scholarly journals Fungi ecological niches of the genus Fusarium Link.

2020 ◽  
Vol 24 ◽  
pp. 00095
Author(s):  
Irina Vorob’eva ◽  
Elena Toropova

Climatic variations and modern agricultural technologies change the fungi distribution area ofthe genus Fusarium Link., and lead to their dominance in pathocomplexes. The parasitic activity of fusarium fungi and localization of their ecological niches is determined by the activity of constantly expanding environmental and anthropogenic drivers. The fundamental niches of Fusarium pathogens are characterized by complexity and multidimensionality. Realized ecological niches change in space and time at the ontogenesis different stages of pathogenic micromycetes; the same species shows high heterogeneity in implementing its fundamental niche depending on environmental factors and the host plant species. The overlap level of ecological niches and interspecific relationships largely determine the species composition of the pathogenic complex of adiscrete phytocenosis.

Author(s):  
N.G. Vasilchenko ◽  
◽  
A.V. Gorovtsov ◽  
V.A. Chistyakov ◽  
M.S. Mazanko

The possibility of using bacteria of the order Bacillales as agents of biological control of phytopathogenic fungi of the genus Fusarium was studied. In the work, 28 soil samples were studied, from which antagonist bacterial strains were isolated. Antagonism was detected by cultivating a pasteurized soil suspension with a culture of the fungus Fusarium graminearum on wort agar. In the course of this work, 1040 antagonist bacterial strains were isolated. Subsequently, the influence of the selected strains of microorganisms on the germination winter wheat seeds and several other morphometric parameters was studied.


2011 ◽  
Vol 4 (3) ◽  
pp. 254-259 ◽  
Author(s):  
I. G. Vorob’eva ◽  
V. A. Chulkina ◽  
A. B. Gorbunov ◽  
M. A. Tomoshevich

1984 ◽  
Vol 5 (3-4) ◽  
pp. 395-410 ◽  
Author(s):  
A. Bea ◽  
S. Bas ◽  
F. Braña ◽  
H. Saint Girons

The study of the external morphology and the geographic distribution of 260 specimens of Vipera seoanei allows the recognition of four more or less distinct morphs. The first one, characterized by a "classical" colouration (see fig. 3, A), barely fragmented cephalic scales and a rather low number of ventral scales is represented on the maps (fig. 1 and 2) by the groups numbered 1, 2 and 3. The second morph (group numbered 4) only differs from the first one by a more fragmented number of cephalic scales. The third one (on the map group number 5) is characterized by the "cantabrica" type of colouration (fig. 3, D), by the strong tendency to melanism in the mountains, by a higher number of ventral scales and by a still more fragmented number of cephalic scales than in morph 4. The fourth morph, which is more or less intermediate in scaling between the neighbouring morphs is only characterized by its "bilineata" or "uniform" type of colouration (fig. 3, B, C). These two types of colouration dominate for 100% on the northern side of the Covadonga massif (marked 7a on the map) but although the percentages of these types of colouration diminish rather strongly outside the mentioned area, one can find them in the main part of the distribution area of the species. The morphs seem to have been formed during periods of geographic isolation caused by climatic variations during the Quaternary Period. They are, however, linked today by more or less large secondary interbreeding zones (numbered 8, 6, 7b and 7c on the maps) and therefore they have not reached the stage of reproductive isolation. Only the third morph (group 5 on the map) taxonomically merits the status of subspecies, which has been named Vipera seoanei cantabrica Braña & Bas, 1983. L'étude de la morphologie externe et de la répartition géographique de 260 spécimens de Vipera seoanei permet de reconnaître 4 ensembles plus ou moins bien individualisés. Le premier, caractérisé par une coloration de type "classique" (fig. 3, A), des écailles céphaliques peu divisées et des plaques ventrales peu nombreuses, correspond aux groupes marqués 1, 2 et 3 sur les cartes. Le second (groupe 4) ne diffère du précédent que par une division plus poussée des écailles céphaliques. Le troisième (groupe 5) est caractérisé par une coloration de type "cantabrica" (fig. 3, D), avec une forte tendance au mélanisme en montagne, et par un nombre de plaques ventrales plus élevé, les écailles céphaliques étant encore un peu plus divisées que dans le groupe 4. Un quatrième ensemble, plus ou moins intermédiaire entre les groupes géographiquement voisins en ce qui concerne l'écaillure, n'est individualisé que par la coloration, de type "bilineata" ou "uniforme" (fig. 3, B, C). Ces deux types de coloration dominent a 100% sur le flanc nord du Massif de Covadonga (7a sur la carte), mais si leur proportion dirninue assez rapidement au-delà, on peut les retrouver dans la majeure partie de l'aire de répartition de l'espèce. Ces ensembles paraissent s'être individualisés au cours de périodes d'isolement géographiques lors des fluctuations climatiques du Quaternaire, mais ils sont actuellement réunis par des zones d'intergradation secondaire plus ou moins larges (8, 6 et 7b sur les cartes) et n'ont donc pas atteint le stade d'isolement reproducteur. D'un point de vue taxonomique, seul le groupe 5, décrit sous le nom de Vipera seoanei cantabrica Braiia et Bas, 1983, mérite un statut sub-spécifique. El estudio de la morfologia extema y de la distribution geografica de 260 ejemplares de Vipera seoanei permite su agrupaciôn en cuatro conjuntos mas o menos individualizados. El primero, caracterizado por una coloration del tipo "clasico" (fig. 3, A), con escamas cefalicas poco divididas y placas ventrales poco numerosas, corresponde a los grupos marcados 1, 2 y 3 sobre los mapas. El segundo (grupo 4) difiere del anterior, unicamente, en presentar una division de las escamas cefalicas algo mas marcada. El tercero (grupo 5) se caracteriza por una coloracion del tipo "cantabrica" (fig. 3, D), con marcada tendencia al melanismo en montana, y por un numero mas elevado de placas ventrales, siendo la division de las escamas cefalicas algo mayor que la observada en el grupo 4. El cuarto conjunto, mas o menos intermedio entre los grupos geogrificamente cercanos por lo que concierne a la folidosis, se caracteriza, unicamente, por la coloracion, tipo "bilineata" o "uniforme" (fig. 3, B, C). Ambos tipos de coloracion dominan el 100% al norte del Macizo de Covadonga (7a, en el mapa) y, aunque su proportion disminuye ripidamente fuera de este area, se puede encontrar en la mayor parte del area de distribucion de la especie. Los diferentes conjuntos parecen haberse individualizado durante periodos de aislamiento geografico originados por variaciones climaticas durante el Cuaternario ; en la actualidad, éstos estan unidos por zonas de intergradacion secundaria mas o menos extensas (8, 6 y 7b, en el mapa) aunque no han alcanzado el estado de aislamiento reproductor. Desde el punto de vista taxonomico, unicamente el grupo 5 merece el status de subespecie y ha sido descrito bajo el nombre de Vipera seoanei cantabrica Braiia y Bas, 1983.


Author(s):  
N S Kozulina ◽  
A V Vasilenko ◽  
A A Vasilenko ◽  
Zh N Shmeleva

2016 ◽  
Vol 64 (1) ◽  
pp. 235
Author(s):  
Jesús Hernandez-Ruiz ◽  
B. Edgar Herrera-Cabrera ◽  
Adriana Delgado-Alvarado ◽  
Víctor M. Salazar-Rojas ◽  
Ángel Bustamante-Gonzalez ◽  
...  

Wild specimens of Vanilla planifolia represent a vital part of this resource primary gene pool, and some plants have only been reported in Oaxaca, Mexico. For this reason, we studied its geographical distribution within the state, to locate and describe the ecological characteristics of the areas where they have been found, in order to identify potential areas of establishment. The method comprised four stages: 1) the creation of a database with herbarium records, 2) the construction of the potential distribution based on historical herbarium records for the species, using the model of maximum entropy (MaxEnt) and 22 bioclimatic variables as predictors; 3) an in situ systematic search of individuals, based on herbarium records and areas of potential distribution in 24 municipalities, to determine the habitat current situation and distribution; 4) the description of the environmental factors of potential ecological niches generated by MaxEnt. A review of herbarium collections revealed a total of 18 records of V. planifolia between 1939 and 1998. The systematic search located 28 plants distributed in 12 sites in 95 364 Km2. The most important variables that determined the model of vanilla potential distribution were: precipitation in the rainy season (61.9 %), soil moisture regime (23.4 %) and precipitation during the four months of highest rainfall (8.1 %). The species potential habitat was found to be distributed in four zones: wet tropics of the Gulf of Mexico, humid temperate, humid tropical, and humid temperate in the Pacific. Precipitation oscillated within the annual ranges of 2 500 to 4 000 mm, with summer rains, and winter precipitation as 5 to 10 % of the total. The moisture regime and predominating climate were udic type I (330 to 365 days of moisture) and hot humid (Am/A(C) m). The plants were located at altitudes of 200 to 1 190 masl, on rough hillsides that generally make up the foothills of mountain systems, with altitudes of 1 300 to 2 500 masl. In natural conditions, distribution of the species is not limited to high evergreen forests, since it was also found in mountain mesophyll and tropical evergreen forests. The location of new specimens of V. planifolia in its wild condition reduces the potential distribution area by 66 %. This area is fragmented into three geographically separated areas. Habitat reduction was due to the increased number of located plants that define the environmental conditions into a more accurate level. Conservation actions can thus be designed and implemented, focusing on more specific areas within the state of Oaxaca, Mexico.


2021 ◽  
Vol 273 ◽  
pp. 01019
Author(s):  
Natalya Ryabova ◽  
Tatiana Tupolskikh ◽  
Valentins Serdyuk ◽  
Nadezhda Gordeeva

Studying the specific and intraspecific structure of populations of causative agents of Fusarium ear of grain crops. The results of experimental studies of samples of grain crops affected by microscopic fungi p.Fusarium. The analysis of the infection of grains, stems and roots of various types of cereals with mitospores fungi was carried out. The variability of pathogenic properties of Fusarium fungi depending on the part of the ear is shown. The results of the research are important for the targeted diagnosis of fusarium of grain crops and plants of the ear.


Larval growth and settlement rates are important larval behaviors for larval protections. The variability of larval growthsettlement rates and physical conditions for 2006-2012 and in the future with potential climate changes was studied using the coupling ROMS-IMBs, and new temperature and current indexes. Forty-four experimental cases were conducted for larval growth patterns and release mechanisms, showing the spatial, seasonal, annual, and climatic variations of larval growthsettlement rates and physical conditions, demonstrating that the slight different larval temperature-adaption and larval release strategies made difference in larval growth-settlement rates, and displaying that larval growth and settlement rates highly depended upon physical conditions and were vulnerable to climate changes.


2020 ◽  
Vol 62 (1-2) ◽  
pp. 151-161
Author(s):  
T. Shagholi ◽  
M. Keshavarzi ◽  
M. Sheidai

Tamarix L. (Tamaricaceae) is a halophytic shrub in different parts of Asia and North Africa. Taxonomy and species limitation of Tamarix is very complex. This genus has three sections as Tamarix, Oligadenia, and Polyadenia, which are mainly separated by petal length, the number of stamens, the shape of androecial disk and attachment of filament on the androecial disk. As there was no palynological data on pollen features of Tamarix species of Iran, in the present study 12 qualitative and quantitative pollen features were evaluated to find diagnostic ones. Pollen grains of 8 Tamarix species were collected from nature. Pollen grains were studied without any treatment. Measurements were based on at least 50 pollen grains per specimen. Light and scanning electron microscopes were used. Multivariate statistical methods were applied to clarify the species relationships based on pollen data. All species studied showed monad and tricolpate (except some individuals of T. androssowii). Some Tamarix species show a high level of variability, in response to ecological niches and phenotypic plasticity, which make Tamarix species separation much more difficult. Based on the results of the present study, pollen grains features are not in agreement with previous morphological and molecular genetics about the sectional distinction.


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