Taiwanese montaneSambucus chinensisseeds require warm stratification, contrasting with other congeneric temperate members

2014 ◽  
Vol 24 (3) ◽  
pp. 217-228 ◽  
Author(s):  
Shun-Ying Chen ◽  
Ching-Te Chien ◽  
Siti N. Hidayati ◽  
Jeffrey L. Walck
Keyword(s):  
North America ◽  
Cold Stratification ◽  
Cold Temperatures ◽  
Tropical Regions ◽  
Morphophysiological Dormancy ◽  
Primary Mechanism ◽  
Northern Latitudes ◽  
Northern Hemispheric ◽  
Response To Temperature ◽  
Seed Characteristics

AbstractMany temperate plant genera, likeSambucus, have species with range disjunctions among North America, Europe and/or Asia. Cold stratification (sometimes in combination with warm stratification) is the primary mechanism to break seed dormancy in these species. For some of these genera showing Northern Hemispheric disjunctions, members also occur in subtropical or tropical regions, mostly confined to higher elevations where climate and vegetation differ from those in northern latitudes. We made two hypotheses concerning germination for the subtropical TaiwaneseSambucus chinensis: (1) seeds from populations exposed to warm temperatures would require warm stratification, and (2) seeds from populations exposed to cold temperatures need cold stratification. We investigated the germination (including embryo growth) of non-stratified seeds over a range of temperatures and tested the effects of cold stratification and of gibberellins GA3and GA4on germination. The amount and timing of germination among populations varied substantially in response to temperature treatments. Seeds from all populations of this species required warm temperatures for dormancy break and germination, regardless of environmental conditions. As such, the majority of seeds had non-deep simple morphophysiological dormancy, which, until now, has not been reported in any members ofSambucus. The seed characteristics of the subtropicalS. chinensisare different from those of temperate members of the genus in which cold stratification is the predominate treatment to overcome dormancy.

scholarly journals Deep simple morphophysiological dormancy in seeds of the basal taxad Cephalotaxus

2011 ◽  
Vol 21 (3) ◽  
pp. 215-226 ◽  
Author(s):  
Chia Ju Yang ◽  
Ching-Te Chien ◽  
Yue Ken Liao ◽  
Shun-Ying Chen ◽  
Jerry M. Baskin ◽  
...  
Keyword(s):  
Sensu Stricto ◽  
Cold Stratification ◽  
Warm Temperature ◽  
Cold Temperatures ◽  
Morphophysiological Dormancy ◽  
Medicinal Value ◽  
Radicle Emergence ◽  
Mature Seeds ◽  
Shoot Emergence ◽  
Seeds Germination

AbstractAlthough mature seeds of the monogeneric conifer family Cephalotaxaceae sensu stricto have underdeveloped embryos, no definitive studies have been done to classify dormancy in this family. Our primary purpose was to determine the kind of dormancy in seeds of Cephalotaxus wilsoniana and to put the results into a broad phylogenetic context for gymnosperms. The species is of horticultural and medicinal value, and information is needed on how to propagate it efficiently from seeds. Embryo growth and germination were monitored for seeds at warm, cold and warm plus cold temperatures, and germination was monitored for seeds subjected to: (1) cold →  warm →  cold →  warm; and (2) warm →  cold →  warm →  cold →  warm temperature sequences. The effects of gibberellic acids GA3 and GA4 were tested on radicle emergence in ungerminated seeds and on shoot emergence in root-emerged seeds. Germination was promoted by ≥ 36 weeks of warm stratification followed by ≥ 8 weeks of cold stratification, but only if seeds were returned to high temperatures. The underdeveloped embryo must increase in length by >120% before the radicle emerges. Neither GA3 nor GA4 was effective in promoting radicle emergence; however, both plant growth regulators increased rate (but not percentage) of shoot emergence in root-emerged seeds. We conclude that seeds of C. wilsoniana have the deep simple level of morphophysiological dormancy (MPD), C1b-C3-B1b; thus, warm stratification followed by cold stratification and then warm-temperature incubation are required for germination. In gymnosperms, MPD is known in cycads, Ginkgo and now in three families of conifers.

scholarly journals Fingerprints of changes in the terrestrial carbon cycle in response to large reorganizations in ocean circulation

2010 ◽  
Vol 6 (5) ◽  
pp. 1811-1852 ◽  
Author(s):  
A. Bozbiyik ◽  
M. Steinacher ◽  
F. Joos ◽  
T. F. Stocker
Keyword(s):  
Carbon Cycle ◽  
Ocean Circulation ◽  
North Atlantic ◽  
Climate Model ◽  
Carbon Stocks ◽  
Meridional Overturning Circulation ◽  
Climate Conditions ◽  
Tropical Regions ◽  
The North ◽  
Northern Latitudes

Abstract. CO2 and carbon cycle changes in the land, ocean and atmosphere are investigated using the comprehensive carbon cycle-climate model NCAR CSM1.4-carbon. Ensemble simulations are forced with freshwater perturbations applied at the North Atlantic and Southern Ocean deep water formation sites under pre-industrial climate conditions. As a result, the Atlantic Meridional Overturning Circulation reduces in each experiment to varying degrees. The physical climate fields show changes that are well documented in the literature but there is a clear distinction between northern and southern perturbations. Changes in the physical variables affect, in return, the land and ocean biogeochemical cycles and cause a reduction, or an increase, in the atmospheric CO2 by up to 20 ppmv, depending on the location of the perturbation. In the case of a North Atlantic perturbation, the land biosphere reacts with a strong reduction in carbon stocks in some tropical locations and in high northern latitudes. In contrast, land carbon stocks tend to increase in response to a southern perturbation. The ocean is generally a sink of carbon although large re-organizations occur throughout various basins. The response of the land biosphere is strongest in the tropical regions due to a shift of the Intertropical Convergence Zone. The carbon fingerprints of this shift, either to the south or to the north depending on where the freshwater is applied, can be found most clearly in South America. For this reason, a compilation of various paleoclimate proxy records of Younger Dryas precipitation changes are compared with our model results.

Morphological and physiological dormancy in seeds of Aegopodium podagraria (Apiaceae) broken successively during cold stratification

2009 ◽  
Vol 19 (2) ◽  
pp. 115-123 ◽  
Author(s):  
Filip Vandelook ◽  
Nele Bolle ◽  
Jozef A. Van Assche
Keyword(s):  
Low Temperature ◽  
Seedling Emergence ◽  
Early Spring ◽  
Temperate Climate ◽  
Cold Stratification ◽  
Dormancy Breaking ◽  
Morphophysiological Dormancy ◽  
Temperature Requirement ◽  
Physiological Dormancy ◽  
Chilling Period

AbstractA low-temperature requirement for dormancy break has been observed frequently in temperate-climate Apiaceae species, resulting in spring emergence of seedlings. A series of experiments was performed to identify dormancy-breaking requirements of Aegopodium podagraria, a nitrophilous perennial growing mainly in mildly shaded places. In natural conditions, the embryos in seeds of A. podagraria grow in early winter. Seedlings were first observed in early spring and seedling emergence peaked in March and April. Experiments using temperature-controlled incubators revealed that embryos in seeds of A. podagraria grow only at low temperatures (5°C), irrespective of a pretreatment at higher temperatures. Seeds did not germinate immediately after embryo growth was completed, instead an additional cold stratification period was required to break dormancy completely. Once dormancy was broken, seeds germinated at a range of temperatures. Addition of gibberellic acid (GA3) had a positive effect on embryo growth in seeds incubated at 10°C and at 23°C, but it did not promote germination. Since seeds of A. podagraria have a low-temperature requirement for embryo growth and require an additional chilling period after completion of embryo growth, they exhibit characteristics of deep complex morphophysiological dormancy.

scholarly journals Surveys of the bee (Hymenoptera: Apiformes) community in a Neotropical savanna using pan traps

2020 ◽  
Vol 60 ◽  
pp. e20206031
Author(s):  
Thaís Andrade Viana ◽  
Anete Pedro Lourenço
Keyword(s):  
North America ◽  
Habitat Complexity ◽  
Sampling Method ◽  
Cost Effective ◽  
Neotropical Savanna ◽  
Tropical Regions ◽  
Bee Community ◽  
Pan Traps ◽  
Bee Abundance ◽  
Local Habitat

Bee populations are declining because of various synergistic threats, and therefore bee survey and monitoring programs are needed. Several techniques have been developed to survey bees, but the most cost-effective and suitable methods to sample bees in several sites at the same time are passive approaches, such as methods involving colored pan traps (also known as Moericke or bowl traps). Several bee surveys using pan traps have been conducted in North America, Europe, and Australia, but only a few such surveys have been done in tropical regions. We used colored pan traps (blue, yellow, and white) to assess the bee community in the Brazilian savanna ecosystem in Rio Preto State Park. Sampling was conducted in October 2013 and March 2014 along permanent trails. We also characterized the local habitat of each trail, and then we compared bee abundance with habitat complexity. In total, 187 individual bees (n = 15 species) were collected, mainly using blue and white traps. Although we were not able to sample most species that were previously recorded in this park, the pan trap method can be used to survey and monitor bee assemblages in combination with another sampling method. Habitat complexity also affected the numbers of bees sampled using the pan traps, and more bees were collected at open sites.

scholarly journals Spiroplasma montanense sp. nov., from Hybomitra Horseflies at Northern Latitudes in North America

1997 ◽  
Vol 47 (3) ◽  
pp. 720-723 ◽  
Author(s):  
Robert F. Whitcomb ◽  
Frank E. French ◽  
Joseph G. Tully ◽  
David L. Rose ◽  
Patricia M. Carle ◽  
...  
Keyword(s):  
North America ◽  
Northern Latitudes

A new species of Phycodes from China (Lepidoptera: Sesioidea: Brachodidae)

Zootaxa ◽  
2011 ◽  
Vol 2797 (1) ◽  
pp. 54
Author(s):  
AXEL KALLIES ◽  
MIN WANG ◽  
YUTAKA ARITA
Keyword(s):  
New Species ◽  
North America ◽  
South America ◽  
Palaearctic Region ◽  
Tropical Regions ◽  
Oriental Region ◽  
Small Family ◽  
A New Species

Brachodidae are a small family of fewer than 140 described species that are distributed worldwide except in North America. They reach their greatest diversity in the tropical regions of Asia and South America; however, many species occur in the Palaearctic region and in Australia, but these are restricted to a small number of genera. More than 40 species are known from the Oriental region and many more await description (Kallies 1998, 2000, 2004).

Underdeveloped embryos and kinds of dormancy in seeds of two gymnosperms: Podocarpus costalis and Nageia nagi (Podocarpaceae)

2013 ◽  
Vol 23 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Shun-Ying Chen ◽  
Carol C. Baskin ◽  
Jerry M. Baskin ◽  
Ching-Te Chien
Keyword(s):  
Seed Plants ◽  
Cold Stratification ◽  
Morphophysiological Dormancy ◽  
Seed Maturity ◽  
Basal Clade ◽  
Radicle Emergence ◽  
Primitive Condition ◽  
Morphological Dormancy

AbstractAlthough it has been speculated that seeds of the gymnosperm family Podocarpaceae have an underdeveloped embryo, no detailed studies have been done to definitively answer this question. Our purpose was to determine if embryos in seeds of two species of Podocarpaceae, Podocarpus costalis and Nageia nagi, from Taiwan are underdeveloped and to examine the kind of dormancy the seeds have. Embryos in fresh seeds of P. costalis were 4.6 ± 0.5 mm long, and they increased in length by about 54% before radicle emergence (germination), demonstrating that the embryo is underdeveloped at seed maturity. Seeds germinated to >90% at 30/20, 25/15 and 25°C in light in ≤ 4 weeks, without any cold stratification pretreatment. Thus, seeds of P. costalis have morphological dormancy (MD). Embryos in fresh seeds of N. nagi were 7.4 ± 0.8 mm long and they increased in length by about 39% before radicle emergence (germination) occurred, indicating that the embryo is underdeveloped at seed maturity. Seeds germinated to < 25% at 30/20 and 25°C in light in 4 weeks but to >90% at the same temperatures in 12 weeks. Thus, most seeds of N. nagi have morphophysiological dormancy (MPD). Although underdeveloped embryos are considered to be a primitive condition in seed plants, they also occur in the most advanced orders. The occurrence of underdeveloped embryos in Podocarpaceae documents that they are not restricted to a basal clade in gymnosperms.

Germination of Viburnum odoratissimum seeds: a new level of morphophysiological dormancy

2008 ◽  
Vol 18 (3) ◽  
pp. 179-184 ◽  
Author(s):  
Carol C. Baskin ◽  
Ching-Te Chien ◽  
Shun-Ying Chen ◽  
Jerry M. Baskin
Keyword(s):  
Incubation Temperature ◽  
Cold Stratification ◽  
Morphophysiological Dormancy ◽  
Physiological Dormancy ◽  
Radicle Emergence ◽  
Viburnum Odoratissimum

AbstractPrevious studies indicated that seeds of Viburnum odoratissimum had only physiological dormancy (PD), but no measurements of embryos were made during the dormancy-break treatments. Thus, we investigated embryo growth and radicle and cotyledon emergence over a range of temperatures. Seeds have underdeveloped embryos, and their length increased about 300% before radicle emergence. Embryos also had PD, as evidenced by delays in beginning of embryo growth (2–3 weeks) and of germination after embryos were elongated (4 weeks). After radicle emergence, epicotyl emergence was delayed 1–8 weeks, depending on incubation temperature, but cold stratification was not required to break PD of the epicotyl. Unlike seeds of many previously studied Viburnum spp., epicotyls of V. odoratissimum have non-deep, rather than deep, PD. Hence, a new level of MPD called non-deep, simple, epicotyl MPD has been identified.

Bears

2020 ◽  
Keyword(s):  
Native American ◽  
North America ◽  
Special Treatment ◽  
Ample Evidence ◽  
Native Peoples ◽  
Atlantic Trade ◽  
Economic Significance ◽  
Northern Latitudes ◽  
Comparative Ethnography ◽  
Native North America

Thanks to Irving Hallowell’s classic 1926 comparative ethnography on the special mythic status of bears in Subarctic cultures, anthropologists are generally aware that peoples throughout the northern hemisphere have treated bears as far more than a subsistence resource, something more akin to another kind of human or, to use Hallowell’s famous phrase, “other-than-human persons.” While Hallowell provided ample evidence of bear ceremonialism in northern latitudes, he found little evidence for the special treatment of bears elsewhere in Native North America. Archaeological and historical research over the last nine decades, however, has produced vast unsynthesized information about the roles of bears in Native American beliefs, rituals, and subsistence. This book is the first collective effort since Hallowell’s formative publication to consider how Native peoples viewed, treated, and used black bears (Ursus americanus) through time across Eastern North America. Contributors draw on zooarchaeological, ethnohistorical, ethnographic, and other evidence of bear hunting, consumption, and use, while contemplating the range of relationships that existed between bears and humans. They have reviewed thousands of pages of ethnohistorical and ethnographic documents and summarized and interpreted data on bear remains from nearly 300 archaeological sites from Quebec to the Gulf of Mexico. Native peoples perceived and related to bears in remarkably diverse ways. Our authors explore the religious and economic significance of bears and bear products (meat, fat, oil, pelts, etc.), bear imagery in Native art and artifacts, and bears in Native worldviews, kinship systems, and cosmologies, along with their role as exported commodities in trans-Atlantic trade.

Otogenic tetanus: Case presentation

1979 ◽  
Vol 93 (12) ◽  
pp. 1235-1236 ◽  
Author(s):  
R. L. Blair ◽  
D. Hussarau
Keyword(s):  
North America ◽  
Rare Disease ◽  
Operative Treatment ◽  
Early Years ◽  
Primary Immunization ◽  
Radical Mastoidectomy ◽  
Case Presentation ◽  
Tropical Regions ◽  
Ear Injury ◽  
Immunization Programmes

AbstractTetanus resulting from ear injury is extremely rare. However, the otologist should be aware that it does occur. A case of otogenic tetanus recently treated by the authors is presented.In Western countries tetanus in now a rare disease because of extensive immunization programmes. Otogenic tetanus is extremely uncommon in North America, but occurs more frequently in tropical regions (De and De, 1970).Less than forty new cases of tetanus are seen in the Province of Ontario (population, 8·4 million) each year (Department of Statistics, Government of Ontario).It has been stated that the operative treatment of otogenic tetanus should include radical mastoidectomy (Black and Atkins, 1972). This is probably true in severe cases but milder cases do not require this form of therapy.Most children in Canada receive primary immunization with Diphtheria, Tetanus and Pertussis vaccine (DTP) in the early years of life. However, especially in large urban centres, there is a large non-immunized or partially immunized immigrant population.Tetanus occurring in such an immigrant is described.

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