Heat tolerance of rhizomes of several understory species

1983 ◽  
Vol 61 (2) ◽  
pp. 452-457 ◽  
Author(s):  
Marguerite A. Flinn ◽  
Joan K. Pringle
Keyword(s):  
Temperature Tolerance ◽  
Pteridium Aquilinum ◽  
Tolerance Index ◽  
Understory Species ◽  
Chamaedaphne Calyculata ◽  
Cornus Canadensis ◽  
Shoot Number ◽  
Different Temperatures ◽  
Maianthemum Canadense ◽  
Study Sites

Rhizomes of eight understory species: Gaultheria procumbens, Maianthemum canadense, Vaccinium angustifolium, Cornus canadensis, Pteridium aquilinum, Kalmia angustifolia, Chamaedaphne calyculata, and Rhododendron canadense were subjected to treatments of 45, 50, 55 and 60 °C for 5 min in a water bath. Selection of these species for study was based on differences in the depth of the rhizomes, in habitat, and in rhizome morphology. Samples were collected from study sites located near Halifax, in the Nova Scotia Acadian Forest region.Maximum shoot growth occurred at different temperatures for the various species: 45 °C for Cornus canadensis; 50 °C for Chamaedaphne calyculata, R. canadense, and V. angustifolium; 55 °C for G. procumbens and M. canadense. Death occurred at or below 60 °C for most species. For comparative purposes, a temperature tolerance index (TTI) was calculated for each species. The TTI indicated that R. canadense and V. angustifolium showed the greatest tolerance to higher temperatures and that K. angustifolia and P. aquilinum showed the least tolerance. Mean shoot number increased significantly following spring treatments for all species except for Cornus canadensis which showed greater increase following autumn treatments.

Understory species interactions in mature boreal mixedwood forests

Botany ◽  
2010 ◽  
Vol 88 (10) ◽  
pp. 912-922 ◽  
Author(s):  
Virginia Chávez ◽  
S. Ellen Macdonald
Keyword(s):  
Environmental Factors ◽  
Species Interactions ◽  
Common Species ◽  
Herbaceous Layer ◽  
Competition Intensity ◽  
Understory Species ◽  
Mixedwood Forests ◽  
Natural Logarithm ◽  
Cornus Canadensis ◽  
Herb Species

We explored interactions among plant growth forms in the understory of mature boreal mixedwood forests in western Canada by investigating the competitive influence of erect shrubs on herbs (forbs and grasses). We established 10 pairs of plots; all erect shrubs were removed in one plot of each pair (removals) and left intact in the other plot (controls). Two years later, we harvested all aboveground biomass of the herbaceous layer (herb biomass: this included graminoids, forbs, trailing shrubs, and species with a woody base but not woody stems) from the 20 plots. We tested for significant differences in understory species biomass and composition between control and removal plots and examined the influence of 25 environmental factors on species composition of the herbaceous layer. Competition intensity was measured by the natural logarithm of response ratio (ln RR) index based on herb biomass. After erect shrub removal, there was a significant increase in herb biomass, mostly due to an increase of the most common species (e.g., Cornus canadensis Linnaeus, Linnaea borealis Linnaeus). The values of competition intensity (ln RR) varied among herb species but were, overall, positive, indicating a release from competition following shrub removal. Composition of the herbaceous layer was significantly different between removal and control plots and was also significantly related to seven environmental factors, which explained 40% of the variation in composition. Our study suggests that there is asymmetric competition for light between erect shrub and herb species in boreal ecosystems.

Experimental Anisakiasis: Cultivation and Temperature Tolerance Determinations1

1976 ◽  
Vol 39 (2) ◽  
pp. 132-137 ◽  
Author(s):  
JEFFREY W. BIER
Keyword(s):  
Culture Medium ◽  
Temperature Tolerance ◽  
Synthetic Analog ◽  
Fish Flesh ◽  
Composition And Structure ◽  
Different Temperatures ◽  
Contracaecum Osculatum ◽  
Newly Hatched Larvae ◽  
Complex Culture

All stages of the anisakine life cycle—egg, larva, and adult—have been used to initiate cultures. Eggs develop to hatching larvae at different temperatures depending on the species or strain. Newly hatched larvae of Phocanema decipiens and Contracaecum osculatum grow to an average 31.1 mm in 52 weeks and 6.5 mm in 32 weeks, respectively. Larvae from fish or those previously cultivated will molt at 35 C in a complex culture medium. P. decipiens and Anisakis marina have produced eggs in vitro. A. marina eggs from cultured females produced viable larvae. Freshness of the larvae used to initiate cultures is considered a major factor in success. The histochemistry of the composition and structure of P. decipiens cuticle in larvae from fish and cultures has been defined; experiments have demonstrated that the processes of cuticular deposition and ecdysis are independent. It has been postulated and evidence provided that a neurosecretory mechanism controls ecdysis; it has also been shown that this system can be stimulated by an insect hormone and a synthetic analog. Larvae in vitro, in fish flesh, and in fried fish fingers, do not survive heating to 60 C for 1 min. The recommended time and temperature found in Japanese and European literature for freezing fish to kill anisakine larvae is −20 C for 24 h; however, some North American species survive after 52 h at this temperature.

Regrowth of forest understory species following seasonal burning

1988 ◽  
Vol 66 (1) ◽  
pp. 150-155 ◽  
Author(s):  
Marguerite A. Flinn ◽  
Ross W. Wein
Keyword(s):  
Fold Increase ◽  
Forest Stand ◽  
Forest Understory ◽  
Stem Number ◽  
Tree Seedling ◽  
Vaccinium Angustifolium ◽  
Understory Species ◽  
Number Of Stems ◽  
Maianthemum Canadense ◽  
Vaccinium Myrtilloides

Small experimental plots in mixed-wood stands of the Acadian Forest were burned in the spring, summer, and autumn to obtain an estimate of the regrowth potential of common forest understory species. The number of stems was measured before burning and then monthly for 5 months thereafter. Supportive experiments on seasonal transplanting were conducted at the same time to determine regrowth potential after interspecific competition had been removed. Regrowth potential of species varied among seasonal burning treatments as expected and was strongest for Maianthemum canadense, Vaccinium myrtilloides, Andromeda glaucophylla, Vaccinium angustifolium, Viburnum cassinoides, and Betula populifolia. These species, which showed a 10-fold increase in stem number, could compete successfully with tree seedling number and composition and thus ultimately alter forest stand composition.

A shade tolerance index for common understory species of northeastern North America

2007 ◽  
Vol 7 (1) ◽  
pp. 195-207 ◽  
Author(s):  
Lionel Humbert ◽  
Daniel Gagnon ◽  
Daniel Kneeshaw ◽  
Christian Messier
Keyword(s):  
North America ◽  
Shade Tolerance ◽  
Tolerance Index ◽  
Understory Species ◽  
Northeastern North America

scholarly journals Assessment of Chickpea (Cicer arietinum L.) Genotypes under Normal and Late Sown Environments using Stress Indices

2021 ◽  
Author(s):  
R. Sunil ◽  
A.K. Chhabra ◽  
Rajesh Kumar Yadav ◽  
Sunil Kumar
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Cicer Arietinum ◽  
Geometric Mean ◽  
Temperature Tolerance ◽  
Tolerance Index ◽  
Stress Indices ◽  
Cicer Arietinum L ◽  
Stress Susceptibility ◽  
Hybridization Programme

Background: Heat stress is a major restrain in chickpea (Cicer arietinum L.) productivity. Developing tolerant chickpea genotypes contributes breeding materials for hybridization programme. Stress indices related to abiotic stresses are found effective in screening of genotypes for high temperature tolerance in chickpea. Methods: An experiment with 24 genotypes under two different environments i.e., timely and late sown conditions was planned to identify the chickpea genotypes tolerant to heat stress, using thirteen stress indices. Stress Susceptibility Index (SSI) is the cardinal index to group genotypes based on their tolerance level. Stress indices Mean Productivity (MP), Geometric Mean Productivity (GMP), Harmonic Mean (HM) Index, Heat Resistant Index (HRI) and Modified Heat Tolerance Index (MHTI) are very effective in identifying stress tolerant genotypes. Result: The result indicated that genotypes H 04-75, H 08-75, H 12-26, H 09-96, ICCV 92944, DCP 92-3 and GNG 2226 are tolerant to heat stress. The identified genotypes can be used as parents in hybridization programme for breeding chickpea cultivars tolerant to high temperature environments.

scholarly journals Site Factors Influence on Herbaceous Understory Diversity in East Texas Pinus palustris savannas

2018 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
Brooke McCalip ◽  
Brian P. Oswald ◽  
Kathryn R. Kidd ◽  
Yuhui Weng ◽  
Kenneth W. Farrish
Keyword(s):  
Forest Structure ◽  
Longleaf Pine ◽  
Basal Area ◽  
Pinus Palustris ◽  
East Texas ◽  
Site Factors ◽  
Understory Species ◽  
Solar Exposure ◽  
Site Characteristics ◽  
Study Sites

Longleaf pine (Pinus palustris) savannas were once dominant across the southeastern U.S., including East Texas and parts of western and central Louisiana. The diverse understory associated with these historical savannas may occasionally be seen today, but not often in longleaf pine ecosystems. This project aimed to define east Texas site characteristics that are necessary to support these ecosystems with a dense and diverse herbaceous understory with little to no midstory cover. Fifty-nine plots across three study sites were established to evaluate the influence of overstory cover, basal area, aspect, elevation, and slope on the number of plant genera present. Forest structure and site characteristics had significant effects on the number of plant genera found. The number of genera increased with higher elevation and slope; as elevation increased, there was a decline in basal area and overstory cover, leading to a more diverse, understory layer. In order to re-establish and maintain a diverse, herbaceous understory in longleaf pine savannas, sites with more open canopies and on slopes with the most solar exposure should be given priority, particularly when planting desired understory species.

The neutralisation of acid rain by the leaves of four boreal forest species

1988 ◽  
Vol 66 (9) ◽  
pp. 1877-1882 ◽  
Author(s):  
B. A. Gaber ◽  
T. C. Hutchinson
Keyword(s):  
Boreal Forest ◽  
Acid Rain ◽  
Cell Walls ◽  
Leaf Surface ◽  
Weather Conditions ◽  
Cornus Canadensis ◽  
Exchange Processes ◽  
Rapid Changes ◽  
Maianthemum Canadense ◽  
Rate Of Evaporation

A field study was carried out in the boreal forest of Ontario to measure the neutralisation response of the leaves of Cornus canadensis, Aralia nudicaulis, Maianthemum canadense, and Acer spicatum to simulated acid rain. Plots of each species were sprayed with pH 5.6, 3.8, or 3.2 rain, and the pH of the raindrops on the leaves and on Parafilm (control) was measured with a microelectrode at 15-min intervals until the leaves dried. Species differed in their ability to neutralise the rain, with C. canadensis consistently neutralising acidic raindrops the most. The neutralisation response varied greatly between pH treatments, with greatest neutralisation occurring at the most acidic pH treatment. Raindrop neutralisation primarily took place within the first few minutes following the spray. For this reason, the dissolution of basic particulates on the leaf surface was probably responsible for the rapid changes in raindrop pH, while slower changes may reflect cation exchange processes with the cell walls. Weather conditions determined the rate of evaporation of the raindrops, and this affected their acidity. High rates of evaporation reduced the time available for leaf surface – raindrop interactions and are probably responsible for the acidification observed in some plots.

A Unifying Model to Estimate Thermal Tolerance Limits in Ectotherms Across Static, Dynamic and Fluctuating Exposures to Thermal Stress

2021 ◽  
Author(s):  
Lisa Bjerregaard Jørgensen ◽  
Hans Malte ◽  
Michael Ørsted ◽  
Nikolaj Andreasen Klahn ◽  
Johannes Overgaard
Keyword(s):  
Thermal Stress ◽  
Thermal Tolerance ◽  
Input Data ◽  
Thermal Injury ◽  
Accumulation Rate ◽  
Temperature Tolerance ◽  
Separate Experiment ◽  
Tolerance Limits ◽  
Dynamic Experiments ◽  
Different Temperatures

Abstract Temperature tolerance is critical for defining the fundamental niche of ectotherms and researchers classically use either static (exposure to a constant temperature) or dynamic (ramping temperature) assays to assess tolerance. The use of different methods complicates comparison between studies and here we present mathematical model (and R-scripts) to reconcile thermal tolerance measures obtained from static and dynamic assays. Our model uses input data from several static or dynamic experiments and is based on the well-supported assumption that thermal injury accumulation rate increases exponentially with temperature (recently re-introduced as Thermal Tolerance Landscapes). The model also assumes thermal stress at different temperatures to be additive and using experiments with Drosophila melanogaster, we validate these central assumptions by demonstrating that heat injury attained at different heat stress intensities and durations is additive. In a separate experiment we demonstrate that our model can accurately describe injury accumulation during fluctuating temperature stress and further we validate the model by successfully converting literature data of ectotherm heat tolerance (both static and dynamic assays) to a single, comparable metric (the temperature tolerated for 1 hour). The model presented here has many promising applications for the analysis of ectotherm thermal tolerance and we also discuss potential pitfalls that should be considered and avoided using this model.

The reproductive biology of boreal forest herbs. II. Phenology of flowering and fruiting

1987 ◽  
Vol 65 (10) ◽  
pp. 2047-2056 ◽  
Author(s):  
Kaius Helenurm ◽  
Spencer C. H. Barrett
Keyword(s):  
Boreal Forest ◽  
Fruit Set ◽  
Pollen Limitation ◽  
Fruit Production ◽  
Fruit Removal ◽  
Cornus Canadensis ◽  
Forest Herbs ◽  
Pollinator Service ◽  
Maianthemum Canadense ◽  
Major Factors

The flowering and fruiting phenologies of 12 boreal forest herbs were recorded during 1979 (flowering and fruiting) and 1980 (flowering only) in spruce–fir forests of central New Brunswick. The species studied were Aralia nudicaulis, Chimaphila umbellata, Clintonia borealis, Cornus canadensis, Cypripedium acaule, Linnaea borealis, Maianthemum canadense, Medeola virginiana, Oxalis montana, Pyrola secunda, Trientalis borealis, and Trillium undulatum. Flowering in the community occurred from mid-May to the end of July. The order of flowering was maintained in the 2 years, but the degree of synchronization of inflorescences differed in several species. Fruiting in the community began in mid-July and extended beyond the end of September. The percentage of buds that ultimately bore fruit ranged from 0 (Cypripedium acaule) to 61% (Aralia nudicaulis). With the exception of Cypripedium acaule, which received little pollinator service, the self-incompatible species, Cornus canadensis, Maianthemum canadense, and Medeola virginiana, experienced the lowest levels of fruit-set. Pollen limitation and predation of developing fruit appear to be the major factors limiting percentage fruit-set in boreal forest herbs. Fruit production varied with time of flowering of inflorescences in several species, with periods of low fruit-set tending to coincide with lower densities of flowering inflorescences. Significant rates of fruit removal by herbivores occurred in all sarocochorous species. Disappearance of fruits from infructescences ranged from 31 (Medeola virginiana) to 95% (Aralia nudicaulis), with highest removal rates occurring during periods of greatest fruit availability.

The effect of aerial insecticide spraying for spruce budworm control on the fecundity of entomophilous plants in New Brunswick

1980 ◽  
Vol 58 (18) ◽  
pp. 2022-2027 ◽  
Author(s):  
G. R. Thaler ◽  
R. C. Plowright
Keyword(s):  
New Brunswick ◽  
Seed Set ◽  
Spruce Budworm ◽  
Spray Application ◽  
Kalmia Angustifolia ◽  
Cornus Canadensis ◽  
Cornus Stolonifera ◽  
Insect Visitation ◽  
Maianthemum Canadense

Eight entomophilous plants, Aralia nudicaulis L., Clintonia borealis (Ait.) Raf., Cornus alternifolia L., Cornus canadensis L., Cornus stolonifera Michx., Kalmia angustifolia L., Maianthemum canadense Desf., and Viburnum trilobum Marsh., all of which bloom shortly after forest spray application in New Brunswick, were shown by bagging experiments to be dependent on insect visitation for seed set. All species showed significantly lower fecundity in fenitrothion-treated than in unsprayed areas. No depression of fecundity in Clintonia borealis or Kalmia angustifolia was found associated with aminocarb (Matacil) spraying.

Sign in / Sign up

Export Citation Format

Share Document