scholarly journals Melilotus officinalis (yellow sweet clover).

Author(s):  
Julissa Rojas-Sandoval

Abstract Melilotus officinalis is a herbaceous legume species, native to parts of Asia and possibly Europe (sources differ on this), that has been extensively introduced to be used as a forage and nitrogen-fixing crop. It has escaped from cultivation and become an invasive weed in many temperate and tropical regions; it can also be toxic to livestock. It is a prolific seeder, and its seeds can remain viable in the soil for many years. It is fast-growing and can grow in a wide range of environmental conditions. Like other nitrogen-fixing legumes, M. officinalis has the potential to alter soil conditions and nutrient cycling. It is allelopathic and so forms dense monospecific stands that displace and inhibit the establishment of native vegetation. In North America, infestations reduce the occurrence of natural fires and degrade native grassland communities that depend on frequent fires. In Alaska and Canada, this species is a serious problem on waterways because it is invading glacial river floodplains. Currently, it is recognized as a conservation problem in North America because it is invading critical natural areas such as national parks and protected lands.

1997 ◽  
Vol 77 (4) ◽  
pp. 693-702 ◽  
Author(s):  
A. Fierro ◽  
J. Norrie ◽  
A. Gosselin ◽  
C. J. Beauchamp

In a greenhouse study, deinking sludge was evaluated as a soil amendment supplemented with four nitrogen (N) fertilization levels for the growth of the grasses Agropyron elongatum (Host.) Beauv. (tall wheatgrass), Alopecurus pratensis L. (meadow foxtail), Festuca ovina var. duriuscula (L). Koch (hard fescue), and four levels of phosphorus (P) for the growth of the legumes Galega orientalis Lam. (galega), Medicago lupulina L. (black medic), Melilotus officinalis (L.) Lam (yellow sweet clover). Fertilizers were applied on the basis of sludge level to maintain uniform carbon (C)/N or C/P ratios across sludge treatments. In one experiment, sand was mixed with 0, 10, 20 or 30% sludge while, in a second experiment, mineral soil was mixed with 0, 27, 53 or 80% sludge (vol/vol). In sand mixtures of 30 and 20% sludge, grasses had similar or greater growth than in unamended mineral soil when N was added at about 6.5 and 8.4 g kg−1 deinking sludge, respectively. For all legumes but Medicago lupulina, P at about 0.8 g kg−1 sludge was required for these sand mixtures. In soil mixtures of 53 and 27% sludge, grasses grew well when supplemental N was about 5.3 and 6.9 g kg−1 sludge, respectively. Legumes required P at 0.5 and 1.2 g kg−1 sludge, respectively. In general, growth was closely related to total amount of added N or P in spite of the wide range of C/N or C/P ratios. When growing in media amended with sludge, grasses needed higher tissue N concentration for an equivalent growth than in control soil; legumes had similar tissue P concentration. The grasses Agropyron elongatum and Alopecurus pratensis as well as the legumes Melilotus officinalis and Galega orientalis are promising species for field testing, based on dry matter production. Deinking sludge can be used as soil amendment when adequate N and P supplements are provided. Key words: Soil amendment, papermill sludge, Agropyron elongatum, Alopecurus pratensis, Festuca ovina, Medicago lupulina, Galega orientalis, Melilotus officinalis


2020 ◽  
Vol 12 (11) ◽  
pp. 2002-2014
Author(s):  
Ling-Ling Yang ◽  
Zhao Jiang ◽  
Yan Li ◽  
En-Tao Wang ◽  
Xiao-Yang Zhi

Abstract Rhizobia are soil bacteria capable of forming symbiotic nitrogen-fixing nodules associated with leguminous plants. In fast-growing legume-nodulating rhizobia, such as the species in the family Rhizobiaceae, the symbiotic plasmid is the main genetic basis for nitrogen-fixing symbiosis, and is susceptible to horizontal gene transfer. To further understand the symbioses evolution in Rhizobiaceae, we analyzed the pan-genome of this family based on 92 genomes of type/reference strains and reconstructed its phylogeny using a phylogenomics approach. Intriguingly, although the genetic expansion that occurred in chromosomal regions was the main reason for the high proportion of low-frequency flexible gene families in the pan-genome, gene gain events associated with accessory plasmids introduced more genes into the genomes of nitrogen-fixing species. For symbiotic plasmids, although horizontal gene transfer frequently occurred, transfer may be impeded by, such as, the host’s physical isolation and soil conditions, even among phylogenetically close species. During coevolution with leguminous hosts, the plasmid system, including accessory and symbiotic plasmids, may have evolved over a time span, and provided rhizobial species with the ability to adapt to various environmental conditions and helped them achieve nitrogen fixation. These findings provide new insights into the phylogeny of Rhizobiaceae and advance our understanding of the evolution of symbiotic nitrogen fixation.


2017 ◽  
Vol 79 (03) ◽  
pp. 289-296 ◽  
Author(s):  
Jamie Van Gompel ◽  
R. Wiet ◽  
Nicole Tombers ◽  
Anand Devaiah ◽  
Devyani Lal ◽  
...  

Background Very few studies have examined vestibular schwannoma (VS) management trends across centers and between providers. The objective of this study is to examine current practice trends, variance in treatment philosophies, and nuanced or controversial aspects of VS care across North America. Methods This is a cross-sectional survey of North American Skull Base Society (NASBS) members who report regular involvement in VS care. Results A total of 57 completed surveys were returned. Most respondents claimed to have over 20 years of experience and the majority reported working in an academic practice with an affiliated otolaryngology and/or neurosurgery residency program. Sixty-three percent of respondents claimed to evaluate VS patients in clinic with both an otolaryngologist and neurosurgeon involved. Eighty-six percent of respondents claimed to operate on VS with both an otolaryngologist and neurosurgeon involved, while only 18% of neurosurgeons and 9% of otolaryngologists performed surgery alone. There was a wide range in the number of cases evaluated at each center annually. Similarly, there was wide variation in the number of patients treated with microsurgery and radiation at each center. Additional details regarding management preferences for microsurgery, stereotactic radiosurgery, stereotactic radiotherapy, and conservative observation are presented. Conclusion VS management practices vary between providers and centers. Overall, most centers employ a multidisciplinary approach to management with collaboration between otolaryngology and neurosurgery. Overall, survey responses concur with previous studies suggesting a shift toward conservatism in management.


2014 ◽  
Vol 24 (3) ◽  
pp. 217-228 ◽  
Author(s):  
Shun-Ying Chen ◽  
Ching-Te Chien ◽  
Siti N. Hidayati ◽  
Jeffrey L. Walck

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.


2008 ◽  
Vol 87 (4) ◽  
pp. 359-361 ◽  
Author(s):  
T. van der Hammen ◽  
B. van Geel

AbstractDuring the warm Bølling-Allerød interstadial, tree species migrated from their refugia in southern Europe northwards into the area within the present temperate climatic zone. It is evident from high levels of charcoal in fossil records in this region that, especially during the later part of the Bølling-Allerød interstadial, many fires occurred. The start of the Younger Dryas was characterised by rapid and intense cooling and rising water tables, with catastrophic effects on the vegetation. Thermophilous pine trees could not survive the cold Younger Dryas climate. Dead wood provided an abundant source of fuel for intense, large-scale fires seen in many records as a concentration of charcoal particles in so-called ’Usselo-soils’ dated to ca 10,95014C BP. A similar trend in increased charcoal indicating increased burning is seen at many sites across North America at this time and it has been suggested by Firestone et al. (2007) that this was caused by an explosion of extra-terrestrial material over northern North America, causing the Younger Dryas climate cooling and Megafaunal extinction. We argue that there is no need to invoke an extraterrestrial cause to explain the charcoal in the fossilized soils. The volume of forest trees that died as a result of the cold Younger Dryas climate would easily have supplied sufficient fuel for intense, large-scale fires and can be used to account for the concentration of charcoal particles. As soils were no longer covered by dense vegetation, much erosion occurred during the Younger Dryas and therefore, at many places, Usselo soils, rich in charcoal, were preserved under aeolian sand dunes.


2021 ◽  
Vol 23 (5) ◽  
pp. 1563-1576 ◽  
Author(s):  
Phillip J. Haubrock ◽  
Gordon H. Copp ◽  
Iva Johović ◽  
Paride Balzani ◽  
Alberto F. Inghilesi ◽  
...  

AbstractThe North American channel catfish Ictalurus punctatus has been introduced to several locations in Europe but has received little or no scientific study despite its invasive attributes, including prolific reproduction, tolerance to a wide range of conditions, opportunistic feeding, at least partial ‘predator release’, and some evidence of environmental impacts (e.g. disease transmission). To assess the species’ potential invasiveness and the likely risks to native species and ecosystems in Europe, available literature from both North America and Europe was reviewed and used to carry out risk screenings of the species for the risk assessment areas, North and South Italy, using the Aquatic Invasiveness Screening Kit (AS-ISK), which was followed by a more detailed evaluation (for both North America and Europe) of the species’ potential impacts using the Environmental Impact Classification of Alien Taxa (EICAT) assessment protocol. The AS-ISK score indicated that channel catfish is likely to pose a high risk of being invasive in both North and South Italy, with EICAT scores indicating “Major” impacts for both North America and Europe, at high and medium confidence levels, respectively. The present results emphasise the urgent need to carry out in-depth studies on introduced populations of this species to understand better its invasive potential so as to inform management decisions on the appropriate control or eradication measures for invaded water bodies.


2018 ◽  
Vol 69 (3) ◽  
pp. 326 ◽  
Author(s):  
Singarayer Florentine ◽  
Sandra Weller ◽  
Alannah King ◽  
Arunthathy Florentine ◽  
Kim Dowling ◽  
...  

Echium plantagineum is a significant pasture weed in the Mediterranean climatic zone of several countries, including Australia. This invasive weed, introduced as an ornamental into Australia (where it is known as Paterson’s curse), quickly became established and is now a significant weed of agriculture. Although E. plantagineum is a well-established, highly competitive weed that thrives under disturbance and is tolerant of a wide variety of conditions, including varying soil moisture and drought, and some aspects of its ecology remain unknown. This study investigated germination response to temperature and light, pH, soil moisture, salinity, and pre-germination exposure of seed to heat and smoke. Temperature was found to be more influential on germination than light and the species is tolerant to a wide range of pH. However, available moisture may limit germination, as may elevated salinity. Management of this weed requires approaches that minimise soil seedbank input or prevent germination of soil seedbanks.


Author(s):  

Abstract A new distribution map is provided for Circulifer tenellus (Baker) (Homopt., Cicadellidae) (Beet Leaf hopper) Hosts: Sugar-beet, tomato, cucurbits, spinach and a wide range of wild plants. Vector of curly top of beet in North America. Information is given on the geographical distribution in EUROPE, Sicily, Spain, ASIA, Israel, AFRICA, Algeria, Canary Islands, Egypt, Libya, Morocco, Republic of South Africa, South-West Africa, Sudan, Tunisia, AUSTRALASIA and PACIFIC ISLANDS, Hawaii, NORTH AMERICA, Mexico, U.S.A., CENTRAL AMERICA and WEST INDIES, West Indies.


Author(s):  
D. W. Minter

Abstract A description is provided for Helminthosphaeria stuppea, which is apparently saprobic and able to colonize woody parts of a wide range of plants. Some information on its associated organisms and substrata, habitats, dispersal and transmission, and conservation status is given, along with details of its geographical distribution (North America (USA (California, Colorado, Utah and Washington)), Europe (Austria, Czech Republic, Denmark, France and UK)) and hosts (including Tsuga mertensiana). No reports of negative economic impacts have been found.


Author(s):  

Abstract A new distribution map is provided for Chrysomphalus ficus[Chrysomphalus aonidum] Ashm. (aonidum auct.) (Florida Red Scale). Hosts: Citrus; wide range of Mono- and Dicotyledons. Information is given on the geographical distribution in ASIA, China, Formosa, Hong Kong, Kowloon, India, Indonesia, Israel, Malaya, Pakistan, Philippines, Syria, AFRICA, Agaléga Island, Algeria, Anglo-Egyptian Sudan, Egypt, Madagascar, Mauritius, Morocco, Northern Rhodesia, Portuguese East Africa, Seychelles, Southern Rhodesia, Union of South Africa, Zanzibar, AUSTRALASIA AND PACIFIC ISLANDS, Australia, Hawaii, Society Islands, NORTH AMERICA, Mexico, U.S.A., CENTRAL AMERICA and WEST INDIES, Honduras, Panama, West Indies, SOUTH AMERICA, Argentina, Brazil, British Guiana, Chile, Colombia, Paraguay, Uruguay, Venezuela, Pakistan, Philippines, Ryukyu Islands, Saudi Arabia, Singapore, South Yemen, Sri Lanka, Syria, Taiwan, Yemen, AUSTRALASIA and PACIFIC ISLANDS, American Samoa, Australia, New South Wales, Northern Territory, Queensland, Caroline Islands, Fiji, Hawaii, Kiribati, New Caledonia, Ogasawara-shoto, Papua, New Guinea, Society Islands, Tuvalu, Western Samoa, NORTH AMERICA, USA, California, Florida, Mississippi, Texas, Washington D.C., CENTRAL AMERICA and CARIBBEAN, Barbados, Bermuda, Cayman Islands, Cuba, Dominica, Dominican Republic, El Salvador, Guadeloupe, Guatemala, Haiti, Honduras, Jamaica, Martinique, Mexico, Montserrat, Panama, Puerto Rico, St. Lucia, St. Vincent, Trinidad, Virgin Islands, SOUTH AMERICA, Argentina, Brazil, Chile, Colombia, French Guiana, Guyana, Paraguay, Surinam, Uruguay, Venezuela.


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