Showing papers by "University of Hohenheim published in 1986"
TL;DR: The results indicate the existence of a specific uptake system for Fe(III)phytosiderophores in roots of barley and all other graminaceous species and two strategies are evident for the acquisition of iron by plants under iron deficiency.
Abstract: Roots of grasses in response to iron deficiency markedly increase the release of chelating substances (;phytosiderophores') which are highly effective in solubilization of sparingly soluble inorganic Fe(III) compounds by formation of Fe(III)phytosiderophores. In barley (Hordeum vulgare L.), the rate of iron uptake from Fe(III)phytosiderophores is 100 to 1000 times faster than the rate from synthetic Fe chelates (e.g. Fe ethylenediaminetetraacetate) or microbial Fe siderophores (e.g. ferrichrome). Reduction of Fe(III) is not involved in the preferential iron uptake from Fe(III)phytosiderophores by barley. This is indicated by experiments with varied pH, addition of bicarbonate or of a strong chelator for Fe(II) (e.g. batho-phenanthrolinedisulfonate). The results indicate the existence of a specific uptake system for Fe(III)phytosiderophores in roots of barley and all other graminaceous species. In contrast to grasses, cucumber plants (Cucumis sativus L.) take up iron from Fe(III)phytosiderophores at rates similar to those from synthetic Fe chelates. Furthermore, under Fe deficiency in cucumber, increased rates of uptake of Fe(III)phytosiderophores are based on the same mechanism as for synthetic Fe chelates, namely enhanced Fe(III) reduction and chelate splitting. Two strategies are evident from the experiments for the acquisition of iron by plants under iron deficiency. Strategy I (in most nongraminaceous species) is characterized by an inducible plasma membrane-bound reductase and enhancement of H(+) release. Strategy II (in grasses) is characterized by enhanced release of phytosiderophores and by a highly specific uptake system for Fe(III)phytosiderophores. Strategy II seems to have several ecological advantages over Strategy I such as solubilization of sparingly soluble inorganic Fe(III) compounds in the rhizosphere, and less inhibition by high pH. The principal differences in the two strategies have to be taken into account in screening methods for resistance to ;lime chlorosis'.
911 citations
TL;DR: In this paper, Wurzeln et al. showed that the rhizosphere pH may be as much as 2 units higher or lower than the pH of the bulk soil.
Abstract: Root-induced changes in the rhizosphere may affect mineral nutrition of plants in various ways. Examples for this are changes in rhizosphere pH in response to the source of nitrogen (NH4-N versus NO3-N), and iron and phosphorus deficiency. These pH changes can readily be demonstrated by infiltration of the soil with agar containing a pH indicator. The rhizosphere pH may be as much as 2 units higher or lower than the pH of the bulk soil. Also along the roots distinct differences in rhizosphere pH exist. In response to iron deficiency most plant species in their apical root zones increase the rate of H+ net excretion (acidification), the reducing capacity, the rate of FeIII reduction and iron uptake. Also manganese reduction and uptake is increased several-fold, leading to high manganese concentrations in iron deficient plants.
Low-molecular-weight root exudates may enhance mobilization of mineral nutrients in the rhizosphere. In response to iron deficiency, roots of grass species release non-proteinogenic amino acids („phytosiderophores”) which dissolve inorganic iron compounds by chelation of FeIII and also mediate the plasma membrane transport of this chelated iron into the roots.
A particular mechanism of mobilization of phosphorus in the rhizosphere exists in white lupin (Lupinus albus L.). In this species, phosphorus deficiency induces the formation of so-called proteoid roots. In these root zones sparingly soluble iron and aluminium phosphates are mobilized by the exudation of chelating substances (probably citrate), net excretion of H+ and increase in the reducing capacity. In mixed culture with white lupin, phosphorus uptake per unit root length of wheat (Triticum aestivum L.) plants from a soil low in available P is increased, indicating that wheat can take up phosphorus mobilized in the proteoid root zones of lupin.
At the rhizoplane and in the root (root homogenates) of several plant species grown in different soils, of the total number of bacteria less than 1 % are N2-fixing (diazotrophe) bacteria, mainly Enterobacter and Klebsiella. The proportion of the diazotroph bacteria is higher in the rhizosphere soil. This discrimination of diazotroph bacteria in the rhizosphere is increased with foliar application of combined nitrogen. Inoculation with the diazotroph bacteria Azospirillum increases root length and enhances formation of lateral roots and root hairs similarly as does application of auxin (IAA). Thus rhizosphere bacteria such as Azospirillum may affect mineral nutrition and plant growth indirectly rather than by supply of nitrogen.
Wurzel-induzierte Veranderungen in der Rhizosphare: Bedeutung fur die Mineralstoffernahrung der Pflanzen Durch von Wurzeln induzierte Veranderungen in der Rhizosphare kann die Mineralstoffernahrung der Pflanzen in verschiedener Weise beeinflust werden. In der vorliegenden Arbeit werden dafur Beispiele gegeben. Veranderungen des Rhizospharen-pH-Wertes konnen in Abhangigkeit von der N-Form oder bei Eisen- bzw. Phosphatmangel auftreten. Diese Veranderungen lassen sich durch Infiltration des Bodens mit einem in Agar gelosten pH-Indikator nachweisen. Der Rhizospharen-pH-Wert kann bis zu 2 Einheiten hoher oder tiefer als der des wurzelfernen Bodens liegen. Auch entlang von Wurzeln treten ausgepragte Unterschiede im Rhizospharen-pH-Wert auf. Bei Eisenmangel kommt es bei den meisten Pflanzenarten in apikalen Wurzelzonen zur pH-Absenkung, Erhohung der Reduktionskapazitat der Wurzeln und der Eisenaufnahme. Auch die Reduktion und Aufnahme von Mangan konnen dadurch stark gefordert werden und zu hohen Mangangehalten in Eisenmangelpflanzen fuhren.
Niedermolekulare Wurzelexsudate konnen die Mobilisierung von Mineralstoffen in der Rhizosphare fordern. Bei Eisenmangel geben die Wurzeln von Gramineen verstarkt nichtproteinogene Aminosauren (“Phytosiderophore”) ab, die anorganische Eisenverbindungen durch Chelatisierung von FeIII auflosen und die als FeIII Chelate auch durch die Plasmamembran in die Wurzeln von Grasern transportiert werden.
Einen besonderen Mechanismus zur Mobilisierung von Phosphat in der Rhizosphare besitzt Weislupine (Lupinus albus L.), bei der Phosphatmangel die Bildung sogenannter Proteoid-Wurzeln induziert. In diesen Wurzelzonen kommt es zur Abscheidung von - wahrscheinlich - Citrat, Absenkung des pH-Wertes und Erhohung der Reduktionskapazitat der Wurzeln und dadurch zu verstarkter Mobilisierung von schwerloslichen Fe- und Al-Phosphaten. In Mischkultur mit Weislupine wird bei Weizen die Aufnahme von Phosphat aus einem P-amen Boden je Einheit Wurzellange stark erhoht. Dies zeigt, das Weizen Phosphat aufnehmen kann, welches von Weislupine in den Zonen der Proteoid-Wurzeln mobilisiert wurde.
In der Rhizosphare verschiedener Pflanzenarten von Naturstandorten betragt der Anteil N2-fixierender Bakterien (vorwiegend Enterobacter und Klebsiella) weniger als 1 % der Gesamtbakterienzahl. Der Anteil der N2-Fixierer ist im wurzelfernen Boden hoher. Diese Diskriminierung der N2-Fixierer in der Rhizosphare wird durch Blattdungung mit Stickstoff verstarkt. Inokulation mit Azospirillum fordert Wurzellangenwachstum, Seitenwurzelbildung und Wurzelhaardichte in ahnlicher Weise wie Applikation von Auxin (IES). Diazotrophe Rhizospharenbakterien (insbesondere Azospirillum) konnten daher durch Bildung von Phytohormonen die Mineralstoffernahrung und das Wachstum sta,rker beeinflussen als durch Verbesserung der N-Ernahrung uber N2-Fixierung.
460 citations
TL;DR: The effects of different nutrient meals and a noncaloric viscous cellulose meal (control) on the motor activity of the canine jejunum were studied and the length of spread of contraction waves was the most important factor that influenced transit.
158 citations
TL;DR: The inhibition of the in vivo synthesis of murein in Bacillus subtilis and the resistance of Mycoplasma mycoides to nisin suggest that the membrane may be excluded as a target, but a general inhibition of macromolecule syntheses in Micrococcus luteus supports the assumption that the cytoplasmic membrane is a target.
140 citations
TL;DR: In this paper, the history of forest decline is discussed with emphasis on symptomatology, development and distribution, and attempts are made, by exploiting knowledge of pollutant emissions and deposition, to deduce the possible causes of European forest decline.
Abstract: Symptoms of recent forest decline were first observed on silver fir (Abies alba) in the early 1970s in “clean-air” areas of southern Germany; they have subsequently been described in the early 1980s for Norway spruce (Picea abies) and recently broad-leaved trees such as European beech (Fagus sylvatica). The history of forest decline is discussed with emphasis on symptomatology, development and distribution. After a discription of results of recent surveys of tree injury, indicating an increase in the occurrence of decline, attempts will be made, by exploiting knowledge of pollutant emissions and deposition, to deduce the possible causes of European forest decline.
135 citations
TL;DR: It is suggested that ethylene-promoted CO(2) production is involved in the regulation of autocatalytic ethylene production in apples.
Abstract: Internal ethylene concentration, ability to convert 1-amino-cyclopropane-1-carboxylic acid (ACC) to ethylene (ethylene-forming enzyme [EFE] activity) and ACC content in the peel of apples (Malus domestica Borkh., cv Golden Delicious) increased only slightly during fruit maturation on the tree. Treatment of immature apples with 100 microliters ethylene per liter for 24 hours increased EFE activity in the peel tissue, but did not induce an increase in ethylene production. This ability of apple peel tissue to respond to ethylene with elevated EFE activity increased exponentially during maturation on the tree. After harvest of mature preclimacteric apples previously treated with aminoethoxyvinyl-glycine, 0.05 microliter per liter ethylene did not immediately cause a rapid increase of development in EFE activity in peel tissue. However, 0.5 microliter per liter ethylene and higher concentrations did. The ethylene concentration for half-maximal promotion of EFE development was estimated to be approximately 0.9 microliter per liter. CO2 partially inhibited the rapid increase of ethylene-promoted development of EFE activity. It is suggested that ethylene-promoted CO2 production is involved in the regulation of autocatalytic ethylene production in apples.
122 citations
TL;DR: Significant developments of the past decade in the area of solar crop drying are reviewed in this article, where solar energy is considered more applicable to low-temperature in-storage drying systems which has gained more importance in the last decade for drying grain and hay.
88 citations
TL;DR: Results indicate a modulating action of menthol on Ca inactivation, which was studied in identified Helix neurons and indicated a sensitizing effect of ment hol on Ca-dependent inactivation.
77 citations
TL;DR: In primary explant, mass and clonal cultures, the relative proportions of FI, FII and FIII cells were found to change as a function of the age of the donor animal and indicate that the differentiation of normal BN rat fibroblasts occurs via a three-phase process.
72 citations
TL;DR: The originally proposed acid-microclimate could not be confirmed under in vivo experimental conditions either in the jejunum or in the colon by direct measurement with pH-sensitive glass-microelectrodes.
Abstract: Segments of guinea pig jejunum, proximal and distal colon and of rat jejunum were superfused either in vivo or in vitro with different electrolyte solutions. The pH in the bulk phase solution and at the surface of the epithelium was measured with two different types of glass pH-microelectrodes, a pointed tip (Hinke-type) and a flat membrane electrode (Dubuisson-type); both types of electrodes gave the same results. The existence of a pH-microclimate at the surface of the mucosa was demonstrated under both in vivo and in vitro conditions. In vivo the pH-microclimate was stable and virtually independent of changes in the luminal bulk phase pH. When the bulk phase pH of the guinea pig colon was changed between pH 5 and pH 8.6, the mean pH in the microclimate was 7.08 +/- 0.15 (n = 163) in the proximal colon and 6.91 +/- 0.14 (n = 75) in the distal colon. In the guinea pig jejunum pH in the microclimate was 7.37 +/- 0.21 (n = 10) while the luminal pH was 7.27 +/- 0.10. Under in vitro conditions, the pH in the microclimate was more acidic (guinea pig jejunum delta pH 0.93, rat jejunum delta pH 0.40, guinea pig proximal colon delta pH 0.22). Addition of glucose (10 mM) or short-chain fatty acids (80-90 mM) to the luminal solution or replacement of sodium by lithium did not influence the pH in the microclimate significantly. Also the addition of acetazolamide, amiloride, SITS or sodium deoxycholate to the luminal solution, did not affect the pH in the microclimate in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)
72 citations
TL;DR: In this article, a ligand exchange reaction between aryltrimethylsilanes (ArSiMe3) and halogenboranes (BX3 or ArBX2) is described.
TL;DR: The application of not only nisin but also virginiamycin increased the alcoholic yield and reduced the numbers of the lactic acid bacteria in the fermenting mashes without any influence on the growth of yeasts.
TL;DR: The analysis of hybrids supported the above findings regarding the analysis of variance, however, the estimates of additive x additive epistasis for yield were considerably smaller and only minimally correlated with those from the diallel analysis.
Abstract: Three flint and three dent maize (Zea mays L.) inbred lines, their possible F1 crosses, F2 and backcross progenies, and all possible three-way crosses were evaluated in a three-year experiment for yield, ear moisture, and plant height. The purpose was to estimate genetic parameters in European breeding materials from (i) generation means analysis, (ii) diallel analysis of generation means, and (iii) analysis of F1 and three-way cross hybrids. Method (i) was based on the F∞-metric model and methods (ii) and (iii) on the Eberhart-Gardner (1966) genetic model; both models extended for heterotic maternal effects.
TL;DR: The results showed that the Sibbald procedure was less precise than CAM, and the use of starved birds led to wrong intercepts but also to misleading regression coefficients in the regression equations used to calculate energy excretion on food intake.
Abstract: 1. Two series of balance trials were performed with adult cockerels and with broiler chickens during their 5th week of life, and one with adult colostomised hens. The latter served to determine the digestibility of protein of the diet under test. 2. All birds were fed the same diet with one exception: in the case of colostomised hens limestone (100 g/kg) was added before feeding. 3. The main purpose of the experiments was to compare the Sibbald procedure for determining the so‐called true metabolisable energy (TME) with apparent metabolisable energy (AME) or TME values obtained by applying a conventional addition method (CAM). 4. The results showed that the Sibbald procedure was less precise than CAM. 5. The Sibbald procedure delivered incorrect TME and AME values, the reason for this being the use of starved birds. This led not only to wrong intercepts but also to misleading regression coefficients in the regression equations used to calculate energy excretion on food intake. 6. In CAM there exi...
TL;DR: A new chloroperoxidase could be detected in Pseudomonas pyrrocinia ATCC 15 958, a bacterium that produces the antifungal antibiotic pyrrolnitrin, and is the first chloroperxidase described from procaryotic sources.
TL;DR: In this paper, an acid catalyzed Wittig reaction was used to give spirocyclopropyl substituted bicyclo[2.2] octanes, which were used as equivalents of senecioic acid esters in the aprotic double Michael reaction.
TL;DR: It is concluded that NIRS can evaluate the quality traits investigated to a similar degree to that of conventional methods of analysis and allows rapid screening of several quality traits simultaneously, it should be particularly attractive for breeding purposes.
Abstract: The prediction of grain and stover quality parameters in maize {Zea mays L.) by near infra-red reflectance spectroscopy (NIRS) was studied. A total of 110 grain and 135 stover samples originating from different genotypes and environments were assayed. Calibration equations for content of crude protein (CP), crude fat (CF), starch (ST), and water soluble carbohydrates (WSC) in grain were obtained by multiple linear regression of known manual values on NIRS data from the odd numbered samples. Calibrations for CP, acid detergent fibre (ADF), in vitro digestible organic matter according to the Tilley & Terry (IVDOM-T & T) and the gas production (IVDOM-Gp) method, respectively, and metabolizable energy (ME) in stover were developed analogously. Equations were validated with the evennumbered .samples and for ME additionally with the 1584 stover samples from an experiment with 66 F1 hybrids tested in six environments. The coefficients of multiple determination (R2) of the prediction equations ranged from 0.80 for IVDOM-Gp and ME in stover to 0.94 for CP in grain. Standard errors of calibration (SEC) and prediction (SEP) were in most cases not higher than commonly reported for conventional manual assays. With regard to the correct ranking of hybrids, prediction equations for ME applied well to stover samples from other environments with one exception. We concluded that NIRS can evaluate the quality traits investigated to a similar degree to that of conventional methods of analysis. Since NIRS is simple and safe to operate and allows rapid screening of several quality traits simultaneously, it should be particularly attractive for breeding purposes.
TL;DR: Most estimates of whitefly populations relate, according to the purpose of the survey, either to the adults or to the last two larval instars including the so-called “pupae”, these stages being easier to count than eggs or small larvae.
TL;DR: By transforming the deviation mean squares into coefficients of variation it was possible to reveal improvements of stability not only by heterogeneity but also by heterozygosity, and additionally, an interaction of both factors in the sense of a diminishing return.
Abstract: With the view to study heterozygosity and heterogeneity as to their effects and interactions on yield and yield stability in maize, the following four types of population structure were formed from eight inbred lines: Homogeneous populations of homozygous plants (the eight inbred lines themselves); heterogeneous populations of homozygous plants (four blends containing four lines each); homogeneous populations of heterozygous plants (16 single crosses); heterogeneous populations of heterozygous plants (four blends containing four single crosses each, and four double crosses). This material was grown in three environments (years).
At both levels of heterozygosity, the blends did not outyield the means of their respective components grown in pure stands. yield stability of the various structural groups was ranked differently by ecovalence and the mean square for deviations from regression. By transforming the deviation mean squares into coefficients of variation it was possible to reveal improvements of stability not only by heterogeneity but also by heterozygosity, and additionally, an interaction of both factors in the sense of a diminishing return.
TL;DR: The retention times of fluid and particles of different lengths were measured in the digestive tract of the llama to study the relationship between retention times and retention time of particles in the intestine and whole digestive tract.
TL;DR: Improved understanding of the biodegradation of halogenated hydrocarbons, as described in this article, will almost certainly result in new biotechnological applications, especially in the area of waste-water treatment.
Abstract: Chlorinated hydrocarbons are widely used because of their chemical and thermal stability as well as their fungicidal, herbicidal, and insecticidal properties. Unfortunately, it is just this stability that makes the compounds persistent in nature; half-lives of more than 15 years are not uncommon. In many countries the use of some chlorinated compounds has been prohibited, even though many such compounds (e.g., DDT) exhibit exactly the desired spectrum of effects. Surprisingly, microbiol systems that can degrade most chlorinated hydrocarbons have been found in nature. Indeed, it is possible, in many cases, to isolate pure cultures of bacteria that can utilize these compounds as the sole source of carbon and energy. Even polychlorinated compounds, such as the wood preservative and herbicide pentachlorophenol, can be utilized as a source of carbon by some bacteria. The study of the biodegradation of halogenated hydrocarbons has led to the discovery of novel catabolic pathways in which unusual and previously undescribed enzymatic activities have been detected. Bacterial enzymes have even been isolated that can replace halogen substituents in aliphatic and aromatic compounds with hydroxyl groups or hydrogen atoms. Improved understanding of the biodegradation of halogenated hydrocarbons, as described in this article, will almost certainly result in new biotechnological applications, especially in the area of waste-water treatment.
TL;DR: It is concluded that phase II and phase III are characterized not only by the occurrence of irregular and regular activity but by a significant change of a number of contraction parameters.
TL;DR: Evidence was obtained that was consistent with the suggestion that in both strains two ld-carboxypeptidase activities are present, and the two activities could be distinguished with regard to their sensitivity to d-amino acids and the β-lactam antibiotic thienamycin.
Abstract: A ld-carboxypeptidase from Escherichia coli K 12 was isolated by Tris-EDTA treatment and purified to electrophoretic homogeneity by DEAE-cellulose chromatography. The enzyme has a molecular weight of approximately 12,000 as determined by sodium dodecyl sulfatepolyacrylamide electrophoresis and by Sephadex G-100 gel filtration. The studies of the substrate specificity of the enzyme revealed that UDP-MurNAc-tetrapeptide is a superior substrate, with a Km value of 1×10-4 mol/l. The activity of the ld-carboxypeptidase was inhibited by d-amino acids and the β-lactam antibiotic nocardicin A. Ki values of 0.3 and 43 mmol/l were determined for nocardicin A and d-homoserine, respectively. The properties of the purified enzyme correspond to activity I in ether treated cells.
TL;DR: In this paper, a solar tunnel dryer with integrated collector was developed and tested for grapes in the field of small-scale agriculture, which can be applied to farms with an acreage of 0.5 to 1.0 hectares.
Abstract: A solar tunnel dryer with integrated collector was developed and tested. This low-cost system can be produced either by small scale industries or farmers themselves using simple tools and relatively cheap materials. Depending on weather conditions about 1000 kg grapes can be dried within 4 to 7 days. According to the drying capacity the solar drying system can be successfully applied to farms with an acreage of 0.5 to 1.0 hectare. Compared to traditional sun drying methods solar drying reduces significantly drying time and mass losses. During drying the crop is completely protected from rain, dust, animals and insects and doesn⢙ come into contact with foreign materials.
TL;DR: The effect of increasing amounts of nitrogen (nitrate or urea) on the nitrogen fixing capacity (acetylene reduction assay = ARA), growth (fresh and dry weight) and the number of stem and root-nodules of the tropical legume Aeschynomene afraspera was studied in hydroponic cultures (in growth cabinet) as well as in pot experiments (field conditions) as discussed by the authors.
Abstract: The effect of increasing amounts of nitrogen (nitrate or urea) on the nitrogen fixing capacity (acetylene reduction assay = ARA), growth (fresh and dry weight) and the number of stem- and root-nodules of the tropical legume Aeschynomene afraspera was studied in hydroponic cultures (in growth cabinet) as well as in pot experiments (field conditions). The experiments were carried out at Dakar in the rainy season of 1985. Plants were grown in the presence of 6 nitrate concentrations (0,3,6,9,12 and 15 mM N/l) in hydroponic solution and with 4 urea concentrations (0,50,100 and 200 kg N/ha) in pots. In both types of experiments, root nodulation and ARA were strongly inhibited by increasing amounts of mineral nitrogen. Stem nodulation and potential nitrogen fixation of stems, however, remained unaffected. Lower amounts of mineral nitrogen even enhanced growth as well as nitrogen fixation. The possible future of this remarkable plant as green manure or fodder in low input countries of the tropics is discussed.
Einflus von mineralischem Stickstoff auf die Knollchenbildung und Stickstoffbindung der stengelknollchenbildenden Leguminose Aeschynomene afrasperaAeschynomene afraspera ist eine rasch wachsende, weitverbreitete Leguminose Senegals und verfugt uber Wurzel- und Stengelknollchen zur symbiotischen Stickstoffbindung (mit Rhizobium sp.). In den vorliegenden Untersuchungen wurde der Einflus steigender Mengen an Stickstoff (Harnstoff oder Nitrat) auf die Pflanzenentwicklung (Frisch- oder Trockengewicht), die Anzahl Knollchen (an Wurzeln und Stengeln) sowie die potentielle Fahigkeit zur Stickstoffbindung (Acetylen-Reduktions-Test = ARA) von A. afraspera in hydroponischen Nahrlosungen sowie in Gefasversuchen untersucht. Die Versuche fanden in der Regenzeit (April bis Juli 1985) auf dem Versuchsgelande des Instituts in Dakar statt. Die Pflanzen wurden aus sterilisiertem Samen gezogen und in hydroponischer Losung mit steigenden Nitratgaben (0,3,6,9,12 und 15 mM Nitrat-N/l) sowie mit steigenden Mengen an Harnstoff (0,50,100 und 200 kg N/ha) in einem Gefasversuch (mit einem sandigen Lehm) unter Freilandbedingungen untersucht. In beiden Versuchsserien wurde die Wurzelknollchenbildung und die ARA signifikant durch steigende Mengen an Stickstoff vermindert. Die Stengelknollchen und ihre potentielle Fahigkeit zur Stickstoffbindung (gemessen als ARA) konnten hingegen von den steigenden Stickstoffmengen nicht beeinflust werden. Durch das gesteigerte Pflanzenwachstum wirkten sich geringe Mengen einer Stickstoffdungung sogar fordernd auf die genannten Eigenschaften aus. Die Bedeutung dieser ersten Ergebnisse fur die low-input Landwirtschaft der Tropen wird diskutiert.
TL;DR: In this paper, the semantic network approach from the psychology of memory is used as a model of consumer information processing to derive six hypotheses about determinants of the types of attributes consumers use in a prepurchase information acquisition situation.
TL;DR: In this article, the authors investigated the tolerance of rye and yellow lupin in solution culture during the seedling stage, in good agreement with their adaptation to acid mineral soils, and found that an 80 fold higher concentration of Al was necessary for rye and rye for comparable growth depression and for horse bean a 5 times higher Al concentration.
Abstract: In Wasserkultur traten zwischen den Pflanzenarten Ackerbohne (Vicia faba „Herz Freya”), Gelbe Lupine (Lupinus luteus „Schwako”), Gerste (Hordeum vulgare „Roland”) und Roggen (Secale cereale „Kustro”) deutliche Unterschiede in der Toleranz gegenuber Al auf: Lupine und Roggen wurden erst bei 80-fach hoherer, Ackerbohne bei 5-fach hoherer Al-Konzentration als Gerste (0.05 μg Al l−1 = 1.85 μM Al) vergleichbar im Wachstum beeintrachtigt. Al-Toxizitat auserte sich bei 7 Tagen Versuchsdauer vor allem in einer Hemmung des Langenwachstums der Keimwurzeln und in noch starkerem Mase der Seitenwurzeln. Die Seitenwurzelanzahl war bei Al-Angebot verringert. Die Trockensubstanzbildung der Wurzeln und insbesondere der Sprosse war dagegen wesentlich weniger beeintrachtigt. Bei Lupine kam es sogar zu einer leichten Forderung der Trockensubstanzbildung bei niedrigem Al-Angebot.
Die unter kontrollierten Bedingungen in Wasserkultur festgestellte hohe Al-Toleranz von Gelber Lupine und Roggen im Keimlingsstadium spiegelte die Anpassung dieser Pflanzenarten an saure Mineralboden wider.
AI tolerance of horse bean, yellow lupin, barley and rye. I. Shoot and root growth as affected by Al supply In solution culture considerable differences existed in Al tolerance between the plant species horse bean (Vicia faba „Herz Freya”), yellow lupin (Lupinus luteus „Schwako”), barley (Hordeum vulgare „Roland”) and rye (Secale cereale „Kustro”): compared to barley (0.05 μg Al l−1 = 1.85 μM Al) an 80 fold higher concentration of Al was necessary for lupin and rye for comparable growth depression and for horse bean a 5 times higher Al concentration. Injury by Al after 7 days of Al treatment was most effectively and sensitively characterized by an inhibition of elongation of seminal and especially of lateral roots. Numbers of laterals were also reduced. Dry matter production of roots and shoots was less affected by Al. In lupin, low Al supply even slightly increased the dry weight.
The high Al tolerance of rye and yellow lupin in solution culture during the seedling stage is in good agreement with their adaptation to acid mineral soils.
TL;DR: It is concluded that TriEL selectively interferes with cytoplasmic and mitotic MTs of the algae, thereby causing the observed inhibitory effects on lorica formation, mitosis, and cytokinesis.
TL;DR: In manchen Landern wurde die Anwendung einiger chlorierter Verbindungen verboten, obwohl sie genau das erwunschte Wirkungsspektrum zeigten (z.B. DDT).
Abstract: Chlorierte Kohlenwasserstoffe finden aufgrund ihrer chemischen und thermischen Stabilitat sowie ihrer fungiziden, herbiziden und insektiziden Wirkung breite Anwendung. Leider fuhren eben diese Eigenschaften auch dazu, das diese Verbindungen in der Natur auserst persistent sind; Halbwertszeiten von 15 Jahren und mehr sind keine Seltenheit. In manchen Landern wurde die Anwendung einiger chlorierter Verbindungen verboten, obwohl sie genau das erwunschte Wirkungsspektrum zeigten (z.B. DDT). Erstaunlicherweise werden dennoch die meisten dieser Verbindungen durch mikrobielle Systeme abgebaut. In vielen Fallen gelang es, bakterielle Reinkulturen zu isolieren, die chlorierte Verbindung wie das Holzschutzmittel und Herbizid Pentachlorphenol kann von einigen Bakterien als einzige Kohlenstoffquelle genutzt werden. Untersuchungen des Abbaus halogenierter Kohlenwasserstoffe fuhrten zur Entdeckung neuer Abbauwege, bei denen sich bisher nicht bekannte enzymatische Reaktionen nachweisen liesen. Es wurden sogar bakterielle Enzyme gefunden, die Halogensubstituenten sowohl in aliphatischen als auch in aromatischen Verbindungen durch Hydroxygruppen oder durch Wasserstoffatome ersetzen. – Die hier beschriebenen neuen Erkenntnisse werden sicherlich in absehbarer Zukunft zu neuen biotechnologischen Verfahren, vor allem auf dem Gebiet der Abwassertechnologie, fuhren.
TL;DR: All 3 mtDNAs investigated contain regions homologous to the plasmid S1 of the CMS-S cytoplasm of Maize (Zea mays), as indicated by hybridization experiments.
Abstract: Molecular characterization of mitochondrial (mt) DNA of rye (Secale cereale L.), free of significant amounts of contaminating chloroplast (cp) DNA, was initiated using the open-pollinated cultivar ‘Halo’ as a source of mtDNA. Based on the compilation of data from restriction patterns, the molecular size of the mtDNA was estimated to be 410 Kb and its buoyant density was determined as 1.705 g/ml. Southern hybridization, using labelled cp genes (P700 and ribulosebiphosphate-carboxylase large subunit), indicated the presence of cpDNA-homologous regions on putative mtDNA fragments. Mt DNAs of inbred lines with fertile and cytoplasmic male sterile (CMS) ‘Pampa’ cytoplasm were also analysed. Whereas the restriction patterns of mtDNAs of ‘Halors and the fertile line turned out to be identical, ‘Pampa’ mtDNA showed a unique restriction pattern, indicating (as in most other CMS systems) the involvement of mtDNA rearrangements in the expression of male sterility in rye. All 3 mtDNAs investigated contain regions homologous to the plasmid S1 of the CMS-S cytoplasm of Maize (Zea mays), as indicated by hybridization experiments. In ‘Pampa’ cytoplasm the S-homologous sequence is located within a rearranged region of mtDNA.