The work ofJermoljev andBrčák (1964) showed that the sap of potato leaves contains substances inactivating X, Y and S viruses and that there was an increasing trend in the content of these substances in varieties resistant to these viruses. In further research it was found that potato tubers of varieties which are resistant and susceptible to the viruses contained the same amounts of inactivating substances. Differences in the power of inactivating the viruses evidently appeared in the leaves. Inactivating substances could be removed by boiling, they did not pass through a dialysing membrane and were adsorbed by animal charcoal. On centrifuging sap from potato leaves in a Spinco L ultracentrifuge for 60 min. at 40,000 r.p.m., the inactivating substances remained in the supernatant. When sucrose gradient centrifugation for 60 min. at 24,000 r.p.m. was employed, the inactivating substances remained in the layer of sap and 10% sucrose. Inhibition of the activity of certain enzyme groups did not affect the power of sap to inactivate X virus. Inactivating substances could be isolated chemically. The best method of isolation, however, was fractionation of sap, after ultracentrifugation, on a Sephadex G 50 column, rinsing the column with McIlvaine buffer at pH 6.5. Inactivating substances can be isolated, concentrated and preserved by lyophilization by this method. It is difficult to say precisely to what chemical group the inactivating substances belong. Some reactions indicate that they may be low molecular proteins.

In field experiments, potato varieties with different lengths of the vegetation period were compared. The methods of growth analysis were applied to the evaluation of these experiments. Some important specific features of potato growth had to be taken into account to make the application of the growth analysis successful and to enable valid and reliable results to be obtained.

Many studies have been made on ribosomes both in plant and animal material, on account of their importance in the proteosynthesis of protein. In plant material, studies have been made on the pea by Ts'o andBonner (1956), Ts'o,Bonner andVinograd (1958),Setterfield et al. (1960) andSisakyan et al. (1963). Ribosome from spinach were investigated byLyttleton (1962) andMurakami (1963) and fromClivia byMikulská et al. (1962). As part of a wider study of the mechanism of biosynthesis of nucleic acids in apple trees, we isolated ribosomes from the young green fruit and studied them by means of electron microscopy. Young apples were selected because cell division is very intense at this stage of growth of the apple.

Lucerne plants in the first crop year as well as plants of spring wheat from different sites of the respective experimental plots showed differences in sap exudation from detopped roots or from stumps of the main shoots, reflecting differences in properties of the soil profile. The differences in sap exudation were observed at a time when the plants did not show any visible differences in water availability.
Differences in the water potential deficit of the leaf blades of lucerne plants in the second crop year and of sugar beet plants, related to differences in soil profile properties, were observed in another series of experiments. Sugar beet plants showed a higher physiological lability than lucerne plants.
The sites characterized by unfavourable plant-water-relations usually gave lower yields. The coefficients of variability for the yields of lucerne fresh matter from irrigated plots were three times lower than those for yields from plots without irrigation, influenced by soil heterogeneity.

The effect of the individual leaf blades of spring wheat on the dry matter of stalks, chaff and grain (caryopses), of spikes and total overground part, was studied. In the experimental plants the individual leaf blades were detached according to the scheme given, at the beginning of shooting, (A), at the beginning of earing (B), and at the beginning of flowering (C). The dry matter (fresh weight) of the stalk was least decreased if either the lowest or the uppermost leaf blade was severed during the developmental phase of shooting. The dry as well as the fresh weights of chaff were least affected in those plants where the leaf blade was removed during the developmental phase of flowering. Both the dry and fresh weights of caryopses were least decreased if either the lowest or the uppermost leaf blade was removed during the developmental phase of flowering. The dry weight as well as the relative water content of chaff and ear grains were most decreased following removal of leaf blades during the developmental phase of shooting. The relative water content of chaff, grains and ears was most decreased following removal of developed leaf blades during the developmental phase of earing. It was confirmed that in addition to the photosynthetic activity of leaves the photosynthesis of other parts of the stem system (stalk internodes, ear awns etc.) participated in the production of total dry matter of experimental plants. The photosynthetic activity of leaf blades was particularly high up to the earing phase, while subsequently the photosynthesis of extrafoliar area (stalk internodes and ears) predominated. In spite of this, participation of the total leaf area is very high in the formation of grain dry matter (over 50%), as well as of the total dry matter of plant (over 80%).

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 gegen den molekular aufgelösten organischen Substanzen die die Fehlingslösung reduzieren. Aus diesem Grunde ändert sich die Korrelation zwischen den osmotischen Gesamtwerten und dem Brechungsindex des Saftes in einzelnen Fällen sowohl als auch während der Vegetation. Diese Verhältnisse sind auch in einzelnen Organen der Kartoffelpflanzen verschieden.
Eine bedeutende Herabsetzung der Bodenfeuchtigkeit, dauernd oder zeitlich, verursacht nur eine relativ geringe Erhöhung der osmotischen Gesamtwerte im Vergleiche mit dem Einflusse der Wetteränderungen. Von diesen Ergebnissen folgt, dass die refrektometrische Methode nicht empfindlich genug ist, um den Einfluss der Bodenfeuchtigkeit auf die osmotischen Verhältnisse in der Kartoffelpflanze bestimmen zu können.

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 converted to values corresponding to CO₂ consumption by means of a coefficient: 0.64 mg of dry matter correspond to 1 mg of CO₂, or, 1 mg of dry matter corresponds to 1.56 mg of CO₂.
2. By the gazometric method of measurement of CO₂ consumption, expressed in mg per dm² of double area of leaf, and per hour. For these measurements an infrared analyser was used under the following conditions: open system, constant illumination, temperature (25°C) and air humidity (45%), as well as constant CO₂ content in the air (0.033 vol.%).
The results prove that in most instances both methods afford, from the quantitative point of view, completely corresponding results. As a cause of a few discrepancies met in some experiments, the influence of cutting off of the leaves and uneasily seizable differences in experimental conditions during the exposure of leaves and segments can be considered. Further, the calculated value for the conversion coefficient, i.e. 0.64, must not in every case necessarily correspond to the chemical composition of formed assimilates. The existence of inhibitory influence of accumulated assimilates in leaf segments on the photosynthetic intensity can be excluded.
When the CO₂ consumption of cut off and non-cut leaves of the same experimental plant was measured, no differences could be observed.
The advantages and possibilities of the use of dry matter increment determination in segments as a measure of photosynthetic intensity are discussed.

Es wird auf Grund von Untersuchungen der chloralysierten Wurzeln vonVicia faba das gegenseitige Verhalten von diploiden und polyploiden Zellen und Geweben diskutiert und konkrete Beispiele angeführt. In ganz jungen Wurzeln entwickeln sich die mixoploiden Gewebe friedlich neben einander, wachsen, teilen und differenzieren sich normal. Aber später, besonders wenn die Wurzelspitzen hoch polyploide Gewebe (8 n, 16 n) enthalten, verhalten sich dieselben gegeneinander feindlich. Die polyploiden Sektoren werden abgetrennt und stellen Teilungen ihrer Zellen sowie ihr Streckungswachstum frühzeitig ein. Es kommt zu Gewebespannungen und in den polyploiden Sektoren kommt es zuweilen zur Bildung von rhexigenen Höhlungen. Diese Vorgänge werden schon im Urmeristem vorbereitet und es kommt zur Unterbrechung der normalen Korrelation zwischen den Geweben verschiedener Ploidie. Zur Homoploidisierung kann auch die Reduktion der Chromosomenzahl in polyploiden Zellen beitragen. Die verschieden hoch ploiden Gewebe können von einander durch Metakutisierung oder Verschleimung der sie trennenden Zellwände getrennt werden. Es handelt sich um verschiedene Vorgänge von Autoregulation, welche zur Diploidisierung, seltener zur völligen Polyploidisierung führt. Die Spitzen älterer mixoploider Wurzeln werden auf diese Weise homoploid.

For specific staining of TMV inclusions the cytochemical method of Hršel for the determination of tryptophan containing proteins was used. This method makes it possible to obtain series of sections in contrast to the methods employed up to the present, so that TMV inclusions from any part of the plant can be detected. Staining was tested "in situ" as well as in preparations of isolated virus particles.

The authors investigated the transport and localization of radioactive phosphorus in ownroot and grafted fruit trees. Radioactive phosphate was usually applied to conductive tissues of a thinner root (about 5-8 mm. in diameter). By periodic measurement of the radioactivity of leaves, the localization of radioactive phosphorus was determined in all top branches, and after 2-2.5 months in the four opposite sectors of the root system.
The experimental trees were grafted fruiting apple trees from 6 to 8 year-old (24 trees), own-root 5-6-year-old apple-trees (20 trees), own-root 4-6-year-old plum-trees (4 trees) and grafted 4-6year-old apricot-trees (4 trees). By applying radioactive phosphorus directly to the conductive tissue of roots a high radioactivity of some top branches was achieved, which made it possible to examine the localization of radioactive phosphorus in the tree-top and in tree roots two to three months after application.
As with separated nutrition (Belavin 1958), radioactive phosphorus injected into a thinner root is transported to most top branches, but most of it is localized only in some of them. After a two-month exposure, no marked equilibration of phosphorus concentration is observed to take place among the principal top branches.
It was demonstrated by measuring the radioactivity of 4 opposite sectors of the root system of grafted trees (16 apple and 4 apricot trees) that two months after exposure radioactive phosphorus can also be found in the roots of the sector opposite to that where radioactive phosphorus had been applied.
It was found by autoradiography that radioactive phosphorus is transported by a definite part of trunk xylem. A small portion, however, is transported horizontally through the trunk. No significant difference was found between own-root (no seedlings) and grafted trees with respect to the transport and localization of radioactive phosphorus. After a certain time the tree distributes the radioactive phosphorus throughout the organism, but the half-time of³²P does not permit of tracing its transport from the root system to the entire top during the subsequent vegetation season.

Wenn sich polyploide Zellstrange oder Sektoren an der Peripherie der Wurzelspitze befinden, so können Initialen, durch deren Teilung sie entstanden sind, ihre weitere Teilung einstellen, und die polyploiden Zellenstränge werden durch Verschleimung der Zellmembran abgetrennt. Es ist ein Chorisevorgang, analog der Abschälung der lateralen Haubenschichten. Nur werden in mixoploiden Wurzelspitzen polyploide Zellstränge abgetrennt, die allerdinga auch vereinzelte diploide Zellstränge enthalten können. Der Vorgang kann zur Diploidisierung der Wurzelspitze wesentlich beitragen. Seltener kann eine Wurzelspitze, wenn sie eine starke Majorität von polyploiden Zellen - insbesondere im Plerom - enthält, die peripheren diploiden Initialen aus der weiteren Teilung ausscheiden, wodurch sie polyploid werden kann. Auch solche Chorisevorgänge beweisen, dass die polyploiden Zellen im Verbande von diploiden Zellen als fremde Elemente - wahrscheinlich stofflich - wirken können.

The preparation of MCPA had no formative effect on the shoot apex although it affected the development of lateral buds formed at the sides. As soon as the compound ceased to act the development of the spike continued normally. The formative effect of MCPA is displayed in the structure of the ear by a partial or complete reduction of its internodes. The inhibitory action of the preparation is sometimes reflected in a blockade of the formation of lateral shoots in a part of one or both orthostichs, or else the lateral bud is initiated but does not continue to develop and thus a branchless node is produced. Occasionally, on the contrary, the preparation has a stimulating effect; segments of the lateral stem of the first order are elongated and develop similarly to the main stem which brings about the so-called "branching" of the spike frequently imitating dichotomy. Rich branching occurs on stimulating several lateral stems. A frequently met morphosis is a locally disturbed distichy, and a decussation of orthostichs or their rotating by an angle of less than 90° and a disturbance in the normal course of mesotonic branching. The formation of apparent or true flower whorls formed in consequence to a reduction of the ear internodes or a disturbance of distichy is usually connected with the reduction of individual inflorescence parts, with an increase in the number of inflorescence parts, with their partial or complete cohesion and with a change of their position.

The localization of acid phosphatase was studied by Gomori's newer technique and by azo-coupling methods (α-naphthyl phosphate + fast red ITR or fast garnet GBC; AS or AS D phosphate + fast blue B or fast red violet LB) in the root tips ofVicia faba L. on paraffin sections (fixation with Wolman's acidified ethanol) and on frozen sections (fixation with Baker's calcium formol). Analogous results were obtained on the material treated in various ways and using different methods. In the broad bean, the reaction is most intense in the cap. In the meristematic zone, the primary core is more intensely stained than the ground parenchyma of the central cylinder. The phloem and xylem poles are usually strongly positive. Using both types of methods on Wolman fixed paraffin embedded material, essentially the same localization of acid phosphatase was found in the root tips ofRicinus communis L.,Lupinus luteus L.,Sinapis alba L.,Allium cepa L. as in the broad bean. InZea mays L. the rhizodermis and the hypodermic layers of the primary core were found to be most active. On sections of Wolman fixed paraffin embedded broad bean the most intense reaction was observed at pH 4.2-4.8. In the same material, both the azo-coupling and the Gomori reaction is inhibited by 10⁼² M NaF, but 10^-2 M tartaric acid only inhibits the Gomori reaction.

A study was made of the influence of accentuators (phenol, aniline) and pH on the stainability of vegetable tissue (roots ofAllium cepa L.) with light green and methylene blue with reference to the theory of the electrostatic basis of staining. - The results obtained on the whole confirmPischinger's theory of the electrostatic basis of staining for light green only, but with methylene blue the situation was found to be much more complicated. Only the alkalization of a watery solution of methylene blue increases its staining ability, whereas the accentuators markedly disturb staining. Prischinge's theory is thus not of general validity, but applies only to one factor of this complicated process. Electrostatic influences acting on staining ability are not so important as other factors in this complicated process in some dyes.

Wurzelspitzen von Pisum sativum wurden zwischen zwei konvergenten Gläschen gequetscht und der weiteren Entwicklung überlassen. Sohon nach 48 Stunden waren alle um das Plerom herum entstandenen Risse durch kallos vergrösserte Perikambiumzellen dort, wo das Perikambium differenziert war, gefüllt. Soweit das Plerom in Verbindung mit der Initialzone verbunden blieb, wuchs es gleichmässig mit dem Periblem weiter. Wurde es jedoch von den Initialen abgerissen, so hörte es auf zu wachsen. Wenn die Spitze des Pleroms abgerissen wurde, differenzierte sie sich nicht weiter, sondern verblieb als schwach wucherndes Gewebehöckerehen ohne Differenzierung. Die grösste prospektive Potenz besitzt das Plerom, die geringste das Periblem. Sofern das Plerom mit der Initialzone in Verbindung bleibt, beginnt die Spitze am dritten oder vierten Tage normal weiter zu wachsen, wurde es jedoch beim Quetschen von den Initialen abgerissen, so entstehen an der Keimwurzel Seitenwurzeln. Zur völligen Isolierung lebender Zellen und ihre Mischung kommt es in den gequetschten Wurzelspitzen nicht.

It was shown that in the horse bean seeds (Vicia faba) the cotyledon proteins are identical, from an immunochemical standpoint, with those coming from the extracotyledon parts (radicle, young stem and embryonal leaves, in totality). However, the beginning of the germinative process exerts a different influence on the antigenic properties of the constitutive parts of the seed. The modification of the antigenic structure in cotyledons takes place slowly. On the contrary, in the extracotyledon parts a rapid decrease was found of the number of antigens present in the non-germinated seed. As the organs become differentiated, the hydrolysis process of these antigens goes on until their almost complete exhaustion. However, it appears that three of the initial antigens remain in the newly arisen leaves. Besides these antigens there are also specific-organ antigens which appear as the respective organs become morphologically differentiated. It was found that in the growing leaves the process of photosynthesis induces the synthesis of antigens characteristic for the mature leaves. The organ-specific antigens occur during plant development at the time when the leaf attains the morphological structure and the functional specialization characteristic for maturity.

The stomata closure in Begonia semperflorens by alpha - rays was studied. Complete closure of the stomata was used as indication of the reaction. The minimal doses with significant results was 2-2. 10⁶ α. cm^-2, the maximum at the dose of approx. 9. 10⁶ α. cm^-2 was found.

Vorkommen und Erscheinungsformen von Kallose wurden an den Zystolithen von 23 Ficus. und 16 weiteren Pflanzenarten aus den Familien der Moraceae, Acanthaceae, Combretaceae, Oleaceae und Urtieaceae untersucht. Zystolithen-Kallose wurde im wesentlichen nur bei der Gattung Ficus gefunden.
In der Zystolithen-Entwicklung vonFicus elastica bestehen die zuerst angelegten Teile des Stieles aus Zellulose. Bei einer Länge von etwa 30 μ werden am Stiel erste Kalloseabscheidungen in Form dünner Überzüge am freien Ende gebildet. In der Folge kommt es häufig zu schichtweise alternierender Anlagerung von Zellulose und Kallose, die neben- und miteinander das Mittelstück des Zystolithen aufbauen. Die äusseren Teile der entkalkten Zystolithen werden stets von einem Mantel aus überwiegend reiner Kallose gebildet.
Das Problem einer Funktion der Zystolithen-Kallose wird diskutiert. Kallose wird-übereinstimmend mit früher vorgebrachten Auffassungen-als Begleiterscheinung des sich während der Entwicklung der Löthozysten verändernden Zellwand-Baustoffwechsels gedeutet.

Soyabean extract contains an activator which passes through parchment paper. The increase in the activity of a mixture of urease and papain with increasing amount of papain in the mixture is due to the increase in the non-dialysable fraction of papain.

The work is concerned with the question of the effect of humic acids on the biological action of agropyrene, the effective substance from the rootstock of Agropyron repens (L.) P. BEAUV. The test organism was the alga Scenedesmus obliquus (TURP.) KRÜGER, cultivated in
mineral solution. The basic biological test was the determination of the number and size of the cells of this alga. It was found that the way in which agropyrene acts on combined application with humus acids depends on which humus fraction is used. It can display a synergic action if humic acid is used, since this substance probably facilitates the penetration of agropyrene into the cells. On the other hand, fulvic acid counteracts the activity of agropyrene and this most probably by mutual binding and blocking of active groups and links.

Bei der Untersuchung von Zellen des Keimsacks von Lilium und des Vegetations-punktes von Triticum wurden plasmatische Einstülpungen und Elemente im Innern der Vakuolen gefunden. Die Plasmaelemente entstehen offenbar durch Abschnüren der Einstülpungen. Die Ursache ihres Entstehens und ihre Bedeutung für die pflanzliche Zelle wurden diskutiert.

Bei den submersen WasserpflanzenPotamogeton perfoliatus L. undP. lucens L. wurde die Anzahl der Epidermalzellen pro Blattflächeneinheit (mit Hilfe der Abdruckmethode) und die Dichte der Blattnervatur (curvimetrisch bei in Lacto-Phenol aufgehellten Blatteilen gemessen) bei oberen, mittleren und unteren Blättern, deren Blattbasis, -mitte, -rand und -spitze untersucht wurden, festgestellt.
Bei beiden Laichkrautarten sind die Unterschiede in der Anzahl der Epidermalzellen pro Blattflächeneinheit bei Blättern verschiedener Insertionshöhe nur am Anfang der Vegetationsperiodo statistisch gesichert, später bei ausgewachsenen Blättern nicht mehr. Die Unterschiede zwischen verschiedenen Blattstellen sind meist nicht signifikant. Die Unterschiede zwischen der Ober- und Unterseite des Blattes sind wohl beiP. perfoliatus, aber beiP. lucens nicht signifikant. Die Unterschiede in der Dichte der Blattnervatur zwischen Blättern verschiedener Insertionshöhe sind mit Ausnahme des Anfanges der Vegetationsperiode und einiger Unterschiede zwischen den mittleren und oberen Blättern beiP. perfoliatus auch nicht statistisch gesichert. Die Unterschiede zwischen verschiedenen Blattstellen sind bei beiden Arten statistisch hoch gesichert.
Dort wo der Einfluss der Wasserumgebung nicht durch die Einwirkung anderer Umwelt-faktoren kompliziert wird, wurde bei erwachsenen Pflanzen von P. perfoliatus und P. lucens nur ein unbedeutender oder kein xeromorphischer nach oben gerichteter Gradient bei den angeführten Merkmalen festgestellt.

A conductometric apparatus for determining the photosynthetic rate suitable predominantly for field measurements is described. In contrast with the hitherto described and applied instruments 3 samples of air can be analyzed here simultaneously, the data are temperature-independent and the entire electronic part of the apparatus is transistorized. The absorbers (300×30×30mm.) and the leaf chambers (140×100×10 mm.) are made of plexiglass. The membrane pump is hand-operated by means of a crank. The conductivity of the absorption solution (0.02N-KOH+0.5% isoamylalcohol+saponin) is measured in a special measuring cell into which the solution is transferred from the individual absorbers. The error of the photosynthetic rate determination is about 10-20% of the value obtained for intensities of 10-20 mg. CO₂ dm.-²h.-¹.

On incubation of the callus tissue ofDaucus carota L. in solutions of glucose-6-¹⁴C and -1-¹⁴C the distribution of radioactivity in the molecule of endogenous glucose will change and the ratio of activities of liberated¹⁴CO₂ (C₆/C₁) will rise The limits of possible changes of specific activity of¹⁴CO₂ and of the C₆/C₁ ratio were calculated with respect to the observed randomization and it was shown that the mutual exchange of carbon atoms in the molecules is not the decisive cause of the rise of the ratio.
The specific radioactivity of¹⁴C in CO₂ is as much as 12 times higher than that of endogenous glucose and fructose and about twice as high as the theoretical maximum. This might indicate that in addition to the cytoplasmic fraction of glucose the callus cells contain a fraction of low metabolic activity, most likely in the vacuoles, that could account for some of the increase of the C₆/C₁ value.
The main reason for the changes in the C₆/C₁ ratio is envisaged in the establishment of isotopic equilibrium between the pentose cycle and glycolysis and other metabolic systems, in particular via triose phosphates, the radioactivity of which can greatly affect the C₆/C₁ ratio, as was shown in a model experiment.

This work is an examination of the possibilities of the application of microchemical iodine reactions in mycology, of their importance in phylogenesis, and of their practical application for the distinguishing of fungi or moulds from the tissue of the host plant. The best results were obtained with the reaction of chlor-zinc-iodine, then with chlor-calcium-iodine, and with iodophosphoric acid. Reactions were tested with different representatives of developmental groups of fungi and with pure cellulose (cotton-plant fibres) for the comparison of the quantity of cellulose, chitin, or of other substances in the cell-walls. BesidesOomycetes, whose cell-wall consists of cellulose, signs of a "cellulose" reaction appear also inZygomycetes. The species of the orderProtomycetales show a cellulose reaction, which fact also speaks rather for the ranking of this group in the division ofOomycetes. However, the microchemical reaction should not be overestimated, as its colour degree and intensity are influenced by the age of the mycelium of the fungi, by the thickness and physical properties of the cell-wall, and by the presence or absence of the cellular content.

The linkage of barley between rough versus smooth awns and long versus short rachilla hair was influenced by different amounts of Ca and Mg. It was found, that not only lack, but also excess causes an increase of the recombination frequency as against the control.