Über Verhinderung der Polyspermie bei Gagea lutea Schult

Bohumil Němec

Biologia plantarum 7:81-85, 1965 | DOI: 10.1007/BF02920622

Es wurde nachgeforscht, ob es vielleicht in den Blüten vonGagea lutea Vorrichtungen gibt, welche eine Polyspermie, d. h. eine Befruchtung durch mehrere Pollenschläuche zu verhindern vermögen. Das Peristom des Eichens liegt vor der Befruchtung der Fruchtknotenwand da an, wohin der Pollenschlauch durch das drüsige Leitgewebe geführt wird und in die Mikropyle eindringt. Wenn nachher der Befruchtungsvorgang vollbracht wird, so verlängert sich bei den meisten Eichen ihr Funiculus an seiner Basis, wodurch das Peristom von der Fruchtknotenwand entfernt und in die Mikropyle kein Pollenschlauch mehr geführt wird. Auch ist jetzt die Mikropyle durch den...

Adaptability in enzymes

Krishna Bahadur, Indra Saxena

Biologia plantarum 7:86-92, 1965 | DOI: 10.1007/BF02920623

In studying inhibitors and activators of enzymes it has often been found that inhibitors act as activators when in very low concentrations and that certain activators (in suitable concentrations) show inhibition. Similar results were obtained in the present work in studying urease from soya bean in the presence of lead acetate. Lead acetate is normally an inhibitor of urease. It was found, however, that in small concentrations of lead acetate increase in the activity of urease occurs. On prolonging the time of the reaction inhibition develops and still later increased enzymatic activity again occurs. The results were elaborated statistically and are...

Reactions and resistance ofChenopodium species to tobacco mosaic virus

Jaroslav Brčák

Biologia plantarum 7:93, 1965 | DOI: 10.1007/BF02920624

Chenopodium species react on infection with tobacco mosaic virus by the formation of chlorotic or necrotic lesions and later by the abscission of infected leaves. A transition of local infection into the stem has been observed exceptionally inChenopodium quinoa, C. hybridum, andC. rubrum, but no systemic infection of the leaves followed. Systemic infection was demonstrated only inC. polyspermum andC. murale. The recovery of new sprouts was demonstrated in C.murale in the late chronic phase of infection.

Comparison of results of photosynthetic intensity measurements in cereal leaves as determined by the dry weight increase or by the gazometric method

Lubomír Nátr, Ivana Kousalová

Biologia plantarum 7:98, 1965 | DOI: 10.1007/BF02920625

In this paper the values of photosynthetic intensities of spring barley leaves measured by two different methods were compared:1. By the gravimetric method of Bartoš, Kubín and Šetlík (1960), modified by Nátr and Špidla (1961) for cereal leaves. Segments were laid on a special support and illuminated for several hours from a constant source of light. The tissues were completely saturated with water, the temperature and the flow-rate of the air were also constant. Photosynthetic intensity is expressed as the increase of dry matter in segments in mg per dm² of a double area of leaf, and per hour. The weight increase of the dry matter is...

The effect of reversion and duplication of leaf disks on the accuracy of photosynthesis determination by the dry weight method

Zdenêk Šesták, Jitka Vodová

Biologia plantarum 7:109, 1965 | DOI: 10.1007/BF02920626

Experiments with sunflower and fodder cabbage showed that reversion of the leaf disks lower side upwards (towards the radiation source) decreased the photosynthetic rate by as much as 26% both at full (2. 10⁵ erg. cm^-2. sec.^-1) and half density of irradiation. On placing two disks one on another the photosynthetic rate was decreased in the upper disk in a similar way as it was on reversion even if it were placed in the normal position (upper side upwards). But assimilation in the lower disk was only a fraction (0-40%) of that of the upper disk and in thick leaves was within the limits of the compensation point. The...

Der Mechanismus der Vitalfärbung des Zellsaftes vonNitella sp. mittels Neutralrot

Marie N. Končalová

Biologia plantarum 7:116-128, 1965 | DOI: 10.1007/BF02920627

Mittels unmittelbarer Analyse auf Grund chemischer Reaktionen, Chromatographie und elektronenmikroskopischer Diffraktion wurden beiNitella sp. im Zellsaft drei organische Säuren festgestellt: Weinsäure, Zitronensäure und eine Säure, deren Identifizierung bisher nicht gelungen ist. Weiter wurde festgestellt, dassNitella-Zellen, die einen langsameren Metabolismus haben oder ein höheres pH des Zellsaftes aufweisen, Neutralrot in ihren Vakuolen viel langsamer ansammeln als Zellen unter normalen Bedingungen. Eine Blockierung der Atemenzyme durch Kyanwasserst off hat aber keinen Einfluss auf die Geschwindigkeit der Aufnahme dieses Farbstoffes...

Root-shoot ratio in irrigated plants

Miroslav Penka

Biologia plantarum 7:129, 1965 | DOI: 10.1007/BF02920628

Relationship between roots and shoots ofPimpinella saxifraga L.,Petroselinum hortense Hoffm.,Lactuca sativa L., andBeta vulgaris subsp.esculenta (Salisbury) Gürke var.altissima Roessig was studied in irrigated and non-irrigated plants. It was found that the irrigation water did not influence distinctly the root-shoot ratio of the experimental plants. From the statical point of view, this relationship could be expressed by the following quantitative ratios for irrigated and non-irrigated plants: 3∶1 forPimpinella saxifraga L., 2∶1 forPetroselinum hortense Hoffm., 9∶1 forLactuca...

The classic Golgi apparatus and vacuoles

Ivan Hršel

Biologia plantarum 7:136-145, 1965 | DOI: 10.1007/BF02920629

The dense vacuoles, considered to be the classic Golgi apparatus in the root meristem ofFagopyrum, were studied by the following methods: 1. Impregnation methods for the demonstration of the Golgi apparatus, 2. cytochemical methods, 3. electron microscopic methods in the light microscope and 4. the electron microscope. A comparison was made with the classic Golgi apparatus in animal cells in the light and electron microscope.Dense vacuoles inFagopyrum and also evidently in other plants, were taken for the classic Golgi apparatus on account of their morphological similarity to the Golgi apparatus in animal cells on impregnation with...

Zur Problematik der Verlässlichkeit der refraktometrischen Methode für die Indikation des Wasserbedarfes der Kartoffeln

Josef Nečas

Biologia plantarum 7:146, 1965 | DOI: 10.1007/BF02920630

Bei Erforschung des Einflusses der herabgesetzten Bodenfeuchtigkeit auf die osmotischen Verhältnisse im Zellsafte der Kartoffelpflanzen wurde die refraktometrische Methode für die Bestimmung deren osmotischen Zustandes bewertet. Es zeigte sich die Notwendigkeit eine gewisse Vorsicht bei ihrer Anwendung zu bewahren. Die Elektrolyte, die von der refraktometrischen Methode verhältnismässig weniger erfasst werden, haben ein wessentliches Übergewicht in der Bildung der osmotischen Gesamtwerte des Zellsaftes der Kartoffeln über den anderen Hauptteil, nämlich die Fehlingslösung reduzierende Substanzen. Sie haben auch oft einen entgegengesetzten Vegetationstrend...

Decomposition of beech wood and holocelulose by mycelium-free culture medium

Roman Sopko, Lubomír Jurášek

Biologia plantarum 7:158, 1965 | DOI: 10.1007/BF02920631

The purpose of this paper is to compare some results achieved in the enzymatic decay of beech wood meal and holocelulose affected by mycelium-free culture filtrate of wood destroying fungusSchizophyllum commune. The fungus had been obtained from the Institute of Plant Physiology, J. E. Purkyně University, Brno.

The influence of EDTA on the mutagenic activity of ethyl methanesulphonate (EMS) inArabidopsis thaliana

Tomáš Gichner, Jiří Velemínský

Biologia plantarum 7:162-164, 1965 | DOI: 10.1007/BF02920632