Distribution of two C cycle enzymes in soil aggregates of a prairie chronosequence

Knowledge of the cycling and compartmentalization of soil C that influence C storage may lead to the development of strategies to increase soil C storage potentials. The objective of this study was to use soil hydrolases and soil aggregate fractionation to explore the relationship between C cycling activity and soil aggregate structure. The prairie chronosequence soils were native prairie (NP) and agricultural (AG) and tallgrass prairies restored from agriculture in 1979 (RP-79) and 1993 (RP-93). Assays for -glucosidase (E.C. 3.2.1.21) and N-acetyl--glucosaminidase (NAGase, EC 3.2.1.30) activities were conducted on four aggregate size fractions (>2 mm, 1–2 mm, 250 m–1 mm, and 2–250 m) from each soil. There were significantly greater amounts of >2-mm aggregates in the RP-79 and RP-93 soils compared to the NP and AG soils due to rapid C accumulation from native plant establishment. Activities for both enzymes (g PNP g^–1 soil h^–1) were greatest in the microaggregate (2–250 m) compared to the macroaggregate (>2 mm) fraction; however, microaggregates are a small proportion of each soil (<12%) compared to the macroaggregates (75%). The RP soils have a hierarchical aggregate system with most of the enzyme activity in the largest aggregate fractions. The NP and AG soils show no hierarchical structure based on aggregate C accretion and significant C enzyme activity in smaller aggregates. The distribution of enzyme activity may play a role in the storage of C whereby the aggrading restored soils may be more susceptible to C loss during turnover of macroaggregates compared to the AG and NP soils with less macroaggregates.     

Free and HF-HO-extractable amino acids determined by high performance liquid chromatography in a loamy sand soil

Summary Amino acids were extracted from fertility plots of a loamy sand soil with 0.05 M HF-HCl and with a 10% ethanol solution (free amino acids) and analysed by reverse-phase high performance liquid chromatography (HPLC). The total quantities of amino-N compounds analysed were 4.4 g/g soil for the acid treatment and 22.6 g/g soil for the 10% ethanol extract. Glycine and glutamic acid were the most abundant of 15 amino-N compounds in the HF-HCl extracts, whereas glutamic acid and ornithine + NH⁺ ₄ were found in the highest concentration in the 10% ethanol extracts. The HF-HCI pretreatment is used to increase the efficiency of the extraction of soil organic matter. Although this pretreatment removed some amino acids, the acids extract less than 1% of the total amino-N content of the crude soil extracts. The pretreatment, therefore, was not overly destructive. Comparisons between the amino acids extracted from the fertility plots were not conclusive, except for glycine, which was greater in concentration in the higher fertilizer N plots of the same crop rotation.     

Effect of drying and rewetting on mineralization and distribution of bacterial constituents in soil fractions

Summary Mineralization of ¹⁴C- and ¹⁵N-labelled whole bacteria, cytoplasm, and cell walls and their distribution in different soil fractions were studied during 211 days of incubation including two drying and rewetting cycles. With any of these three soil amendments, almost 60% of C derived from cellular constituents was released as CO₂, 15% was incorporated into the living microbial biomass and 25% was distributed into protected microbial metabolites or recalcitrant microbial products. The distribution of C and N derived from the amendments in the different soil fractions showed that constituents adsorbed on fine clay (<0.2 m were more rapidly decomposed than those adsorbed on silt (50-2 ) and coarse clay (2–0.2 ), indicating a faster organic matter turnover in fine clay than in silt and coarse clay. Although alternate soil drying and rewetting cycles did not significantly affect the mineralization of bacterial constituents, the cycles did have an important effect on the size and specific activities of newly formed microbial biomass. This suggests the presence of an active and a dormant fraction of soil biomass.     

Effects of nitrification inhibitors on denitrification of nitrate in soil

Summary The influence of 28 nitrification inhibitors on denitrification of nitrate in soil was studied by determining the effects of different amounts of each inhibitor on the amounts of nitrate lost and the amounts of nitrite, N₂O and N₂ produced when soil samples were incubated anaerobically after treatment with nitrate or with nitrate and mannitol. The inhibitors used included nitrapyrin (N-Serve), etridiazole (Dwell), potassium azide, 2-amino-4-chloro-6-methylpyrimidine (AM), sulfathiazole (ST), 4-amino-1,2,4-triazole(ATC),2,4-diamino-6-trichloromethyl-s-triazine (CL-1580), potassium ethylxanthate, guanylthiourea (ASU), 4-nitrobenzotrichloride, 4-mesylbenzotrichloride, sodium thiocarbonate (STC), phenylmercuric acetate (PMA), and dicyandiamide (DCD).Only one of the nitrification inhibitors studied (potassium azide) retarded denitrification when applied at the rate of 10 g g^–1 soil, and only two (potassium azide and 2,4-diamino-6-trichloromethyl-s-triazine) inhibited denitrification when applied at the rate of 50 g g^–1 soil. The other inhibitors either had no appreciable effect on denitrification, or enhanced denitrification, when applied at the rate of 10 or 50 g g^–1 soil, enhancement being most marked with 3-mercapto-1,2,4-triazole. Seven of the inhibitors (potassium azide, sulfathiazole, potassium ethylxanthate, sodium isopropylxanthate, 4-nitrobenzotrichloride, sodium thiocarbonate, and phenylmercuric acetate) retarded denitrification when applied at the rate of 50 g g^–1 soil to soil that had been amended with mannitol to promote microbial activity.Reports that nitrapyrin (N-Serve) and etridiazole (Dwell) inhibit denitrification when applied at rates as low as 0.5 g g^–1 soil could not be confirmed. No inhibition of denitrification was observed when these compounds were applied at the rate of 10 g g^–1 soil, and enhancement of denitrification was observed when they were applied at the rate of 50 or 100 g g^–1 soil.     

Seasonal changes and the effects of fertiliser on some chemical,biochemical and microbiological characteristics of high-producing pastoral soil

Summary A 2-year study (1983–1984 to 1984–1985) was conducted to estimate temporal and seasonal changes and the effects of fertiliser on some soil chemical, biochemical and microbiological characteristics. The soil used was a Typic Vitrandept under grazed pasture. Soil samples were taken regularly to a depth of 75 mm from paired unfertilised and fertilised (500 kg ha^– 30% potassic superphosphate) plots. Except for organic C, fertiliser had little or no effect on the characteristics measured. Organic C averaged about 9.2% in unfertilised soil and was about 0.3% higher in the fertilised soil. The size of the microbial biomass fluctuated widely in the 1st year (3000 g C g^–1 in February to 1300 g C g^–1 in September) but there was less variation in the 2nd year (range 1900 g C g^–1 to 2500 g C g^–1 soil). CO₂ production values (10- to 20-day estimates averaged 600 g of CO₂-C g^–1 soil) were generally higher in spring compared to the rest of the year. Water extractable C increased over winter and declined through spring in both years (range 50 g C g^–1 soil to 150 g C g^–1 soil). Mineral-N flush values were higher in summer (300 g N g^–1 soil) and lower in winter months (200 g N g^–1 soil). The pattern of variation of microbial N values was one of gradual accumulation followed by rapid decline. This rapid decline in values occurred in spring and autumn (range 130–220 g N g^–1 soil). N mineralisation and bicarbonate-extractable N showed no clear trend; these values ranged from 100–200 and 122–190 g N g^–1 soil, respectively. There was a significant correlation (0.1%) between N mineralisation and bicarbonate-extractable N in the late summer-autumn-early winter period (February–August) in both years but not in spring. These results and their relationships to climatic factors and rates of pasture production are discussed.     

Mineral-fixed ammonium in clay- and silt-size fractions of soils incubated with 15N-ammonium sulphate for five years

Summary Four soils with 6, 12, 23, and 47% of clay were incubated for 5 years with ¹⁵N-labeled (NH_{4 2}SO₄ and hemicellulose. The incubations took place at 20°C and 55% water-holding capacity. Samples of whole soils, and clay- (<2 m) and silt-(2–20 m) size fractions (isolated by ultrasonic dispersion and gravity sedimentation) were analysed for labeled and native mineral-fixed ammonium. Mineral-fixed ammonium in non-incubated soil samples accounted for 3.4%–8.3% of the total N and showed a close positive correlation with the soil clay content (r ² = 0.997). After 5 years of incubation, the content of mineral-fixed ammonium in the clay fraction was 255–430 g N g^–1, corresponding to 71%–82% of the mineral-fixed ammonium in whole soils. Values for silt were 72–166 g N g^–1 (14%–33% of whole soil content). In the soils with 6% and 12% clay, less than 1 % of the labeled clay N was present as mineral-fixed ammonium. In the soil with 23% clay, 3% of the labeled N in the clay was mineral-fixed ammonium. Labeled mineral-fixed ammonium was not detected in the silt fractions. For whole soils, and clay and silt fractions, the proportion of native N present as mineral-fixed ammonium varied between 3% and 6%. In contrast, the proportion of labeled N found as mineral-fixed ammonium in the soil with 4701o clay was 23%, 38% and 31% for clay, silt, and whole-soil samples, respectively. Corresponding values for native mineral-fixed ammonium were 12%, 16%, and 10%. Consequently, studies based on soil particle-size fractions and addressing the N turnover in clay-rich soils should consider the pool of mineral-fixed ammonium, especially when comparing results from different size fractions with those from fractions isolated from soils of a widely different textural composition.     

Seasonal changes in microbial biomass and nutrient flush in forest soils

Microbial biomass and N, P, K, and Mg flushes were estimated in spring, summer, autumn, and winter samples of different forest soils. The microbial biomass showed significant seasonal fluctuations with an average distribution of 880±270 g C g^-1 soil in spring, 787±356 g C g^-1 soil in winter, 589±295 g C g^-1 soil in summer, and 560±318 g C g^-1 soil in autumn. The average annual concentrations of C, N, P, K, and Ca in the microbial biomass were 704, 106, 82, 69 and 10 g g^-1 soil, respectively. Microbial C represented between 0.5 and 2% of the organic soil C whereas the percentage of microbial N with respect to the total soil N was two-to threefold higher than that of C; the annual fluctuations in these percentages followed a similar trend to that of the microbial biomass. Microbial biomass was positively correlated with soil pH, moisture, organic C, and total N. The mean nutrient flush was 31, 15, 7, and 4 g g^-1 soil for N, K, P, and Mg, respectively, and except for K, the seasonal distribution was autumn spring winter summer. The average increase in available nutrient due to the mineralization of dead microbial cells was 240% for N, and 30, 26, and 14% for P, K, and Mg, respectively. There was a positive relationship between microbial biomass and the N, P, K, and Mg flushes. All the variables studied were significantly affected by the season, the type of soil, and the interaction between type of soil and season, but soil type often explained most of the variance.     

Suppression of methane oxidation in aerobic soil by nitrogen fertilizers,nitrification inhibitors,and urease inhibitors

Concentrations of CH₄, a potent greenhouse gas, have been increasing in the atmosphere at the rate of 1% per year. The objective of these laboratory studies was to measure the effect of different forms of inorganic N and various N-transformation inhibitors on CH₄ oxidation in soil. NH ₄ ⁺ oxidation was also measured in the presence of the inhibitors to determine whether they had differential activity with respect to CH₄ and NH ₄ ⁺ oxidation. The addition of NH₄Cl at 25 g N g^-1 soil strongly inhibited (78–89%) CH₄ oxidation in the surface layer (0–15 cm) of a fine sandy loam and a sandy clay loam (native shortgrass prairie soils). The nitrification inhibitor nitrapyrin (5 g g^-1 soil) inhibited CH₄ oxidation as effectively as did NH₄Cl in the fine sandy loam (82–89%), but less effectively in the sandy clay loam (52–66%). Acetylene (5 mol mol^-1 in soil headspace) had a strong (76–100%) inhibitory effect on CH₄ consumption in both soils. The phosphoroamide (urease inhibitor) N-(n-butyl) thiophosphoric triamide (NBPT) showed strong inhibition of CH₄ consumption at 25 g g^-1 soil in the fine sandy loam (83%) in the sandy clay loam (60%), but NH ₄ ⁺ oxidation inhibition was weak in both soils (13–17%). The discovery that the urease inhibitor NBPT inhibits CH₄ oxidation was unexpected, and the mechanism involved is unknown.     

Effects of animal manure and mineral fertilizer on the total carbon and nitrogen contents of soil size fractions

Summary Soil was sampled in autumn 1984 in the 132 field (sandy loam soil) of the Askov long-term experiments (started in 1894) and fractionated according to particle size using ultrasonic dispersion and sedimentation in water. The unmanured plot and plots given equivalent amounts of N (1923–1984 annual average, 121 kg N/ha) in either animal manure or mineral fertilizer were sampled to a depth of 15 cm, fractionated and analysed for C and N. Mineral fertilizer and animal manure increased the C and N content of whole soil, clay (<2 m) and silt (2–20 m) size fractions relative to unmanured samples, while the C content of the sand size fractions (fine sand 1, 20–63 m; fine sand 2, 63–200 m; coarse sand, 200–2000 m) was less affected. Clay contained 58% and 65°70 of the soil C and N, respectively. Corresponding values for silt were 30% and 26%, while sand accounted for 10% of the soil C. Fertilization did not influence this distribution pattern. The C : N ratio of the silt organic matter (14.3) was higher and that of clay (10.6) lower than whole-soil C:N ratios (12.0). Fertilization did not influence clay and silt C : N ratios. Animal manure caused similar relative increases in the organic matter content of clay and silt size fractions (36%). In contrast, mineral fertilizer only increased the organic matter content of silt by 21% and that of clay by 14%.     

Effects of mesofauna exclusion on the microbial biomass in two moder profiles

Summary In December 1988, litterbags (mesh size 45 or 1000 m) were exposed in the organic layer of a limed and unlimed moder soil under beech forest in the Solling area (Germany). At both sites, substrata from the L1, L2, F1, F2 and from the H Layer were sampled shortly before the beginning of the experiment, defaunated, filled separately into litterbags and replaced in the respective horizons in the field. Litterbags were retrieved on three sampling dates (May, September, and November 1989). The soil microbial biomass was estimated by means of the fumigation extraction method. The results show that the effects of excluding mesofauna from the 45-m litterbags were different in different horizons, on different sampling dates and in different study sites. Calculation of the average effect from the three sampling dates revealed that mesofauna exclusion reduced the microbial biomass C at both sites. It was concluded from horizon- and season-specific differences between the two litterbag treatments that a depression in microbial biomass C in the organic layer of a moder soil by mesofaunal grazers is confined to situations where environmental conditions cause strong feeding pressure and when the microflora is exposed to environmental stress.     

Beiträge zur Kulturpflanzen-Flora I

Zusammenfassung Folgende Arten der GattungAmaranthus L. werden zur Körnergewinnung angebaut:A. caudatus L. (mit ssp.caudatus und ssp.mantegazzianus (Passer.) Hanelt),A. cruentus L. undA. hybridus L. em. Robins. convar.erythrostachys (Moq. in DC.) Thell. Die Einordnung und Benennung dieser Sippen werden erörtert. Ihre geographisch weit getrennten Anbauareale in Mittel- und Südamerika sowie in Asien, vor allem Indien bis China, haben bei den Diskussionen um vorkolumbische transpazifische Kulturbeziehungen zwischen Amerika und Asien eine Rolle gespielt. Alle drei Arten sind eindeutig amerikanischen Ursprungs, sie gehören zu den ältesten Kulturpflanzen der indianischen Landwirtschaft. Dagegen liegen keinerlei Belege für einen entsprechend alten Anbau in Asien vor. Vieles spricht dafür, daß sie über Europa, ursprünglich als Zierpflanzen, dorthin gelangten (16.–17. Jahrhundert) und durch die Übertragung der Art und Weise der Nutzung bereits bekannter Kulturpflanzen in den Ackerbau der betreffenden Gebiete übergingen.Im Gegensatz dazu stehen die sowohl in systematischer wie geographischer Hinsicht unterschiedenen Gemüsearten der Gattung. Die wichtigsten von ihnen sindA. tricolor L. em. Fiori et Paol. undA. lividus L. em. Thell.; beide sind altweltlichen Ursprungs und werden in Süd- und Ostasien bzw. im südlichen Europa seit langem kultiviert. Einige weitere, früher z. T. als häufig angebaut bezeichnete Gemüse-Arten erwiesen sich als nur von lokaler Bedeutung (A. dubius Mart. ex Thell.,A. viridis L.) oder als reine Sammelpflanzen (A. celosioides H. B. K.,A. spinosus L.,A. graecizans L. em. Aschers.).

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Summary The following taxa of the genusAmaranthus L. are cultivated as grain amaranths:A. caudatus L. (ssp.caudatus and ssp.mantegazzianus (Passer.) Hanelt),A. cruentus L. andA. hybridus L. em. Robins. convar.erythrostachys (Moq. in DC.) Thell. Systematics and nomenclature of these taxa have been discussed. Their widely separated areas of cultivation in Central and Southern America resp. in Asia (especially in India and China) have suggested speculations about precolumbic transpacific cultural relations between America and Asia. All the mentioned species are doubtlessly of an American origin, they belong to the oldest cultivated plants of the American agriculture. There are no evidences which would prove a cultivation of a likewise long history in Asia. But there are many indications for an introduction via Europe to Asia originally as ornamentals which have been subsequently adopted by the agriculture of these Asiatic regions, utilizations of previously known cultivated plants having been transferred to them.The vegetable species of the genus are differentiated taxonomically and geographically from the grain amaranths. The most important are:A. tricolor L. em. Fiori et Paol. andA. lividus L. em. Thell., they are of Old World origin and have been grown already long ago in Southern and Eastern Asia resp. in Southern Europe. Some further species, hitherto supposed to be ± widely cultivated ones, proved to be only of local importance (A. dubius Mart. ex Thell.,A. viridis L.) or as taxa, growing spontaneously and only collected for foodA. celosioides H. B. K.,A. spinosus L.,A. graecizans L. em. Aschers.).

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Amaranthus L.:A. caudatus L. ( caudatus mantegazzianus (Passer.) Hanelt),A. cruentus L. A. hybridus L. em. Robins. convar.erythrostachys (Moq. in DC.) Thell. , . , ( ) , . . ; , , , 16–17 . , , . , , . ¶rt; :A. tricolor L. em. Fiori et Paol. A. lividus L. em. Thell.; , . , , (A. dubius Mart. ex Thell.,A. viridis L.) , (A. celosioides H. B. K.,A. spinosus L.,A. graecizans L. em. Aschers.).

     

Potential for organic sulfur accumulation in a variety of forest soils at saturating sulfate concentrations

Summary Increasing the sulfate concentration and concomitant increases in the organic S concentration failed to exert any effect on organic S mobilization in samples collected from all depths within the mineral soil profile, from 15 sites differing in soil type, vegetation, and geographic location. Mobilization capacities at saturating concentrations of sulfate for organic S formation generally tended to increase with increasing depth. The potentials for the accumulation of organic S with various sulfate inputs exhibited saturation kinetics similar to those observed for organic S formation; values for the former parameter ranged from 3×10^-3 to 12.6 mol S g^–1 dry weight 24 h^-1 for the uppermost (A, E) soil horizons, 3 nmol to 10 mol S g^-1 dry weight 24 h^–1 for intermediate (primarily AB) soil horizons, and from 3 nmol to 13.4 mol S g^-1 dry weight 24 h^–1 for the lowermost (B, C) soil horizons. Irrespective of depth, the Fullerton, Tarklin, and Loblolly sites in Tennessee and the Florida site showed the least net accumulation of organic S at saturation (<0.2 mol S g^-1 dry weight 24 h^–1 for all horizons examined), while the Duke Forest (North Carolina), Douglas Fir (Washington), Whiteface (New York) and the Howland (Maine) sites had the highest potential net accumulation of organic S at saturation (>1.0 mol S g^-1 dry weight 24 h^-1 for most horizons examined).     

Influence of phenamiphos on the vesicular-arbuscular mycorrhizal symbiosis in Leucaena leucocephala

Summary Concentrations of phenamiphos ranging from 0 to 40 rg/g soil were established in a typical Oxisol (Tropeptic Eutrustox), inoculated or uninoculated with Glomus aggregatum. The effect of the nematicide on the development of vesicular-arbuscular mycorrhizal (VAM) symbiosis was evaluated in the greenhouse using Leucaena leucocephala as an indicator host plant. Treatment of soil with phenamiphos did not have a significant influence on the development of mycorrhizal activity measured in terms of subleaflet phosphorus concentrations. Similarly, the nematicide did not have an adverse effect on the level of mycorrhizal colonization or on the P content of shoots, as determined at the time of harvest. However, shoot dry weight was adversely influenced by phenamiphos when the chemical was applied to the uninoculated soil at 20 g/g soil or higher, and when it was applied to the inoculated soil at 40 g/g soil. It is concluded that phenamiphos is not likely to influence the growth of Leucaena or its symbiotic association with VAM fungi if the concentrations applied do not exceed levels known to suppress nematodes.Hawaii Institute of Tropical Agriculture and Human Resources Journal series No. 3146     

Effect of the insecticide methidathion on agricultural soil microflora

Summary We studied the effects of the organophosphorus insecticide methidathion, at concentrations of 10, 50, 100, 200 and 300 g g^-1 in an agricultural soil, on fungi, total bacterial populations, aerobic N₂-fixing bacteria, denitrifying bacteria, nitrifying bacteria (phases I and II), and nitrogenase activity (acetylene reduction assay). The presence of 10–300 g g^-1 of methidathion significantly increased fungal populations (colony-forming units). Denitrifying bacteria, aerobic N₂-fixing bacteria and N₂ fixation were significantly increased at concentrations of 50–300 g g^-1. The total number of bacteria increased significantly at concentrations of 100–300 g g^-1. Nitrifying bacteria decreased initially at concentrations of 300 g g^-1, but recovered rapidly to levels similar to those in the control soil without the insecticide.     

Eine zweiblütige Pflanze beiEranthis hyemalis (L.) Salisb

Zusammenfassung Die Gestaltung der Blütenregion einer spontan aufgetretenen, zweiblütigen Pflanze vom Sternblütigen Winterling,Eranthis hyemalis wird analysiert und beschrieben. Das die Nebenblüte tragende Parakladium entspringt der Achsel des unteren Involukralblattes.

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Eranthis hyemalis (L.)Salisb. with a two-flowered stem

Summary Studies in the flower region of an exceptional spontaneously two-flowered stem of the Winter Aconite,Eranthis hyemalis. The shoot (paracladium) bearing the accessory flower arises from the axil of the outermost leaf of the involucre.

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Eranthis hyemalis (L.)Salisb.

, , ,Eranthis hyemalis. , , .

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Herrn Prof. Dr. Drs. h. c.Hans Stubbe zum 75. Geburtstag gewidmet.

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Ich behalte gemäß Intern. Code, Art. 73 die vonLinné gewählte Schreibung bei, obgleich die klassische Form hiemalis seither weithin zu finden ist (s. aber z. B. Syllabus 1964,Clapham, Tutin andWarburg 1959,Lawalrée 1955).     

Disturbance effects on soil solution chemistry due to heating cable installation

Installation of heating cables for warming soil was used to evaluate the effect of disturbance on soil solution chemistry within a northern hardwood forest (Adirondack Mountains, New York). Differences in response among treatments suggested the importance of both the depth and timing of cable installation. There were increases (p>0.05) in many solutes within pilot study plots in which surrogate cable was installed at 15 cm depth. Most notably, mean nitrate concentrations for the 1st year following disturbance were 744 eq l^-1 at 15 cm depth compared to 7 eq l^-1 for the non-disturbed control. A comparison of pilot plots with 5 cm cable depth and an unheated soil-warming control plot with the same cable disturbance showed that the seasonality of soil disturbance may have a key role in response to disturbance. The soil solution response was diminished if installation occurred during the spring, a period of rapid uptake of nitrogen by vegetation. Mean nitrate concentrations were 176 eq l^-1 for 5-cm pilot plots (installed in fall 1991) versus 6 eq l^-1 for 5-cm, unheated soil-warming control plots (installed in spring 1992). Disturbance effects were attenuated over time and not generally apparent 1 year after installation.     

Der Genfonds anMalus-Arten in der DDR und seine Nutzung

Zusammenfassung Die ursprüngliche Naumburger Malus-Artenkollektion wurde in das Institut für Obstforschung Dresden-Pillnitz überführt. Sie umfaßt 237 Arten und Varietäten und damit die wichtigsten Vertreter der 5 Sektionen vonMalus - Malus, Sorbomalus, Chloromeles, Eriobolus, Docyniopsis (nachRehder 1954). Die bereits vorliegenden Untersuchungsergebnisse an dieser Kollektion über Pollenfertilität, Apomixis, Schorf-, Mehltau- und Blutlausresistenz sowie Virustoleranz werden mitgeteilt.Auf die nationale und internationale Bedeutung dieses Genfonds, der für den Austausch zur Verfügung steht, wird hingewiesen.

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Genetic resources ofMalus in the GDR and their utilization

Summary The collection ofMalus germplasm originally located in Naumburg has been transfered to the Institute of Fruit Research in Dresden-Pillnitz. It contains 237 species and forms and therewith important representatives of the 5 sections ofMalus - Malus, Sorbomalus, Chloromeles, Eriobolus, Docyniopsis (according toRehder 1954). The results already obtained on the basis of this germplasm concerning pollen fertility, apomixis, resistance to scab, mildew, woolly aphid, and virus tolerance are presented here. The national and international importance of thisMalus collection which is available for distribution is stressed.

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Malus

Malus, . , -. 237 :Malus, Sorbomalus, Chloromeles, Eriobolus, Docyniopsis ( , 1954). , , , , , , , . , , , .

     

Effect of increasing oxygen concentration on total denitrification and nitrous oxide release from soil by different bacteria

Summary The effect of increasing oxygen concentrations (0, 5, 10 and 20 Vol% O₂) on total denitrification and N₂0 release was studied in model experiments using a neutral pH loamy soil relatively rich in easily decomposable organic matter and supplied with nitrate (300 g nitrate N/g dry soil). The sterilized soil was inoculated with three different denitrifying bacteria (Bacillus licheniformis,Aeromonas denitrificans andAzospirillum lipoferum) and incubated (80% WHC, 30°C). The gas volume was analysed for O₂, CO₂, N₂O, NO and N₂ by gas chromatography and the soil investigated for changes in ammonium, nitrite, nitrate, pH, total N and C as well as water-extractable C. WithB. licheniformis andAeromonas denitrificans total denitrification increased remarkably with increasing pO₂ as the result of intensified mineralization.Azospirillum lipoferum, however, showed the highest activity at 5 vol% O₂. WithB. licheniformis N₂O was released only in anaerobic conditions and at 5 Vol% O₂ (maximum) or 10 Vol% 02, but not at 20 Vol%, whereasAeromonas denitrificans produced N₂O only in the presence of He gas (maximum) or at 5 Vol% O₂. In contrast to these bacteria, N₂O production withAzospirillum lipoferum was restricted to 10 Vol% O₂ (maximum) and to 20 Vol% 02, with some traces at 5 vol% O₂. With a certain set of conditions, total denitrification and N₂O formation seem to be governed by the mineralization rate of the organisms in question. The increased demand for electron acceptors by a high turnover rate rather than the presence of anaerobic conditions seems to have determined the rate of denitrification.     

Über einige infraspezifische Sippen vonMalva verticillata L.

Zusammenfassung Malva verticillata L. ist eine alte Kulturpflanze Chinas. Auf Grund habitueller Unterschiede werden einige infraspezifische Sippen häufig als eigene Arten geführt. Die Diagnosen einiger Taxa sind verschieden interpretiert worden, andere wurden bisher übersehen. Als nomenklatorischer Typus der Art ist das Exsikkat aus dem Linné-Herbarium anzusehen. Es ist nicht ausgeschlossen, daß dieses Exemplar eine heterozygote Pflanze ist. Gestützt auf Kreuzungsanalysen wird die nahe Verwandtschaft der untersuchten Taxa nachgewiesen. Für die Gliederung in vier Varietäten werden Blatt- und Sproßmerkmale herangezogen.M. crispa L.,M. mohileviensis Down.,M. meluca Graebn. undM. pamiroalaica Ilj. sind keine selbständigen Arten.

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Summary Malva verticillata is an old cultivated plant of China. The different habit of some infraspecific taxa led to the assumption of several species. The diagnoses of some taxa have been interpreted in a different manner, other have been overlooked. As nomenclatural type the exsiccate from the Linnaean Herbarium must be considered. It is not out of question that this specimen is a heterocygotic plant. Supported on an analysis of descendants after hybridization the high degree of relationship of the investigated Taxa is pointed out. For classification (four varieties) characters of leaves and shoots are used.M. crispa L.,M. mohileviensis Down.,M. meluca Graebn., andM. pamiroalaica Ilj. are synonyms of infraspecific Taxa.

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Malva verticillata L. . , ; . , . . , . . 4 , .M. crispa L.,M. mohileviensis Down.M. meluca Graebn. M. pamiroalaica Iljin .

     

Die Aminosäuren-Zusammensetzung des sedimentierbaren Plasma-Proteins verschiedener Segmente der Keimlingswurzel vonPisum sativum

Zusammenfassung Wurzeln etiolierter Erbsenkeimlinge wurden im Phywe-Homogenisator zerkleinert, die Zellwandreste wurden durch Filtration entfernt und die Plasmapartikel durch Zentrifugieren bei 20 000 g abgetrennt. In den auf diese Weise sedimentierten Plasmaproteinen wurde durch etwas modifizierte quantitative Papierchromatographie nach McFarren die Aminosäurezusammensetzung untersucht. Dazu wurden die Proteinhydrolysate auf Schleicher & Schüll-Papier 2043b mit sechs verschiedenen Laufmitteln getrennt (Phenol pH 1; Phenol pH 12; Methyläthylketon-Pyridin-Puffer pH 6,2 = 5:1:1; t-Butanol pH 8,5; n-Butanol-Eisessig-Wasser = 4:1:5; Kollidin pH 9). In dieser Weise wurden 15, jeweils 1 mm lange Wurzelsegmente, von der Spitze an gerechnet, getrennt analysiert. Im Partikelprotein keines dieser Segmente konnte -Aminobuttersäure oder Hydroxyprolin nachgewiesen werden. Die Proteine aus den verschiedenen Wurzelabschnitten ergaben eine sehr ähnliche Aminosäurezusammensetzung. Geringe Unterschiede zeigten die Spitzensegmente (0–4 mm) gegenüber den älteren Wurzelabschnitten. Im Protein der jüngsten Segmente fanden sich etwas mehr Aminosäuren der Aspartat- und Glutamatfamilie sowie Arginin und Tryptophan, welche in den älteren Wurzelteilen in geringerer Menge vorkommen. Diese enthielten jedoch mehr aromatische und langkettige Aminosäuren als die Spitzensegmente. Die Aminosäurenzusammensetzung der sedimentierbaren Partikelproteine der Erbsenwurzel wird mit entsprechenden Angaben in der Literatur über andere Leguminosenproteine, besonders aus Erbsen, verglichen.

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Summary Roots of etiolized pea seedlings were homogenized by Phywe-blendor, cell debris removed by filtration, and plasmatic particles collected by centrifuging at 20 000 g. From cell particles isolated in such way the amino acid composition in cytoplasmic proteins was analyzed by quantitative paper chromatography by the somewhat modified McFarren method. Amino acids of hydrolized proteins were separated on Schleicher & Schuell paper 2043b by 6 different solvents (phenol pH 1; phenol pH 12; methylethylketone-pyridine-buffer pH 6,2 = 5:1:1; t-butanol pH 8,5; n-butanol-acetic acid-water = 4:1:5; collidine pH 9). In such way proteins of fifteen segments, each of 1 mm length, were investigated, beginning with the top. In all segments analyzed neither -aminobutyric acid nor hydroxyproline were found in the proteins of pea root particles. Amino acid composition in proteins of different root segments proved to be similar. Slight differences were found between top segments (1–4) and the older ones. Proteins of the youngest segments contain more amino acids of the aspartate and glutamate family as well as arginine and tryptophane than the older segments. These, however, contained more aromatic and long chain amino acids than the top segments. The amino acid composition in proteins of pea roots is compared with data on other leguminous proteins, in particular of peas, described in literature.

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