INCREASING WINTER SURVIVAL OF DORMOAT SEEDS BY A TREATMENT INDUCING SECONDARY DORMANCY

1974 ◽  
Vol 54 (3) ◽  
pp. 565-571 ◽  
Author(s):  
C. J. ANDREWS ◽  
V. D. BURROWS
Keyword(s):  
Cold Hardiness ◽  
Storage Time ◽  
Incubation Temperature ◽  
Winter Survival ◽  
Water Volume ◽  
Humid Atmosphere ◽  
Secondary Dormancy ◽  
Two Factors ◽  
Incubation Temperatures ◽  
Stimulation Of

Treatment of partially after-ripened dormoat (Avena sativa L. × A. fatua L.) seeds by soaking in water and incubation in an enclosed humid atmosphere for 2 wk induces secondary dormancy and increases the winter survival of field plantings. Immediately after treatment, the seeds are highly dormant when incubated on moist filter paper in petri plates at 20 C, but there is a slight stimulation of germination at low incubation temperature (7 C) and during incubation in soil. The germination response to these two factors increases with time, and reaches 100% when tested after 6 wk dry storage. Germination in petri dishes at 20 C increases slowly with storage time, attaining 57% or less after 12 wk. Germination is increased by decreasing water volume during test, to a level similar to that obtained by incubation of seeds in soil. Survival of dormoat seeds through the winter of 1970–71 was increased an average of threefold by the treatment, to a maximum of 40% in several strains. There is no increase in seed cold hardiness due to the treatment. The treatment increases the dormancy level of seeds before planting, and seed with induced secondary dormancy is only slightly stimulated to germinate by low incubation temperatures. Both these factors increase the number of un-germinated seeds entering winter.

scholarly journals Evidence of interpopulation variation in the germination of Eryngium maritimum L. (Apiaceae)

Plant Ecology ◽  
2021 ◽  
Author(s):  
I. Cortés-Fernández ◽  
M. D. Cerrato ◽  
A. Ribas-Serra ◽  
C. Cardona ◽  
C. González ◽  
...  
Keyword(s):  
Incubation Temperature ◽  
Potential Effect ◽  
Mean Annual Temperature ◽  
Cold Stratification ◽  
Mediterranean Populations ◽  
High Germination ◽  
Two Factors ◽  
Different Temperatures ◽  
Incubation Temperatures ◽  
Eryngium Maritimum

AbstractGermination is considered as one of the most crucial steps in a plant’s lifetime. The germination of Eryngium maritimum, a dune species located across all European coasts, has been extensively analysed in Northern populations, where it is considered a locally endangered species. However, less attention has been given to southern populations, where the knowledge about the germination of the species is very limited. The main objective of the present study was to analyse the effect of cold stratification in one Mediterranean and one Atlantic population of the species, as well as to compare the potential variation of seed dormancy among a latitudinal gradient in European populations based on current literature. Seeds collected from Mallorca (Mediterranean, Spain) and Asturias (Atlantic, Spain) were germinated at different temperatures and cold stratification periods ranging from 4 to 20 weeks. These results were merged with the results of previous studies to test the potential effect of latitude and climatic variables in germination. Although the optimal incubation temperature was 10 ºC, the highest final germination percentages (up to 96%) was obtained in both populations combining specific cold stratification periods (5 ºC) and constant incubation temperatures (15–20 ºC). Atlantic seeds needed longer cold stratification times to reach high germination percentages compared with Mediterranean seeds. Apart from the stratification response, significant differences in viability and in germination were observed between the Atlantic and the Mediterranean populations. Considering data from previous studies in the analysis, the results suggest that there is a potential effect of latitude in the ecological germination requirements, by which the higher the latitude, the longer the cold stratification period required to germinate, with a correlation with the mean annual temperature. These results suggests that two factors, modulation of dormancy relating to adaptative or maternal effects and viability, govern the germination of the species.

THE EFFECT OF GONADECTOMY ON THE RESPONSE OF THE PITUITARY I. C. S. H.-CONTENT TO STEROID SEX HORMONES

1960 ◽  
Vol XXXV (II) ◽  
pp. 245-252 ◽  
Author(s):  
G. P. van Rees ◽  
F. J. A. Paesi
Keyword(s):  
Sex Hormones ◽  
Sex Steroids ◽  
Low Dose ◽  
Testosterone Propionate ◽  
Preceding Paper ◽  
Direct Consequence ◽  
Two Factors ◽  
Reflex Stimulation ◽  
Steroid Sex Hormones ◽  
Stimulation Of

ABSTRACT In the experiments reported in this paper the hypothesis that the decrease in the pituitary I. C. S. H.-content, which occurs after administration of steroid sex hormones in gonadectomized animals, is counteracted by a reflex stimulation of the hypophysis initiated by the operation has been investigated. If treatment with a low dose of testosterone propionate (100 μg) was started immediately after castration, the resulting decrease in the pituitary I. C. S. H.-content became more marked if the reflex stimulation of the hypophysis had been prevented. If, however, two months were allowed to elapse before the beginning of treatment, the presence or absence of this reflex was no longer of importance for the effect of testosterone propionate on the pituitary I. C. S. H.-content. And yet, in this case too, the decrease in the pituitary I. C. S. H.-content by testosterone propionate was less than in intact animals (see preceding paper). Hence this decrease appears to be counteracted by two factors: one rapidly occurring and short lasting, resulting from a reflex elicited by gonadectomy; the other gradually increasing in potency and possibly a direct consequence of the continued absence of pituitary inhibiting sex steroids.

Phytotoxic Effect of Decaying Quackgrass (Agropyron repens) Residues

Weed Science ◽  
1979 ◽  
Vol 27 (6) ◽  
pp. 595-598 ◽  
Author(s):  
T. V. Toai ◽  
D. L. Linscott
Keyword(s):  
Incubation Temperature ◽  
Soil Surface ◽  
Water Soluble ◽  
Water Extracts ◽  
Phytotoxic Activity ◽  
Phytotoxic Effect ◽  
Effects Of Temperature ◽  
Incubation Temperatures ◽  
Toxin Formation ◽  
Agropyron Repens

We studied the effects of temperature (5, 10, 20, and 30 C) on the phytotoxic activity of decaying quackgrass [Agropyron repens (L.) Beauv.] leaves and rhizomes that were incubated in soils for 0, 1, 2, 4, and 6 weeks. Alfalfa (Medicago sativa L.) seeds were grown for 96 h in water, water extracts of control soils, and water extracts of soil with quackgrass rhizomes or leaves. Dried quackgrass rhizomes and leaves contained water-soluble toxins that inhibited alfalfa seedling development and growth. There was a strong interaction between incubation time and temperature on the development of additional toxins by decomposing quackgrass. High incubation temperature (30 C) accelerated toxin formation and ultimate decay. Intermediate temperature (20 C) delayed toxin formation and decay. Low incubation temperatures (5 C and 10 C) prevented formation of additional toxin. In all extracts of quackgrass and soil that had been incubated for 6 weeks, normal alfalfa seedling number equaled that in water. However, seedling growth varied with incubation temperatures.Treatment of quackgrass with glyphosate [N-(phosphonomethyl) glycine] in the greenhouse did not influence the toxicity of decaying quackgrass leaves. The highest toxic effect was noted after 1 week of decay on the soil surface.

Thermal and water source effects upon the stability of enteroviruses in surface freshwaters

1989 ◽  
Vol 35 (4) ◽  
pp. 474-480 ◽  
Author(s):  
Christon J. Hurst ◽  
William H. Benton ◽  
Kim A. McClellan
Keyword(s):  
Bacterial Growth ◽  
Incubation Temperature ◽  
Water Source ◽  
Inactivation Rate ◽  
Human Enterovirus ◽  
Strongly Correlated ◽  
Artificial Lake ◽  
Viral Inactivation ◽  
Term Survival ◽  
Incubation Temperatures

The long-term survival of three human enterovirus serotypes, Coxsackievirus B3, echovirus 7, and poliovirus 1 was examined in samples of surface freshwater collected from five sites of physically different character. These were an artificial lake created by damming a creek, a small groundwater outlet pond, both a large- and a medium-sized river, and a small suburban creek. Survival was studied at temperatures of −20, 1, and 22 °C. The average amount of viral inactivation was 6.50–7.0 log10 units over 8 weeks at 22 °C, 4–5 log10 units over 12 weeks at 1 °C, and 0.4–0.8 log10 units over 12 weeks at −20 °C. The effect of incubation temperature upon viral inactivation rate was statistically significant (p < 0.00001). As determined by pairing tests, survival was also significantly related to both viral serotype and water source at each of the three incubation temperatures (p ≤ 0.05). Efforts were made to determine whether the rate of viral inactivation observed at the different incubation temperatures was related to characteristics inherent to the water that was collected from the different locations. The characteristics examined included physical and chemical parameters, indigenous bacterial counts, and the amount of bacterial growth that the waters would support (measured as the maximum number of generations which seeded bacteria could undergo after being placed into either pasteurized or sterile-filtered water samples). Analysis of viral inactivation rate versus these characteristics revealed three apparent effectors of viral persistence. These were (i) hardness and conductivity, both of which strongly correlated with one another; (ii) turbidity and suspended solids content, both of which strongly correlated with one another; and (iii) the number of generations of bacterial growth that a sample was capable of supporting, which also correlated with hardness and conductivity.Key words: virus, survival, inactivation rate, water.

Nest temperature´s influence on morphology of Dermochelys coriacea hatchlings incubated in hatcheries in Oaxaca, Mexico

2021 ◽  
Author(s):  
Jesús García-Grajales ◽  
Juan Francisco Meraz ◽  
José Luis Arcos García ◽  
Eustacio Ramírez Méndez
Keyword(s):  
Incubation Temperature ◽  
Carapace Width ◽  
Principal Component ◽  
Dermochelys Coriacea ◽  
Egg Mass ◽  
Natural Environments ◽  
Data Logger ◽  
Geometric Morphometric ◽  
Low Weight ◽  
Incubation Temperatures

The influence of nest incubation temperatures on the carapace shape and morphological traits of Dermochelys coriacea (Vandelli 1761) hatchlings incubated in two hatcheries of Oaxaca, Mexico was evaluated. This study was carried out from October 2016 through May 2017. On each beach, there are community groups consisting of volunteers without association with universities, that protect and relocate the nests to increase hatching success. In each translocated nest, a data logger was placed in the centre of the egg mass. Hatchlings were collected as they emerged from each nest. The carapaces of the hatchlings were photographed and subjected to geometric morphometric analysis; later, hatchlings were weighed and their bodies were measured. The mean temperature of 12 nests in each hatchery were recorded, with no significant differences between hatcheries. The principal component analysis (PCA) revealed an overlapping of the carapace shape under different duration of temperature. Temperature had a significant influence on hatchling morphology. Higher mean incubation temperatures produced hatchlings with low weight, smaller appendage; narrower carapace width and shorter flippers length. Lower mean incubation temperatures produced hatchlings that had greater weight, greater appendage width, wider carapace width and longer flipper length. Results indicate that the D. coriacea hatchlings incubated in hatcheries demonstrate morphology that varies in relation to nest incubation temperature in a similar way to hatchlings produced in natural environments.

Effect of Salt Concentration and Incubation Temperature on Formation of Histamine, Phenethylamine, Tryptamine and Tyramine During Miso Fermentation

1986 ◽  
Vol 49 (6) ◽  
pp. 423-427 ◽  
Author(s):  
K.-D. HENRY CHIN ◽  
P. E. KOEHLER
Keyword(s):  
Salt Concentration ◽  
Incubation Temperature ◽  
High Salt ◽  
Soybean Paste ◽  
Salt Level ◽  
Low Salt ◽  
Two Factors

Two factors, salt concentration and incubation temperature, were examined for their effect on the formation of histamine, phenethylamine, tryptamine and tyramine during miso (soybean paste) fermentation. Misos containing 5 and 10% NaCl were prepared and incubated at 25 and 35°C. The effect of each factor was determined from the chemical and microbiological changes in the misos during fermentation. Salt level was a significant factor in the formation of amines. Higher amine levels were found in low-salt (5% NaCl) formulations than in high-salt (10% NaCl) misos. Incubation temperature within the range of 25 to 35°C during fermentation had little effect on amine formation in misos.

scholarly journals Analisis Efektifitas Tepung Jamur sebagai Larvasida Aedes aegypti

2012 ◽  
Vol 14 (1) ◽  
pp. 126
Author(s):  
Yekki Yasmin ◽  
Lenni Fitri ◽  
Betty Mauliya Bustam
Keyword(s):  
Aedes Aegypti ◽  
Beauveria Bassiana ◽  
Storage Time ◽  
Natural Sciences ◽  
The Other ◽  
Biology Department ◽  
Randomized Design ◽  
Two Factors ◽  
Result Show ◽  
Completely Randomized Design

This research is about effectivity analysis of two kinds of fungi i.e. Beauveria bassiana and Metharrizium anisopliae as Aedes aegyptilarvacide, it has been conducted at laboratories Zoology in Biology Department, Mathematics and Natural Sciences Faculty, Syiah KualaUniversity. Aims of this research were estimating maximum time storage of fungi powder as effective larvacide and the number of bacteriacolonies were found in water used for experiment. This research was used Completely Randomized Design (CRD). The experiments consistof two factors i.e kind and saving time of fungi. The result show that the longer the storage time of Beauveria bassiana the more ineffectiveit was as larvacide and the least fungi colonies were found. Metharrizium anisopliae on the other hand, the longer it was kept, the moreeffective it was as larvacide and the more fungi colonies were found.

scholarly journals Effects of constant incubation regimes on eggs and hatchlings of the egg-laying skink, Oligosoma suteri

2021 ◽  
Author(s):  
◽  
Kelly Maree Hare
Keyword(s):  
Hatching Success ◽  
Incubation Temperature ◽  
Unit Length ◽  
Condition Index ◽  
Egg Laying ◽  
Maternal Influence ◽  
Temperature Dependent ◽  
Sprint Speed ◽  
Fitness Traits ◽  
Incubation Temperatures

<p>The conditions under which reptilian eggs are incubated affect survival probability and physiological attributes of the progeny. The egg-laying skink, Oligosoma suteri, is the only endemic oviparous lizard in New Zealand. No controlled laboratory incubation had previously been undertaken, and thus no information was available on the requirements for successful captive incubation. I studied the effects of incubation regime on the eggs and hatchlings of O. suteri to four months of age. Oligosoma suteri eggs (n = 174) were randomly distributed among three constant incubation temperatures (18°C, 22°C and 26°C) and two water potentials (-120 kPa and -270 kPa). Hatching success and hatchling survival were greatest at 22°C and 26°C, with hatchlings from 18°C incubation suffering from physical abnormalities. Incubation regime and maternal influence did not affect sex of individuals, with equal sex ratios occurring from each incubation treatment. Hatchlings from the 22°C and -120 kPa incubation treatments were larger, for most measurements, and warmer incubation temperatures resulted in increased growth rates. Juveniles from 22°C and 26°C and individuals with greater mass per unit length (condition index) sprinted faster over 0.25 m. Sprint speed was positively correlated with ambient temperature. At four months of age sprint speed decreased in 18°C individuals and individuals incubated at 26°C and -270 kPa compared to their performance at one month. The results suggest that the most successful captive incubation regime for O. suteri is 22°C and -120 kPa. This study also shows that temperature-dependent sex determination does not occur in O. suteri, but that fitness traits are influenced by incubation temperature.</p>

JUVENILE LYMPHOCYTIC THYROIDITIS

PEDIATRICS ◽  
1962 ◽  
Vol 30 (6) ◽  
pp. 917-926
Author(s):  
Krishna M. Saxena ◽  
John D. Crawford
Keyword(s):  
Antibody Test ◽  
Lymphocytic Infiltration ◽  
Thyroid Stimulating Hormone ◽  
Test Results ◽  
Lymphocytic Thyroiditis ◽  
Results Of Treatment ◽  
Two Factors ◽  
The Moment ◽  
Tsh Stimulation ◽  
Stimulation Of

Lymphocytic thyroiditis was the most common cause of nontoxic goiters in childhood, comprising about 40% of these and 20% of all goiters seen in our pediatric endocrine clinic. The diagnosis should be considered whenever a nontoxic goiter does not diminish significantly in size within about two weeks in response to thyroid-stimulating-hormone (TSH) suppressive doses of USP thyroid. Observations on 32 children with lymphocytic thyroiditis have been recorded. The diagnosis was proven histologically in 23. In nine patients the diagnosis was presumptive. The condition occurred mostly in preadolescent girls as a slowly developing firm, diffuse, and smooth or nubbly goiter with or without symptoms of anxiety, nervousness and pressure in the neck. The majority of patients were euthyroid when first encountered, though examples both of mild hyperthyroidism and hypothyroidism were also seen. A high protein-bound iodine value, a large discrepancy between protein-bound iodine and butanol-extractable iodine, and positive tanned erythrocyte antibody test results provided the best diagnostic criteria apart from biopsy. The pathological picture is one of hyperplasia with lymphocytic infiltration and atrophy of thyroid follicles and epithelium. Treatment consisted in giving TSH suppressive doses of thyroid for a prolonged period. The results of treatment were not entirely satisfactory. Genetic predisposition, probably manifested in an abnormal cellular hypersensitivity, and excessive TSH stimulation of the thyroid seem for the moment the two factors in pathogenesis best supported by laboratory evidence.

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