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.

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.

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.

Senf- (Sinapis alba L.) und Zuckerrübenpflanzen wurden in der Phase des ersten echten Blattpaares mit dem Herbizid Pyrazon (=1-Phenyl-4-amino-5-chlorpyridazon-6) in Form eines Spritzpulvers-Pyramin-in der Konzentration 0,4% besprüht. 1, 4, 7 und 14 Tage nach der Besprühung wurde mit Hilfe der volumetrischen Methode nachJermakov und Mitarbeitern die Katalase-Aktivität im Blattsaft gemessen. Es wurde festgestellt, dass die Katalase-Aktivität in den Blättern der sensitiven Pflanze (Senf) durch die Einwirkung von Pyrazon im Vergleich mit dem Blattsaft aus unbesprühten Blättern herabgesetzt erschien, wogegen sie in den Blättern der resistenten Pflanze (Zuckerrübe) nicht abgesunken war.

The unicellular algaeScenedesmus obliquus (125),Chlorella pyrenoidosa (82) andCoccomyxa solorinae saccatae (111) were studied with respect to the form of uptake of potassium, phosphate, calcium and zinc ions and to the energy sources involved: light under autotrophic conditions, glucose under mixotrophic or heterotrophic conditions (in light and in darkness or together with yeast extract as an auxotrophic substrate). We respected the trophic conditions of algae when preparing the experimental material (precultivation). The following conditions were reached:
(1) The three algae grow faster in a glucose medium under mixotrophic conditions and are capable of growing on it also heterotrophically:Ch. pyrenoidosa andSc. obliquus grow substantially better thanC. solorinae saccatae. The first two algae grow more intensively in a glucose medium containing yeast extract whileCoccomyxa does not. After cultivation under mixotrophic conditions the first two diminish endogenous respiration, the third raises it. Glucose stimulates respiration in the first two when grown autotrophically, while after mixotrophic cultivation the effect of glucose is suppressed inCh. pyrenoidosa and in the other two only after growth on glucose with yeast extract.
(2) A relationship between sorption and metabolism was established for potassium in all the algae investigated. The effect of light is generally positive, heterotrophic components (glucose and possibly yeast extract) stimulate the uptake in the dark as long as they represent a suitable mixotrophic medium for the given alga.
(3) The uptake of K⁺ was proportional to concentration in solution and independent of Ca²⁺.
(4) The uptake of phosphate is clearly stimulated by light, while no stimulation under mixotrophix or heterotrophic conditions on glucose was observed-actually, a depression usually took place.
(5) At concentrations from 10^-6M to 10^-2M the uptake of phosphate is non-linearly but positively related to the concentration in the medium. The presence of Ca²⁺ is the cause of non-metabolic forms of phosphate sorption.
(6) Two forms of calcium uptake were found: the predominant one is adsorption which can be associated with the presence of phosphate ions; the metabolic uptake represents a considerably lower fraction which is characterized either by a light dependence or at least by a rise of calcium content between t=0.1-6 h.
(7) The absorbed Ca²⁺ can be washed out up to 75% with dilute hydrochloric acid. The total adsorption and remainder after washing depend on the pH of the solution from which the sorption took place (a considerable rise beyond pH 6.5). A substantial effect on the formation of the adsorption system was found to be due to organic nutrients. Algae after mixotrophic precultivation possess a decreased sorptive capacity.

In a previous communication (Bartoš, Kubín andŠetlík 1960) a method was reported, which makes it possible to measure the average rate of photosynthesis in a representative sample of a large number of leaves. The sampling is made by cutting out disks of leaf tissue, following a definite pattern. Isolated leaf disks are then illuminated under controlled conditions and the rate of photosynthesis is estimated by weighing the increment of dry matter in a given time interval.
Data published in the present paper demonstrate that this method can be successfully used for a characterisation of photosynthetic capacity (specific rate of photosynthesis, seeBartoš, Kubín andŠetlík 1960). Both specific values for individual plants and average values for homogenous plant populations may be estimated with very good accuracy. One of the chief factors which render this possible is obviously the surprising homogeneity of the photosynthetic tissue of leaves. Samples of very small size may serve as representative of a large total leaf area, e.g. of a population under field conditions.
Preliminary results of comparative investigations suggest that, with the plant varieties examined, differences in photosynthetic capacity are not very great, both between and within populations of diverse varieties. Differences as large as 50% have been encountered so far solely between values of photosynthetic capacity estimated for individual plants in a population. On the other hand, values of average photosynthetic capacity in populations of crop plant varieties within one species or genus are, as a rule, not very distinct and quite often no statistically significant difference can be demonstrated in such cases. Even if the varieties belong to different genera, differences in photosynthetic capacity in their populations greater than some 50% have been found only as an exception.
In considering all these results one important fact must be taken into account, i.e. the intensity of illumination in the apparatus. Contrary to what was intended and awaited, the radiation intensity used was not high enough to saturate photosynthesis in leaf disks. The light dependence of photosynthesis in isolated portions of leaf tissue apparently has a somewhat different character from that usually assumed for intact leaves of higher plants.

Exeised roots ofSolanum laciniatum Ait. grown in vitro in a liquid medium will form the typical rich white callus with a high water content. Its formation is made possible by the presence of 2,4-dichlorophenoxyacetic acid and niyo-inositol in the nutrient medium. Choline, ascorbic acid, riboflavin, calcium pantothenate and biotin are inactive. A mixture of thiamine, pyridoxine and nicotinic acid will induce only slight proliferation.

The effect of sowing density (21, 85, 340 and 3400 plants per 1 m on the leaf area index (LAI), vertical arrangement of developing foliage and dry matter production was investigated in stands of wheat (Triticum aestivum L. cv. Niva).
1. With increasing sowing density.
a) The LAI increased and the highest LAI = 9.6 was obtained with 3400 plants. m-2. The largest development of foliage took place at ear emergence with 85, 340 and 3400 plants. rn-2, and in the flowering phase with 21 plants. m-2.
b) The overal leaf area duration was reduced, with a difference of 11 days between the lowest and the highest density.
c) The number of leaves formed per one stem increased from 5 to 8.
2. An increase in theLAI affected the vertical distribution of leaf area and resulted in increased differenoes in relative light intensity between the top and bottom layers of the leaf canopy. Differences inLAI were linked with differences in leaf area duration and in the relative proportions of leaves of different age in the total number of leaves per 1₂
3. a) Shoot dry matter production increased with increasing density; the maximum of 3811 g. m_-2 was obtained with 3400 plants._M-2.
b) The dependence of grain yield on sowing density had a parabolic character; the maximum yields of 47001 g. m-2 and 442.8 g m-2 were obtained with 340 and 85 plants. respectively.
c) The optimum LAI for the formation of grain yield was 2.3 to 3.2.
d) The crop growth rate (C) increased with increasing density; the highest mean recorded C = 594 g. m. week-1 corresponded to LAI = 9.6.
4. Thinning the stands of 3400, 340 and 85 plants. m-2 in the phases of the 3rd leaf (22 days after sowing) and of tillering (30 days after sowing) to the next lower density resulted in a reduced LA leaf and tiller number, crop growth rate, shoot dry matter production and grain yield as compared with both the initial and standard densities. The role of foliage with respect to both maximum dry mater production and maximum grain yield was defined by an optimum range of relations between the rate of foliage development, leaf area, vertical structure and distribution of light intensity within the stand operating as a self-controlling system.

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.