scholarly journals Effects of Various Environmental Conditions on the Growth of Amaranthus patulus Bertol. and Changes of Herbicide Efficacy Caused by Increasing Temperatures

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1773
Author(s):  
Hyun-Hwa Park ◽  
Do-Jin Lee ◽  
Yong-In Kuk

Understanding the effects of climate change on weed growth and herbicide activity is important for optimizing herbicide applications for effective weed control in the future. Therefore, this study examined how climate change affects the growth of Amaranthus patulus and the efficacy of soil and foliar herbicides at different temperatures. Although the control values for A. patulus differed between herbicides and temperature, the control values increased with increasing time after the herbicide treatments. Under growth conditions in which the temperature remained constant, the efficacy of soil-applied herbicides, ethalfluralin, metolachlor, linuron, and alachlor, on A. patulus was highest when the weeds were grown at high temperature. In particular, 100% control values of A. patulus were achieved in response to metolachlor treatments at the total recommended dosage in growth chambers at 35 °C. The efficacy of foliar herbicides, glufosinate-ammonium, bentazone, and mecoprop, on A. patulus was also highest when the plant was grown at high temperature, except for glyphosate isopropylamine, which had similar efficacy rates regardless of the temperature. A. patulus was 100% controlled in response to glufosinate-ammonium, bentazone, and mecoprop at the recommended dosages in growth chambers at 30 and 35 °C. Under growth conditions in which the temperature changed from day to night, the efficacy of soil-applied herbicides, alachlor and linuron, on A. patulus was highest when the weeds were grown at high temperature. On the other hand, the efficacy of the soil-applied herbicides metolachlor and linuron on A. patulus was similar regardless of the temperature. The efficacy of foliar herbicides, glyphosate isopropylamine, glufosinate-ammonium, bentazone, and mecoprop, on A. patulus was highest when the weeds were grown at high temperature. Although herbicide efficacy varied depending on whether the weeds were grown at constant or alternating temperatures, herbicide efficacy was generally highest when the temperature was high.

2019 ◽  
Vol 32 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Luma Rayane de Lima Nunes ◽  
Paloma Rayane Pinheiro ◽  
Charles Lobo Pinheiro ◽  
Kelly Andressa Peres Lima ◽  
Alek Sandro Dutra

ABSTRACT Salinity is prejudicial to plant development, causing different types of damage to species, or even between genotypes of the same species, with the effects being aggravated when combined with other types of stress, such as heat stress. The aim of this study was to evaluate the tolerance of cowpea genotypes (Vigna unguiculata L. Walp.) to salt stress at different temperatures. Seeds of the Pujante, Epace 10 and Marataoã genotypes were placed on paper rolls (Germitest®) moistened with different salt concentrations of 0.0 (control), 1.5, 3.0, 4.5 and 6.0 dS m-1, and placed in a germination chamber (BOD) at temperatures of 20, 25, 30 and 35°C. The experiment was conducted in a completely randomised design, in a 3 × 4 × 5 scheme of subdivided plots, with four replications per treatment. The variables under analysis were germination percentage, first germination count, shoot and root length, and total seedling dry weight. At temperatures of 30 and 35°C, increases in the salt concentration were more damaging to germination in the Epace 10 and Pujante genotypes, while for the Marataoã genotype, damage occurred at the temperature of 20°C. At 25°C, germination and vigour in the genotypes were higher, with the Pujante genotype proving to be more tolerant to salt stress, whereas Epace 10 and Marataoã were more tolerant to high temperatures. Germination in the cowpea genotypes was more sensitive to salt stress when subjected to heat stress caused by the low temperature of 20°C or high temperature of 35°C.


Biomolecules ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1153
Author(s):  
Jutta Ludwig-Müller ◽  
Roman Rattunde ◽  
Sabine Rößler ◽  
Katja Liedel ◽  
Freia Benade ◽  
...  

With the introduction of the new auxinic herbicide halauxifen-methyl into the oilseed rape (Brassica napus) market, there is a need to understand how this new molecule interacts with indigenous plant hormones (e.g., IAA) in terms of crop response. The aim of this study was to investigate the molecular background by using different growth conditions under which three different auxinic herbicides were administered. These were halauxifen-methyl (Hal), alone and together with aminopyralid (AP) as well as picloram (Pic). Three different hormone classes were determined, free and conjugated indole-3-acetic acid (IAA), aminocyclopropane carboxylic acid (ACC) as a precursor for ethylene, and abscisic acid (ABA) at two different temperatures and growth stages as well as over time (2–168 h after treatment). At 15 °C growth temperature, the effect was more pronounced than at 9 °C, and generally, the younger leaves independent of the developmental stage showed a larger effect on the alterations of hormones. IAA and ACC showed reproducible alterations after auxinic herbicide treatments over time, while ABA did not. Finally, a transcriptome analysis after treatment with two auxinic herbicides, Hal and Pic, showed different expression patterns. Hal treatment leads to the upregulation of auxin and hormone responses at 48 h and 96 h. Pic treatment induced the hormone/auxin response already after 2 h, and this continued for the other time points. The more detailed analysis of the auxin response in the datasets indicate a role for GH3 genes and genes encoding auxin efflux proteins. The upregulation of the GH3 genes correlates with the increase in conjugated IAA at the same time points and treatments. Also, genes for were found that confirm the upregulation of the ethylene pathway.


2019 ◽  
Vol 82 (6) ◽  
pp. 1071-1081
Author(s):  
KRISTIN BJORNSDOTTIR-BUTLER ◽  
SUSAN McCARTHY ◽  
RONALD A. BENNER

ABSTRACT Histamine-producing Erwinia and Pluralibacter spp. capable of producing toxic histamine levels were isolated from ingredients commonly used in tuna salad preparations. The characterization and control of these histamine-producing bacteria are necessary to prevent illness from tuna salad consumption. We confirmed the identity of two Erwinia spp. and one Pluralibacter sp. previously isolated from tuna salad ingredients through whole genome sequencing and phylogenic analysis and characterized them for growth and histamine production at different temperatures, pH values, and salt concentrations. In addition, we examined the effects of dried vinegar (DV) powder on growth and histamine production of these strains in inoculated tuna salad preparations. Optimum growth temperatures in tryptic soy broth (TSB) for the two Erwinia spp. and one Pluralibacter sp. were 30.1, 31.1, and 33.9°C, respectively, and growth in TSB was observed at 5°C for both genera. Optimum histamine production of Erwinia persicina, Erwinia spp., and Pluralibacter spp. in TSB with histidine occurred from 25 to 30°C, pH 4 to 6, and 0 to 4% NaCl. No significant growth or histamine production was observed in tuna salad preparations stored at 4°C. Growth and histamine production by Erwinia or Pluralibacter spp. was inhibited in tuna salad containing celery and onion and 2% DV, whereas significant growth and histamine production occurred in tuna salad without DV. Understanding optimum growth conditions and histamine production can provide guidance to tuna salad manufacturers in formulating products and adjusting processing conditions that minimize hazards from these histamine-producing bacteria. Addition of 2% DV to tuna salad preparations may prevent histamine production in the event of temperature abuse. HIGHLIGHTS


Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Guanghui Jiang ◽  
Jianping Zuo ◽  
Teng Ma ◽  
Xu Wei

Understanding the change of permeability of rocks before and after heating is of great significance for exploitation of hydrocarbon resources and disposal of nuclear waste. The rock permeability under high temperature cannot be measured with most of the existing methods. In this paper, quality, wave velocity, and permeability of granite specimen from Maluanshan tunnel are measured after high temperature processing. Quality and wave velocity of granite decrease and permeability of granite increases with increasing temperature. Using porosity as the medium, a new wave velocity-permeability model is established with modified wave velocity-porosity formula and Kozeny-Carman formula. Under some given wave velocities and corresponding permeabilities through experiment, the permeabilities at different temperatures and wave velocities can be obtained. By comparing the experimental and the theoretical results, the proposed formulas are verified. In addition, a sensitivity analysis is performed to examine the effect of particle size, wave velocities in rock matrix, and pore fluid on permeability: permeability increases with increasing particle size, wave velocities in rock matrix, and pore fluid; the higher the rock wave velocity, the lower the effect of wave velocities in rock matrix and pore fluid on permeability.


2014 ◽  
Vol 1039 ◽  
pp. 107-111
Author(s):  
Yang Chen ◽  
Gui Qin Li ◽  
Bin Ruan ◽  
Xiao Yuan ◽  
Hong Bo Li

The mechanical behavior of plastic material is dramatically sensitive to temperature. An method is proposed to predict the mechanical behavior of plastics for cars, ranging from low-temperature low temperature ≤-40°C to high temperature ≥80°C. It dominates the behavior of plastic material based on improved constitutive model in which the parameters adjusted by a series of tests under different temperatures. The method is validated with test and establishes the basis for research and development of plastic parts for automobile as well.


Parasitology ◽  
2015 ◽  
Vol 142 (10) ◽  
pp. 1290-1296 ◽  
Author(s):  
SIRPA KAUNISTO ◽  
LAURA HÄRKÖNEN ◽  
MARKUS J. RANTALA ◽  
RAINE KORTET

SUMMARYImmunity of parasites has been studied amazingly little, in spite of the fact that parasitic organisms, especially the arthropod parasites, need immunity to survive their own infections to successfully complete life cycles. Long-term effects of challenging environmental temperatures on immunity have remained unstudied in insects and parasites. Our study species, the deer ked (Lipoptena cervi; Linnaeus 1758), is an invasive, blood-feeding parasitic fly of cervids. Here, it was studied whether thermal stress during the pupal diapause stage could modify adult immunity (encapsulation capacity) in L. cervi. The effect of either a low temperature or high temperature peak, experienced during winter dormancy, on encapsulation response of active adult was tested. It was found that low temperature exposure during diapause, as long as the temperature is not too harsh, had a favourable effect on adult immunity. An abnormal, high temperature peak during pupal winter diapause significantly deteriorated the encapsulation capacity of emerged adults. The frequency and intensity of extreme weather events such as high temperature fluctuations are likely to increase with climate change. Thus, the climate change might have previously unknown influence on host-ectoparasite interactions, by affecting ectoparasite's immune defence and survival.


2011 ◽  
Vol 71-78 ◽  
pp. 1057-1061 ◽  
Author(s):  
Ke Fang Yin ◽  
Yang Han ◽  
Yi Liu

With the centrally pulling-out test, the bond strength of reinforced concrete is measured with different temperatures and different cooling ways after high temperature; and the ultimate bond strength and slip of reinforced and concrete under different conditions are analyzed. The results show that the bonding strength declines gradually with the increase of temperature, and the ultimate slippage also decreases gradually.


Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1818
Author(s):  
Andrea Mura ◽  
Alessando Ricci ◽  
Giancarlo Canavese

Plastics are widely used in structural components where cyclic loads may cause fatigue failure. In particular, in some applications such as in vehicles, the working temperature may change and therefore the strength of the polymeric materials. In this work, the fatigue behavior of two thermoplastic materials (ABS and PC-ABS) at different temperatures has been investigated. In particular, three temperatures have been considered representing the working condition at room temperature, at low temperature (winter conditions), and high temperature (summer conditions and/or components close to the engine). Results show that high temperature have big impact on fatigue performance, while low temperatures may also have a slight positive effect.


2018 ◽  
Vol 6 (1-2) ◽  
pp. 117-141 ◽  
Author(s):  
Timothy Crownshaw ◽  
Caitlin Morgan ◽  
Alison Adams ◽  
Martin Sers ◽  
Natália Britto dos Santos ◽  
...  

Maintaining steady growth remains the central goal of economic policy in most nations. However, as evidenced by the advent of the Anthropocene, the global economy has expanded to a point where limits to growth are appearing. Facing the end of growth requires a careful re-examination of plausible future conditions. We draw on a diverse literature to present an interdisciplinary exploration of post-growth conditions in the areas of climate change, ecological impacts, governance, and education, finding that such conditions may invalidate many prevalent assumptions regarding the future. The post-growth world, while subject to significant uncertainty and heterogeneity, will be characterized by profound hazards and discontinuities for both human and natural systems. Furthermore, we argue that an economic paradigm change will be predicated on an involuntary and unplanned cessation of growth. This implies a necessary strategic expansion of the heterodox economic discourse to formulate appropriate responses in view of likely post-growth realities.


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