Die Chromosomenzahlen von Thymian und Bohnenkraut

Ohne Zusammenfassung     

Einfluss der Kaliumdynamik im wurzelnahen Boden auf die Magnesiumaufnahme von Pflanzen

Influence of potassium dynamics at the soil-root interface on magnesium uptake of plants At the soil-root interface potassium concentration of the soil solution can be depleted by potassium uptake of the plant. The influence of this effect on the magnesium uptake of ryegrass, barley, maize and rape was studied in pot experiments with luvisols from loess. The results have shown that the rate of magnesium uptake was doubled when the potassium concentration at the root surface decreased below 20 μmol K/1. Magnesium uptake is therefore inhibited by K concentrations above this limit. Application of potassium fertilizer increases the potassium concentration of the soil solution. However, via exchange of adsorbed Mg ions from the soil matrix, K application also increases magnesium concentration of the soil solution. As a result of K application magnesium uptake increases in this case if K concentration of the soil solution at the root surface is kept below 20 μmol K/1 by K buffering or K uptake. Magnesium uptake decreases however, if K concentration exceeds 20 μmol/1 soil solution because the inhibitory effect of potassium on Mg uptake is stronger than the favourable influence of Mg concentration.     

EinBatrachospermum der Sektion Contorta Skuja aus Kuba

Zusammenfassung Es wird über ein Vorkommen der bisher nur aus China bekannten Süßwasser-RotalgeBatrachospermum intortum Jao 1941 an mehreren Standorten im gebirgigen Osten (Provinz Oriente) der Insel Kuba berichtet. Es dürfte sich um den ersten Nachweis der Gattung für diese Antilleninsel handeln.

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ABatrachospermum, Sect. Contorta Skuja from Cuba

Summary Batrachospermum intortum hitherto known only from China, was found on several localities in the mountainous eastern part of Cuba (Prov. Oriente). This may be the first report of the genus for this island.

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Batrachospermum Contorta Skuja

Batrachospermum intortum Jao 1941, , . ( ). .

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Ergebnisse der 1. Kubanisch-deutschen Alexander von Humboldt-Expedition 1967/68, Nr. 33.     

Untersuchungen des Plutoniumgehalts von Pflanzen

Investigations to the content of plutonium in plants The content of Plutonium was analysed in different parts of plants and several plant species were analysed in order to find differences in the content Pu. The results indicate a deposition of Pu on the surface of the plants.     

Beziehung zwischen dem Stickstoff-Entzug der Pflanzen und der Abnahme von spezifisch gebundenem NH4-N im Boden

Relationship between the N uptake of plants and the mobilization of nonexchangeable NH₄-N In a pot experiment with ryegrass (Lolium multiflorum) the relationship between the release of nonexchangeable NH₄⁺ and the N uptake of plants was studied. For this purpose the surface soil of an alluvial soil and of a grey brown podsolic soil was labelled with ¹⁵NH₄-N. The following results were obtained: After treating the soil with 15-N the alluvial soil contained 4,55 mg and the grey brown podsolic soil 1,64 mg nonexchangeable ¹⁵NH₄-N/100 g soil. In the alluvial soil 72% and in the grey brown podsolic soil 66% of the nonexchangeable ¹⁵NH₄⁺ had been released during the growing season when ryegrass was planted. However, without plants there was no change in the content of labelled nonexchangeable NH₄⁺ in the alluvial soil or only a slight decrease in the grey brown podsolic soil. A highly significant correlation was found between the ¹⁵NH₄-N released and the ¹⁵N uptake of ryegrass in the alluvial soil (r = 0,78⁺⁺⁺) as well as in the grey brown podsolic soil (r = 0,98⁺⁺⁺).     

Isolierung von Solasodin-glykosiden aus Pflanzen der GattungSolanum L.Solanum-Alkaloide. XXVIII. Mitteilung

Zusammenfassung Über die alkaloidchemische Untersuchung von 68Solanum-Arten der UntergattungenArchaeosolanum Bitt. undLeptostemonum (Dun.) Bitt. sowie der SektionMorella (Dun.) Bitt. (UntergattungEusolanum Bitt.) wird ausführlich berichtet. Aus 40 Arten konnten Solasodin-glykoside (Solasonin, Solamargin,-Solamargin bzw. -Solanigrin) isoliert werden (Tabelle 1), so daß in Verbindung mit weiteren Literaturbefunden (Tabelle 2) nunmehr 67 solasodinführende Pflanzen bekannt sind.

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Summary A report of the chemical examination of 68Solanum species for alkaloids is given. These species belong to the subgeneraArchaeosolanum Bitt. andLeptostemonum (Dun.) Bitt., as well as to the sectionMorella (Dun.) Bitt. of the subgenusEusolanum Bitt. From 40 species solasodine glycosides (solasonine, solamargine,-solamargine, -solanigrine) have been isolated (table 1). Together with the earlier literature (table 2) 67 solasodine containing plants are known up-to-date.

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68 Solanum, Archaeosolanum Bitt.,Leptostemonum (Dun.) Bitt. Eusolanum Bitt. Morella (Dun.) Bitt. 40 : , ,- - (. 1). (. 2) , 67 , .

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XXVII. Mitteilung: Schreiber, K., Kulturpflanze11, 422–450 (1963), voranstehend.

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Auszug aus der Habilitationsschrift von K. Schreiber, Univ. Jena 1961; vorläufige Mitteilungen: Schreiber (1956, 1957a und 1958a), Schreiber und Mitarb. (1961).     

Ammoniakemissionen aus alternden Pflanzen und bei der Zersetzung von Ernterückständen

Ammonia emissions from senescing plants and during decomposition of crop residues NH₃ emissions from plant stands, measured under simulated environmental conditions with the wind tunnel method, ranged between 0.8 and 1.4% of the N content of the shoot, equivalent to 1.1 to 2.9 kg NH₃-N ha^?1. The highest emissions were observed in faba beans whereas the emissions in winter wheat, spring rape and white mustard were lower. The total NH₃ emissions were not affected by removing a part of the ears (sink reduction), but emissions occurred earlier, as did the plant senescence. This suggests that the NH₃ emissions are closely related to senescence. NH₃ emissions from decomposing crop residues ranged from 0.9 to 3.7% of the N content. The emissions from sugar beet leaves and potato shoots with high water content reached from 8.6 up to 12.6 kg N ha^?1, whereas the emissions from field bean straw with high dry matter and N content were relatively low. (3.1 kg N ha^?1, or 0.9% of the N content). The NH₃ emissions from sugar beet leaves were reduced by 81% by ploughing and 63% by mulching.     

Phytochemische Untersuchungen an Pflanzen der einheimischen Flora und des Gaterslebener Sortiments I. Mitteilung

Zusammenfassung 317 Pflanzenarten aus 73 Familien der einheimischen Flora und des Gaterslebener Sortiments wurden nach einem ausführlich beschriebenen Standardverfahren orientierend auf Alkaloide, Saponine, Triterpene und Sterine untersucht.

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Summary 317 plant species from 73 families of the indigenous flora and of the sortiment in Gatersleben have been preliminarily investigated for alkaloids, saponins, triterpenes, and sterols, using a fully described standard procedure.

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m 317 73 - «», «», «» «». .

     

Phytochemische Untersuchungen an Pflanzen der kubanischen Flora

Zusammenfassung In Zusammenarbeit zwischen der Akademie der Wissenschaften Kubas und der Deutschen Akademie der Wissenschaften zu Berlin wurden 1165 Pflanzenarten aus 149 Familien der kubanischen Flora nach Standardverfahren orientierend auf Alkaloide und Saponine untersucht. Die Ergebnisse sind in Tabelle 2 aufgeführt.

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Phytochemical investigations in plants of the Cuban flora

Summary In cooperation of the Academy of Sciences of Cuba with the German Academy of Sciences at Berlin 1165 species from 149 plant families of the Cuban flora have been preliminarily investigated by standard methods with regard to the occurrence of alkaloids and saponins. The results are compiled in table 2.

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1165 149 . . . 2.

     

Bestimmung der Gehalte an osmotisch wirksamen Substanzen in Pflanzen

Determination of osmotically effective substances in plants A simple method is proposed for the determination of the osmotic potential ψo in leaves of plants grown in saline soils. The ψo-value of the leaf sap is determined from the water content of the fresh leaves and its content of osmotically effective substances (OWS) determined in the ground dry matter of the leaves. The OWS-content is measured cryoscopically in 0,5% acetic acid (30 ml/1g DM). The ψo-value of the leaf sap is obtained by relating the OWS-contents to the leaf water contents of the fresh matter.     

Schwermetall- und Nährelementgehalte von Pflanzen und Bodenproben schwermetallhaltiger Halden im Raum Bleiberg in Kärnten (Österreich) I. krautige Pflanzen

Heavy metal- and nutrient contents of plants and soil samples from metal liferous waste dumps in Bleiberg (Carinthia, Austria). I. herbaceous plants Lead and zinc concentration in the fine fraction (< 0,2 mm) of mine dump material were twice as high as in coarser fraction (2–0,2 mm) (table 1). Due to high metal levels in roots of several mine dump plants (table 3) interactions between plants and soil-microorganisms are assumed. Furthermore root originating exsudates (organic acids) are probably responsible for an increase in heavy metal availability in soil in spite of a general high pH of soil solution. The low mobility of lead within intact plants is caused by a selective affinity of this metal to cell wall pectines. On the other hand a physiological barrier (endodermis/pericycel) in primary roots of these plants is assumed, which partly prevents lead from upward transport into the shoots. Heavy metal compartmentation may be part of a tolerance mechanism diminishing a surplus of toxic metals within plant metabolism.     

Kleine Beobachtungen an Pflanzen aus dem Schaugarten des Instituts I. Ein eindrucksvoller Fall von Chorismus beiLysimachia punctata L.

Summary There is described a hitherto unknown case of Chorismus inLysimachia punctata. L. Some factors influencing the irritability are investigated.

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Lysimachia punctata L.

     

Phytochemische Untersuchungen an Pflanzen der einheimischen Flora und des Gaterslebener Sortiments

Zusammenfassung In Fortführung früherer Untersuchungen wurden weitere 148 Pflanzenarten aus 20 Familien vor allem des Gaterslebener Sortiments nach einem Standardverfahren orientierend auf vorkommende Alkaloide und Saponine geprüft.

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Summary In continuation of former investigations 148 further plant species belonging to 20 families mainly from the collection at Gatersleben have been studied preliminarily for occurring alkaloids and saponins using a standard procedure.

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. 148 20 , . .

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II. Mitteilung: Aurich und Mitarb. (1966).     

Perspektiven für die gentechnische Manipulation der Virusresistenz bei Pflanzen

Die Entwicklung der Gentechnik führte in jüngster Zeit zu Möglichkeiten, ökonomisch interessante Merkmale von Kulturpflanzen zu manipulieren. Hierzu zählt die Krankheitsresistenz und speziell die Virusresistenz. Da das Virushüllprotein eine herausragende Rolle bei der in der Pflanzenvirologie seit langem bekannten Erscheinung der Prämunität zu spielen scheint, wurde durch mehrere Gruppen versucht, die Hüllproteingene verschiedener Pflanzenviren in deren Wirtspflanzen zu transferieren und zur Expression zu bringen. Die transgenen Hüllprotein-exprimierenden Pflanzen erwiesen sich in ähnlicher Weise als virusresistent wie prämunisierte Pflanzen.Eine zweite Strategie zur Beeinflussung der Virusresistenz betrifft die Nutzung des antisense-RNA-Prinzips. Allerdings waren die bisher beschriebenen Effekte immer weitaus geringer als jene im Falle der Hüllproteingen-Expression. Offensichtlich wurden noch nicht die sensitiven Targetsequenzen getroffen, zu denen in erster Linie Ribosomen- und Replikase-Bindungsstellen gehören dürften. Zwei weitere Strategien zur Manipulation der Virusresistenz wurden in letzter Zeit diskutiert und in ersten Modellversuchen geprüft: