Identification trials were carried out to determine a virus-like disease of Impatiene parviflora DC. Two forms of foliar symptoms were observed:
a) Chiorotie and necrotic areas sometimes fallen out, leaving the leaves "shot holed";
b) milder foliar symptoms consisting of slight greenish yellow areas and spots often scarcely visible except by transmitted light.
Results of experiments with the first form of the disease demonstrate the identity of the causal virus with cabbage black ringspot virus; the second type of symptoms was caused by a Strain of cucumber mosaic virus inducing unusual symptoms in tobacco plants.

In der Arbeit wurde die Möglichkeit der allelopathischen Beeinflussung von Folgepflanzen durch Vorkulturen bei der Kultivierung in abgestuften Zeitintervallen nacheinander auf demselben Bodensubstrat bei folgenden Konabinationen von Pflanzen untersucht: Mohn - ZuckerrÜbe, Ackersenf - Gerste, Hanf - Korn, Zwiebel - Raps. Die Versuche wurden in Gefassen mit Komposterde, welche im Laufe des Versuches im Garten in den Boden eingelassen worden waren, durchgefÜhrt. Es wurde das Wachstum der Vorkulturen und der Folgepflanzen in den ersten Wachstumsphasen untersucht. Von der Aussaat der Folgepflanzen wurde in Bodenproben die Respirationsintensität, die aktuelle Feuchtigkeit und der Gehalt an physiologisch zugänglichem Stickstoff, Phosphor und Kalium bestimmt.
In allen untersuchten Kombinationen waren die Folgepflanzen durch die Kultivierung der Vorkultur und die nachfolgende Lagerung des Bodensubstrates beeinflusst. Die Wachstumsveränderungen der Folgepflanzen standen teilweise mit dem Gehalt an physiologisch zugänglichem Stickstoff im Bodensubstrat in Korrelation. Aus dem Charakter der Wachstumsveränderungen ging jedoch auch klar hervor, dass sich hier auch allelopathische Faktoren beteiligt haben. Sehr inhibierend wirkte Mohn auf ZuckerrÜbe, weniger inhibierend wirkte Ackersenf auf Gerste und Zwiebel auf Raps. Die Wirkung von Hanf auf Korn zeigte mit der Lagerungsdauer des Bodensubstrates zusammenhängende Veränderungen.
Veränderungen im Gehalt an physiologisch zugänglichem Stickstoff, Phosphor und Kalium im Versuchsbodensubstrat entsprachen nicht der Menge der angewachsenen Pflanzenmasse der Vorkultur, was durch die angewendete Kultivierungsmethode bedingt war. Die verhältnismässig schnelle Erneuerung der durch die Vorkultur erschöpften Nitrate im Versuchsbodensubstrat in der Zeit der Bodenlagerung wurde wahrscheinlich durch Nitrifikationsprozesse verursacht.
Den festgestellten Veränderungen der Respirationsintensität des Versuchsbodensubstrates nach kann sich auch die Bodenmikroflora an der allelopathischen Beinflussung beteiligen.

1. A number of varieties of cultivated juteGorchorus oHtorius L. andG. capsularis L. were tested in artificially created drought, waterlogging and control conditions.
2. The number of lateral roots with secondary growth was reduced to the minimum inC. capsularis under waterlogged conditions, but the weight of the roots was increased to the maximum, due to the production of numerous spongy and fibrous roots.C. olitorius suffered in both the characters under similar environment and failed to produce fibrous and spongy root. This species gained in root weight and lateral root number in drought under whichC. capsularis suffered in these two characters. These were the main features of adaptation of these two species.
3. Within species among varieties the variations regarding these two characters have been found to be controlled by genotypes. Lateral root number within both the species has been found to be a more strongly heritable character than root weight. Expected genetic advance has revealed the scope of selection for lateral root number.
4. While variations among thé varieties within species have been interpreted as an expression of phenotypic flexibility, the variation between species is an expression of phenotypic plasticity, which is an outcome of basically physiological mechanisms.Corchorus capsularis L. andC. olitorius L. are two cultivated jute species. The most striking distinction between these two species hitherto known is that whileG. capsularis can withstand waterlogging successfully,C. olitorius cannot. This general view formed the basis of testing these species under artificially created environmental stresses to find out the general components contributing to this specific difference.

The redox potential of wilted leaves of cereal seedlings grown in a greenhouse was higher than in the fresh leaves. However, the redox potential in the wilted leaves of plants during the stem extension was lower than in fresh leaves. The reaction of barley leaves var. Japan 2003, which belongs to the dundar-beyi Zhuk.-group, differed materially from the European cereal varieties. The cause of the change of redox potential is discussed in connection with the ontogeny of cereals and resistance against obligate parasites.

Root formation in the etiolated pea stem sections and inhibition of this process is described in the present paper. Sodium fluoride, iodoacetic acid, norvaline, phenylserine, 5-bromuracil and 2-thiouracil did not inhibit the root formation completely. Complete inhibition, however, was observed after treatment of pea stem sections by kinetin, ethionine and chloramphenicol (5 X 10^-5 M, 1 x 10^-2 M, and 1 x 10^-2 16 hours after sectioning). The concentration of kinetin which produced complete inhibition of root formation simultaneously stimulated the growth of the lateral buds.
Root formation under the conditions described below can be divided into two stages. The first stage 64 hours from the beginning of the experiment, the second stage 64 hours later. Further, the first stage includes the formation of the meristematic cells in the pericycle areas. In the second stage are included the growth of roots and differentiation of root-tissues. Roots were formed, first of all, in the short vertical region of the sections near to the basal buds. Secondary xylem formation was also observed during the cultivation of the sections. This process was stimulated by kinetin.

Immediate response of water uptake by intact plants ofPisum sativum L. to the introduction of high concentrations of α-naphtaleneacetic acid (NAA), β-indoleacetic acid (IAA), 2,4-dichlorophenoxyacetic acid (2,4-D), 2-methyl-4-chlorophenoxyacetic acid (MCPA), coumarin was determined by a series of potometric measurements. Growth substances were present in the root medium in two concentrations: 10^-3 m and 10^-2 m; the concentration of coumarin was 5. 10^-4 m and that of EDTA was 10^-3 m.
The response of water uptake to the application of the growth substances and coumarin was always negative. EDTA did not affect immediately the intensity of water uptake. The inhibition of water uptake brought about by the growth substances takes place immediately. Coumarin causes slow, progressively increasing inhibition of water uptake. A coincidence was found as to the time course of the changes in the water uptake intensity in the presence of high concentrations of growth substances and coumarin in the root medium with the time course of changes of transpiration intensity, found under analogous conditions by Allerup (1964). This may be considered as another justification for the hypothesis, according to which the rapid changes of transpiration intensity in the presence of high concentrations of growth substances in the root medium are caused by rapid changes of the intensity of water uptake.

The differentiation of tissues is closely connected with the proteosynthesis. One can therfore assume that tissues with different types of cell growth (meristematic or elongation growth) and with different degrees of differentiation are different in their protein composition. In order to compare the protein composition of different plant organs, the method of disc electrophoresis on a polyacrylamide gel has been used by some authors. As compared with other methods used up to now, e. g. isolating proteins on DEAE cellulose or in Sephadex, this method does not need so much material and its resolution ability seems to be higher. It is also quicker and enables the study of several samples simultaneously. Its disadvantage is that proteins can be identified mainly by means of Rf and their quantity, measured from the intensity of staining of individual fractions in the gel, which may be misleading due to different sorption capacity of different proteins (FričFričová 1967). None the less, it is good for comparison of protein composition of individual parts of the plant body.
Different methods have been used to compare protein composition of individual growth zones in roots.Barsky,Ivanov andPushakova (1965) used luminiscence microscopy and found that in maize roots it is not possible to find substantial differences by this method.Morgan andReith (1954) arrived at similar conclusions. On the other hand,Steward et al. (1965) andMorris (1966) found qualitative differences in protein composition of different parts of pea roots using acrylamide electrophoresis. The results of the last named authors show considerable discrepancies in details, due perhaps to a different method of extraction (buffer, pH, purifying method).
We have used acrylamide gel electrophoresis for investigating proteins in precisely defined growth zones of theVicia faba root.

White-rot fungi causing the white decay of wood, secrete polyphenol oxidase type enzymes which catalyze the oxidation of diphenols to quinones. If the substrate also contains amino acids, they can be oxidized secondarily to a red pigment, the intensity of which depends on the activity of oxidation oxoenzymes. This finding was used for devising a quick test to demonstrate the oxidases secreted into the cultivation medium by wood-rotting fungi. As substrates we used hydroquinone and glycine. We tested a total of 89 species and 131 strains of wood-rotting fungi. Simultaneously, we compared the newly devised test with the most common test for the detection of polyphenoloxidases, with the guaiacol test. It follows from the results that the new test, in which the intensity of the red colour was estimated colorimetrically, permits to divide the wood-rotting fungi into two groups, the positively and the negatively reacting ones. This division does not fully coincide with that obtained by means of the guaiacol test.

Coleoptile and root tips ofTriticum aestivum cv. Arnej 624 and those ofAvena sativa cv. Victory (Svalöf) as well as dry excised embryos ofTriticum aestivum cv. Rival (Svalöf) and those ofArachis hypogaea cv. 34 3A. H. were cultivated in media containing various concentrations of sucrose and growth regulators, like ascorbic acid, indole-3-acetic acid and gibberellin. Growth, differentiation and water uptake of the various explants were determined at regular time intervals. Further, the concentration of the endogenous ascorbic acid in mg./g. fresh weight, as well as the amount of this growth regulator utilized as per cent of the total were determined.
Although all the three growth regulators promote growth in the explants, their effect is best felt when sucrose of a higher concentration (1.0 per cent) is added to the medium. In fact, the response to 1.0 per cent sucrose is sometimes as good as a combination of a growth regulator with sucrose, especially in the case of root explants.
The results clearly indicate that the biosynthesis of ascorbic acid in the explants is catalyzed by the addition of indole-3-acetic acid as well as gibberellin. Simultaneously, the utilization of ascorbic acid is also appreciably increased by the presence of these growth regulators.
Addition of 1.0 per cent sucrose to the medium containing the above mentioned growth regulators augments to a considerable extent not only the concentration of ascorbic acid, but also steps up its utilization. Enhancement of ascorbic acid as well as its increased utilization are correlated with rapid imbibition of water, growth and differentiation.
The role of ascorbic acid in growth is discussed; and on the basis of the data presented here it is postulated that: (1) auxin and gibberellin function in the growth process by catalyzing the biosynthesis of ascorbic acid; and (2) that ascorbic acid not only participates in activation of various enzyme systems, but also stimulates the production of adenosine triphosphate by acting as an electron donor in photosynthetic phosphorylation as well as oxidative phosphorylation; (3) that the above action of ascorbic acid creates a favourable redox balance for synthesis of nucleic acids, proteins, enzymeproteins, and cell-wall constituents, thus enabling the processes of cell division and enlargement to proceed at a fast rate; and (4) that the relative rates of cell division and cell enlargement as well as "ageing" will determine the pattern of plant development.

Schizaphis graminum (Rondani) is proved to be an additional vector of maize mosaic virus (MMV). The pH range for the infectivity of the virus in extracted juice is found to be from 4.4 to 9.0, the optimum being 5.6 to 7.2. Effect of certain chemicals on the virusin vitro has also been studied. Cross protection between MMV and Sugar-cane mosaic virus (SMV) indicated positive results. It has been concluded on the basis of similar physical properties, tolerance towards certain chemicals, host range, symptomatology, aphid vectors and positive immunological tests, that MMV and SMV are related viruses.

The paper deals with the resaturation of water saturation deficit in fourStipa species tested under various ecological conditions. Attention is paid to the relations between the saturation and oversaturation types of curves, on the one hand, and soil moisture on the other. The oversaturation type appears in plants well supplied with soil moisture. The explanation of this phenomenon is discussed.

We compared the occurrence of peroxidase isozymes in protein extract from roots, hypocotyls and cotyledons of 10 dayCucurbita pepo plants and of adult leaves of older plants by means of starch gel and polyacryl amide gel electrophoresis. We reached maximum discrimination by means of starch gel electrophoresis: 11 zones were ascertained on the cathode side and about 2 on the anode side at pH 3.1. Two zones occurred regularly:A and (the latter having a more complicated structure). ZoneD is characteristic for roots, but is it suppressed and seldom found with leaves. On the other hand zonesC ₁ andC ₂ are clearly discernible with leaves but are substantially less evident with roots. The character of anodic zoneZ is discussed later in this paper.

The cytoplasmic components of broad bean (Vicia faba L.) root tip cells were studied light- and electronmicroscopically. Using a light microscope, differences were revealed between cells from the cortex and from the central cylinder. For electron microscope studies the cells near the boundary between the mentioned parts of the root tip were selected at a distance of about 2 mm from the initials. The orientation of objects during embedding made possible fairly accurate localization. No peculiar, strikingly osmiophillic bodies were seen, which could be identified without doubt as osmiophillic platelets. It follows that some of the current cytoplasmic components, perhaps more or less altered were described as osmiophillic platelets. After fixation with KMnO₄, in which case the electronmicrographs are most instructive, the leucoplasts show several inclusions, mostly only partially limited against the matrix; it is not clear whether the true membrane is concerned here. The origin of intravacuolar membraneous formations is discussed.

The transmission of the carrot mosaic virus (CMV) by the aphidsAcyrtJiosiphon pisum HARRÍS,Cavariela aegopodii SCOP, andMyzus persicae SULZ was proved experimentally. It was observed simultaneously that CMV has a non-persistent character. CMV can be transmitted already 2 min after acquisition feeding by the aphidsMyzus persicae SDLZ andCavariella aego-podii Scop. When the time of acquisition feeding is prolonged to 4 min, CMV is transmitted also by aphidAcyrthosiphon pisum HAREÍs. The host range of the investigated virus wasalso determined and its transmission to 8 plant species, belonging to 4 families, was achieved. On the basis of studies of the vector virus relationship and of the host range, further proof was given for the different character of the Australian Carrot motley dwarf virus, theApivm virus 1 Roland and CMV. The experiments showed that preliminary starving of the aphids for 1 h increases their ability to transmit the virus by 3-3%.

Durch die Erforschung des Verlaufes der Winterruhe im Zeitabschnitt von 1954 bis 1959 konnten wir Ergebnisse erzielen, auf Grund derer man behaupten kann, dass die Aprikose unter den Bedingungen der Südslowakei im Verlauf des Monates August ins Stadium der echten Winterruhe eintritt und diese im Verlauf des Monates Dezember beendet. Unter diesen Bedingungen braucht die Aprikose 1200-1300 Stunden Temperaturen unter 6°C, um die echte Winterruhe zu überwinden. Von zwölf Aprikosensorten, die wir durch Abschneiden und Versetzen der Äste in Zimmertemperatur auf die Dauer der Winterruhe geprüft haben, trieb die Sorte "Ananas" im Vergleich mit den übrigen Sorten regelmässig um 6-10 Tage später aus. Diese Tatsache ist auch mit den praktischen Erfahrungen im Einklang, die bei der Haltung von Aprikosenbäumen unter den normalen ökologischen Bedingungen der gemässigten Zone gesammelt wurden, unter denen die angeführte Sorte im Vergleich mit den übrigen Sorten um 3-6 Tage später blüht. Nach der Ansicht des Verfassers kann man nicht von einer direkten Abhängigkeit zwischen der Dauer der echten Winterruhe und der Frostfestigkeit der Aprikose sprechen. Die Pflanze ist nach Beendigung der echten Winterruhe von Temperaturbedingungen in starkem Masse abhängig. Unter günstigen Temperaturbedingungen (ohne Temperaturschwankungen) sind die Apriklsenbäume fähig, Frösten bis zu -20°C zu widerstehen.

Mit Hilfe eines volumetrischen Mikrorespirometers (nachZurzycki) wurde die Atmungsintensität an Vegetationskegoln von Winterweizen in drei, den Übergang vom vegetativen zum generativen Zustand bezeichnenden Etappen der Organogenese bestimmt. Die Atmungsintensität bezogen auf einen Vegetationskegel, das Trockengewicht oder den Proteinstickstoff war in der 2. und 3. Etappe der Organogenese niedrig, in der 4. Etappe höher. Die festgestellten Unterschiede sind wahrscheinlich mit den anatomischen Veränderungen, die in den Vegetationskegeln im Laufe des Differenzierungsprozesses stattfinden, verbunden. Dies betrifft besonders den steigenden Anteil der sich streckenden zentralen Markzellen und die mit dem Beginn der 4. Etappe verbundene Differenzierung der Ährchenprimordien. Man kann annehmen, dass die Änderungen der Atmungsintensität mit der Induktion der Blühreife nur indirekt zusammenhängen und eher mit dem anatomischen Umbau des Apikalmeristems im Laufe der Ontogenese verbunden sind.

Antiserum against the X virus inhibitor was prepared by immunizing rabbits with the inhibitor antigen obtained in two ways: (1) ultracentrifugation of potato leaf sap in a Spinco L for 1 h at 40000 r.p.m., (2) ultracentrifugation and fractionation of the sap on a Sephadex G-50 column.
The antiserum is specific against the inhibitor protein and does not react with other proteins of the plant or with the X virus. Direct serological analysis makes it possible to determine in the potato leaf sap either the presence or the absence of the X virus inhibitor, to follow the degree of inactivation of the inhibitor due to various factors and finally to determine the relative amount of inhibitor in various cultivars and hybrids of the potato plant.
A detailed description of the method for determining the amount of the X virus inhibitor in the leaf sap from various potato cultivars and hybrids is given. The amount of sap required for analysis is very small (1-2 ml) which makes it possible to carry out analyses on individual plants. The duration of analysis is about 1 h.
The determination of the inhibitor amount in the potato leaf sap agrees with that of the inhibitory potency of the cell sap in 87.7% cases.

Investigations were made on the effect of exposing barley seeds to gamma-radiation (5-40 kR), alone and in combination with the application of zinc (soaking the seeds in solutions containing 5.10^-5-5.10^-1% Zn for 12 hours before sowing) on growth and on the content of tryptophan, indole auxins and gibberellin-like substances in seven-day plants. Radiation decreased both growth and the content of tryptophan (e.g. by about 53% at 30 kR), of indole auxins (by about 60% auxin in the zone of IAA on the chromatogram at 30 kR), and also the content of gibberellin-like substances (by about 67% gibberellin content in the zone of GA₃ on the chromatogram) of plants. The irradiation of standard samples of tryptophan, indolyl-acetic acid and gibberellic acid alone with many times greater doses (up to 1000 kR) did not lead to marked radiochemical degradation of these substances. It can be assumed that radiation damages the enzyme systems "synthesizing" natural growth substances in plants. The damaging effect of radiation on auxins is already displayed in the synthesis of tryptophan, which is inhibited.
Zinc interacts with the damaging effect of radiation on growth. Optimum concentrations of zinc (5.10^-3% Zn) counteract the effect of radiation, up to doses of about 12 kR, on the growth in height in 7-day plants so that it is equal to the controls. Normal content of tryptophan and auxin in the position of indolecetic acid on chromatograms can only be reached by the addition of zinc when the dose of radiation was not greater than about 8 kR, which is less than the influence exerted by zinc on the restitution of growth. On the other hand, the biosynthesis of gibberellin-like substances at the position of gibberellic acid on chromatograms can be restored by zinc to their original level to doses of up to 30 kR. The increased biosynthesis of auxins and gibberellins caused by zinc in irradiated plants is explained by the activation of the remaining and non-damaged enzyme systems carrying out this biosynthesis. The activation of the biosynthesis of growth substances by zinc will also contribute to the restitution effect of zinc on the growth of plants from irradiated seeds.

The influence of penicillin in concontrations of 8.3-10,000 IU/ml on algaChlorella pyrenoidosa was studied. Depending on temperature, the concentrations of 14 to 6,000 IU/ml have a stimulating influence on algal growth which may go as far as 1572% as against the control. The differences in temperature (15° to 18°C or 25° to 28° C) and in the concentration of mineral substances in the Knop solution employed do not affect the mode of action of penicillin, but affect the absolute production of algae whose maximum lies between 2,500 and 3,000 IU penicillin/ml.

The paper presents results obtained from studying the linkages of the Rf₁ gene causing the restoration of fertility of pollen in the T type of cytoplasmic sterility of maize with signal genes of the 3rd chromosome in the F₂ and B₁ hybrid generations. Crossing of the fertility-restorer lines obtained on the basis of T cytoplasm with signal lines carrying recessive genes of the 3rd linkage group was carried out during the coupling phase.
The data obtained on the linkage of genes indicates that the Rf₁ gene is located at the proximal end of the long arm of the 3rd chromosome between loci d₁ and ba₁. The linear sequence of genes and the map of their distances were determined on the basis of experimental recombined values as follows: d₁-26-Rf₁-16(?)-ba₁-42-sh₂.

Application of a 1% aqueous solution of 2-methyl-4-chlorophenoxyacetic acid at the three-leaf phase brings about abnormalities in the development of barley ovule. The most typical abnormality is the complete or partial abortion of the embryonal sac, disturbances in the orientation of the embryonal sac (associated with the development of an integumental excrescence) and concrescences of two or more ovules. The abnormal ovules remain mostly unfertilized, which can have a negative influence on the crop.

Senf- und Zuckerrübenpflanzen wurden in der Phase des ersten echten Blattes mit dem Herbizid Pyrazon (= 1-Phenyl-4-amino-5-chlorpyridazon-6) in der Form eines Suspensionspräparates Pyramin in 0,4% Konzentration besprüht. Nach 1, 4, 7 und 14 Tagen nach der Besprühung wurde die Respiration der oberirdischen Pflanzenteile mit Hilfe von Warburgs Respirometer bestimmt. Der Stoffwechselquotient (in μl des verbrauchten O₂ pro 1 mg Trockenmasse in 1 Std. ausgedrückt) war beim Weissen Senf, der gegen Pyrazon sensitiven Pflanze, im Vergleich zu den Kontrollpflanzen gesenkt. Die Senkung der Respiration war desto grösser, je grösser die Zeitspanne zwischen Besprühung und Respirationsbestimmung war. Bei der Zuckerrübe, der gegen Pyrazon resistenten Pflanze, sank die Respiration nur den ersten Tag nach der Besprühung, wogegen sie zu den weiteren untersuchten Terminen nur unbedeutend herabgesetzt war. Bei der Anwendung von schwach subletalen Aufwandmengen war der Stoffwechselquotient der Zuckerrübe 7 und 14 Tage nach der Besprühung sogar höher als bei den Kontrollpflanzen. Diese Unterschiede waren jedoch nicht signifikant.

Pure cultures ofChlorella pyrenoidosa (82) andScenedesmus obliquus (125) were grown in the nutrient medium according to Benson in the presence of 0.05m sugars or 0.025m sodium salts of organic acids. The density of culture was measured throughout the course of growth. Satisfactory heterotrophic sources of nutrition forChlorella pyrenoidosa appear to be galactose, glucose and acetate, whereasScenedesmus utilizes glucose, cellobiose and acetate. The growth ofChlorella in the light is enhanced by galactose, glucose, fructose, cellobiose and maltose, that ofScenedesmus by glucose, fructose, cellobiose, galactose, maltose, acetate and pyruvate. Soluble starch suppresses growth of both cultures. The role of the substrates is discussed. It follows from the results that the growth-promoting sugars and organic acids can act not only as a source of carbon during general carbon shortage but also as ergastic material. The mechanism of utilization of some organic substrates will be taken up in a subsequent paper.

Cresol red was found to be the most suitable of the six colour pH indicators tested for the colorimetry of CO₂ concentration within the range of 100 to 2000 p.p.m. In the region near pH 8-2 (corresponding approximately to 300 p.p.m. CO₂)this indicator is most suitablein view of its low unit concentration, although somewhat greater differences in absorbancy can be found on changing pH by one unit if an approximately six-fold higher concentration of thymol blue is used. For higher concentrations of CO₂ (pH below 7-5) phenol red is most appropriate. Tropaeolin 000 and aurin (rosolic acid) are not suitable. It is more convenient in spectrophotometry and colorimetry using filters with narrow spectral ranges to apply any of the above indicators in the green-yellow-orange spectral region rather than in blue radiation.
When the air to be measured is bubbled through a bicarbonate solution, an equilibrium between the CO₂ concentration in the air and pH value is established in less than 10 min for differences in CO₂ concentration from 100 to 400 p.p.m. Partial pressure of CO₂ and the experimentally established pH value are related by the altered equation: pH =α- 0-934 log P. The values of α at different temperatures were determined.

The relation of the M₁ root length and the frequency of M₁ chlorophyll chimeras to the sterility grade and to the frequency of M₂ mutants ofArabidopsis thaliana is demonstrated.

Wir verfolgten die gegenseitige Beeinflussung von in Wasserkultur gezogenen Hafers und Gerste. In den Experimenten wurde die mögliche Konkurrenz um Wachstumsfaktoren entfernt und es wurde die Rolle der Wurzelausscheidungen bei der gegenseitigen Beeinflussung des Wachstums und der NPK-Anhäufung in den Versuchspflanzen geprüft. In einer Variante wurde periodisch stets jeden zweiten Tag auf die Dauer von 6 Stunden die Nährlösung aus den Kultivierungsgefässen geschöpft. Nach 43tägigem Kultivieren wurde eine signifikante Wachstumsinhibition des Hafers und Stimulation der Gerste festgestellt. Im Einklang mit den Wachstumsveränderungen war der N- und K-Gehalt auf 1 g Trockensubstanz erhöht bzw. herabgesetzt. Dagegen war der Gehalt des gesamten P, hauptsächlich in den Wurzeln, beim inhibierten Hafor aus der Mischung höher und bei der stimulierten Gerste niedriger. Wir setzen voraus, dass die Veränderungen durch die Wurzelausscheidungen der mitgezogenen Pflanzen verursacht wurden.

Azo-coupling methods were used for demonstrating non-specific esterase in the wheat root in all parts of a transverse section, usually with the exception of the woody parts of the vascular bundle. The central cylinder gave a more intense reaction than the primary cortex and the rhizoderm. The reaction was not inhibited by dodecyl sulphate. A weakening of the reaction intensity was observed after application of AgNO₃. The Tween method did not yield reliable results.

Seeds of the beanPhaseolus vulgaris L. (Veltruská Saxa cultivar) were gathered gradually at different stages of development, starting at fertilization up to full maturity. Seeds were freeze-dried and the dry solid used for preparing extracts which were analyzed by immunoelectrophoresis for the presence of proteins resembling those contained in the cotyledons of a mature seed. Proteins from cotyledons of the first stages of development of bean seedlings were analyzed similarly.
After a preparatory period, approximately from the second-third seed development stage, there is a period of intense protein synthesis that characterizes cotyledons of a mature seed. These proteins increase in quantity and are differentiated in quality up to maturity when a single antiserum detected a total of 12. After germination both the quantity and number of these proteins decreases.
It was found that some proteins are metabolically more active, both during synthesis and cleavage. This holds e.g. for phaseolin during maturation, as well as during germination. In addition, phaseolin changes its electrophoretic mobility, which is apparently due to proteolytic hydrolysis of phaseolin molecules.
During the last phase of maturation, viz. dehydration of seeds, some new proteins suddenly appear, apparently synthesized from pre-formed peptide chains.
In the discussion the possibility is taken up that the beginning on the synthesis of specific proteins characteristic for mature seeds is the cause underlying the disturbances in the embryonal development of distant hybrids.

Peroxidase isozymes were studied in the case of two diseases:Tilletia controversa in wheat andPuccinia recondita in rye. The method employed was that of disc-electrophoresis on acrylamid gel. In the case of systemic disease (Tilletia controversa) no change was found in the isozyme pattern until a concentration of pathogen took place in the ears that began to form. Proofs are given that the new isozyme in unmatured ears comes from the pathogen. In the case of rye infected withPuccinia recondita a new isozyme was found; the latter does not originate in the pathogen, its origin is being discussed.

The vessel member length-diameter and perforation plate-vessel member length relations inDioscorea alata L. have been investigated. The two types of vessel elements, one with scalariform perforation plate and the other with foraminate perforation plate, have been considered for correlation tests; the variables being vessel member length and diameter, and vessel member length and perforation plate length. Significant positive correlation was found only in the case of perforation plate length and vessel member length for types with scalariform perforation plates.