THE INTERACTION OF HIGHER PLANTS AND SOIL MICRO-ORGANISMS: I. MICROBIAL POPULATION OF RHIZOSPHERE OF SEEDLINGS OF CERTAIN CULTIVATED PLANTS

1940 ◽  
Vol 18c (7) ◽  
pp. 307-317 ◽  
Author(s):  
M. I. Timonin

The microbial population in the rhizosphere of wheat, oats, alfalfa, and peas was studied and the relative abundance of different types of micro-organisms recorded. By means of the plating method it was found that bacteria and actinomycetes were 7 to 71 times greater in the rhizosphere than in the soil distant from the roots, whereas fungi were but 0.75 to 3.1 times more numerous.Different varieties of plants affected the activity of the various groups of soil micro-organisms differently. Thus fungi were more numerous in the rhizosphere of oats, and bacteria in the rhizosphere of alfalfa. Seventeen genera of fungi were represented in isolates from the rhizosphere of seedlings and the soil distant from the roots. However, no marked difference was observed in the types isolated from the rhizosphere of different varieties of seedlings. A fungus isolated from the rhizosphere of alfalfa proved to be a new species and the genus Spicularia Persoon was amended to include it.

1940 ◽  
Vol 18c (9) ◽  
pp. 444-455 ◽  
Author(s):  
M. I. Timonin

Comparative studies of flax varieties resistant and susceptible respectively to wilt, and of tobacco varieties resistant and susceptible to black root rot, showed higher numbers of micro-organisms in the rhizosphere of the susceptible than of corresponding resistant plants. Though plants of the same variety showed considerable variation in rhizosphere population under field and greenhouse conditions, the general trend remained the same. The abundance of micro-organisms in the rhizosphere of plants of the same variety grown in plots receiving different fertilizer treatment showed relatively little difference, even though the soils varied greatly in productivity.Numbers of micro-organisms in the rhizosphere of flax were greater when the water content of the soil was maintained at 30%, than when held at 60%, of total moisture-holding capacity. However, the microbial population in the soil distant from the roots was lower in the drier soil.Differential counts of fungi and actinomycetes indicated that the number of colonies developing from spores or conidia comprised a small proportion of the total count. Sporulation of fungi was more profuse in soil distant from the plant than in the rhizosphere.The contact slide method indicated a greater number of micro-organisms in the rhizosphere than in soil distant from the roots and showed differences between the rhizosphere of resistant and susceptible varieties which agreed with results from the plating method.


2019 ◽  
Vol 49 (4) ◽  
pp. 324-329 ◽  
Author(s):  
Efigenia de MELO ◽  
Carlos Alberto CID FERREIRA ◽  
Rogério GRIBEL

ABSTRACT We describe and illustrate a new species of Coccoloba (Polygonaceae), named Coccoloba gigantifolia, from the Brazilian Amazon. It resembles Coccoloba mollis Casar, but differs from the latter species by its much larger leaves in the fertile branches. The species has only been recorded in the Madeira River basin, in the states of Amazonas and Rondônia, in the central and southwestern Brazilian Amazon. The description was based on herbarium material, cultivated plants, and individual trees in their natural habitat. We provide illustrations, photographs, and an identification key with morphological characteristics that distinguish the new taxon from the other two related taxa of the Coccoloba sect. Paniculatae, as well as comments on the geographic distribution and conservation status of the species.


PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2313 ◽  
Author(s):  
Julio Parapar ◽  
Juan Moreira ◽  
Daniel Martin

The study of material collected during routine monitoring surveys dealing with oil extraction and aquaculture in waters off Myanmar (North Andaman Sea) and in the Gulf of Thailand, respectively, allowed us to analyse the taxonomy and diversity of the polychaete genusTerebellides(Annelida). Three species were found, namelyTerebellidescf.woolawa,Terebellides hutchingsaespec. nov.(a new species fully described and illustrated), andTerebellidessp. (likely a new species, but with only one available specimen). The new species is characterised by the combination of some branchial (number, fusion and relative length of lobes and papillation of lamellae), and thoracic (lateral lobes and relative length of notopodia) characters and is compared with all species described or reported in the SW Indo-Pacific area, as well as with those sharing similar morphological characteristics all around the world. The taxonomic relevance of the relative length of branchial lobes and different types of ciliature in branchial lamellae for species discrimination in the genus is discussed. A key to allTerebellidesspecies described in SE Indo-Pacific waters is presented.


Phytotaxa ◽  
2019 ◽  
Vol 406 (3) ◽  
pp. 199-205
Author(s):  
EVGENIY S. GUSEV ◽  
DMITRY A. KAPUSTIN ◽  
NIKITA A. MARTYNENKO ◽  
ELENA E. GUSEVA ◽  
MAXIM S. KULIKOVSKIY

Mallomonas gusakovii sp. nov. is described from Vietnam based on silica-scale morphology studied by means of transmission and scanning electron microscopy. This species belongs to section Quadratae and is characterized by large and broad scales of three types with an internal reticulation, V-shaped rib and a forward projecting wing. Different types of the V-shaped rib in taxa from section Quadratae are discussed. Scales of Mallomonas gusakovii were found only in two sites in Phu Quoc Island, Southern Vietnam.


Microbiology ◽  
2000 ◽  
Vol 81 (2) ◽  
pp. 475-484 ◽  
Author(s):  
R. N. GOURLAY ◽  
R. H. LEACH ◽  
C. J. HOWARD

Summary: Two similar micro-organisms with the characteristics of the order Mycoplas-matales were isolated from the eyes of calves with conjunctivitis. Both isolates produced only a slight pH decrease in broth and did not ferment glucose or hydrolyse arginine or urea -- hence they were almost undetectable by fluid cultures. Other biological characters included sterol dependence, indicative of the genus Mycoplasma, production of film and spots, growth at low temperature (20°C) or low pH (4.7), and failure to reduce tetrazolium. The two strains were serologically indistinguishable from each other, but distinct from known bovine and other Mycoplasma species tested. Because of their distinct biological and serological characteristics they are proposed as forming a separate new species, Mycoplasma verecundum, with strain 107 (nctc10145) as the type strain.


Author(s):  
Helmut Lehnert ◽  
Robert Stone ◽  
Wolfgang Heimler

A new species of Erylus from the Aleutian Islands is described. This is the first record of the genus from the Aleutian Islands. The new species differs from all other known species of Erylus in the presence of different types of monaxonic megascleres, ranging from oxeas, strongyles, styles, tylostyles to tylotes, often with unequal ends and irregular modifications of these types. The lack of a secondary category of asters is also unusual for the genus.


2010 ◽  
Vol 55 (1) ◽  
Author(s):  
František Moravec ◽  
Jean-Lou Justine

AbstractExaminations of materials of trichinelloid nematodes recently collected from the digestive tract of marine fishes off New Caledonia, South Pacific, revealed the presence of several species of the families Capillariidae and Trichosomoididae, including capillariids Pseudocapillaria novaecaledoniensis sp. nov. from the deep-sea Pristipomoides argyrogrammicus (Valenciennes) (Lutjanidae) and Pseudocapillaria echenei (Parukhin, 1967) from Echeneis naucrates Linnaeus (Echeneidae), and the trichosomoidid Huffmanela sp. (female) from Bodianus perditio (Quoy et Gaimard) (Labridae). P. novaecaledoniensis is characterized mainly by the structure and length (318–321 µm) of spicule and the presence of a dorsal cuticular membrane interconnecting both ventrolateral caudal lobes in the male (subgenus Ichthyocapillaria Moravec, 1982). The previously poorly known P. echenei is redescribed and recorded for the first time from the South Pacific Ocean. In addition, five morphologically different types of capillariid females without generic identification, designated as Capillariidae gen. spp. 1–5, each of them probably representing a new species, were recorded from Fistularia commersonii Rüppell (Fistulariidae), Synodus dermatogenys Fowler (Synodontidae), Carangoides oblongus (Cuvier) (Carangidae), Diagramma pictum (Thunberg) (Haemulidae) and Stegostoma fasciatum (Hermann) (Stegostomidae), respectively. Capillaria decapteri is transferred to Pseudocapillaria Mendonça, 1963 as P. decapteri (Luo, 2001) comb. nov.


Author(s):  
R.L. Burt ◽  
M.B. Forde

Early plant introduction in Australia and NZ involved familiar European species and simple general principles. 'First-generation' pasture cultivars in both countries were based on naturalized or cultivated material originally brought by colonists. Later, imported material was systematically used to improve these established varieties and produce 'second-generation' cultivars more closely adapted to local ecological conditions and agronomic systems. This simple approach proved inadequate for new and difficult environments which required different types of plant, and new species were sometimes tried and discarded prematurely because their potential was not fully displayed in the limited material initially available. Experience with Sfylosanthes in Australia shows that full suites of germplasm are necessary to evaluate a new species properly, and that such material should be deliberately and systematically collected from areas of similar or more extreme climate, particular attention being paid to edaphic characteristics. To obtain suitable legumes for the cold dry high country of the South Island collections from homologous regions in places such as Chile, Argentina, Kashmir, and the USSR may be useful. Keywords: plant introduction, Stylosanthes, Lotus, South America, Australia, New Zealand


1991 ◽  
Vol 69 (7) ◽  
pp. 1402-1406 ◽  
Author(s):  
G. L. Barron

Dwayaangam heterospora is described as a new Hyphomycete attacking the eggs of rotifers and nematodes. The fungus attaches to the eggshell by an appressorium-like swelling. After penetration a postinfection bulb is produced from which haustorium-like assimilative hyphae develop and consume the contents of the egg. The fungus produces several morphologically different types of conidia from inconspicuous conidiogenous cells. The conidia are solitary, hyaline and septate and are either scolecospores or staurospores. Key words: egg parasite, rotifers, Dwayaangam, Triposporina, aquatic hyphomycetes.


1975 ◽  
Vol 40 (310) ◽  
pp. 127-130 ◽  
Author(s):  
Sidney A. Williams ◽  
Richard V. Gaines

SummaryCarlfriesite is a new species found in relative abundance at the Bambollita (now La Oriental) mine in the Sierra La Huerta near Moctezuma, Sonora. Colour primrose yellow (R.H.S. 4B) with pale yellow streak. H = 3½, Dmeas = 6·3, Dcalc = 5·93. Fair cleavage on {010}. Monoclinic with a 12·585 Å, b 5·658, c 9·985, β 115° 35′. Space group Cc or C2/c. Strongest lines are 3·167 (10), 3·082 (9B), 5·063 (6), 2.832 (6), 3·369 (4), 4·825 (3), 2·698 (3), and 4·o89 (2). Feeble pleochlroism in pale yellow with γ > α = β α = 1·982, β = 2·095, γ 2·19 2Vα, = 79° calc. Occurs with cerussite and chlorargyrite in an oxidized assemblage derived from hessite, galena, and bornite.


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