sodium salt of acifluorfen on soybean. Increased soybean injury was observed in 1983 when acifluorfen at 0.6 kg ai/ha was applied to soybeans infested with soybean thrips versus plants where soybean thrips were controlled. Soybean injury measured by percent defoliation and visual injury ratings was reduced when thrips were controlled versus soybeans where thrips were not controlled with carbaryl at 0.9 kg ai/ha in 1983. Soybean thrips alone did not reduce soybean seed yield in this study. Acifluorfen reduced soybean photosynthetic rate, shoot weight, root weight, and seed yield. Trifluralin had no effect on soybean growth parameters measured in this study.

Trifluralin‐Substituted Amide Herbicide Interactions

AbstractSubstituted amide and dinitroaniline herbicides are used to selectively control annual grasses and certain broadleaf weeds in soybean [Glycine max (L.) Merr.]. Often, additional herbicide must be applied to control other broadleaf weed species. The objective of this study was to determine if combinations of selected soil‐applied herbicides could be used to control or suppress the growth in soybean of weeds that cannot be controlled with currently available herbicides. Field trials were conducted in 1982 and 1983 to evaluate the effects of two different application methods of trifluralin [2,6‐dinitro‐ N, N‐dipropyl‐4‐(trifluromethyl) benzenamine] and alachlor [2‐chloro‐ N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl)acetamide] or metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1 ‐methylethyl) acetamide] combinations for controlling broadleaf weeds, including morningglory (Ipomoea spp.) and jimsonweed (Datura stramonium L.), in soybean. No significant differences in the control of broadleaf weeds were found between a sequential application and a tank‐mix application of the two herbicides applied as a shallow incorporation. Both herbicide combinations provided good to excellent control of morningglory, and fair to good control of jimsonweed. The control of three Ipomoea species was not significantly different when combinations included either substituted amide. Greenhouse sand culture studies showed significant interaction effects of trifluralin plus alachlor combinations on the growth inhibition of soybean, hemp sesbania [Sesbania exaltata (Raf.) Rydb. ex A. W. Hill], morningglory, jimsonweed, velvetleaf (Abutilon theophrasti Medik), and sicklepod (Cassia obtusifolia L.). Soybean was much less sensitive to the herbicide interaction effects than were broadleaf weeds.

Effects of trifluralin and metabolites on the decomposition of selected substrates by soil microorganisms

The effects of trifluralin and 12 of its soil-formed metabolites on the decomposition of radio-labelled glucose, protein and cellulose were determined, using 14CO2 evolution from soil as a measure of decomposition. Trifluralin increased 14C-glucose mineralization rates, but these increases could be eliminated by adding N. Trifluralin had no inhibitory effect on the mineralization of protein or cellulose, but five of the metabolites inhibited glucose mineralization. None of the trifluralin metabolites affected protein mineralization. Seven trifluralin metabolites increased the rate of cellulose mineralization when applied at rates exceeding those that would be expected in soil. After considering the rate of metabolite application and the magnitude of the responses observed these compounds are expected to have no major effects on the microbial decomposition processes in soil.

Differential Cucurbita spp. Tolerance to the Herbicide Trifluralin

Abstract A germination test of seven Cucurbita entries in a dark growth chamber indicated no effects of trifluralin on germination. Increasing the plant population/pot of butternut type squash (C. moschata Poir, cv. Ponca) did not improve trifluralin tolerance. A factorial arrangement of three treatments (six Cucurbita entries × five trifluralin doses × three herbicide incorporation zone placements in pots) with a randomized complete block design was used in two greenhouse experiments. The incorporation zone treatments included surface layering (above seed), subsurface layering (below seed), and full-pot incorporation of the herbicide dose. The layering treatments increased concentration (ppm) of the herbicide due to the concentrated dose in a small volume of sand medium (200 vs. 500 g quartz sand). Total plant dry weight differences were detected between zoning treatments. After an initial stimulating effect, plant dry weight decreased over the dose range. The C. maxima Duch, PI 182202, and C. pepo L., PI 234252, showed the highest tolerance. Adventitious roots developed and senescence of the primary root occurred above the subsurface treated layer that had been treated at high trifluralin concentrations. The root zone was the primary site of herbicide action. C. moschata, C. pepo, and C. maxima spp. (21 entries) were screened in two tests for tolerance to trifluralin over a range of 0 to 0.4 ppm incorporated in quartz sand. Entry, herbicide dose, and entry × dose interaction effects were significant. C. maxima PI lines 368567 and 179264 exhibited the highest tolerance regardless of dose. Chemical name used: α,α,α-trifluoro-2,6-dinitro-N, N-dipropyl-p-toluidine (trifluralin).

Effects of trifluralin, benomyl and metalaxyl on the incidence and severity of root disease in annual Medicago spp., and evaluation of cultivars for resistance to root rot

The herbicide trifluralin increased both the incidence and severity of root rot in four Medicago truncatula cultivars and reduced their dry matter production. In glasshouse studies with a naturally infested soil from Kaniva, medic root disease was controlled by soil incorporation of metalaxyl but not by soil treatment with benomyl. The known biological activity of metalaxyl suggests that the fungi responsible for the root rot were Peronosporales. The same fungicides failed to control medic root diseases in a field trial at Dooen in 1984. Medic cultivars varied in their susceptibility to root rot, some having moderate resistance, although none were immune. The susceptibility rankings established in glasshouse tests with naturally infested soil were supported by field observations. The results show that there is potential for control of medic root diseases by selecting resistant medic cultivars.

The influence of seed quality on response of cotton seedlings to the preplant herbicide trifluralin

Abstract Effects of the preplant herbicide trifluralin ( a , a , a -trifluoro-2,6-dinitro- N , N -dipropyl- p -toluidine) were studied on cotton ( Gossypium hirsutum L.) seedlings derived from seeds of four cultivars subjected to accelerated aging. Trifluralin effects were determined by measuring stand, lateral root production, damage to taproot, and seedling height. These parameters were measured under laboratory and field conditions. The tests were designed to evaluate the combined effects of trifluralin and seed quality on seedling emergence and development. The detrimental effects of seed aging and trifluralin were similar in the four tests. The adverse effects of seed aging were reduced stand, increased numbers of damaged taproots and decreased seedling height. Significant cultivar by aging interactions for stand were detected. Trifluralin reduced seedling height in the laboratory tests but to a lesser extent than the adverse effect of aging. Trifluralin had minor effects on stand and taproots but caused a drastic reduction in number of lateral roots. The trifluralin by aging interaction was significant for lateral roots in three of the four tests. Therefore, seed quality must be carefully considered when evaluating responses of seedlings to trifluralin. The absence of a consistent cultivar by trifluralin interaction for lateral roots indicated minor difference in tolerance to trifluralin among these cultivars.

WHEAT AND TRITICALE ROOT DEVELOPMENT AS AFFECTED BY TRIFLURALIN

A growth chamber study was conducted to investigate the effects of trifluralin on root morphology of wheat and triticale seedlings. Five spring wheat cultivars, five durum wheat cultivars and three triticale cultivars were grown for 15 days in soil treated with 0, 0.4 and 0.8 ppm trifluralin. Root damage from trifluralin in both wheat and triticale was greater at 0.8 ppm than 0.4 ppm. The 0.4 ppm rate of trifluralin reduced dry weight of Canuck, Hercules and Carman compared to the control; however, at 0.8 ppm, root dry weight of all cultivars was reduced compared to the control. Trifluralin injury symptoms included increased number of seminal roots, decreased seminal root extension, increased root diameter, and reduced root dry weight. As a group, the roots of spring wheat were injured more by trifluralin than the roots of either durum wheat or triticale. Differences in root damage amongst the cultivars was more apparent after the appearance of the second radicle root. A negative correlation was obtained between caryopsis lipid content (μg lipid per caryopsis) and root dry weight among the cultivars at the 0.8 ppm trifluralin rate.Key words: Trifluralin, wheat, triticale, root morphology, lipid

Effects of Trifluralin on Root Morphology and Mineral Status of Wheat (Triticum aestivum) Seedlings

Growth chamber studies using one soil investigated the effects of trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) at 0.0, 0.4, and 0.8 ppmw on the root development and the mineral status of wheat (Triticum aestivumL. ‘Neepawa’) seedlings. The 0.8-ppmw trifluralin rate increased the number of seminal roots, reduced lateral root production, decreased root extension, caused root tips to swell (club-like appearance), and reduced root dry weights. However, 0.4-ppmw trifluralin caused only slight damage to the seedlings. Towards the end of the two-week growth period, damaged seedlings showed signs of recovery, which included an increased number of seminal roots, development of normal root extensions from clubbed root tips, and development of normal lateral root patterns. Trifluralin increased percent calcium and magnesium and decreased percent nitrogen, phosphorus, and potassium in wheat plants. The nutrient concentrations were more affected in 21-day-old plants than in 35-day-old plants, indicating the wheat seedlings were able to recover from trifluralin injury.

Histopathology and enlargement of the pituitary of a teleost exposed to the herbicide trifluralin

Abstract. Pituitaries of sheepshead minnows, Cyprinodon uariegatus, exposed for 19 months to 1‐5 μg/l trifluralin in the laboratory exhibited enlargement, pseudocysts, congestion of blood vessels and oedema. Most of the fish with an enlarged pituitary also had induced diffuse and/or focal vertebral hyperostosis and other dysplastic vertebral changes. Several speculative mechanistic paths are suggested for the mode of effect of trifluralin on the vertebral and pituitary tissues. Abnormal enlargement or variation in sizes of pituitaries from fish of the same age, along with histopathological findings may be related to the environmental quality of the fish's habitat, and provide indications of stress within individuals resulting from toxicant exposure.

Two Sites of Inhibition of the Photosynthetic Electron Transport Chain by the Herbicide Trifluralin

Abstract The effect of trifluralin on the photosynthetic electron transport has been investigated by oxygen evolution and thermoluminescence m easurem ents. The results confirm the earlier observations that trifluralin at low concentrations blocks electron transport between the two photosystems probably at the same site as DBMIB does. At higher concentrations however, trifluralin inhibits the reaction from H2O →pBQ also and affects the thermoluminescence of chloroplasts in a manner sim ilar to DCMU. These results suggest that trifluralin has a second inhibitory site therefore the use of trifluralin as a specific inhibitor of electron transport has to be questioned.

Trifluralin effects on carrot callus tissue

The effect of trifluralin on the growth, oxygen uptake, and adenosine phosphates level of carrot ( Daucus carota L.) callus tissue was determined over a period of 18 days after subculture. The herbicide (10 −4 and 10 −5 M) reduced fresh weight gain significantly; the reduction was less with lower trifluralin concentrations. Dry weight accumulation was not inhibited until after Day 6 of the test period and thereafter was reduced by all concentrations tested. Oxygen consumption was inhibited by trifluralin (10 −4 and 10 −5 M) throughout the test period. Concentrations of 10 −6.10 −7, and 10 −8 M produced variable effects. The response profile of O 2 consumption in the presence of dinitrophenol was different from that of trifluralin. Analysis of adenosine phosphates level gave no clear response trend. Energy charge values of 0.7 to 0.85 were obtained for untreated tissue. Trifluralin had no effect on energy charge until Day 9 (10 −4 M) and after Day 15 (all concentrations).

Behavior of trifluralin in aquatic model ecosystems.

These data illustrate the variation that can be obtained when using different model ecosystem designs in studying the behavior of pesticides in the aquatic ecosystem. These differences were probably related to the rapid metabolism and degradation of soil-incorporated trifluralin in the first experiment and to the continuous input of trifluralin in the second experiment. A very important difference between the two ecosystems was the toxic effect of trifluralin on the algae and fish during the second experiment. We believe that the risks of trifluralin in the aquatic ecosystem are greatest when there is a continuous input of tribluralin. With an occasional soil-incorporated input, the degradation processes would minimize this risk.

The mutagenic effect of trifluralin-containing herbicide on mouse bone marrow in vivo

The mutagenic effect of Trifluralin (2,6-dinitro- N,N-dipropyl-4-trifluor-methyl-anilin) on the chromosomes of mouse bone marrow was studied in vivo. Trifluralin, a herbicide, which at a 26% concentration labeled OLITREF is on the market, was administered ip in a single dose of 0.20 g/kg, and also in fractions to CFLP strain male mice. The single dose of 0.20 g/kg was found to be mutagenic, while a dose of one-hundredth of the LD 50 caused no observable mutagenic change.

Trifluralin effects on tobacco callus tissue: Mitosis and selected metabolic effects

Inhibition of growth of pith callus of tobacco ( Nicotiana tabacum, var. S-73) by the herbicide trifluralin (α,α,α - trifluoro - 2,6 - dinitro - N,N- dipropyl - p - toluidine) was previously observed. Inhibition of cell division in callus tissue of varying age by this herbicide was investigated using the Feulgen reagent and light microscopy. Upon staining and counting the number of cells in each phase of mitosis, a decrease in the number of cells in metaphase, anaphase, and telophase in the treated tissues was found. In addition to this reduction, arrested metaphases and multinucleated cells were observed. Similar results were observed with 10 −4 M colchicine. The effects of trifluralin on incorporation of 14C-precursors into callus RNA, DNA, and protein were also investigated. Apparent RNA, DNA, and protein synthesis in callus were inhibited by trifluralin (5 × 10 −6 M) treatment. The inhibition, however, was not expressed until 5–7 days after initiating treatment. Colchicine also affected apparent RNA, DNA, and protein synthesis; however, these effects were different than those observed with trifluralin. Incorporation of 14C-amino acids into protein was most severely inhibited by colchicine.

Influência de herbicidas na nodulação da soja (Glycine max L. Merr.)

Um experimento foi conduzido em Campinas, em latossolo vermelho escuro, barrento, por dois anos consecutivos, para testar o efeito dos herbicidas trifluralin, vernolate e alachlor e duas doses de nitrogênio, na nodulação e produção de soja, CV santa rosa, inoculada. No primeiro ano, os herbicidas não influenciaram a nodulação aos 35, 58 e 98 dias após o plantio. A aplicação de nitrogênio diminuiu o peso dos nódulos secos observados aos 58 dias, e seu número e peso, aos 98 dias. A produção de grãos foi semelhante para todos os tratamentos. No segundo ano, a nodulação das plantas inoculadas não foi influenciada pela aplicação de nitrogênio, porém nos tratamentos com nodulação espontânea (não inoculados), o peso dos nó dulos secos diminuiu significativamente, nas três épocas, devido à aplicação daquele nutriente. Os tratamentos inoculados produziram maiores quantidades de sementes em comparação com os tratamentos não inoculados. Houve interação significativa de inoculação x adubação nitrogenada, sendo que o aumento devido à adubação só foi verificado no tratamento sem inoculação. Nos canteiros em que se fez a aplicação de herbicidas, a produção de grãos foi maior; não foi , entretanto, possível atribuir esse efeito à aplicação dos herbicidas.

Alachlor and Trifluralin Effects on Nutrient Uptake in Oats and Soybeans1

AbstractAlachlor [2‐chloro‐2′,6′‐diethyl‐N‐(methoxymethyl)acetanilide] and trifluralin (α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) have been reported by several investigators to inhibit root growth in a variety ot plants. However, the biochemical significance of this inhibition is not known. The inhibition of root growth could interfere wth the uptake of plant nutrients. The greenhouse experiments of the present study were conducted to determine what effects the herbicides, alachlor and trifluralin have on the growth and on the uptake of H32PO2−4 and 35SO2−4 of oats (Avena sativa L. ‘Neal’) and soybeans [Glycine max (L.) Merr. ‘Clark 63’]. Oats is regarded as an alachlor and trifluralin‐sensitive species, and soybean is regarded as an alachlor and triflurafin‐tolerant species. Root weight of both species was reduced with increasing concentrations of both soil‐incorporated herbicides. The reduced root biomass of soybean was accompanied by a proportional reduction in shoot biomass, but in oats the shoot biomass was reduced more than the root biomass. Root biomass and the accumulation of H32PO2−4 and 35SO2−4 in oat and soybean shoots were directly correlated.Alachlor and trifluralin altered biochemical processes in oats and soybeans which control root and shoot growth. The herbicides selectively altered the plants' abilities to absorb H32PO2−4 and 35SO2−4.

The effect of Trifluralin on the formation of ectotrophic mycorrhizae in some pine species.

Pot experiments were performed to investigate the effects of Tritluralin on the mycorrhizal symbiosis of conifer seedlings. Infected forcst soils and potting mixturcs were mixed, pottcd and treated with Trifluralin at levels of 0.2 and 0.4ml/m2 Seeds of Pinus sylvestris L. and Picea abies (L.) Karst. were sown in the pots. The concentrations tested, though recommended by the manufacturer produced phytotoxicity. The seedling growth in general and that of the rootsystem and laceral roots in particular, were severely inhibited. Mycorrhizal development in the seedlings was consequently adversely affected.