Daily cycles in serum gonadotropin levels in the goldfish: effects of photoperiod, temperature, and sexual condition

1978 ◽  
Vol 56 (11) ◽  
pp. 2430-2442 ◽  
Author(s):  
Alice Hontela ◽  
R. E. Peter
Keyword(s):  
Temperature Regime ◽  
Environmental Conditions ◽  
Mature Gonad ◽  
Daily Variations ◽  
Environmental Regimes ◽  
Daily Cycles ◽  
Serum Gonadotropin ◽  
Effects Of Temperature

The effects of temperature (12 and 21 °C) and photoperiod (16 h light, 8 h dark; 8 h light, 16 h dark) on daily cycles of serum gonadotropin (GtH) in goldfish with a regressed gonad (GSI = 1.1%), females undergoing ovarian recrudescence (GSI = 5.2%), and females with a mature gonad (GSI = 11%) were investigated. Serum GtH levels were measured by radioimmunoassay. Fish with regressed gonads either did not show significant daily fluctuations in serum GtH levels under different environmental regimes or showed daily fluctuations smaller in magnitude than those of females undergoing ovarian recrudescence or mature females. The patterns of daily variations of GtH levels under the same photoperiod and temperature regime were somewhat similar in the latter two groups. Also, under similar environmental conditions, although the GtH levels of females undergoing ovarian recrudescence and mature females were higher than the GtH levels in fish with regressed gonads most of the time during the 24-h period, during a portion of the 24-h period the GtH levels of all three groups were similar.

Relationships between temperature and Pacific hake distribution vary across latitude and life-history stage

2020 ◽  
Vol 639 ◽  
pp. 185-197 ◽  
Author(s):  
MJ Malick ◽  
ME Hunsicker ◽  
MA Haltuch ◽  
SL Parker-Stetter ◽  
AM Berger ◽  
...  
Keyword(s):  
Life History ◽  
Environmental Effects ◽  
Environmental Conditions ◽  
Vancouver Island ◽  
Additive Models ◽  
Life History Stage ◽  
Fish Stocks ◽  
Merluccius Productus ◽  
Multiple Dimensions ◽  
Effects Of Temperature

Environmental conditions can have spatially complex effects on the dynamics of marine fish stocks that change across life-history stages. Yet the potential for non-stationary environmental effects across multiple dimensions, e.g. space and ontogeny, are rarely considered. In this study, we examined the evidence for spatial and ontogenetic non-stationary temperature effects on Pacific hake Merluccius productus biomass along the west coast of North America. Specifically, we used Bayesian additive models to estimate the effects of temperature on Pacific hake biomass distribution and whether the effects change across space or life-history stage. We found latitudinal differences in the effects of temperature on mature Pacific hake distribution (i.e. age 3 and older); warmer than average subsurface temperatures were associated with higher biomass north of Vancouver Island, but lower biomass offshore of Washington and southern Vancouver Island. In contrast, immature Pacific hake distribution (i.e. age 2) was better explained by a nonlinear temperature effect; cooler than average temperatures were associated with higher biomass coastwide. Together, our results suggest that Pacific hake distribution is driven by interactions between age composition and environmental conditions and highlight the importance of accounting for varying environmental effects across multiple dimensions.

Control of Kochia in Sugarbeets With Benzadox

Weed Science ◽  
1970 ◽  
Vol 18 (1) ◽  
pp. 183-185 ◽  
Author(s):  
D. M. Weatherspoon ◽  
E. E. Schweizer
Keyword(s):  
Acetic Acid ◽  
Beta Vulgaris ◽  
Temperature Regime ◽  
Environmental Conditions ◽  
Growth Chamber ◽  
Kochia Scoparia ◽  
Simulated Rain ◽  
Chamber Studies ◽  
Growth Chamber Studies

Benzadox [(benzamidooxy)acetic acid] applied at 1, 2, 3, and 4 lb/A as a postemergence treatment controlled kochia [Kochia scoparia(L.) Schrad.] selectively in sugarbeets (Beta vulgarisL.). Control increased as the rate of benzadox increased, but some kochia survived at the 4-lb/A rate. Competition from these plants reduced the yields of sugarbeet roots and sucrose. Where surviving kochia plants were removed by hand 7 weeks after emergence, all sugarbeets treated with benzadox yielded as well as the hand-weeded checks. In growth chamber studies, the activity of benzadox was increased by temperature and decreased by simulated rain which occurred within 4 hr following application. Under a temperature regime of 70 F day and 40 F night, if simulated rain was delayed for 8 hr, the control of kochia was identical to that obtained where no simulated rain followed treatment. The growth chamber studies confirmed our results with the performance of benzadox under different environmental conditions in the field.

scholarly journals Development of MILIONCAST, an Improved Model for Predicting Downy Mildew Sporulation on Onions

Plant Disease ◽  
2004 ◽  
Vol 88 (7) ◽  
pp. 695-702 ◽  
Author(s):  
Tijs Gilles ◽  
Kath Phelps ◽  
John P. Clarkson ◽  
Roy Kennedy
Keyword(s):  
Relative Humidity ◽  
Environmental Conditions ◽  
Temporal Pattern ◽  
Random Model ◽  
Controlled Environment ◽  
High Humidity ◽  
Potted Plants ◽  
Effects Of Temperature ◽  
Improved Model ◽  
Accuracy Of Prediction

The effects of temperature and relative humidity on Peronospora destructor sporulation on onion (Allium cepa) leaves were studied under controlled environmental conditions. Sporangia were produced most rapidly at 8 to 12°C after 5 h of high humidity during dark periods. The greatest number of sporangia was produced at 100% relative humidity (RH), and sporulation decreased to almost nil when humidity decreased to 93% RH. A model, named MILIONCAST (an acronym for MILdew on onION foreCAST), was developed based on the data from these controlled environment studies to predict the rate of sporulation in relation to temperature and relative humidity. The accuracy of prediction of sporulation was evaluated by comparing predictions with observations of sporulation on infected plants in pots outdoors. The accuracy of MILIONCAST was compared with the accuracy of existing models based on DOWNCAST. MILIONCAST gave more correct predictions of sporulation than the DOWNCAST models and a random model. All models based on DOWNCAST were more accurate than the random model when compared on the basis of all predictions (including positive and negative predictions), but they gave fewer correct predictions of sporulation than the random model. De Visser's DOWNCAST and ONIMIL improved their accuracy of prediction of sporulation events when the threshold humidity for sporulation was reduced to 92% RH. The temporal pattern of predicted sporulation by MILIONCAST generally corresponded well to the pattern of sporulation observed on the outdoor potted plants at Wellesbourne, UK.

Propanil Plus Methyl Parathion on Rice (Oryza sativa)

Weed Science ◽  
1988 ◽  
Vol 36 (3) ◽  
pp. 335-339 ◽  
Author(s):  
Gene D. Wills ◽  
Joe E. Street
Keyword(s):  
Oryza Sativa ◽  
Soil Moisture ◽  
Environmental Conditions ◽  
Methyl Parathion ◽  
Field Experiments ◽  
Controlled Environment ◽  
Planting Dates ◽  
Effects Of Temperature ◽  
Effect On Yield ◽  
Wilting Point

Effects of propanil [N-(3,4-dichlorophenyl)propanamide] applied to three- to four-leaf rice (Oryza sativaL.) 1 or 7 days before, after, or tank mixed with methyl parathion (O,O-dimethyl-O-4-nitrophenyl phosphorothioate) were determined under different environmental conditions. Field experiments determined the effect on yield of drill-seeded rice, ‘Labelle’ for two planting dates in 1982 and ‘Lemont’ for one planting date in 1986. Treatments were applied at sunrise and at noon. Growth chamber and greenhouse experiments determined the effects of temperature, relative humidity (RH), and soil moisture on response of Labelle rice. In all experiments, propanil, both alone and with methyl parathion, resulted in 20 to 30% leaf burn during the first week after treatment with rapid recovery to less than 10% injury after 3 to 4 weeks. In field experiments, yields were not reduced in the treated rice below that in the untreated controls. In controlled-environment experiments, rice was not injured by propanil plus methyl parathion more than by propanil alone after 2 to 4 weeks. Both treated and untreated rice were injured more by the environmental conditions of high (40 C) temperature, low (40%) RH, and low (near the wilting point) soil moisture than by low (30 C) temperature, high (100%) RH, and flooded soil.

scholarly journals Effects of Temperature, Light, and Rainfall on Superficial Scald Development in Apples

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 750E-750
Author(s):  
William J. Bramlage ◽  
Sarah A. Weis
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
New England ◽  
Environmental Conditions ◽  
Cool Temperature ◽  
Relative Importance ◽  
Light Conditions ◽  
Fruit Maturation ◽  
Superficial Scald ◽  
Effects Of Temperature

Preharvest environmental conditions apparently determine susceptibility of apples to postharvest scald development. Cool temperature, as hours below 10C, can greatly reduce susceptibility, but greater than 30C appears to enhance it. These effects appear to interact, because a high-temperature episode can cause loss of some low-temperature benefit. Shading of fruit increases their scald susceptibility and preharvest light conditions, along with preharvest rainfall, appear to be factors in scald susceptibility in New England. Fruit maturation reduces scald susceptibility. We are constructing models of contributions of these variables to scald susceptibility of fruit grown under different environmental conditions, and in this the relative importance of these variables is being evaluated.

Germination strategies of annual forbs from south-eastern Australian semiarid grasslands

2012 ◽  
Vol 60 (4) ◽  
pp. 340 ◽  
Author(s):  
Andrew J. Scott ◽  
John W. Morgan
Keyword(s):  
Temperature Regime ◽  
Environmental Conditions ◽  
Seed Banks ◽  
Constant Darkness ◽  
Continuous Darkness ◽  
Soil Seed Banks ◽  
South Eastern ◽  
Single Temperature ◽  
Risk Spreading ◽  
Main Strategy

Germination is a key process driving the composition and dynamics of annual-forb communities and soil seed banks. We tested the germination biology of 20 annual forbs from semiarid grasslands in southern Australia, under a single temperature regime (20/10°C) in either constant darkness or 12-h diurnal light, to assess whether their laboratory germination responses are consistent with transient seed banks and rapid field emergence. Germination in the light was generally moderate to high, with most (70%) species achieving >35% final germination. Additionally, most (90%) species began germinating within 5 days, and all species achieved at least 50% of final germination within 10 days, suggesting that rapid and synchronous germination is the main strategy of annual forbs in this region. However, several species had seeds that continued to germinate for a prolonged period, and in most species, a fraction of seeds did not germinate, demonstrating risk-spreading strategies. Additionally, the germination of most (79%) species was significantly inhibited by continuous darkness. Despite the potential for the formation of large persistent seed banks through low germination in some species and dark inhibition in most, rapid germination and prevailing environmental conditions apparently prevent this in the field.

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