Fusarium in paddy soils of West Malaysia

Summary The fusarium population in paddy soils of West Malaysia showed considerable variation in size but was generally small. In many soils fusaria were not recovered. Only 3 species ofFusarium, F. oxysporum, F. roseum andF. solani were found. Of these.F. roseum was the most widely distributed species and occurred in highest numbers per g soil, whileF. oxysporum was the most restrictive in distribution and occurred in lowest numbers per g soil.     

The bacterial biogeography of British soils

Despite recognition of the importance of soil bacteria to terrestrial ecosystem functioning there is little consensus on the factors regulating belowground biodiversity. Here we present a multi-scale spatial assessment of soil bacterial community profiles across Great Britain (> 1000 soil cores), and show the first landscape scale map of bacterial distributions across a nation. Bacterial diversity and community dissimilarities, assessed using terminal restriction fragment length polymorphism, were most strongly related to soil pH providing a large-scale confirmation of the role of pH in structuring bacterial taxa. However, while α diversity was positively related to pH, the converse was true for β diversity (between sample variance in α diversity). β diversity was found to be greatest in acidic soils, corresponding with greater environmental heterogeneity. Analyses of clone libraries revealed the pH effects were predominantly manifest at the level of broad bacterial taxonomic groups, with acidic soils being dominated by few taxa (notably the group 1 Acidobacteria and Alphaproteobacteria). We also noted significant correlations between bacterial communities and most other measured environmental variables (soil chemistry, aboveground features and climatic variables), together with significant spatial correlations at close distances. In particular, bacterial and plant communities were closely related signifying no strong evidence that soil bacteria are driven by different ecological processes to those governing higher organisms. We conclude that broad scale surveys are useful in identifying distinct soil biomes comprising reproducible communities of dominant taxa. Together these results provide a baseline ecological framework with which to pursue future research on both soil microbial function, and more explicit biome based assessments of the local ecological drivers of bacterial biodiversity.     

Yeasts in some Netherlands soils

Summary In 12 Netherlands soil samples, in two successive analyses carried out in the autumn of 1952, the author has isolated up to 105 cultures of yeasts to be classified under the following species:Kloeckera apiculata, Torulopsis inconspicua, Torulopsis pulcherrima, Candida Guilliermondii, Rhodotorula mucilaginosa, Aureobasidium pullulans, Hansenula saturnus, Hansenula californica, Saccharomyces mangini, Saccharomyces ellipsoideus andPichia membranefaciens. In all the soils examined the quantity of yeasts found has been very small. The results obtained do not offer evidence for any relationship between manurial treatment and species and number of yeasts occurring. Sporeforming yeasts were less numerous than non-sporeforming ones.

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Riassunto Da 12 terreni Olandesi, in due successive analisi, eseguite nell'autunno 1952, l'A. riferisce di avere isolato ben 105 colture pure di lieviti da riportare alle seguenti specie:Kloeckera apiculata, Torulopsis inconspicua, Torulopsis pulcherrima, Candida Guilliermondii, Rhodotorula mucilaginosa, Aureobasidium pullulans, Hansenula saturnus, Hansenula californica, Saccharomyces mangini, Saccharomyces ellipsoideus ePichia membranefaciens. In tutti i terreni esaminati la quantità di lieviti riscontrati è stata molto esigua; non è stata posta in evidenza alcuna influenza in rapporto alle diverse concimazioni ed è stata rilvata la scarsissima diffusione delle specie sporigene su quelle incapaci di formare spore.

     

Nitrification in some tropical soils

Summary Nitrification of soil N in 8 mineral and 2 histosols having a wide range in pH (3.4 to 8.6), organic C (1.22 to 22.70%) and total N (0.09 to 1.20%) was studied by measuring nitrate fromation under aerobic incubation of the soil samples at 30°C for 4 weeks. The amounts of NO₃-N produced in the soils varied from 0 to 123 μg/g of soil. Soil N in the two acid sulfate soils and one other acid soil did not nitrify under conditions that stimulate nitrification. Soils having pH more than 6.0 nitrified at a rapid rate and released NO₃-N ranging from 98 to 123 μg/g. The two organic soils differed considerably in their capacity to nitrify though the total amounts of mineral N released were similar in these soils. The amounts of NO₃-N formed in the soils was highly positively correlated with the soil pH but was not significantly correlated with the organic C of total N content of the soils. Statistical analysis also showed that nitrate formation was not significantly correlated with soil pH in soils having pH higher than 6.0.     

Lipid constituents of some Fusarium species

Summary The lipid constituents of Fusarium aquaeductuum Lagerh., F. aquaeductuum Lagerh. var. medium and F. sambucinum Fuck. have been studied. In the mycelia of these three fungi -carotene, lycopene and rhodoxanthin were present. Ergosterol was also present and the fatty acid pattern showed a slight qualitative difference between the three fungi.Use of the presence of carotenoids in fungi as a taxonomic tool is discussed and it is concluded that it cannot yet be considered reliable.     

Distribution of Zearalenone-Producing Fusarium Species in Japan

One hundred sixty-six isolates of Fusarium spp. from domestic cereal grains, feed, and other sources were examined for their ability to produce zearalenone on autoclaved moist rice grains. They belonged to the following species (number of producers/number tested): F. roseum (9/28), F. roseum (Culmorum) (3/4), F. roseum (Gibbosum) (2/5), F. roseum (Avenaceum) (1/2), F. roseum (Scirpi) (0/1), F. tricinctum (1/4), F. tricinctum (Sporotrichiella) (0/7), F. lateritium (1/1), F. episphaeria (0/2), F. moniliforme (0/3), F. oxysporum (0/12), F. rigidiusculum (0/4), F. solani (0/4), F. splendens (0/1), F. nivale (0/2), and Fusarium spp. (15/86). Zearalenone was isolated from molded rice by ethanol extraction and purified by column chromatography. Selected isolates of F. roseum M-3-2 and F. roseum (Gibbosum) A-O-2 produced 50 to 100 mg of zearalenone per kg of rice. Increased yields (250 to 407 mg/kg of rice) were obtained by F. roseum M-3-2 when the substrate was supplemented with 1% peptone.     

Chromosome studies in some British bryophytes

Abstract

The chromosomes of one moss and thirty liverworts are described and discussed taxonomically. Those of Lepidozia pearsonii (n = 8 + 1m), Telaranea murphyae (n = 9), Leioeolea badensis (n = 8 + 1m), Pleetoeolea paroiea (n = 9), Nardia compressa (n = 8 + 1m), N. geoscyphus (n = 9), Lophoeolea bispinosa (n = 8 + 1m), L. semiteres (n = 8 + 1m), Saccogyna viticulosa (n = 8 + 1m), Scapania curta (n = 16 + 2m), S. compacta (n = 8 + 1m), Porella laevigata (n = 8 + 1m) and P. cordaeana (n = 8 + 1m) are believed not to have been reported previously and, despite references in the literature to the cytology of Riccia crystallina and Gymnocolea inflata, reasons are given for suggesting that the present counts of n = 7 + 1m and n = 8 + 1m, respectively, may also be the first. The remaining species have been recorded cytologically in other parts of the world but not previously for Great Britain, or not with the present karyotype.     

Urea hydrolysis in some tea soils

The influence of application of hexachlorocyclohexane (HCH=gamma BHC), to a submerged tropical field soil at rates equivalent to recommended field rates (1–2.5kg a.i./ha) and twice this level, upon the rhizosphere soil nitrogenase, nitrogen fixers, and soil redox potential (Eh) was investigated. The rhizosphere soil from HCH-treated field exhibited significantly higher nitrogenase activity than that from untreated fields. HCH retarded the drop in redox potential of the field soil upto 80 days after transplantation under submerged conditions. Populations of nitrogen-fixingAzospirillum sp. and Azotobacter, to a greater extent, and anaerobic organisms, to a lesser extent, were stimulated in HCH-treated soils. Results indicate the stimulation of heterotrophic nitrogen-fixing bacteria by HCH in submerged paddy soils.     

Chemistry of Cr in some Swedish soils

The effect of Si(OH)₄ on Cr toxicity and elemental concentrations in ryegrass were investigated in a growth chamber using an acid and a neutral mineral soil. Each soil was treated with 50 mg Cr, as CrO₃, kg⁻¹ soil dry weight, singly, or in combination with 25 mg Si as Si(OH)₄. Plants growing in unamended soils were used as controls. Chromium toxicity, expressed as decrease in shoot or root dry weight, was increased by the Si. This increase was accompanied by a higher Cr uptake particularly on the acid soil. The shoot and root dry weights were significantly correlated (P=1%) with the concentration of Cr, where r=−0.80 and −0.65, respectively. Uptake of Al, Cu, Fe, P and Zn did not show any consistent relationship to the magnitude of Cr toxicity.     

Notes on some British Barbulas

Abstract

The moss Hypnum cupressiforme var. heseleri is reported new to the British Isles and its status is discussed. Line drawings and a photographic illustration are provided. It was found growing on an apple tree on the Royal Estate, at Flitcham in West Norfolk. It differs from other species of Hypnum in its distinctive rounded-concave leaf form and julaceous branches. The habitat and ecology are broadly similar to those in the other European sites from which this moss has been reported.     

Phosphorus status of some ethiopian soils

The capacity to sorb P varied among some Ethiopian soils. Volcanic ash soils sorbed the maximum P while Fluvisols and Regosols sorbed the least. Sorption of P was significantly correlated with exchangeable and extractable forms of Fe and Al as well as pH and organic matter. But is was not related to the clay content of the soils. The role of Al was more important than that of Fe even though more dithionite and oxalate extractable Fe than Al was found in all soils.     

Distribution of rare actinomycetes in Japanese soils

The distribution of rare actinomycetes in 237 soil samples from various locations throughout Japan was investigated using a special isolation medium, HV agar.The populations (colony forming units) of these actinomycetes per gram of dried soil were Microtetraspora 6 × 10³, Saccharomonospora 1.7 × 10⁴, Dactylosporangium 5.4 × 10⁴, Streptosporangium 1.2 × 10⁵, Microbispora 1.4 × 10⁵, Nocardioforms 1.9 × 10⁵, and Micromonospora 6.8 × 10⁵. Streptomycetes 2.2 × 10⁶, and Unidentified actinomycetes 0.9 × 10⁶ were also observed.Their distributions seemed to be associated with environmental factors such as soil type (Land Use Classification), soil pH, humus content, and the characteristics of the humic acid. In general, the largest populations were found in soils of cultivated fields, which were rich in humus and had pH values between 6.5–7.0.However, the distribution of some genera in cultivated field soils (154 samples) was remarkable. The numbers of Microbispora and Streptosporangium were the largest in humus-rich acidic (pH 5.0–6.05) soils with low humic acid Δ log K values (black colored humic acid). Saccharomonospora was found most frequently in relatively humus-poor alkaline (pH 7.0–7.5) soils having higher Δ log K values (brown humic acid).Dactylosporangium and Microtetraspora, Saccharomonospora, and Micromonospora were most frequently isolated from mountainous forest soils, level-land forest or cultivated field soils, and pasture soils, respectively.