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.

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 Pollenschlauch verstopft. Das unbefruchtete Eichen scheidet irgend welche Substanz aus seiner Mikropyle aus, durch welche die Pollenschäuche chemotropisch angezogen werden. Einige wenige Eichen reagieren jedoch nicht nach der Befruchtung durch ein Wachstum des Funiculus an seiner Basis und das Peristom wird von der Fruchtwand (Plazenta) nicht entfernt. Das schoint jedoch nur eine Ausnahme zu sein.

Es wird der Aufbau und die Arbeitsweise eines motorisierten und mit URAS-Geräten für CO₂ und H₂O ausgerüsteten Feldlabors beschrieben. Die wichtigsten Voraussetzungen für den Einsatz der URAS-Instrumentarien im Freiland sind ein geländegängiges Fahrzeug, in das alle empfindlichen Geräteteile federnd montiert sind, Stromzufuhr ausreichender Frequenz-und Spannungskonstanz und eine ausreichende Temperaturisolation der Fahrezugaussenwände. Ausserdem ist das URAS-Instrumentarium in einen thermostierten Schrank einzubauen und das Fahrzeug während der Messungen am Standort fest mit Stützen zu arretieren, um Erschütterungen der Registriereinrichtungen zu vermeiden. Die empfindlichsten Geräteteile müssen ausgebaut und möglichst erschütterungsfrei transportiert werden.
Weitere technische Einzelheiten werden erörtert und spezielle methodische Probleme zur Ausschaltung der Übertemperaturen in den Küvetten diskutiert.

Die Arbeit behandelt die gegenseitige Beziehung zwischen Hanf und Roggen in Wasserkultur bei nicht ergänzter Mineralernährung. Nach 18-tägiger Kultivierung in Nährlösung mit³²P wurden beweiskräftige Phosphorsorptions- und Transpirationsdifferenzen zwischen den Kontrollpflanzen und der Mischung gefunden. Die Hanf-Kontrolle verbrauchte in 18 Tagen 85,5% Phosphor, Hanf in der Mischung 94%, die Roggen-Kontrolle 95,3%, Roggen in der Mischung 106,7% auf je eine Pflanze umgerechnet. Das Wachstum wurde nicht beeinflusst. Die Ergebnisse lassen sich nicht bloss durch Nährstoffkonkurrenz zwischen den beteiligten Arten, sondern durch die Anwesenheit eines weiteren Faktors erklären.

Mit Ultrarot-Absorptionsschreibern für CO₂ und H₂O wurden die apparente Photosynthese, die Respiration und Transpiration von Maispflanzen und-blättern unter konstanten Bedingungen untersucht.
Zwischen den 3 geprüften Sorten, "Schindelmeiser", "Siloma" und "WIR 25" ergaben sich keine signifikanten Sortenunterschiede hinsichtlich der apparenten Photosynthese obwohl sich die Sorten-bedingt durch die unterschiedliche Vegetationsdauer-in den Erträgen deutlich unterscheiden; die Einzelpflanzenstrenungen innerhalb der Sorten lagen bei 25%.
Bei fast gleich grosser Einzelpflanzenstreuung innerhalb der Sorte zeigte sich eine signifikant
Bei fast gleich grosser Einzelpflanzenstreuung innerhalb der Sorte zeigte sich eine signifikant höhere Transpiration bei "WIR 25" als bei den beiden anderen Sorten. Die höchste apparente Photosynthese wiesen die Blätter auf, die dem Kolben am nächsten inseriert waren (4.-5. Blatt).
Die CO₂-Aufnahme je Blattfläche und Stunde war bei den verschiedenen Abschnitten des Blattes unterschiedlich; im Mittelteil wurden signifikant höhere Werte als im basalen Teil der Blattspreite beobachtet. Die CO₂-Aufnahme korrelierte positiv mit der mineralischen Ernährung.
Es gab keine Unterschiede in der CO₂-Aufnahme bei den Pflanzen ohne und mit Kolben. Bei Pflanzen ohne Kolben können die produzierten Assimilate (Saccharose) nicht gespeichert werden; sie überschwemmen deshalb die ganze Pflanze und werden zu einem grossen Teil nachts veratmet. Der effektive Stoffgewinn an Trockenmasse dieser kolbenlosen Pflanzen erreicht nur 70% von denen mit Kolben.

Agar-gel electrophoresis was used for studying the protein fractions of apple-tree blossom and leaf extracts and some qualitative differences were found. The finding is discussed in connection with flower-bud differentiation.

Plants of ten varietal populations of maize and their progenies in S₃ generation had been evaluated for their resistance to sources of corn smut in conditions of increased infection level. According to the infection degree, the experimental material was divided into classes (I-V) corresponding to five categories of resistance.
The relative representation of progenies from populations differing in their susceptibility to the parasite in their particular classes showed that the heterozygous varietal populations posses some imunological structure.
1. In the composition of the populations the resistant forms prevail over the susceptible ones. In the populations studied 82.8-98.5% dissected at selfing were grouped into classes I-III.
2. The basis of resistance of populations is formed by a group of forms ranged into the second class of resistance. This group being equally represented in all populations (31.1-40.8%) independently of their susceptibility to corn smut.
3. The differences in disease attack of plants of the particular populations had been influenced by the relative participation of selfed progenies, ranged on the one hand into class I and on the other hand into classes III and IV. The occurence of progenies in these categories in populations arranged consecutively from higher to lower resistance varied in conformity on extent 46.2-15.5%, 11.5-37.5% and 1.5-17.8%.
The experimental data showed, among others that the general smut attack of plants in populations (23.5-49.6%) corresponded in most instances to the average attack of progenies in S₃ generation (21.0-44.2%).

Whereas experiments directed towards proving the infectious character of the hop curl disease did not give reliable proof of its virus character (we have not been able to transfer it neither by cuttings nor by graft), but made possible its differentiation from the English nettlehead hop virus disease, the practical experiences and results presented in this paper show that nutritional conditions essentially affect the known variability of the external manifestations of the hop curl disease. Especially such nutrients play a role which with the normal fertilising techniques are not returned to the soil in sufficient quantity. Since the hop curl disease was noticeably inhibited in a nutritional field experiment on application of the salts of some elements, predominantly of B, Mg, Mo, Mn, Ni, I and Zn, it appears possible to apply "symptomatic therapy" of the hop curl disease, which could have wide practical importance for limiting this disease.
In order to supplement the provocation field experiments, comparative investigations of the chemical composition of the leaves from healthy and hop curl diseased plants were carried out. Quantitative analysis of the biogenic elements carried out by the usual methods and by polarography showed a regularly higher content of P, K, Ca and a lower content of Zn in the diseased plants as compared to healthy ones. The differences observed in the content of N, Na, Mg, S, Fe and Cu were not always in the same sense. Chemical analysis was accompanied by parallel spectral analysis of ash. This made it possible to obtain a considerably complete survey of the qualitative and approximately quantitative representation of a whole series of other elements in healthy and diseased plants; however, no characteristic differences were recorded.
Finally the results obtained in the present work are confronted with the findings of other researches, especially from Germany, and discussed.

1. In tetraploid Phaseolus sp. × P. calcaratus cross, shrivelled but viable seeds were produced. One hybrid was raised but it died within a month. Another hybrid was raised to flowering by artificially culturing the embryos before shrivelling.
2. The F₁ of tetraploid Phaseolus sp. × P. calcaratus cross, had various leaf abnormalities at an early stage. In most of the characters the hybrid was intermediate between the two parents. The twining habit of P. calcaratus dominated in the hybrid. The F₁ plant had 10.7 per cent pollen fertility. The hybrid died within a week of flowering.
3. In P. calcaratus × tetraploid Phaseolus sp. cross, rudimentary, non-viable seeds were produced.
4. The incompatibility barriers are active - (a) at post-fertilization stages causing shrivelled and rudimentary seeds and (b) in the F₁ generation causing hybrid lethality and sterility. The importance of embryo culture techniques in removal of the first type of crossability barriers is stressed.

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 sativa L., and 1∶1 for beetroot. From the dynamic point of view it is possible to state that this ratio changes in the course of individual development. With plants cultivated for their aerial parts, it increased with age, while with plants cultivated for their roots, it decreased with age. The irrigation water produced much greater morphological changes (the shape and the surface area) in the root and shoot system of experimental plants.

The effect of different exposures to RTG radiation (100 r, 250 r, 500 r, 1000 r, 2500 r, 5000 r) on the changes of the permeability of the epidermal cells ofAllium cepa L., variety Všetaty, bulbs was studied during three vegetation periods. Bulbs from growing plants (followed from the development phase of bulb growth) and bulbs immediately after harvesting were used for the experiments.
It was demonstrated in our experiments by plasmolysis that the radiation-induced changes of cell permeability were irreversible. When plasmolytic agents of non-electrolyte character (1M sucrose, 1M glycerol, 1M urea) were used, the equilibrium state (total plasmolysis) was reached more rapidly with the irradiated bulbs than with the unirradiated controls. When electrolytes were used (0.5M KNO₃, 0,5M KBr), total plasmolysis occurred less rapidly with the irradiated objects than with the controls. These relationships were manifest during the whole ontogenesis ofAllium cepa L. An exposure to 100 r was sufficient in our experiments for causing the mentioned changes, proving a considerable sensitivity of the osmotic properties of the epidermal cells ofAllium cepa L. bulbs to ionizing RTG radiation.
Plasmolytic experiments after smaller exposures than 100 r of RTG-rays are in preparation.

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 discussed in relation to the use of "adaptation" of urease in unfavourable conditions in reaction mixtures by the action of lead acetate.

Während Assimilations- und Transpirationsmessungen die Durchlüftung den Pflanzenteile und die Reaktion der lebenden Zellen mit der sie umgebenden Luft nur gemeinsam widerspiegeln, lässt sich mit dem radioaktiven Edelgas⁸⁵Kr der Gaswechsel zwischen Aussenluft und Interzellularluft unabhängig vom Stoffwechsel und ohne künstliche Druckdifferenzen erfassen. Der Gassaustausch zwischen der Interzellularluft und der Aussenluft wird dabei durch die Austrittsgeschwindigkeit des vorher kurzfristig durch Diffusion oder Unterdruck eingeführten⁸⁵Kr aus dem Pflanzenteil charakterisiert.
Orientierende Versuche unter Freilandbedingungen an den benadelten Zweigen einiger Koniferen sowie Zweigstücken mit und ohne Rinde erbrachten Unterschiede in der Geschwindigkeit des Gaswechsels sowohl zwischen verschiedenen Pflanzen unter gleichen Bedingungen als auch bei der gleichen Pflanze unter verschiedenen Bedingungen.

Investigating weeds for viruses in ruderal localities of Greater Prague two forms of mosaic diseases inSisymbrium loeselii Jusl. were demonstrated (green and yellowish-green mosaic). Transmission tests carried out on differential host plants showed that the green mosaic is caused by cabbage black ringspot virus (CBRV) and the yellowish green by mixed infection of CBRV and tobacco mosaic virus (TMV).
TMV-isolate is characterized as an unusual necrotic strain; its capability to reproduce in cruciferous plant in nature is unique.
It was ascertained that green mosaic was commonly spread overSisymbrium plants in ruderal ***DIRECT SUPPORT *** A01GP029 00004 associations on Prague territory; epidemiological significance of this discovery is discussed.

The primary roots ofVicia faba seedlings were placed in a solution of 5-azacytidine and their further growth was observed after being replaced in running tap water. No inhibition of elongation occurred during the action of the 10^-5 M solution of 5-azacytidine for 24 hours, but during subsequent cultivation in water in the absence of inhibitor, further growth was blocked. This inhibition could be overcome by cytidine, uridine, sodium azide, 5-azidomethyluracil and simultaneously with the 5-azacytidine solution. Inhibition was accompanied by a high incidence of chromosome stickiness and to a less extent by an incidence of chromosome aberrations. The occurrence of stickiness and chromosome aberrations was prevented by adding excess cytidine to the 5-azacytidine solution.

In dieser Arbeit wurden allelopathische Eigenschaften von Roggen, Weizen, Gerste und Hafer studiert, die sich bei gegenseitigen Beziehungen dieser Getreidearten geltend machen können.
Als Beweis für die Wurzelbeeinflussung der angeführten Getreidearten wurde eine Methode verwendet, bei der die erwähnten Getreidearten in derselben Kultivierungserde wuchsen, und zwar teils unmittelbar nacheinander, teils in abgestuften Zeitintervallen nacheinander mit verschiedenlanger Lagerungszeit der Erde.
Die Versuchsergebnisse haben die Ansichten zahlreicher Verfasser bestätigt, die behaupten, dass die angegebenen Getreidearten allelopathish aktiv sind. Roggen, Weizen und Hafer beeinflussten signifikant das Wachstum der nachfolgenden Kulturen; dabei erwiesen die Ergebnisse nicht deutlich jene Beeinflussung, die durch das Erschöpfen der Nährstoffe durch die vorhergehende Pflanze bedingt worden wäre.
Die angewandte Methode einer nachfolgenden Kultivierung erwies sich geeignet als Beweis für die allelopathischen Eigenschaften der Pflanzen unter natürlichen Bodenbedingungen. Die erwähnte Methode lässt sich vorteilhaft insbesondere in jenen Fällen anwenden, bei denen der Unterschied im Habitus der oberirdischen Teile der Pflanzenarten das Studium des Charakters ihrer gegenseitigen Beziehungen bei gemeinsamem Wachstum unmöglich macht. Diese Methode könnte ebenfalls eine Anwendung in der landwirtschaftlichen Praxis finden, wenn eine geeignete Zeitfolge der Pflanzen bei der unmittelbare Reihenfolge auf demselben Standort ermittelt werden soll.

NaN₃-a respiratory inhibitor and anaerobic conditions (nitrogen) decrease the mutagenic activity of N-ethyl-N-nitrosourea and N-methyl-N-nitrosourea inArabidopsis thaliana. DNP-an uncoupling agent increases the effect of both nitrosoureas, but this may not be caused by the specific action of DNP.

The polymorphism of the dictyosomes in the root meristeme ofFagopyrum is connected with their various functions in secretory processes and cell differentiation. The dictyosomes containing vesicular dilatations of the cisternae, which in this object occur more frequently than in others, probably participate in a similar way as the Golgi apparatus of the animal cell in the formation of lysozomes, in the formation of elements belonging to the group of dense bodies analogical lysozomes. These bodies are present in large numbers in the cytoplasm of cells, containing dictyosomes with vesicular dilatations. The other forms of the dictyosomes reveal indications of their participation in the production of the carbohydrate material of the cell walls, like most dictyosomes of other plant objects. However, no fusion of the Golgi vesicles with the plasmalemma was observed. According to their morphological appearance the typical forms of dictyosomes were classified on the basis of their relationship to secretory processes. Simultaneously the morphology and function of the Golgi apparatus was compared in the animal and plant cell. Several morphological varieties of the dictyosomes of plant cells, observed after the action of pathogenic factors and the effect of the fixation procedures, were also noticed in small quantities in the cells of the investigated objects.

Plants of two varieties of winter wheat-Besostoya 1 and Etoile de Choisie- were raised in the field. The same number of selected plants from each variety were frozen once in a refrigerator at a temperature of -15°C for 24 hrs. After freezing, the plants were gradually thawed and returned to the field. Early in the spring, test and control plants were treated with one of following diluted solutions: vitamin B₁, vitamin B₆, indolyl-3-acetic acid and adenine (the four solutions at a concentration of 0.01% and 5% urea solution in water) by immersion for 15 hrs. at a temperature of 18-20°C. The plants were measured in the spring and in the summer, the yield being determined after ripening.
It was found that all substances used helped to diminish the deleterious consequences of overwintering and to raise the yield of the plants. Vitamin B₆ exerted the strongest influence. Vitamin B₆ treated plants produced higher or slightly lower yields than those of the non-frozen control. Plants treated with vitamin B₁ gave yields close to, but in most cases lower than those of the non-frozen control.
The yields of plants treated with solutions of the remaining substances were appreciably lower than those of the non-frozen controls.
Plants of the more winter-hardy variety Besostoya 1 recovered relatively more easily under the effect of the substances used than the plants of the less winter-hardy variety Etoile de Choise.