The foliar absorption and subsequent distribution of sodium, chlorine, calcium and zinc in one-year-old rooted cuttings ofForsythia intermedia ZABEL, and root absorption of phosphorus byTaxus cuspidata SIEB. and Zucc, was established. The percentage of the applied nutrient translocated out of the treated leaf was used as a criterion of mobility. Sodium and chlorine were found to be mobile, calcium immobile, and zinc slightly mobile. Less than one percent of the phosphorus applied to the shoots of both actively growing and semi-dormantTaxus cuspidata plants was recovered in the roots after a 12-day absorption-transport period. Six percent of the total phosphorus recovered in the tops was derived from a single soil application of a water soluble fertilizer (10-52-17) after 12 days, although, less than. 0.5 percent of the applied fertilizer phosphorus was absorbed.

The persistent nature of oat sterile-dwarf virus (OSDV) and wheat striate virus (WSV) has also been examined in an experiment using larvae of the vectorCalligypona pellucida Fabr. These larvae were grown from eggs under conditions excluding the possibility of their contamination by feeding on virus-infected plants. The eggs were from females of a population in which preliminary tests had shown that 14.4% of the individuals were non-infected, 61.2% infected with OSDV, 1.9% infected with WSV and 22.5% infected with OSDV and WSV simultaneously. Several months of individual examination of the infectivity of control larvae, which had never had the opportunity to feed on virus-infected plants, showed that none of them transmitted OSDV, although their parents were infected with it to a high degree (83.7%). On the other hand, 14.9% of the insects transmitted WSV, with which their parents were infected to a lesser degree (24.4%). Thus the larvae concerned must have acquired WSV transovarially from the female parents, and this must have taken place in a high proportion of cases. This remarkable characteristic enabled WSV to be separated from OSDV, with which it often occurs in Czechoslovakia. Larvae which went through acquisition feeding on WSV-infected oats showed, as compared with the control, a 61.6% increase of infectivity after a period corresponding to 26 to 34 days' circulation period of the virus in the vector's body and an increase of 98.2% after a circulation period lasting 40 to 51 days. Evidently mutual antagonism between OSDV and WSV in the body of the vector does not arise, since the infection of a leafhopper with one virus does not seem to prevent its infection with the other. Cross protection between OSDV and WSV in the host cereals either does not exist or is quite insignificant, because the hosts can suffer from both viruses at the same time. However, the symptoms of one virus can be masked to a varying degree by the symptoms of the other.

The authers compared taxon and organ specificity of proteins of several species of the familyViciaceae, using qantitative serological methods. Each organ possesses a defined organ specificity of protein characters, the species specificity being preserved. On the basis of the results obtained both methodical and more detailed ontogenic and phylogenetic assumptions and conclusions could be drawn.

In addition to the oat sterile-dwarf virus (OSDV) as the main agent causing grave damage to cereal crops in the Bohemian-Moravian Highlands during 1954-56, when the disease reached catastrophic proportions, it was found that wheat striate virus (WSV) also played a part. Symptomatological study showed that there are characteristic differences between the effect of WSV on the host plants and that of OSDV. Similarly to OSDV, however, WSV is specifically spread by the leafhopperCalligypona pellucida Fabr. Following long-term individual testing of vectors taken from localities infested with OSDV and WSV, four groups of insects were distinguished according to their pathogenic effects on cereal crops: 1. nonpathogenic, 2. producing OSDV symptoms, 3. producing WSV symptoms, 4. producing for the most part OSDV symptoms, but occasionally WSV or symptoms characteristic for both viruses simultaneously. WSV is persistent in its vector and is transferred byC. pellucida larvae at different stages of development and by imagos of both sexes. WSV tends to be transferred less regularly than OSDV. Considerable differences in efficiency of carrying WSV are to be found between individual leafhoppers, so that it is possible to assume the existence of races with varying efficiency in this respect. Among field populations in this country less efficient races prevail. For the transmission of WSV to be effected it was necessary for the vector to remain on the host for at least nine hours, but it seems that a shorter period might suffice. Extracts of crushed leaves of wheat plants suffering from the striate disease and from infective leafhoppers failed to cause infection when inoculated mechanically (by rubbing, injection) into plants. Attempts to achieve transmission through the soil or by dodder (Cuscuta campestris Yunck.) gave negative results. It was not possible to determine the thermal inactivation point of the virus in the live vector. The mosaic (zakuklivanie) virus of oat and the Russian mosaic of winter wheat as described in the U.S.S.R. differ from OSDV and WSV among other points by the production of typical inclusions and by the fact that they can easily be induced to crystallize.

Practical directions and examples are given for the use of quantitative ring precipitation to determine the intensity of cross reactions. The ability of this method to reproduce objectively the intensity of an antigen-antibody reacting system under various concentrations was verified. A comparison was made between Boyden's method of "complete curves" and the quantitative ring precipitation method.
The advantage of using quantitative ring precipitation is the saving of antiserum (0.05 ml. is sufficient for one determination), the smaller demand on working time and a noticeably reduced sensitivity to non-specific factors.
Quantitative ring precipitation (QRP) is a suitable method for quantitative experiments in immunochemistry and for purposes of comparative serology.

The growth of pollen tubes evokes changes in the level of free amino-acids in the style. This has been demonstrated in the cases of alanine, valine, leucine-isoleucine, serine, threonine, γ-aminobutyric acid, asparagine, glutamic acid and proline. These changes take place mainly in the parts of the style where the pollen tubes are present.
The most marked changes are an increase in the level of γ-aminobutyric acid and alanine and a decrease in glutamic acid. The intensity of these processes is much greater following compatible pollination than in the case of incompatible autogamy. On the assumption that the main course of γ-aminobutyric acid and alanine katabolism takes place by transamination with α-ketoglutaric acid, the basic nature of the above changes is explained as being due to a relative deficiency of the latter acid.
Alongside a reduction in the level of sugars an accumulation of asparagine takes place in pollinated styles. The rise in its level is considerably more rapid in cross-pollinated than in self-pollinated styles. If accumulation of asparagine is a result of more intensive consumption of proteins during respiration when there is a scarcity of sugars, it follows from the above results as from previous work (TUPý 1961), that pollen tubes use substrates from the style tissues for respiration and that this process is limited in the case of incompatible inhibition.
At the time when the pollen tubes are growing through the styles, the levels of γ-aminobutyric acid and alanine are already rising in the ovaries of pollinated flowers. This increase is quantitatively in direct ratio to the rate of pollen tube growth, which depends on the compatible or incompatible character of the pollination.

1. Photoperiodic experiments with the effect of short day during vernalization of winter wheat under field conditions have shown that the short day enhances development if applied during vernalization. Short day applied after vernalization prolonged the development.
2. At low intensity artificial illumination and under optimal vernalization temperatures vernalization proceeds the faster the longer the illumination. On increasing illumination intensity differences between the effect of short and long day are obliterated. Vernalization in the dark takes place only if saccharides are added.
3. It is assumed that even in green plants the accumulation of a certain amount of ergastic material, particularly saccharides, represents one of the conditions of vernalization. This accumulation may be achieved by longer illumination (under conditions of vernalization temperature and low illumination intensity), i.e. by a direct photosynthetic effect, or else by short day (under field conditions) causing a specific, photoperiodically controlled growth reaction which inhibits growth. When vernalization proceeds in the dark saccharides must be supplied.

If the flowers for experiment were separated from the plants one day before pollination and incubated in water at a temperature of 25° C, pollen tube growth in the pistils made itself apparent during the following three days in the glucose and fructose level. On the first day after pollination the amount of these sugars in the apical style parts was higher in non-pollinated flowers, while on the other hand, in most cases it was lower in the basal sections and ovaries than in the corresponding parts of pollinated flowers. During the next two days there was a greater loss of both carbohydrates where pollination, particularly allogamy, occurred, so that after the third day the glucose and fructose level was highest in the non-pollinated pistils and lowest after compatible pollination. This decrease was most pronounced in the ovaries even though the compatible tubes had not yet penetrated into them. In experiments in which the flowers were left on plants cultivated under field conditions, a decrease in the glucose and fructose content of their pistils had not occurred even 80 hours after compatible pollination.
From these facts the following conclusions can be drawn: The growth of the tubes through the styles causes an increased inflow of carbohydrates into the whole pistils. Both compatible and incompatible tubes use sugars from the style tissue. Both these phenomena are more intense after allogamy than in the case of incompatible autogamy. In view of the fact that compatible tubes grew normally through the styles even with a lowered glucose and fructose level, an absolute rise in the content of these sugars in the pistils is not necessary for tube growth.
The proportion of glucose/fructose in pollinated styles changes in favour of glucose. The value of this quotient rises both in the apical and basal style parts mainly, however, after compatible pollination. This phenomena is in agreement with the previous hypothesis (TUPý 1959, 1960), according to which, in the respiratory process, pollen tubes consume mainly sucrose and from this, primarily its fructofuranose component.

Proof is given in this paper that dwarfing of wheat, which occurs in several regions of Czechoslovakia, is a virus infection. The virus was transmitted by means of naturally infected imagos of the leaf-hopperPsammotettix alienus DAHLB. to spring wheat and spring barley. It was also found that it is transmissible to a high degree by larvae grown from eggs which are then artificially infected at the source of infection. An attempt to transmit the virus by means of the aphidsBhopalosiphon oxycanthae (SCHRANK.) andSitobium granarium (KIRBY) MORDV. was negative. Nor was it possible to transmit it by soil, wheat grains or by mechanical inoculation with sap from diseased plants.
The Russian mosaic virus of winter wheat would seem, in view of its vector, to be the most closely related to the wheat dwarf virus. It differs, however as regards the symptoms produced on the host cereals, by having a different vector and by the absence of inclusions in the cytoplasm of infected plants. These facts indicate that we are probably dealing with a new virus, which has not previously been described.

In der vorliegenden Arbeit ist eine einfache Methode beschrieben, mit deren Hilfe es möglich ist, die kritische Bodenfeuchtigkeit ganz objektiv zu bestimmen, bei der die Pflanzen absterben und zwar im Gegensatz zur Bestimmung des Welkungspunktes, die durch subjektive Fehler belastet ist.
Versuche an Sonnenblumen, Bohnen, Mais, Weizen, Buchweizen, Gräsern, Waldholzbäumen und verschiedenen Arten und Abarten des Zuchtweizens zeigten, dass die Bodenfeuchtigkeit, bei der die Pflanzen absterben, bei den verschiedenen Arten und Abarten verschieden ist. Ferner sind andere Arbeiten des Autors zitiert (Stojanov 1955, 1957b, und 1958) in denen er zeigte, dass diese kritische Feuchtigkeit sich nicht nur mit der Dichte der Bestände von Monokulturen, mit der Zusammensetzung der Bestände von Mischkulturen, sondern auch weiter sowohl unter dem Einfluss verschiedener chemischer Stoffe, als auch ihrer Konzentration änder.
Die Werte der Bodenfeuchtigkeit, beider die Pflanzen absterben, bzw. die Punkte des dauernden Welkens sind nicht nur für das Überleben von Pflanzen in der Zeit der Trockenheit wichtig, sondern beeinflussen wahrscheinlich die Ernte auch in Fällen, in denen diese Bodenfeuchtigkeitswerte nicht erreicht werden. Das ergibt sich aus den Untersuchungen vonMaximov undkomiserko, welche zeigten, dass das Pflanzenwachstum vom Abstand (von der Differenz) der Bodenfeuchtigkeit vom Punkte des unzugänglichen Wasser des Bodens abhängig ist.

In a hybridisation experiment, the hereditary fixation of mutations of a branched form of rye, characterized by an enlargēd number of blossoms and inflorescence parts, was studied. It was found that the hereditary fixation of this form was monomerily recessive with respect to the rye sort Dobřenická trsnatá, the spike formation being normal. It was also shown that neither particularly good nor particularly bad soil conditions had any effect on the split ratio of 3 : 1 in the F₂ generation. The mutation form studied was stable within a very wide interval of soil and climatic conditions. We are probably dealing here with a stable disturbance in the morphogenetic process resulting in spike formation.

Antagonism of three saprophytes to the pathogen,Rhizoctonia solani was studied in plate cultures under different conditions of temperature, pH, and nutrition. The antagonistsTrichoderma viride andChaetomium cochlioides were found more effective in the inhibition of the growth ofR. solani at temperatures 25 and 20° and this conforms to their growth-temperature relationship.T. viride was found more effective in acid media as reported by others, whereas other antagonists and especiallyC. cochlioides was more effective in the alkaline medium. Hence the suggestion is made that soil amendments increasing the activity ofC. cochlioides might be a good control measure against the pathogen in alkaline soils.
The most interesting result of the investigation is that, contrary to the previous reports,R. solani appeared to be more cellulolytic thanT. viride andC. cochlioides and this result was unaffected by the use of NH₄C1 as N-source.

The author investigated in the course of two years the osmotic pressure of 70 trees of 7 apple tree sorts, 5 of these bearing fruit periodically and 2 every year. At the beginning of the experiment, one half of the trees were without fruit and the other half with fruit-set. The experiment was carried out on 10-12-year-old trees (stock M II, M IX and M IV) in the NW apple-growing region of Bohemia (Střčžovice, Těchobuzice). Three or four times during every vegetation season leaves of brachyblasts of fruit-bearing and resting apple trees were removed and the osmotic pressure of their cell sap as well as its electric conductivity were measured. Once in every season, terminal buds of brachyblasts usually giving rise to flower buds were removed and treated identically as the leaves.
It follows from the data obtained that growing fruits bring about a decrease in osmotic pressure of leaves of apple trees by 2-6 atmospheres, depending on the amount of fruit-set and on the season. This decrease depends very little on weather and differences in osmotic pressure of the cell sap of fruit-bearing and resting apple trees are highly significant in July. The cell sap osmotic pressure in buds is decreased less - by 1-2 atmospheres. A significant positive correlation between the value of osmotic pressure and flöwer-bud formation of the sort Boskopská červená was demonstrated. In sorts bearing fruit annually, no such correlation, could be observed.

Kinetin and 6-benzylaminopurine were applied to apple-trees (Malus domestica) with the aim of regulating growth and metabolism of buds. A single dose of 20-200;Cg. kinin counteracted the inhibitory effect of the fruit on bud growth. Lower doses resulted in thickening of buds, higher doses in bursting of buds to form twigs.
It was found with the aid of radioactive phosphate that the inhibitory effect of fruits is reflected particularly in a considerable decrease of incorporation of radioactive phosphate into the fraction of free nucleotides, especially in meristematic tissues. Furthermore the rate of synthesis of nucleoproteins and phospholipids is considerably decreased in the buds of a fruit-bearing apple-tree as compared with those of one which is barren in the given year.
The kinins bring about a change in the metabolism of buds adjacent to fruits (both of their meristem and scale integuments) and the incorporation of radioactive phosphate resembles after a seven-day exposure very much that in the buds of a barren apple-tree.
Radioactive 6-benzylaminopurine-^9-14C was synthesized here and autoradiography revealed that it is localized in the vicinity of the point of application, predominantly in the bark and in the phloem. It is little transported toward the apical end, somewhat more toward the basal end of the shoot (an X-ray film darkens several cm. away from the point of application). After an extended period of time another radioactive substance was isolated from the experimental material, the substance differring from 6-benzylaminopurine in itsRF value during paper chromatography. The substance is being further investigated.

1. It was found in agreement with the results of Fang and co-workers (1960) that gibberellic acid in concentrations between 2 and 80 mg./l. does not affect the ratio of radioactivities of¹⁴CO₂ liberated from glucose-6-¹⁴C and -1-¹⁴G (C₆/C₁) when acting for several hours on sliced wheat leaves, and that at a concentration of 10 mg./l. it does not alter the degree of inhibition of respiration due to fluoride, iodoacetate and malonate or the consumption of oxygen. A linear relationship was established between the decrease in¹⁴CO₂ liberation from glucose-¹⁴C and the concentration of gibberellic acid.
2. The C₆/C₁ ratio as well as the absolute values of radioactivity decrease more rapidly in the course of several days after the germination of plants grown in a solution of gibberellic acid (10-20 mg./l.) than in the water-grown control.
3. Fluoride inhibits the respiration of plants grown in gibberellic acid more than of those grown in water, its tissue concentration being either equal or less in the gibberellic-grown plants; the effect of iodoacetate and malonate is the same with plants of equal age (4 days) in both variants. The possible causes of this phenomenon are discussed.

During stimulation of wheat leaf respiration by fluoride at 100 to 200 p. p. m. fluorine in dry tissue the ratio of radioactivities of¹⁴CO₂ released from glucose-6-¹⁴C and that released from glucose-l-¹⁴C (C₆/C₁) increases due especially to an increased output of 6-¹⁴CO₂ which suggests an activation of glycolysis. The absolute values of radioactivity of¹⁴CO₂, however, are decreased by the action of fluoride due to its inhibition of the transport of glucose into leaves.

1. Differences in the net photosynthesis rate (PR) and in chlorophyll (a+b) content in leaves of different age in the leaf rosette of Nicotiana sanderae hort. were studied. The PR was estimated by two different methods, viz. the dry-weight and the gazometric method.
2. Highest PR and highest chlorophyll content (referred to leaf area) were found in the young but well developed leaves, i.e. the third and fourth counting from the top (a leaf of 20 cm.² area served as first leaf). These leaves are designated here as "photosynthetically mature".
3. The decrease in PR during leaf ageing was more rapid than that of the chlorophyll content. At a certain chlorophyll content (about 2.25 to 2.45 mg./ /dm.²) the rate of net photosynthesis drops to zero.
4. The PR is linearly proportional to the amount of chlorophyll (referred to unit area), independent of the position of the leaf in the genetic spiral. No substantial differences in the results were found on using two completely different methods.

New Chromatographic methods, chromatography in centrifugal field and thin-layer chromatography on alumina, were used for separating physiologically active gibberellins A₁ and A₃. Paper electrophoresis was found unsuitable for the separation of the two gibberellins. For centrifugal chromatography the system benzene-acetic acid-water (4:1:2) was found convenient. In both the centrifugal and thin layer chromatography the overflowing technique was applied with great success. In the case of centrifugal separation bromophenol blue was used to indicate the position of the solvent front. Development was stopped when the spot of the indicator reached 3/4 of the paper length. For separating on a thin layer of alumina the solvent system benzene-acetic acid (100:23) was used. Here again the solvent was left to overflow; for dimensions of the thin layer of 10 X 23 cm 60 ml of the solvent mixture were used. The spots were detected in both cases with 0.5% potassium permanganate. The detection of the spot of gibberellin A₃ using 70% sulphuric acid after thin layer chromatography was found unsufisfactory. Sulphuric acid may be replaced by 70% perchloric acid. Both analyses take about 6 hrs. which reduces the time necessary for their completion to one working day.

A method is described for the application of the dry weight increment technique of photosynthesis measurement to plants with narrow leaf-blades (e.g. Festuca, Stipa etc.). A sample of leaf tissue is represented by the area of a frame filled with leaf segments placed side by side. The leaf segments 26 mm. in length are cut out from the leaves with a special punch; their number in the sample must be determined empirically for each plant species. In connection with this problem the authors describe the relationship between the intensity of photosynthesis and the number of segments in a sample.
The accuracy of the indirect determination of dry weight increment with the aid of control samples is maximally ±1% for ten estimations and 5% probability, which makes it possible to determine photosynthesis with an accuracy of ±10% when the assumed dry weight increment is 10%.

Experiments on the effect of sodium humate on the swelling and germination of the winter wheat Pyšelka (Triticum vulgare Vill.) and on the changes in respiration intensity of swelling seeds during the first 24 hours of swelling, are described.
It was found that sodium humate at a concentration of 100 mg./l. accelerates the uptake of water by swelling seeds during the initial phase of swelling. The fact that the seeds take up a sufficient amount of water sooner makes it possible for the activation of enzyme systems which ensure normal germination to take place, thereby bringing about an increase in respiration intensity. The energy released during respiration is then utilized for more rapid growth of the embryo which is morphologically reflected in the rate of germination.

The different components of humus-alcoholic extract, humic acids and fulvic acids-progressively isolated from compost garden soil and deprived of minerál ions by electrodialysis, were, after addition to Sachs's nutrient solution, found to have differing effects on the growth of stems and roots of tomato plants. Similarly, differences in the effect on oxygen intake of leaves and roots was confirmed and varying amounts of chlorophyll were determined in the leaves. Fulvic acids were shown to be more active components of humus than humic acids. Morphological changes in the root system were found to be more typical for an estimation of the action of the different components of humus than the changes in physiological characteristics mentioned above.

Humus acid (Humussäure Riedel de Haen AG. Seelze Hannover) in 0.01% concentration increases the respiration intensity of plant roots grown in water cultures both as regards O₂ consumption and CO₂ production, while RQ (CO₂:O₂) is only very slightly increased. The plants used in these experiments were the winter wheat Pyšelka (Triticum vulgare Vill.), maize Zaj íček's "Český koňský zub" (Zea mays L.) and the gourd Veltrusská velkoplodá (Cucurbita maxima L.). O₂ consumption and CO₂ production were determined on separated root tips by the direct Warburg method. It was found that the effect of humus acid is not only to increase respiration intensity in the roots of the experimental plants, but also their lengths and dry weights (for all experimental plants); for maize and gourd the dry weights of overground parts were also increased, which indicates that increased respiration intensity was linked with more intensive growth of the plants.