Long-term effects of 2, 4-D application on plants. I. Effects on the weed community in a wheat crop

1987 ◽  
Vol 65 (12) ◽  
pp. 2530-2536 ◽  
Author(s):  
Larry Hume
Keyword(s):  
Chenopodium Album ◽  
Dry Weight ◽  
Abundant Species ◽  
Species Group ◽  
Wheat Crop ◽  
Long Term Effects ◽  
Thlaspi Arvense ◽  
Tolerant Species ◽  
The Difference

At Indian Head, Saskatchewan, there are plots that have been sprayed annually with 2,4-D for 36 years, since 1947. Herbicide application rates since 1969 in two sets of plots were 0.42 and 1.12 kg/ha, along with control plots with no application. The crop was wheat in a 3-year wheat – wheat – fallow rotation. The plots were monitored throughout the growing season in 1982 and 1983. The 14 most abundant species on these plots were grouped as susceptible, moderately tolerant, or highly tolerant to 2,4-D. These three groups differed significantly from each other with respect to the number of emerging seedlings during four separate time periods, survival to crop harvest, plant dry weight, and seed production. In all treatments, plant number and size decreased with emergence date, with only a few small plants emerging late in the season. Over the long term, 2,4-D use significantly reduced the number of plants of susceptible species, but it did not eliminate them. Reduced numbers of susceptible plants enabled the number of plants of highly tolerant species to increase. Even in plots treated with high rates of 2,4-D, plants of the susceptible species, Chenopodium album L. and Thlaspi arvense L., were still as abundant as those of any other species group. The overall effect of 2,4-D application was to reduce the difference in performance of susceptible and tolerant species, resulting in changes in quantitative aspects of community structure. No new major species has become established since 1947 as a result of 2,4-D application.

Long-term effects of 2,4-D application on plants. II. Herbicide avoidance by Chenopodium album and Thlaspi arvense

1988 ◽  
Vol 66 (2) ◽  
pp. 230-235 ◽  
Author(s):  
Larry Hume
Keyword(s):  
Life Cycle ◽  
Chenopodium Album ◽  
Herbicide Tolerance ◽  
Long Term Effects ◽  
Annual Life Cycle ◽  
Thlaspi Arvense ◽  
Immature Seeds ◽  
Winter Annual ◽  
Dichlorophenoxy Acetic Acid

Research plots in a wheat–wheat–fallow rotation at Indian Head, Sask., were sprayed annually with 2,4-dichlorophenoxy-acetic acid (2,4-D) for 36 consecutive years. Two species susceptible to 2,4-D, Chenopodium album L. and Thlaspi arvense L., were dominant in these plots. From 1981 to 1983, C. album and T. arvense seedlings that emerged during four periods of the growing season were marked and their mortality, seed production, and size recorded. From these data and other studies, 10 ways in which C. album and T. arvense managed to survive herbicide application were identified. These are intermittent germination, herbicide tolerance, small size of late-emerging seedlings, short life cycle, hardiness, failure of control practices, long-term dormancy, seed dispersal, viability of immature seeds, and winter annual life cycle of T. arvense.

scholarly journals Cl− More Detrimental Than Na+ in Rice Under Long-Term Saline Conditions

2018 ◽  
Vol 10 (10) ◽  
pp. 66
Author(s):  
Hanh Duy Dao ◽  
Yoshihiko Hirai
Keyword(s):  
Grain Yield ◽  
Salinity Tolerance ◽  
Dry Weight ◽  
Long Term Effects ◽  
Negative Effects ◽  
Rice Varieties ◽  
Treatment Groups ◽  
Whole Plant ◽  
The Difference

Rice is considered sensitive to salinity and hence, improving the salinity tolerance of rice is desired to increase productivity. Most research on salinity tolerance for the growth and grain yield of rice focuses on the toxicity of sodium (Na+) and not chloride (Cl−); the information on the negative effects of Cl− on rice is still limited. To learn the difference in the long-term effects of Na+ and Cl− on the whole plant and grain productivities, three rice varieties differing in salinity tolerance were grown in pots irrigated by water with NaCl and KCl in the same molar concentration. The whole plant dry weight and grain yield in all varieties decreased to the same extent after NaCl and KCl treatments compared to the control during the full heading and maturity stages. However, Na+ content in shoots of all varieties under NaCl treatment were higher at all stages than that under KCl treatment and the control. In the most cases, the Cl− content in plants was similar in the NaCl and KCl treatment groups. There was a negative significant correlation between the relative dry weight and grain yield (treated/control) and the Cl− content in the plants. From these results, it was suggested that plant dry weight and grain yield under long-term salinity conditions was reduced by Cl− toxicity rather than Na+ toxicity.

Comparison of soil CO2 emissions from three different tillage methods on chernozem soil

2021 ◽  
Author(s):  
Márton Dencső ◽  
Ágota Horel ◽  
Zsófia Bakacsi ◽  
Eszter Tóth
Keyword(s):  
Greenhouse Gas Emission ◽  
Environmental Parameters ◽  
Conventional Tillage ◽  
No Tillage ◽  
Chernozem Soil ◽  
Long Term Effects ◽  
Tillage Practices ◽  
The Difference ◽  
Tillage Methods

<p>Tillage practices influence soil CO<sub>2</sub> emissions, hence many research investigate the long-term effects of conservation and conventional tillage methods e.g. ploughing and no-tillage on soil greenhouse gas emission.</p><p>The experiment site is an 18-years-old long-term tillage trial established on chernozem soil. During 2020, we took weekly CO<sub>2 </sub>emission measurements in the mouldboard ploughing (MP), no-tillage (NT), and shallow cultivation (SC) treatments Tillage depth was 26-30 cm, 12-16 cm and 0 cm in the cases of MP, SC and NT respectively. The experiment was under wither oat cultivation.</p><p>We investigated the similarity in the CO<sub>2</sub> emission trends of SC to MP or NT treatments. Besides CO<sub>2</sub> emission measurements, we also monitored environmental parameters such as soil temperature (Ts) and soil water content (SWC) in each treatment.</p><p>During the investigated year (2020 January - December) SC had higher annual mean CO<sub>2</sub> emission (0.115±0.083 mg m<sup>-2</sup> s<sup>-1</sup>) compared to MP (0.099±0.089 mg m<sup>-2</sup> s<sup>-1</sup>) and lower compared to NT (0.119±0.100 mg m<sup>-2</sup> s<sup>-1</sup>). The difference of the CO<sub>2</sub> emissions was significant between SC and MP (p<0.05); however, it was not significant between SC and NT (p>0.05) treatments. The Ts dependency of CO<sub>2</sub> emission was moderate in all treatments. CO<sub>2</sub> emissions were moderately depended on SWC in MP and SC, and there was no correlation between these parameters in NT.</p><p>The annual mean CO<sub>2</sub> emission of the SC treatment was more similar to the NT, than to the MP treatment.</p>

A COMPARISON OF MCP AND 2,4-D FOR THE CONTROL OF ANNUAL WEEDS IN GRAIN CROPS

1957 ◽  
Vol 37 (1) ◽  
pp. 69-83 ◽  
Author(s):  
H. A. Friesen ◽  
D. R. Walker
Keyword(s):  
Chenopodium Album ◽  
Amaranthus Retroflexus ◽  
Seedling Stage ◽  
Dichlorophenoxyacetic Acid ◽  
Growth Stages ◽  
Thlaspi Arvense ◽  
Wild Mustard ◽  
The Difference ◽  
Lamb’S Quarters ◽  
2,4 Dichlorophenoxyacetic Acid

Oats, flax and barley were sprayed with various formulations of MCP (2-methyl-4-chlorophenoxyacetic acid) and 2,4-D (2,4-dichlorophenoxyacetic acid) at a number of Experimental Farms in Western Canada in 1954 and 1955. Each formulation was applied at 4 and 8 ounces of acid equivalent per acre at each of two dates, viz., Date 1, when the weeds were in the seedling stage less than 3 inches in height; and Date 2, at a stage coinciding with the first appearance of buds on the major weed species.Stinkweed (Thlaspi arvense, L.), wild mustard (Brassica kaber (DC.) L.C. Wheeler var. pinnatifida (Stokes) L.C. Wheeler), lamb's quarters (Chenopodium album L.), Russian pigweed (Axyris amarantoides L.), and ball mustard (Neslia paniculata L.), were effectively controlled by each of the MCP and 2,4-D formulations used. Russian thistle (Salsola kali L.), and red-root pigweed (Amaranthus retroflexus L.), were not satisfactorily controlled by MCP, whereas hemp nettle (Galeopsis tetrahit L.) was not controlled by 2,4-D. Wild buckwheat (Polygonum convolvulus L.) was not controlled by any of the treatments. Each treatment was more effective when applied during the seedling stage of the weeds.On the basis of wood control and yield of grain the results of this study favour the use of MCP over 2,4-D with either oats or flax. Oats was significantly more tolerant to MCP, particularly if treated during the early growth stages when weed competition was most critical. With flax, the difference in tolerance was most pronounced in favour of MCP at the later date of treatment. The 2,4-D ester and low volatile ester resulted in a preponderance of plant deformities, lowered the yields of both oats and flax and delayed the maturity of flax significantly. Barley yields in this study were not adversely affected by any of the treatments.

Logging-residue extraction does not reduce the diversity of litter-layer saprotrophic fungi in three Swedish coniferous stands after 25 years

2009 ◽  
Vol 39 (9) ◽  
pp. 1737-1748 ◽  
Author(s):  
Johan Allmér ◽  
Jan Stenlid ◽  
Anders Dahlberg
Keyword(s):  
Woody Debris ◽  
Abundant Species ◽  
Litter Layer ◽  
Natural Forests ◽  
Long Term Effects ◽  
Saprotrophic Fungi ◽  
Clear Cut ◽  
Logging Residues ◽  
Logging Residue

Logging residues, consisting of branches and treetops, are increasingly being extracted for biofuel purposes in Fennoscandia, thereby decreasing the availability of fine woody debris (FWD). Little is known about the importance of FWD and litter to fungal diversity, although they constitute the major components of dead organic matter in both managed and natural forests. We investigated the long-term effects of removing logging residue on the saprotrophic fungi community in the litter layer by using an experiment established 25 years ago, comprising stands with and without removal of clear-cut slash. The fungal communities were identified using terminal restriction fragment length polymorphism from standardized baits of wood and needles left in the litter layer for 30 months. A total of 74 fungal taxa were recorded. No differences in species richness or frequency of abundant species were detected between the stands with and without slash removal, suggesting that the extraction of logging residues has a negligible long-term impact on abundant saprotrophic fungi. Twenty-five of the 36 abundant species colonized wood and needles indiscriminately, while 10 species occurred exclusively on wood or needles and only one species mainly on wood. The importance of litter to certain wood-inhabiting fungi may therefore be underrated. The frequent records of Trichaptum abietinum (Dicks.) Ryvarden indicate that wood-inhabiting species may, surprisingly, be found in the litter layer.

scholarly journals Can aphids learn to cope with the pressure of endophytic fungi in their food plants?

2007 ◽  
Vol 13 ◽  
pp. 333-336
Author(s):  
S.A. Härri ◽  
J. Krauss ◽  
C.B. Müller
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Rhopalosiphum Padi ◽  
Food Plants ◽  
Long Term Effects ◽  
Test Environment ◽  
Life History Parameters ◽  
Strain Adaptation ◽  
The Difference

Plant-endophyte associations can have major impacts on the dynamics of consumer interaction-webs but long-term effects of mycotoxins and the ability of herbivores to adapt to these toxins have not been studied. To understand the potential of aphids to cope with mycotoxins, we compared the life-history parameters for aphids conditioned for several generations on endophyte-infected plants with those of endophyte-naïve aphids on both endophyteinfected and endophyte-free grasses. Aphids conditioned on endophyte-infected plants produced more offspring during the first days of adulthood than endophyte-naïve aphids independent of the endophyte infection of the test environment. However, the endophyte-conditioned aphids tended to have a shorter lifespan, which resulted in similar numbers of total offspring produced for endophyte-conditioned and endophyte-naïve aphids. The difference in life-history parameters caused by the conditioning environment suggests that the effects of endophytes on herbivore life-history traits may represent an adaptive change that should be considered in future studies of endophyte-herbivore interactions. Keywords: Rhopalosiphum padi, Neotyphodium lolii, Lolium perenne, common strain, adaptation, long-term effects, microbes, endosymbionts, reproductive strategy, life-history traits

scholarly journals Growth of Transplants and in Vitro-cultured Clones of Asparagus in Response to CO2 Enrichment and Supplemental Lighting

1990 ◽  
Vol 115 (3) ◽  
pp. 364-368 ◽  
Author(s):  
Yves Desjardins ◽  
André Gosselin ◽  
Michel Lamarre
Keyword(s):  
Co2 Enrichment ◽  
Dry Weight ◽  
Plant Size ◽  
Asparagus Officinalis ◽  
Photon Flux ◽  
Long Term Effects ◽  
Shoot Dry Weight ◽  
Supplemental Lighting

Asparagus (Asparagus officinalis L.) transplants and in vitro-cultured clones were grown and acclimatized under two photosynthetic photon flux (PPF) conditions (ambient and ambient + 80 μmol·s-1·m-2) and three atmospheric CO2 concentrations (330, 900, and 1500 ppm). Short- and long-term effects were measured in the greenhouse and after two seasons of growth in the field, respectively. In the greenhouse, CO2 enrichment (CE) and supplemental lighting (SL) increased root and fern dry weight by 196% and 336%, respectively, for transplants and by 335% and 229%, respectively, for clones. For these characteristics, a significant interaction was observed between SL and CE with tissue-cultured plantlets. In the absence of SL, CE did not significantly increase root or shoot dry weight. No interaction was observed between CE and SL for transplants, although these factors significantly improved growth. It was possible to reduce the nursery period by as much as 3 weeks with CE and SL and still obtain a plant size comparable to that of the control at the end of the experiment. Long-term effects of SL were observed after two seasons of growth in the field. Supplemental lighting improved survival of transplants and was particularly beneficial to in vitro plants. Clones grown under SL were of similar size as transplants after 2 years in the field.

Short and long term effects of feeding supplements of oats, wheat and lupin grain on the production of ewes lambing in autumn

1984 ◽  
Vol 24 (126) ◽  
pp. 332
Author(s):  
PA Kenney ◽  
GB Roberts
Keyword(s):  
Milk Production ◽  
Dry Matter ◽  
Poor Quality ◽  
Long Term Effects ◽  
Bare Ground ◽  
Wool Production ◽  
Short And Long Term ◽  
The Difference

Four groups, each of about 40 Border Leicester x Merino ewes due to lamb in May, 1978, were held on bare ground and hand-fed poor quality hay, either alone or with oat, wheat or lupin grain at 270 g dry matter/head.d, from two weeks before until six weeks after lambing. A fifth group of ewes grazed separately on green pasture. After hand-feeding ceased in July 1978, ewes from all five groups grazed together and were re-joined with rams in November-December. Increases in wool production (90-230 g greasy fleece), milk production (9-23 ml/h) and growth of lambs (20-4 1 g/d) resulted from feeding supplements to the hay-fed ewes. Ewes fed oats and lupins performed best and, compared with those fed wheat, produced fewer fleeces with major faults (8 and 12% vs 29%, respectively) and less milk (58 and 62 ml/h vs 49 ml/h, respectively). At the end of hand-feeding, the ewes were 18-23 kg lighter than those that had been at pasture, but by the time joining took place in November-December, the difference was only 4-8 kg. Ewes fed hay alone mated 8-12 d later and lambed 5-9 d later (May 1979) than ewes in all other groups. Also, 6% of the ewes fed lupins or allowed to graze pasture during lambing in 1978 were barren in 1979, compared with 25% of barren ewes in all other treatments. It was concluded that wheat, in contrast to lupins and oats, was an inadequate supplement for lambing ewes consuming only low quality roughage.

Early Response in Albuminuria and Long-Term Kidney Protection during Treatment with an Endothelin Receptor Antagonist: A Prespecified Analysis from the SONAR Trial

2021 ◽  
pp. ASN.2021030391
Author(s):  
Hiddo Heerspink ◽  
Di Xie ◽  
George Bakris ◽  
Ricardo Correa-Rotter ◽  
Fan-Fan Hou ◽  
...  
Keyword(s):  
Chronic Kidney Disease Stage ◽  
Renin Angiotensin System ◽  
Treatment Phase ◽  
Early Response ◽  
Disease Stage ◽  
Diabetic Patients ◽  
Long Term Effects ◽  
Double Blind ◽  
The Difference

Background Whether early reduction in albuminuria with atrasentan treatment predicts its longterm kidney protective effect is unknown. Methods To assess long-term effects on kidney outcomes of atrasentan versus placebo in the SONAR trial, we enrolled diabetic patients with chronic kidney disease (stage 2-4) and a urinary albumin creatinine ratio (UACR) of 300 mg/g-5000 mg/g; participants were receiving maximum tolerated renin angiotensin system inhibition. After 6 weeks exposure to 0.75 mg/day atrasentan (enrichment period), participants were randomized (stratified by UACR response during enrichment, ranging from ≤60% to >0%) to continue atrasentan or transition to placebo. Primary kidney outcome was a composite of sustained serum creatinine doubling or end-stage kidney disease. Results UACR response to atrasentan during enrichment persisted throughout the double-blind treatment phase and predicted the primary kidney outcome, whereas UACR levels with placebo remained below pre-enrichment values in the two highest UACR response strata and exceeded pre-enrichment values in the two lowest strata. As a result, early UACR response to atrasentan during enrichment was also associated with the primary kidney outcome during placebo. Accordingly, the predictive effect of early albuminuria changes during atrasentan was eliminated after placebo correction, leading to a consistent relative risk reduction for the primary kidney outcome with atrasentan compared with placebo, irrespective of the initial UACR response. The difference between atrasentan and placebo in UACR during double-blind treatment was also consistent across UACR response strata. Conclusions Our findings do not support UACR response as a causal predictor of atrasentan's treatment effect. However, because of UACR's variable trajectory with placebo, aspects of the trial design, day-to-day variability in albuminuria, and potential long-lasting effects of atrasentan may have contributed.

Correlation of cognitive disorders and catecholamine excretion in anorexia nervosa

2021 ◽  
pp. 675-681
Author(s):  
Marina Stanislavovna Artemieva Marina Stanislavovna Artemieva ◽  
Boris Dmitrievich Tsygankov ◽  
Roman Aleksandrovich Suleymanov ◽  
Ivan Evgenievich Danilin ◽  
Aleksandr Romanovich Arseniev ◽  
...  
Keyword(s):  
Weight Loss ◽  
Anorexia Nervosa ◽  
Cognitive Disorders ◽  
Medical Psychology ◽  
Long Term Effects ◽  
Mental Performance ◽  
Catecholamine Excretion ◽  
The Difference ◽  
Prolonged Abstinence

The article presents the analysis of correlation and dynamics of clinical and psychophysiological characteristics of the long-term effects of long-lasting abstinence from food on the example of 500 women with anorexia nervosa (AN), who applied for help to the Department of Psychiatry and Medical Psychology, FSAEI HE Peoples’ Friendship University of Russia in 1989-2017. The adverse effects of prolonged abstinence from food are shown; the indicators of catecholamine excretion (dopamine, adrenaline, norepinephrine), encephalography data, mental performance and memory of those examined at various stages of AN weight loss and gain were studied. The difference in the excretion of catecholamines in AN and psychogenic vomiting, which can be used for differential diagnosis, was demonstrated.

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