The relationship ofChironomus ripariuslarval Se body burden and body concentration to larval dry mass and effects on sensitivity to selenium

2001 ◽  
Vol 20 (8) ◽  
pp. 1630-1640 ◽  
Author(s):  
T. Vernon Beaty ◽  
Albert C. Hendricks
Keyword(s):  
Body Burden ◽  
Dry Mass ◽  
The Relationship ◽  
Body Concentration

Assessing the toxicity of lead in sediments to Hyalella azteca: the significance of bioaccumulation and dissolved metal

1999 ◽  
Vol 56 (8) ◽  
pp. 1494-1503 ◽  
Author(s):  
Uwe Borgmann ◽  
Warren P Norwood
Keyword(s):  
Screening Tool ◽  
Water Concentration ◽  
Dry Mass ◽  
Overlying Water ◽  
Organic C ◽  
Complexing Capacity ◽  
Large Water ◽  
The Relationship ◽  
Pb Concentration ◽  
Body Concentration

The relationship between bioaccumulation and toxicity of Pb to Hyalella was the same for animals exposed to Pb in water alone and for those exposed to Pb-spiked sediments, provided that the animals were gut cleared before Pb analysis. The same critical body concentration (about 126 nmol·g dry mass-1) can be used to predict Pb toxicity in both water-only and sediment exposures. Furthermore, Pb bioavailability in Pb-spiked sediments was due primarily to dissolved metal: animals caged above the sediments accumulated the same amount of Pb and had the same mortality as animals exposed directly to sediment. Increasing the water to sediment ratio from 4:1 to 67:1 resulted in a lower dissolved organic C and lower total dissolved Pb concentration in the water but no change in bioavailable Pb (i.e., bioavailable Pb was not proportional to total dissolved Pb). The overlying water concentration may be a useful indicator of bioavailable Pb in sediment tests, provided a large water to sediment ratio is used to reduce the effect of sediment on overlying water quality (i.e., Pb-complexing capacity). Although less reliable than body concentration measurements, this could provide a useful screening tool for possible Pb-induced toxicity because it can be measured without test animals present.

scholarly journals Irrigation management strategies for reducing verticillium wilt severity in eggplants

2020 ◽  
Vol 46 (1) ◽  
pp. 9-13
Author(s):  
Ricardo Nunes Cabral ◽  
Waldir Aparecido Marouelli ◽  
Adalberto C. Café-Filho
Keyword(s):  
Verticillium Wilt ◽  
Water Availability ◽  
Management Strategy ◽  
Irrigation Management ◽  
Management Strategies ◽  
Dry Mass ◽  
Infested Soil ◽  
Irrigation Strategy ◽  
Available Soil Moisture ◽  
The Relationship

ABSTRACT Verticillium wilt in eggplants is a root disease of difficult control. In this study, we report the relationship between soil water availability and the disease intensity in order to identify management strategies that are unfavourable to the pathogen and capable of reducing the disease progression and the damage caused by it. Four irrigation management strategies were compared in soil infested or not infested with Verticillium dahliae, which consisted of: irrigating when the available soil moisture was maintained at 90% (WA90%), 55% (WA55%) and 20% (WA20%) during the entire growing cycle, and kept at 20% in the vegetative stage, and at 90% in the production stage (WA20-90%). Experimental design was in randomized blocks, including eight treatments in factorial arrangement (4x2) and three replicates. The management strategy WA20-90% led to a significant reduction in the disease severity and in the extent of xylem colonization by the pathogen. The dry mass of plants in infested soil was 12% lower than that of control treatments and was higher with the irrigation strategy WA90% than with WA55% or WA20%. The strategy WA20-90% was efficient in reducing the disease with no significant reduction in dry mass.

scholarly journals Persistent, Ecotoxic and Bioaccumulative Compounds and their Possible Environmental Effects

1996 ◽  
Vol 68 (9) ◽  
pp. 1771-1780 ◽  
Author(s):  
K. Ballschmiter
Keyword(s):  
Critical Period ◽  
Environmental Fate ◽  
Body Burden ◽  
Substantial Part ◽  
Environmental Distribution ◽  
Major Class ◽  
The Relationship ◽  
Pollutant Transfer ◽  
Environmental Compartments

The relationship between physicochemical properties, environmental distribution and effects of organochlorine compounds as a major class of persistent organic pollutants (POPs) are discussed. The environmental fate of a compound includes its transport and dispersion in the environment as well as its accumulation and transformation in defined environmental compartments. Accumulation and transformation as the result of environmental distribution may have long-term consequences; this is indicated by the ultimate accumulation and long-term bioactivity of several widely spread organochlorines, and is clearly evident in the decomposition of chlorofluorocarbons in the stratosphere.Depending on the order of trophic levelsbiomagnifiaction factors of 10,000 up to 100,000 are encountered for persistentsemivolatile organochlorines such as 4,4'-DDE, PCB congeners or some Toxapheneconstituents. Mammals show intra-species pollutant transfer during thelactation period. While the mother animal is partly depleting its bodyburden, the calve accumulates in a critical period of its life via themilk a concentrated input of persistent organochlorines. A similar depletionphenomenon is also found for fish and crustacean which enrich in the eggsa substantial part of the accumulated body burden of the female.The air skimming of semivolatiles by plantsurfaces leads to surprisingly high levels of pollutants in the uppersoil layers of forests that otherwise would be considered pristine interms of human activities.

scholarly journals Cuttings of Lippia alba with emphasis on time for seedling formation, substrates and plant growth regulators

2015 ◽  
Vol 33 (2) ◽  
pp. 230-235 ◽  
Author(s):  
Cristina B Lima ◽  
Ana C Boaventura ◽  
Marli M Gomes
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Dry Mass ◽  
Mineral Fertilizers ◽  
Shoot Height ◽  
Lippia Alba ◽  
Statistical Designs ◽  
Time Required ◽  
The Relationship

We aimed to establish the period of time required for seedlings formation, as well as to evaluate the effect of substrates and plant growth regulators in cuttings of L. alba. Three experiments were performed, with statistical designs chosen according to each test objectives. Rooting (%), shoot height (cm), longest root length (cm), leaves number, fresh and dry matter masses (g), were analyzed. The absolute rate of shoot and root system growth, together with the relationship between dry mass of roots and shoots were efficient in predicting the period of greatest speed and accumulation of organic matter in plants. The plant growth regulators favored the vegetative performance of seedlings, with better development 30 days after the cuttings containing mineral fertilizers, vermicompost, clay soil and sand commercially known as 'medium sand'.

scholarly journals Spectral Indices: In-Season Dry Mass and Yield Relationship of Flue-Cured Tobacco under Different Planting Dates and Fertiliser Levels

ISRN Agronomy ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Ezekia Svotwa ◽  
J. Anxious Masuka ◽  
Barbara Maasdorp ◽  
Amon Murwira
Keyword(s):  
Spectral Characteristics ◽  
Dry Mass ◽  
Coefficient Of Determination ◽  
Planting Dates ◽  
Randomized Design ◽  
Crop Development ◽  
Best Fitting ◽  
Whole Plants ◽  
Relationship Of ◽  
The Relationship

This experiment investigated the relationship between tobacco canopy spectral characteristics and tobacco biomass. A completely randomized design, with plantings on the 15th of September, October, November, and December, each with 9 variety × fertiliser management treatments, was used. Starting from 6 weeks after planting, reflectance measurements were taken from one row, using a multispectral radiometer. Individual plants from the other 3 rows were also measured, and the above ground whole plants were harvested and dried for reflectance/dry mass regression analysis. The central row was harvested, cured, and weighed. Both the maximum NDVI and mass at untying declined with later planting and so was the mass-NDVI coefficient of determination. The best fitting curves for the yield-NDVI correlations were quadratic. September reflectance values from the October crop reflectance were statistically similar (P>0.05), while those for the November and the December crops were significantly different (P<0.05) from the former two. Mass at untying and NDVI showed a quadratic relationship in all the three tested varieties. The optimum stage for collecting spectral data for tobacco yield estimation was the 8–12 weeks after planting. The results could be useful in accurate monitoring of crop development patterns for yield forecasting purposes.

Ecological energetics of Palaearctic Tetraonidae in relation to chemical composition and digestibility of their winter diets

1988 ◽  
Vol 66 (6) ◽  
pp. 1382-1388 ◽  
Author(s):  
A. V. Andreev
Keyword(s):  
Chemical Composition ◽  
Body Mass ◽  
Dry Mass ◽  
Metabolizable Energy ◽  
Physiological Level ◽  
Available Energy ◽  
Energy Demands ◽  
Ecological Energetics ◽  
Winter Diets ◽  
The Relationship

Parameters of digestion and energetics of free-living grouse were plotted against body mass to determine whether a general relationship exists between quantitative food intake, digestibility, and energy demands of individuals of different sizes, and to clarify the relationship between chemical composition of the diet and individual energetic demands of different species. Regression analysis showed a positive correlation between each of the parameters (except dry mass of caecal faeces) and body mass, reflecting a relationship between differences in chemical composition of the browse in the diets and its digestibility. Modelling intermediary metabolism in three grouse species revealed that about 50% of metabolizable energy originated from carbohydrate oxidation; the rest was shared among fiber (9–35%), protein (9–14%), and crude fat (12–25%). The more nitrogen in the diet, the higher were estimates of total digestibility, as well as those of fiber and fat. A generalized model of nitrogen demands of individuals is proposed and predictions from the model are compared with particular determinations based upon actual data from different species. The digestibility of natural grouse diets, and consequently available energy, is essentially dependent upon the concentration of protein in the diet. This suggests that it is necessary for grouse to exceed the minimal physiological level of nitrogen intake, not only to create reserves, but also to function effectively in the presumed need to detoxify and digest those fractions of the diet that are difficult to absorb.

scholarly journals 257 LEAF PETIOLE NITRATE AND POTASSIUM LEVELS IN POTTED PLANTS GROWN AT THREE NITROGEN AND POTASSIUM LEVELS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 466e-466
Author(s):  
Erica M. Bergman ◽  
Michelle Marshal ◽  
Brian Weesies ◽  
Bill Argo ◽  
John Biernbaum
Keyword(s):  
Leaf Blade ◽  
Dry Mass ◽  
Hydraulic Press ◽  
Water Soluble ◽  
Leaf Petiole ◽  
Potted Plants ◽  
Petiole Nitrate Concentration ◽  
Soluble Fertilizer ◽  
Relationship Of ◽  
The Relationship

Twelve species of flowering potted plants were grown in a peat-based medium with water soluble fertilizer concentrations of 50, 100, or 200 mg·liter-1 N and K2O. Leaf blade or leaf petiole samples were collected six to eight weeks after planting. Sap was expressed using a hydraulic press and levels of nitrate nitrogen and potassium were determined using Cardy flat sensor ion meters. Petiole nitrate level ranged from 520 to 6300 mg·liter-1 and potassium levels ranged from 870 to 3600 mg·liter-1. The petiole nitrate concentration and change in petiole nitrate levels with changes in media nitrate levels was crop dependent. Leaf blade nitrate and potassium concentrations were lower than leaf petiole concentrations. The relationship of petiole nitrate to final plant fresh and dry mass and appearance at flowering will be presented.

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