Redroot Pigweed (Amaranthus retroflexus) Seed Germination Responses to Afterripening, Temperature, Ethylene, and Some Other Environmental Factors

Germination responses of redroot pigweed (Amaranthus retroflexusL.) seeds to temperature, water potential, atmospheric ethylene and carbon dioxide concentrations, light, and nitrate ion were examined individually. Seeds kept in dry storage at −20 C and tested within 2 yr of harvest germinated at 35 C (12 to 25%) or 39.5 C (40 to 65%), but only 0 to 2% at 30 C and below. Germination at 35 C was prevented by water potentials below −4 bars. When seeds were kept in dry storage at 24 to 28 C, afterripening became evident within 2 months. After storage at this temperature for 4 yr, seeds showed 38% germination at 14 C, 40% at 35 C and −8 bars water potential, and over 90% under more favorable conditions. Ethylene (1 to 100 ppmv) or continuous light enhanced germination at 30 C regardless of degrees of afterripening, although the ethylene effect was most dramatic in nonafterripened seeds. Ethylene at 100 ppmv caused 40% germination in these seeds, compared to 1% for controls. Neither carbon dioxide (0.001 to 4.5% v/v) nor dissolved potassium nitrate (0.02 to 0.2% w/v) influenced germination. These results are discussed in relation to environmental factors influencing field emergence of redroot pigweed.

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Differential Gas Exchange Responses of Two Biotypes of Redroot Pigweed to Atrazine

Weed Science ◽

10.1017/s0043174500065449 ◽

1976 ◽

Vol 24 (1) ◽

pp. 68-72 ◽

Cited By ~ 9

Author(s):

L. D. West ◽

T. J. Muzik ◽

R. E. Witters

Keyword(s):

Carbon Dioxide ◽

Gas Exchange ◽

Photosynthetic Activity ◽

Guard Cells ◽

Stomatal Resistance ◽

Amaranthus Retroflexus ◽

Redroot Pigweed ◽

Mesophyll Tissue ◽

Diffusive Resistance ◽

Mesophyll Resistance

Differences were shown to exist in photosynthetic rate, transpiration rate, and carbon dioxide leaf diffusive resistance between atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] susceptible (S) and resistant (R) plants of redroot pigweed (Amaranthus retroflexusL.). Chlorbromuron [3-(4-bromo-3-chlorophenyl)-1-methoxy-1-methylurea] and diruon [3-(3,4-dichlorophenyl)-1,1-dimethylurea] were the only herbicides tested that controlled both biotypes, but all of the herbicides except norea [3-(hexahydro-4,7-methanoindan-5-yl)-1,1-dimethylurea] controlled the S biotype. Although photosynthetic activity and transpiration were reduced in both biotypes by atrazine at 50 and 70 ppm, the decline was much greater in the S biotype than in the R biotype and persisted a longer time in the S biotype. Leaf CO2diffusive resistances of the biotypes were increased by atrazine applications. Mesophyll resistance was increased to a greater extent than stomatal resistance suggesting that reduction of photosynthesis is due to a greater effect of atrazine on the mesophyll tissue than on the guard cells.

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Some effects of nitrate-treated soil upon the sensitivity of buried redroot pigweed (Amaranthus retroflexus L.) seeds to ethylene, temperature, light and carbon dioxide

Plant Cell & Environment ◽

10.1111/j.1365-3040.1989.tb02131.x ◽

1989 ◽

Vol 12 (5) ◽

pp. 581-588 ◽

Cited By ~ 20

Author(s):

G. H. EGLEY

Keyword(s):

Carbon Dioxide ◽

Amaranthus Retroflexus ◽

Treated Soil ◽

Redroot Pigweed

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New method for quantitatively assessing susceptibility of citrus fruit to oleocellosis development and some factors that affect its expression

Australian Journal of Experimental Agriculture ◽

10.1071/ea96070 ◽

1998 ◽

Vol 38 (3) ◽

pp. 279 ◽

Cited By ~ 3

Author(s):

B. L. Wild

Keyword(s):

Carbon Dioxide ◽

Environmental Factors ◽

Citrus Fruit ◽

Laboratory Method ◽

Sensitivity Testing ◽

Oil Glands ◽

Citrus Peel ◽

Rate Of Development ◽

Carbon Dioxide Concentrations ◽

Colour Development

Summary. A quantitative laboratory method for determining the susceptibility of citrus fruit to oleocellosis (rind oil damage) has been developed. This method allows the evaluation of various factors which govern the extent of rind oil damage to the rind. By using this method, it has been established that the development of oleocellosis symptoms was affected by temperature, with temperatures <10˚C reducing the rate of development of the disorder. Unfortunately, when the temperature was raised again after storage, oleocellosis development proceeded as normal. Other environmental factors such as oxygen and carbon dioxide concentrations were also shown to affect the rate and extent of colour development of the rind blemish. This method of determining sensitivity of citrus peel to rind oil also established that the degree of surface exposure to sunlight increased the rind’s susceptibility to the oil. The effects of different coatings and chemicals which may affect the toxicity of the rind oils were also investigated, with artificial wax coatings being shown to reduce oil damage by up to 35%. This finding indicates the importance of thorough wax application to fruit. The tape method of sensitivity testing, as illustrated in this paper, also demonstrates that variations in oleocellosis development are not only due to changes in the pressure required to break the oil glands but also the ability of the peel to tolerate the released oil.

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Allelopathic effects of redroot pigweed (Amaranthus retroflexus L.) aqueous extract on cucumber and wheat

Allelopathy Journal ◽

10.26651/allelo.j/2019-46-1-1198 ◽

2019 ◽

Vol 46 (1) ◽

pp. 55-72 ◽

Cited By ~ 2

Author(s):

H. Bakhshayeshan-Agdam ◽

S. Y. Salehi-Lisar ◽

R. Motafakkerazad

Keyword(s):

Aqueous Extract ◽

Amaranthus Retroflexus ◽

Redroot Pigweed ◽

Allelopathic Effects

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Snowfall-albedo feedbacks could have led to deglaciation of snowball Earth starting from mid-latitudes

Communications Earth & Environment ◽

10.1038/s43247-021-00160-4 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Philipp de Vrese ◽

Tobias Stacke ◽

Jeremy Caves Rugenstein ◽

Jason Goodman ◽

Victor Brovkin

Keyword(s):

Carbon Dioxide ◽

Atmospheric Carbon Dioxide ◽

Climate Models ◽

Hydrological Cycle ◽

High Surface ◽

Dust Deposition ◽

Carbon Dioxide Concentrations ◽

Maximum Temperatures ◽

Carbon Dioxide Levels ◽

Earth’S Climate

AbstractSimple and complex climate models suggest a hard snowball – a completely ice-covered planet – is one of the steady-states of Earth’s climate. However, a seemingly insurmountable challenge to the hard-snowball hypothesis lies in the difficulty in explaining how the planet could have exited the glaciated state within a realistic range of atmospheric carbon dioxide concentrations. Here, we use simulations with the Earth system model MPI-ESM to demonstrate that terminal deglaciation could have been triggered by high dust deposition fluxes. In these simulations, deglaciation is not initiated in the tropics, where a strong hydrological cycle constantly regenerates fresh snow at the surface, which limits the dust accumulation and snow aging, resulting in a high surface albedo. Instead, comparatively low precipitation rates in the mid-latitudes in combination with high maximum temperatures facilitate lower albedos and snow dynamics that – for extreme dust fluxes – trigger deglaciation even at present-day carbon dioxide levels.

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Carbon Capture and the Aluminium Industry: Preliminary Studies

Environmental Chemistry ◽

10.1071/en06018 ◽

2006 ◽

Vol 3 (4) ◽

pp. 297 ◽

Cited By ~ 43

Author(s):

Graham Jones ◽

Gargi Joshi ◽

Malcolm Clark ◽

David McConchie

Keyword(s):

Carbon Dioxide ◽

Red Mud ◽

Carbon Capture ◽

Total Alkalinity ◽

Industrial Processes ◽

Carbonate Alkalinity ◽

General Acceptance ◽

Maximum Value ◽

Carbon Dioxide Concentrations ◽

Bicarbonate Alkalinity

Environmental Context. Carbon dioxide concentrations in the atmosphere are rising every year by 1.5–3.0 ppm and there is now a general acceptance that increased efforts must be made to reduce industrial sources of this greenhouse gas. Carbonation of red mud wastes produced by aluminium refineries has been carried out to study the capacity of these wastes to capture carbon dioxide. Removal is very rapid, with the added carbon dioxide recorded as a large increase in bicarbonate alkalinity. Although these results can only be considered preliminary, the experiments indicate that these wastes can potentially remove up to 15 million tonnes of carbon dioxide produced in Australia per annum. Furthermore, the carbonated waste can be used in other industrial processes to add further value to these waste materials. Abstract. Carbonation of raw red mud produced by aluminium refineries and a chemically and physically neutralized red mud (Bauxsol™) has been carried out to study the capacity of these wastes to capture carbon dioxide. After only 5 min of carbonation of raw red mud, total alkalinity dropped 85%. Hydroxide alkalinity was almost totally consumed, carbonate alkalinity dropped by 88%, and bicarbonate alkalinity increased to 728 mg L–1. After 24 min carbonation, the bicarbonate alkalinity reached its maximum value of 2377 mg L–1, and hydroxide and carbonate alkalinity were virtually absent. After 30 and 60 min carbonation, bicarbonate alkalinity started to decrease slightly as the pH of the slurry increased. After 5 min carbonation of Bauxsol™, total and bicarbonate alkalinity dropped 89% and 9%, respectively. After 20 min carbonation, bicarbonate alkalinity dropped another 11%, but after 30 min carbonation bicarbonate alkalinity increased 26% to levels found in the original Bauxsol material, and pH was stable. Based on these experiments, a calculation of the amount of carbon dioxide that could be removed annually at aluminium refineries in Australia is potentially 15 million tonnes, and suggests that further studies are necessary to maximize this carbon removal process. Furthermore, carbonation produces a product, which can potentially be used in other industrial and agricultural activities to remove toxic metals and nutrients.

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