Ecophysiology of seed dormancy and germination in the mesic woodland herbaceous perennial Corydalis ambigua (Fumariaceae) in Japan

2005 ◽  
Vol 83 (6) ◽  
pp. 571-578 ◽  
Author(s):  
Tetsuya Kondo ◽  
Nori Okubo ◽  
Taku Miura ◽  
Carol C Baskin ◽  
Jerry M Baskin
Keyword(s):  
Laboratory Experiments ◽  
Snow Melt ◽  
Natural Conditions ◽  
Hydrastis Canadensis ◽  
Morphophysiological Dormancy ◽  
Germination Phenology ◽  
Metal Frame ◽  
Diurnal Temperatures ◽  
Herbaceous Perennial ◽  
Do So

In Japan, the herbaceous perennial Corydalis ambigua Cham. et Schlecht. occurs in Tohoku and Hokkaido, where it grows in deciduous woodlands. Seeds have an underdeveloped embryo that is physiologically dormant at the time of dispersal in late May. In laboratory experiments, embryos did not grow when kept continuously at 5 °C or at alternating diurnal temperatures of 25/15 °C. However, following warm stratification at 25/15 °C, they grew at 15/5 °C and continued to do so at 0 °C. Radicles emerged after a relatively long period at 0 or 5 °C, following warm stratification at 25/15 °C and then incubation at 15/5 °C. Embryos began to develop in autumn in seeds under near-natural conditions in a metal frame-house, and they had grown to an average of about 90% of their full length by December. Beginning in December, the seed coat split, exposing the endosperm, and in March both the radicle and the cotyledon emerged under the snow or immediately after snow melt. Dormancy in seeds of C. ambigua is the same as that in seeds of Hydrastis canadensis L., which has been described as a special type of deep simple epicotyl morphophysiological dormancy.Key words: Corydalis ambigua, embryo growth, morphophysiological dormancy, seed germination phenology, underdeveloped embryo.

Persistent, vertical-migration rhythms in benthic microflora.: II. Field and Laboratory Studies On Diatoms From The Banks Of The River Avon

1966 ◽  
Vol 46 (1) ◽  
pp. 191-214 ◽  
Author(s):  
F. E. Round ◽  
J. D. Palmer
Keyword(s):  
High Temperatures ◽  
Vertical Migration ◽  
Laboratory Experiments ◽  
Biological Clock ◽  
Diatom Species ◽  
Laboratory Studies ◽  
Natural Conditions ◽  
Constant Illumination ◽  
Different Temperatures ◽  
Clock Hypothesis

The vertical migration of two Euglena species and several diatom species into and out of the sediment on the banks of the River Avon has been studied under natural conditions. All species have been shown to migrate vertically upwards when exposed during daylight. Tidal flooding of the sediment is generally preceded by re-burrowing of the algae beneath the surface. Methods have been devised to follow these migrations in both the field and laboratory. Laboratory experiments show that these migrations are rhythmic, continuing under constant illumination and temperature and removed from tidal influence. The effect of three different temperatures and three different light intensities has been investigated. Transfer from low to high temperatures has been shown to reset the phase of the rhythm. The results are discussed in relation to other work and to the ‘biological clock’ hypothesis.

scholarly journals Physiological tolerances account for range limits and abundance structure in an invasive slug

2009 ◽  
Vol 276 (1661) ◽  
pp. 1459-1468 ◽  
Author(s):  
Jennifer E Lee ◽  
Charlene Janion ◽  
Elrike Marais ◽  
Bettine Jansen van Vuuren ◽  
Steven L Chown
Keyword(s):  
Laboratory Experiments ◽  
Climatic Factors ◽  
Range Limits ◽  
Sensitive Species ◽  
Species Preference ◽  
Absolute Limit ◽  
Drainage Line ◽  
Physiological Tolerances ◽  
Linear Decline ◽  
Do So

Despite the importance of understanding the mechanisms underlying range limits and abundance structure, few studies have sought to do so. Here we use a terrestrial slug species, Deroceras panormitanum , that has invaded a remote, largely predator-free, Southern Ocean island as a model system to do so. Across Marion Island, slug density does not conform to an abundant centre distribution. Rather, abundance structure is characterized by patches and gaps. These are associated with this desiccation-sensitive species' preference for biotic and drainage line habitats that share few characteristics except for their high humidity below the vegetation surface. The coastal range margin has a threshold form, rapidly rising from zero to high density. Slugs do not occur where soil-exchangeable Na values are higher than 3000 mg kg −1 , and in laboratory experiments, survival is high below this value but negligible above it. Upper elevation range margins are a function of the inability of this species to survive temperatures below an absolute limit of −6.4°C, which is regularly exceeded at 200 m altitude, above which slug density declines to zero. However, the linear decline in density from the coastal peak is probably also a function of a decline in performance or time available for activity. This is probably associated with an altitudinal decline in mean annual soil temperature. These findings support previous predictions made regarding the form of density change when substrate or climatic factors set range limits.

Bargaining Process and Channel Efficiency

2020 ◽  
Vol 66 (7) ◽  
pp. 2845-2860 ◽  
Author(s):  
Ernan Haruvy ◽  
Elena Katok ◽  
Valery Pavlov
Keyword(s):  
Operations Management ◽  
Laboratory Experiments ◽  
Wholesale Price ◽  
Analytical Models ◽  
Bargaining Process ◽  
Supply Chain Contracts ◽  
Channel Efficiency ◽  
Contract Performance ◽  
Do So ◽  
Additional Channel

The behavioral literature has demonstrated that the format of supply chain contracts matters even when theoretically it should not and that contracts that in theory coordinate channels fail to do so in laboratory experiments. The existing body of experimental evidence uses an ultimatum bargaining protocol to test analytical models, but there is no reason to think that bargaining in supply chains is in the form of ultimatum offers. We investigate the effect of bargaining on contract performance by extending the bargaining protocol to allow the manufacturer to make concessions. We test coordinating contract with bargaining in the laboratory by comparing wholesale price and the two-part tariff contracts using two different bargaining protocols. We then develop and estimate a statistical model of behavior with bargaining and find that this model organizes our data well. Our main finding is that the contracts that we study are more efficient when participants are allowed to make concessions. The additional channel efficiency is owing to more efficient offers made by manufacturers. The higher channel efficiency primarily benefits the retailer—the weaker party. Our main contribution is the observation that, when testing analytical models of contracts in the laboratory, the way that the bargaining process is implemented, such as the ability to make concessions, has a critical effect on conclusions. This paper was accepted by Vishal Gaur, operations management.

Field Experiments

2004 ◽  
Vol 42 (4) ◽  
pp. 1009-1055 ◽  
Author(s):  
Glenn W Harrison ◽  
John A List
Keyword(s):  
Laboratory Experiments ◽  
Field Experiments ◽  
Trading Rules ◽  
Subject Pool ◽  
The Subject ◽  
Do So

Experimental economists are leaving the reservation. They are recruiting subjects in the field rather than in the classroom, using field goods rather than induced valuations, and using field context rather than abstract terminology in instructions. We argue that there is something methodologically fundamental behind this trend. Field experiments differ from laboratory experiments in many ways. Although it is tempting to view field experiments as simply less controlled variants of laboratory experiments, we argue that to do so would be to seriously mischaracterize them. What passes for “control” in laboratory experiments might in fact be precisely the opposite if it is artificial to the subject or context of the task. We propose six factors that can be used to determine the field context of an experiment: the nature of the subject pool, the nature of the information that the subjects bring to the task, the nature of the commodity, the nature of the task or trading rules applied, the nature of the stakes, and the environment that subjects operate in.

Intermediate morphophysiological dormancy allows for life-cycle diversity in the annual weed, Turgenia latifolia (Apiaceae)

2014 ◽  
Vol 62 (8) ◽  
pp. 630 ◽  
Author(s):  
Miregul Nurulla ◽  
Carol C. Baskin ◽  
Juan J. Lu ◽  
Dun Y. Tan ◽  
Jerry M. Baskin
Keyword(s):  
Life Cycle ◽  
Low Temperatures ◽  
Western China ◽  
Intermediate Complex ◽  
Dormancy Breaking ◽  
Morphophysiological Dormancy ◽  
Temperature Regimes ◽  
Germination Phenology ◽  
Physiological Dormancy ◽  
Winter Annual

Our aim was to determine the seed dormancy-breaking requirements and type of life cycle of Turgenia latifolia in north-western China. At dispersal in July, only 0–9% of the seeds germinated at 5/2°C, 15/2°C, 20/10°C and 25/15°C; thus, 91% of the seeds exhibited physiological dormancy (PD) and 9% were non-dormant. Also, the embryo was underdeveloped and embryo length : seed length ratio increased from 0.38 in fresh seeds to 0.79 at germination. Seeds buried in dry soil at the four temperature regimes for 12 weeks germinated to ≥50% when tested in darkness at 5/2°C, and those buried at 15/2°C and 20/10°C germinated to ≥50% when tested at 15/2°C. Seeds have intermediate complex morphophysiological dormancy (MPD). PD was broken at high and/or low temperatures, but embryo growth was completed only at low temperatures; gibberellic acid (GA3) promoted germination. Seeds buried under natural conditions during summer germinated to ~70% and ~55% at 5/2°C and 15/2°C, respectively, in darkness in autumn. In a germination-phenology study, cumulative germination was ~20% and ~80% in autumn and spring, respectively. Intermediate complex MPD allows the species to behave as a winter annual and as a short-lived summer annual.

scholarly journals Constant timing of medusa release in bivalve-inhabiting hydrozoans of the genus Eugymnanthea (Hydrozoa: Leptomedusae: Eirenidae)

2008 ◽  
Vol 88 (8) ◽  
pp. 1607-1609 ◽  
Author(s):  
Shin Kubota
Keyword(s):  
Light Intensity ◽  
Water Temperature ◽  
Breeding Season ◽  
Laboratory Experiments ◽  
Mytilus Galloprovincialis ◽  
Congeneric Species ◽  
Natural Conditions ◽  
Night Time

At the end of the breeding season in autumn, under natural conditions, mature medusae of Eugymnanthea japonica are released from its host Mytilus galloprovincialis at night-time. In laboratory experiments, mature medusae of the congeneric species E. inquilina are also released at night-time in autumn. At that time of the year, sunset is earlier and the water temperature is lower than in summer, when, under natural conditions, medusa release of E. japonica takes place at sunset instead. The release thus takes place at the same hours of the day in summer as well as in autumn. The circadial timing of medusa release of E. japonica is likely constant throughout the whole period in the breeding season and not correlated with the decrease of light intensity at sunset.

Efficiency of filter feeding of black fly larvae (Diptera: Simuliidae)

1978 ◽  
Vol 56 (7) ◽  
pp. 1608-1623 ◽  
Author(s):  
Daniel C. Kurtak
Keyword(s):  
Laboratory Experiments ◽  
Black Flies ◽  
Natural Conditions ◽  
Filter Feeding ◽  
Black Fly ◽  
The Mean ◽  
Fly Larvae ◽  
Single Larva

Larvae of nine species of black flies were exposed to synthetic particles in the laboratory. Sizes and concentrations of particles were chosen to simulate natural conditions. Smaller particles (diameter 5–10 μm) were offered at a rate of 50–100/cephalic fan area per second, and larger ones (diameter approximately 150 μm) at 0.3–1.0/cephalic fan area per second. Experiments were conducted at water velocities of 30, 50, and 70 cm/s.In all the laboratory experiments, only a small percentage of the particles passing through an area equal to that of the cephalic fans of a single larva were ingested. Particles larger than the spacing between the fan rays were ingested more efficiently than smaller ones. At 50 cm/s, the mean percentage ingested for all species was 1.6% (0.14–8.3%) of particles 150 μm in diameter and 0.094% (0.0026–0.76%) of particles 5–10 μm in diameter. The percentage of material ingested decreased at higher concentrations and water velocities. There were significant differences among the species.Experiments were done with one of the species in the field with similar results.Based on this work, an individual black fly larva in nature probably ingests 1–10% by weight of the material passing through its cephalic fans.

Settlement of the gastropod Concholepas concholepas on shells of conspecific adults

2004 ◽  
Vol 84 (3) ◽  
pp. 651-658 ◽  
Author(s):  
Patricio H. Manríquez ◽  
Sergio A. Navarrete ◽  
Armando Rosson ◽  
Juan Carlos Castilla
Keyword(s):  
Laboratory Experiments ◽  
Natural Conditions ◽  
Field Surveys ◽  
Adult Conspecific ◽  
Mean Size ◽  
Settlement And Metamorphosis ◽  
Shallow Subtidal ◽  
Commercially Important ◽  
The Mean ◽  
Concholepas Concholepas

Competent larvae of the commercially important marine gastropod Concholepas concholepas (Gastropoda: Muricidae) ‘loco’, were collected in the field and exposed in the laboratory to adult conspecific shells with and without barnacle epibionts. Settlement and metamorphosis was induced by the presence of barnacles on shells of live or dead conspecifics, but not by C. concholepas shells without barnacles. Results from laboratory experiments agreed well with field surveys showing the presence of recruits on conspecific shells overgrown with barnacles in shallow subtidal habitats (∼3–30 m deep), suggesting the potential importance of barnacles in inducing settlement and metamorphosis of locos under natural conditions. Most loco recruits were found below the C. concholepas shell apex, feeding on barnacles, inhabiting crevices among them, and inside dead barnacles. The mean size of recruits on locos' shells increased over four months from the beginning of the settlement season and no individual larger than 1·5 cm was observed, suggesting that they abandon adult loco shells at this size, roughly 5–6 months after settlement.

scholarly journals FEATURES OF SEED GERMINATION AND EMBRYO DEVELOPMENT OF REPRESENTATIVES OF THE FAMILY RANUNCULACEAE

Ekosistemy ◽  
2021 ◽  
pp. 100-110
Author(s):  
A. A. Erst
Keyword(s):  
Seed Germination ◽  
Embryo Development ◽  
Climatic Conditions ◽  
Key Factors ◽  
Natural Conditions ◽  
Factors Affecting ◽  
Morphophysiological Dormancy ◽  
The Family ◽  
Long Time ◽  
Growing Conditions

The ability of seeds to maintain viability for a long time without germination is one of the most important adaptive properties of plants. The article analyzes the dormancy types of seeds of the Ranunculacea family and describes the key factors affecting seed germination and embryo development (warm and cold stratification, exposure to gibberellic acid) under artificially created conditions. It is noted that five levels of seed morphophysiological dormancy are described for the representatives of this family: non-deep simple, deep simple, deep simple epicotyl, intermediate complex and deep complex, which are mainly associated with adaptation to survival in difficult climatic conditions. In the review, various types of dormancy are considered in terms of their adaptive significance for representatives of the Ranunculacea family. To overcome each type of dormancy, a set of optimal conditions is necessary, which correlates with the growing conditions of species or individual populations in natural conditions. Therefore, the development of techniques for overcoming the seeds dormancy under artificial conditions is closely related with the study of the ecology of a particular species and the natural conditions of growth. The analysis of literature data revealed a significant problem: 40 % of the analyzed sources did not indicate the type of dormancy of seeds of the representatives of the Ranunculaceae family and, probably, the list of morphophysiological dormancy levels will be supplemented in the course of further studies.

scholarly journals Fluid Dynamics Experiments for Planetary Interiors

2021 ◽  
Author(s):  
Michael Le Bars ◽  
Ankit Barik ◽  
Fabian Burmann ◽  
Daniel P. Lathrop ◽  
Jerome Noir ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Laboratory Experiments ◽  
Fluid Flows ◽  
Review Article ◽  
Planetary Interiors ◽  
Numerical Studies ◽  
Long Duration ◽  
Planetary Cores ◽  
Experimental Approaches ◽  
Do So

AbstractUnderstanding fluid flows in planetary cores and subsurface oceans, as well as their signatures in available observational data (gravity, magnetism, rotation, etc.), is a tremendous interdisciplinary challenge. In particular, it requires understanding the fundamental fluid dynamics involving turbulence and rotation at typical scales well beyond our day-to-day experience. To do so, laboratory experiments are fully complementary to numerical simulations, especially in systematically exploring extreme flow regimes for long duration. In this review article, we present some illustrative examples where experimental approaches, complemented by theoretical and numerical studies, have been key for a better understanding of planetary interior flows driven by some type of mechanical forcing. We successively address the dynamics of flows driven by precession, by libration, by differential rotation, and by boundary topography.

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