THE BIOLOGY OF CANADIAN WEEDS.: 77. Echinochloa crus-galli (L.) Beauv.

1986 ◽  
Vol 66 (3) ◽  
pp. 739-759 ◽  
Author(s):  
M. A. MAUN ◽  
S. C. H. BARRETT

Echinochloa crus-galli (L.) Beauv., barnyard grass (pied-de-coq), is an annual grass and a cosmopolitan weed with a range from 50°N to 40°S latitude. In Canada, it extends up to 53°N latitude in the prairies and is widely distributed along roadsides and in cultivated fields of all provinces. The success of this weed may be attributed to the production of large numbers of small, easily dispersed seeds per plant, possession of seed dormancy, rapid development and ability to flower under a wide range of photoperiods, and relative resistance of mature plants to herbicide sprays. In this review a summary of biological information on E. crus-galli is presented.Key words: Barnyard grass, weed biology, Echinochloa crus-galli

2019 ◽  
Vol 70 (11) ◽  
pp. 917 ◽  
Author(s):  
Asad Shabbir ◽  
Bhagirath S. Chauhan ◽  
Michael J. Walsh

Echinochloa colona and E. crus-galli are two important annual grass weeds distributed throughout the summer cropping regions of Australia. Both species are highly problematic weeds, responsible for yield losses of up to 50% in summer grain crops. The success of Echinochloa species as weeds is attributed to their rapid growth, prolific seed production, seed dormancy and adaptability to a wide range of environments. Importantly, E. colona has evolved resistance to glyphosate in Australia, with resistant populations now widespread across the summer cropping regions. Fallow management of E. colona with glyphosate alone is risky in terms of increasing the chance of resistance and highly unsustainable; other control strategies (residual herbicides, strategic tillage, etc.) should be considered to complement herbicides. This review provides a summary of current information on the biology, ecology and management of Echinochloa species. The knowledge gaps and research opportunities identified will have pragmatic implications for the management of these species in Australian grain cropping systems.


1983 ◽  
Vol 63 (4) ◽  
pp. 997-1014 ◽  
Author(s):  
S. I. WARWICK ◽  
L. D. BLACK

A review of biological information is provided for Sorghum halepense (L.) Pers., Johnson grass. A native of southern Eurasia to India, S. halepense occurs as a weed in most tropical and temperate areas of the world, and has recently become established in 10 counties in Southern Ontario. Listed as one of the world’s worst weeds, S. halepense infestations result in severe crop losses either from competition or alleleopathic effects and/or by serving as an alternative host for several crop pests. The species is, however, an important forage crop in the southeastern United States and other areas of the world. Johnson grass has several features which contribute to its success as a weed, including the production of extensively creeping rhizomes and large numbers of seeds, rhizomes which regenerate easily if cut into small pieces in cultivation procedures, self-compatibility, seed longevity, seed dormancy and vigorous growth under a wide range of environmental conditions. To date, one population of S. halepense from Brant County, Ontario is known to produce rhizomes which successfully overwinter in Canada. This population would appear to be distinct from the other Ontario populations and is characterized by smaller seeds and seedlings and lower rates of germination. A combination of repeated tillage, proper herbicides and crop rotation will give the best control of Johnson grass.Key words: Sorghum halepense, Johnson grass, biological review


1987 ◽  
Vol 27 (3) ◽  
pp. 367 ◽  
Author(s):  
JM Scott ◽  
GJ Blair

Competition from the annual grass weed rat's tail fescue (Vulpia myuros [L.] C. C. Gmelin) seriously reduces the establishment of autumn sown, direct-drilled pastures on the Northern Tablelands of New South Wales. Field populations of rat's tail fescue of 43 000 seedlings m-2 have been observed. The effect of a range of rat's tail fescue populations (0, 5, 10,20,40 and 80x 103 seeds m-2) on the early growth of lucerne and phalaris was measured in a glasshouse experiment in soil amended with either high or low levels of nitrogen and phosphorus. Under both fertility regimes, competition from rat's tail fescue was severe at densities of 5x 103 seeds m-2 and above with leaf number, plant height and DM yield of the sown species being markedly reduced in the presence of rat's tail fescue. In 2 further glasshouse experiments with lucerne, a wide range of seed-applied herbicides (EPTC, benfluralin, napropamide, chlorthal-dimethyl, trifluralin, oryzalin, alachlor, diclofop-methyl and 2,2-DPA) were evaluated at several rates to control germinating rat's tail fescue. EPTC significantly reduced weed density at rates as low as 0.35 kg ha-1 and was the only herbicide to significantly reduce the yield of rat's tail fescue (at rates as low as 0.1 kg ha-1) and to allow an increase in the yield of the sown lucerne. Confirmation of the effectiveness of seed-applied EPTC under direct-drill conditions is still needed.


1970 ◽  
Vol 19 (1-2) ◽  
pp. 264-267 ◽  
Author(s):  
F.H. Reuling ◽  
J.T. Schwartz

In the late 1950's and early 1960's, it became evident that some glaucoma patients developed elevations of intraocular pressure, which were difficult to control, following prolonged use of systemic or ocular medications containing corticosteroids (Chandler, 1955, Alfano, 1963; Armaly, 1963). In addition, some patients without glaucoma, when treated with steroids for long periods of time, developed clinical signs of chronic simple glaucoma (McLean, 1950; François, 1954; Covell, 1958; Linner, 1959; Goldman, 1962). Fortunately, the elevation of intraocular pressure was reversible if the drug was discontinued.Over the past decade, extensive investigation of the “steroid response” has been undertaken. For this presentation, the steroid response may be considered as a gradual elevation of intraocular pressure, occurring over several weeks, in an eye being medicated with corticosteroid drops several times a day. The elevation in pressure is usually accompanied by a reduction in the facility of aqueous outflow. When relatively large numbers of subjects were tested with topical steroids, so that a wide range of responsiveness could be observed, a variation in individual sensitivity was demonstrated. Frequency distributions of intraocular pressure or change in pressure following steroids showed a skew toward the high side. On the basis of trimodal characteristics which they observed in such frequency distributions, Becker and Hahn (1964), Becker (1965) and Armaly (1965, 1966) considered the possible existence of several genetically determined subpopulations. These investigators distinguished three subpopulations on the basis of low, intermediate, and high levels of pressure response. It was hypothesized that these levels of response characterized three phenotypes, corresponding to the three possible genotypes of an allele pair, wherein one member of the pair determined a low level of response, and the other member determined a high level of response (Armaly, 1967).


Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1125
Author(s):  
Raluca Nicu ◽  
Florin Ciolacu ◽  
Diana E. Ciolacu

Nanocelluloses (NCs), with their remarkable characteristics, have proven to be one of the most promising “green” materials of our times and have received special attention from researchers in nanomaterials. A diversity of new functional materials with a wide range of biomedical applications has been designed based on the most desirable properties of NCs, such as biocompatibility, biodegradability, and their special physicochemical properties. In this context and under the pressure of rapid development of this field, it is imperative to synthesize the successes and the new requirements in a comprehensive review. The first part of this work provides a brief review of the characteristics of the NCs (cellulose nanocrystals—CNC, cellulose nanofibrils—CNF, and bacterial nanocellulose—BNC), as well as of the main functional materials based on NCs (hydrogels, nanogels, and nanocomposites). The second part presents an extensive review of research over the past five years on promising pharmaceutical and medical applications of nanocellulose-based materials, which have been discussed in three important areas: drug-delivery systems, materials for wound-healing applications, as well as tissue engineering. Finally, an in-depth assessment of the in vitro and in vivo cytotoxicity of NCs-based materials, as well as the challenges related to their biodegradability, is performed.


Genetics ◽  
1996 ◽  
Vol 143 (2) ◽  
pp. 961-972 ◽  
Author(s):  
Marie-Jeanne Perrot-Minnot ◽  
Li Rong Guo ◽  
John H Werren

Abstract Wolbachia are cytoplasmically inherited bacteria responsible for reproductive incompatibility in a wide range of insects. There has been little exploration, however, of within species Wolbachia polymorphisms and their effects on compatibility. Here we show that some strains of the parasitic wasp Nasonia vitripennis are infected with two distinct bacterial strains (A and B) whereas others are singly infected (A or B). Double and single infections are confirmed by both PCR amplification and Southern analysis of genomic DNA. Furthermore, it is shown that prolonged larval diapause (the overwintering stage of the wasp) of a double-infected strain can lead to stochastic loss of one or both bacterial strains. After diapause of a double-infected line, sublines were produced with AB, A only, B only or no Wolbachia. A and B sublines are bidirectionally incompatible, whereas males from AB lines are unidirectionally incompatible with females of A and B sublines. Results therefore show rapid development of bidirectional incompatibility within a species due to segregation of associated symbiotic bacteria.


Parasitology ◽  
1915 ◽  
Vol 8 (1) ◽  
pp. 11-16 ◽  
Author(s):  
L. E. Robinson

Variability in the size and, in a lesser degree, the taxonomic features of male ticks, has arrested the attention of all who have had occasion to examine moderately large numbers of examples of the same species. In the case of the female tick, this variability, though doubtless coextensive with that of the male, is more or less obscured by the wide range of variation in size, depending upon the degree of engorgement; and, also, by the fact that in the female tick the taxonomic characters are, as a rule, less pronounced. The present note is only concerned with variability in the size of the male.


1998 ◽  
Vol 78 (1) ◽  
pp. 155-165 ◽  
Author(s):  
Suzanne I. Warwick ◽  
David A. Wall

A review of biological information is provided for Erucastrum gallicum (Willd.) O.E. Schulz. A European native, it was introduced into Canada and the United States in the early 1900s and spread rapidly along the railroads. The species occurs in all the provinces and the Northwest Territories and is particularly abundant in the Prairie provinces and mid-western United States. It is a summer annual, rarely a winter annual or biennial species, and is characterized by high reproductive output. Plants occur most commonly on waste ground and along roadsides and railroads, followed by agricultural fields. Erucastrum gallicum is of allopolyploid origins (n = 15, 7 + 8 chromosomes), and contains a single multi-locus isozyme genotype. The species is a close relative of Brassica and is capable of limited genetic exchange with the canola species, B. rapa and B. napus. The possible transfer of genes from transgenic canola varieties to Erucastrum gallicum poses a remote, but potential, environmental risk. Populations of Erucastrum gallicum, including both Old World and North American populations, constitute a valuable germplasm resource as potential sources of beneficial agronomic traits, such as disease resistance for canola crop improvement. Key words: Dog mustard, Erucastrum gallicum, weed biology, risk assessment, germplasm, canola


1913 ◽  
Vol 17 (2) ◽  
pp. 117-131
Author(s):  
Hans Zinsser

The experiments recorded in this paper confirm the observations of Friedberger that acutely toxic bodies can be produced from typhoid bacilli by the action of sensitizer and complement and that, when small quantities of bacteria are used, an excess of sensitization either interferes with the formation of the poisons or leads to a cleavage of the bacterial proteid beyond the poisonous intermediate products spoken of as anaphylatoxins. Unlike the experience of other workers with poisons of this nature, however, our experiments have shown that the action of complement upon typhoid bacilli strongly sensitized or not at all sensitized may be carried on, at body temperature, for considerably longer than twelve hours without leading to a destruction of the poisons, and that this is true when the quantities of the bacteria used vary within the wide range of from one to twelve agar slants. It has been found, in fact, that in the case of this microorganism prolonged exposure at the higher temperature of considerable quantities of bacteria constitutes an unfailing method of regularly obtaining powerful poisons. The results obtained by the use of smaller quantities and the less vigorous complement action at low temperatures are far less regular or satisfactory. It would appear from this that complement action of considerable vigor is required to obtain from this bacillus any appreciable yield of anaphylatoxin, and that the poison, once formed, is not as unstable as that found in other microorganisms by Neufeld and Dold and others. In fact, although we have never observed complete lysis in vitro of the typhoid bacilli treated with antibody and complement, the sensitized bacteria exposed to the action of complement for as long as fifteen hours at 37.5° C. showed, in our experiments, much disintegration, and yet powerful poisons were present. Were the influence of lysis or of the too vigorous action of the serum bodies as rapidly poison-destroying in the case of this bacillus as it has been shown to be in the case of some other bacteria, it would be hard to understand how anaphylatoxins could play any part in the toxemia of typhoid fever. This phase of our experiments, however, seems to indicate that the conditions prevailing in the infected body at the height of this disease would furnish ideal criteria for anaphylatoxin production, since, in such cases, vigorously sensitized bacilli, in large numbers, are under the prolonged influence of considerable quantities of complement, conditions exactly comparable to those prevailing in our experiments. Granted that this state of affairs is actually the case, then the subsidence of the disease might depend merely upon limitation of the supply of antigen, as the increasing bactericidal action of the blood constituents come into play, and upon the consequent diminution of the anaphylatoxin. For as the bacteria diminish and the sensitizer increases, a changed proportion between them is established which, finally, as experiment has shown, results in a failure of anaphylatoxin production. For although our experiments have shown that, within a wide latitude of relative proportions of bacteria and antibody, anaphylatoxin can be formed, beyond this range an excess of one or the other element eventually will prevent their formation. It is not, however, the purpose of this paper to discuss the mechanism of the subsidence of the disease since this phase of the work will necessitate further experimental study. In regard to the experiments with kaolin, we were unable to confirm the contention of Keysser and Wassermann, though it is more than likely that toxic bodies could be formed by the action of complement upon any foreign proteid rendered amenable to its action. We are not inclined to attribute too much importance to these negative results, recording them merely as they occurred. However, should it be found subsequently that anaphylatoxins can be formed in this way, it seems unlikely that they are formed from the sensitizer or amboceptor as matrix, since this was not specifically adsorbed out of concentrated serum by the kaolin in our experiments. On the basis of experiments with so called endotoxins, ,we feel that the existence of such preformed intracellular poisons as an element in typhoid toxemia has not been proved, and is not absolutely necessary for the explanation of the phenomena occurring in this disease. However, the diarrhea, the hemorrhagic lesions, and the protracted symptoms following the injection of extracts and filtrates of the bacillus, differing so strikingly from the acute illness with rapid death or equally rapid recovery resulting from anaphylatoxin poisoning, would justify the assumption that poisons of this nature may still play a part in the disease, adding an additional specific characteristic to the clinical picture. As stated before, however, it is not improbable that all these characteristics may represent merely a more protracted or subacute state of anaphylatoxin toxemia. The experiments with autolysates, although none of them were fatal in their results upon guinea pigs, have sufficiently indicated that poisons comparable to anaphylatoxins can be formed in this way. This would indicate that a reaction of proteolysis, which may take place slowly by autolysis, is hastened by the action of complement, and its velocity is still further augmented by the increase, within certain limits, of the sensitization,—a conception which would attribute to the combined action of complement and sensitizer a function not incomparable to that of the bodies spoken of as catalytic agents.


Author(s):  
Denis V. Kapsky ◽  
◽  
Sergey S. Semchenkov ◽  
Evgeny N. Kot ◽  
◽  
...  

The rapid development of the transport sector leads not only to positive changes in the life of cities and towns, to an increase in convenience and comfort for residents, but also worsens the ecology and their living environment. The “profitable-safe” dilemma can be solved by the approach of environmentally oriented selection of the type of route passenger transport and decisionmaking in favor of electric route passenger transport. The article discusses the types of such transport on the example of the experience of their use in the Republic of Belarus. The classification and systematization developed by the authors are presented with subsequent recommendations for its application. On the basis of the results of the authors’ research, the issues of interaction of rail and non-rail route vehicles with an electric drive with the organization of road traffic are separately considered. The presented materials can be useful to a wide range of readers, as well as to specialists conducting research and practical development in the field of electrically powered route vehicles and traffic management.


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