The exposure ofTaraxacum officinale L. at flowering time to a weak magnetic field resulted in (1) retarded opening and the closing of the inflorescence, (2) wilting and death after prolonged exposure. Controls were unchanged. Plants exposed to the effect of magnetic fields were degenerated in subsequent year.

Experiments with isolated wheat roots and with intact wheat plants showed that glutamic acid decarboxylase from the roots takes part in the transformation of substance in the medium and that its activity is influenced by the medium. Glutamic acid decarboxylase is thus a factor taking part in the formation of substances excreted by the plants roots.

The rather equal development of the two cotyledons determines the bilateral symmetry in the pea seedling, just as their unilateral position results in the dorsiventrality of the epicotyl and root. The morphogenic manifestation of the symmetry relations conditioned, in the first place, by a different distribution of auxin out of the cotyledons may be enhanced by means of exogenous growth regulators, particularly IAA, GA₃, and TIBA.

Cultures of the coenobial four-celled chlorococcal algaScenedesmus quadricauda were synchronized. Ontogeny of the species, proceeding analogously to that of the unicellular forms, was studied; however, the cells in the coenobium ripen successively. The paramoters of the synchronized cultures were followed and according to the obtained results an objective method of evaluation of the synchronization-degree of the algal cultures, on the basis of information theory, was suggested.

Einige durch Chloroalhydrat behandlung erzielte mixoploide Wurzelspitzen vonVicia faba verzweigen sich dichotomisch und es hat sich herausgestellt, dass die Dichotomie in jenen Wurzeln vor sich geht, welche einen polyploiden axialen Strang, der bis in das Transversalmeristem hineinragt, enthalten. Zu beiden Seiten dieses Streifens differenziert sich durch entsprechend orientierte Zellteilungen je ein neues Transversalmeristem. Wenn der polyploide Streifen nicht axial verläuft, so spaltet sich die Wurzelspitze in einen stärkeren weiter wachsenden und einen schwächeren, meist sein weiteres Wachstum einstellenden Teil. Da sich die polyploiden meristematischen Zellen in einem diploiden Gewebe als fremde Elemente verhalten können, was sich in den häufig vorkommenden Chorisen äussert, so kann die Dichotomie der mixoploiden Wurzelspitzen durch eine Schwächung der normalen Korrelationen zwischen den Initialzellen erklärt werden, ähnlich wie wenn die Wurzelspitze durch einen medianen Längsschnitt angeschmitten wäre. Da werden, wie seinerzeitLopriore (1896) gezeigt hat, die beiden Hälften der Wurzelspitze restituiert und wachsen als zwei selbständige Wurzeln weiter. Verläuft der Einschnitt nicht median, so stellt der schwächere Teil der Wurzelspitze sein Wachstum früher oder später meist ein. Normal dichotomisch sich verzweigende Wurzeln tun das ohne auslösende Wirkung polyploider, axial verlaufender Zellstreifen.

Mittels unmittelbarer Analyse auf Grund chemischer Reaktionen, Chromatographie und elektronenmikroskopischer Diffraktion wurden beiNitella sp. im Zellsaft drei organische Säuren festgestellt: Weinsäure, Zitronensäure und eine Säure, deren Identifizierung bisher nicht gelungen ist. Weiter wurde festgestellt, dassNitella-Zellen, die einen langsameren Metabolismus haben oder ein höheres pH des Zellsaftes aufweisen, Neutralrot in ihren Vakuolen viel langsamer ansammeln als Zellen unter normalen Bedingungen. Eine Blockierung der Atemenzyme durch Kyanwasserst off hat aber keinen Einfluss auf die Geschwindigkeit der Aufnahme dieses Farbstoffes durch die lebenden Zellen.
Auf Grund der Ergebnisse dieser Arbeit ist die Annahme möglich, dass die Aufnahme basicher Parbstoffe durchNitella auf Grund eines Ionengefälles vor sich geht und dass seine Geschwindigkeit unmittelbar von der Konzentration organischer Säuren im Zellsafte beeinflusst wird.

The given data shows that between the halves of lateral leaflets ofMedicago sativa there exists an anatomical symmetry of the epidermis as well as in the case when both lateral leaflets are compared one with another. In spite of several differences, which may be caused by the environmental conditions, the analysis of variance shows that these differences have no importance in the total variability of obtained data.
Similarly, the symmetry was shown by the study of water loss of the pairs' lateral leaflets. In this case the total course of the water loss curve must be appreciated, which is the same in the curves of a leaflets' pair of the same leaf. Differences in the absolute water loss are caused probably by the manipulation with the material before the experiment.

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

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

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

Cyanus segetum LAM. was transferred from a long to a short photoperiodic regime at various stages of ontogenesis and the development of the plant investigated. The morphology of the leaves ofCyanus segetum was dependent on the photoperiodic regime. On a short photoperiodic regime, pinnately sected leaves were formed, but only if development was inhibited while the shoot apex still had a structure characteristic for the vegetative plant. The ability to influence the shape of the leaves by a short day ends before the morphological differentiation of the inflorescence at the time of the disappearance of the vegetative structure and the formation of the meristematic mantle. After this time all leaves were smooth-edged like those of the controls on a long day. Although the ability to influence leaves was limited to the period of initiation of the leaf primordia, it was not restricted to the primordia then being initiated. The conditions of development also affected leaves whose primordia had already been initiated. This was evidently due to the action of photoperiodic conditions via ontogenesis. The position of the axils was also changed in dependence on the photoperiodic regime.

Statmographs were used for determining the curves of weight decrement of severed root tips of the squash (Cucurbita maxima L.) with time and were examined under controlled conditions. The existence of two qualitatively different fractions of water could not be demonstrated by the method used, all the curves obtained displaying a completely continuous character, without any inflexion point. The basic shape of the curves remained preserved on desiccation at different temperatures (20-40° C), at different relative humidity (45-90%), with plants of different age and different composition of aqueous media (Knop's nutrient solution, calcium-free medium, distilled water). Not even a 0.01% solution of potassium humate which significantly raised the water content of root tissue affected the shape of the desiccation curves. A continuous release of water was also observed when the meristematic root zone and the zone of longitudinal growth were dried separately.

Quantitative determination of chlorophyll a and β can be made by paper chromatography of acetone extracts of plant material with colorimetric measurement of the eluates from the separated zones.
From the suitable solvent systems which give adequate separation of the pigments at a distance of 20 cm. from the start,Hager's mixture (1955) separates the chlorophylls better than the toluene-isopropanol (400: 1 v/v.) mixture, which, however, is better for the separation of carotenoids. Twice the amount of chlorophyll is separated on Whatman 31 ET paper, equally well and with the same time of development, as on Whatman No. 3 paper, on which it is possible to separate a maximum of about 15 μg of chlorophyll pigments per 1 em. start length. Losses on elution are, however, higher on using Whatman 31 ET paper. In plants with a high chlorophyllase activity, the error of determining chlorophyll a andb is greatly reduced if the leaves are placed for 1 min. in boiling water before extraction. For elution of chlorophylla andb from paper it is better to use anhydrous acetone, for chlorophyllides 80% acetone.
A comparison of the procedure investigated with the method of two-wave length spectrophotometric measurement of crude acetone extracts showed that in view of the average 10% loss, the chromatographic method is hardly suitable for determining the absolute amounts of chlorophylla andb, although the relation (a/b) can be determined with similar precision by both methods. Moreover, in view of the greater amount of work involved the chromatographic method can only be recommended for confirming the results of spectrophotometrie determination. Quantitative determination of chlorophylls from the area of the spot or from the "R_F" value can only be of an informative character.

The growth OfRhizoctonia solani in different carbohydrates was studied. The rate of growth of the fungus was traced by taking the dry weights of mycelia obtained from the carbohydrate medium at regular intervals and shifts in the pH were recorded. Different carbohydrate sources had different effects on the growth of the organism. The exoenzymes from the organism were capable of cleaving carbohydrates irrespective of whether the fungus grew in them or not.

An investigation was made of the anatomical structure of the shoot apex of wheat in the first four stages of organogenesis according toKuperman (1961). It was found that the shoot apex is first covered only with dermatogen (first stage). Then the hypodermis gradually differentiates (second stage) followed by differentiation of the subhypodermis (third stage). In the first stage, the central core of the apex is formed by more or less uniform isodiametric cells so that no zones are distinguishable. During the initiation of the primordia of the assimilating leaves, i.e. in the second stage, a group of larger cells was observed in the apical part of the hypodermis and can be compared with the central zone described in dicotyledons. Under it there is a characteristic group of smaller cells. In the third stage the differences between these groups of cells become less clear and in the fourth stage are no longer observable. No differences were found in the manner of initiating the leaf and bud primordia during the period of ontogenesis studied. There is, however, an alteration in the extent of growth between the bud primordium and the corresponding leaves. Short-day photoperiodic inhibition, always started on the days when the shoot apices were collected for anatomical study, showed that the determination of the primordia of the leaves and axillary buds as parts of the inflorescence is complete by the end of the third stage, at the time when the primordia in the central part of the ear are initiated

Six-day leaves of wheat (Triticum vulgare) were used to test the effect of oxygen, nitrogen and different mixtures of these gases, methylene blue and L-cysteine on the inhibition of respiration by sodium fluoride and monoiodoacetic acid using the Warburg manometric method. In an atmosphere of 100% oxygen total respiration was increased by an average of 45%, 10% oxygen led to a decrease in respiration by 20%. However, no simultaneous changes were found in the degree of inhibition by these enzyme poisons. On decreasing the oxygen content to 5% inhibition of respiration was almost doubled while at the same time respiration fell by an average of 23%. In nitrogen, the respiration rate varied around 10% and inhibition was almost 100%. The results showed that the action of enzyme poisons is only influenced by different oxygen content at low oxygen tension and is evidently associated with the dominance of a given energy system (glycolysis).
On using methylene blue and L-cystein in concentrations of 10-3M a decrease in the relative inhibition of respiration by enzyme poisons was also found. The total respiration rate, however, was only raised by 6-8%. Since the change in the degree of inhibition on using these substances is caused by an increase in the participation of respiratory processes resistant to glycolytic inhibitors it can, in this case be assumed that there is an increase in the activity of the pentose cycle in such tissue.

The pathophysiology of tomato plants infected with potato witches' broom was studied. Changes in dry weight, content and composition of ash and the amount of different phosphorus and nitrogen fractions were investigated. All analyses were carried out separately in leaves, stems and preliminarily also in flowers. Considerable disproportions found in the distribution of metabolites among the individual organs investigated correspond to a great extent to the morphological picture of the disease. The leaves of diseased plants are actually starving and their growth and development are greatly inhibited. On the other hand, the stems are overflowing with metabolites, in particular with nitrogenous ones. They are thickened and along their entire length rootlets and sprouts appear forming the characteristic brooms. The authors assume that the disturbances in flower formation in diseased plants are due to the lack of essential metabolites. Diseased plants contain an increased amount of alkaline metals and alkaline earths.

1. The relation between the manifestation of the factors for the row number, development and fertility of lateral florets and kernel weight of barley was investigated.
2. Kernel weight was found to depend on the number of rows as well as on the development and fertility of the lateral florets.
3. The possibility of a genetic linkage between the factors for row number and kernel weight was discussed.

As lipids can be a source of artefacts during intracellular localization of enzymes by cytochemical methodsin situ it was the aim of the present work to obtain orientation data on the distribution of lipids in the meristematic plant cells. The different fixation and object embedding methods examined revealed that it is best to fix the material by some formol fixative and without chroming, to embed it in polyethyleneglycol media. An alcoholic solution of Sudan black was found to be most reliable. In the meristematio cells the cytoplasm is usually stained more intensely than the nucleus. The ground cytoplasm is stained weakly while cytoplasmic particles are stained intensely. In some cases an intense black staining of nuclei, particularly in the prolongation zone, can be achieved. The staining intensity of cell components does not decrease on extracting lipids with pyridine. After extracting the dye from stained cell components a browninsh residual coloration remains. Chromatography of Sudan black revealed in all the samples tested slowly moving spots (blue and violet) and rapidly moving ones (red II, yellow, red I, colourless).

Im Jahre 1900 veröSentlichte ich einen vorläufigen Bericht über durch Schwerkraft bewegliche Stärkekörner in bestimmten Pflanzenzellen, die man als tierischen Statozysten analoge Vorrichtungen ansprechen könnte. Über diesen Gegenstand erschien 1901 meine ausführliche Arbeit, in welcher ich eine auffallende zytologische Reaktion beschrieben habe, die in stärkeführenden Columellazellen der Wurzelhaube bei geotropiseher Reizung erscheint: Diese Reaktion, welche ich als ein Symptom, dass die erwähnten Zellen den Schwerkraftreiz zu rezipieren vermÖgen, betrachtete, wurde später sehr selten nachuntersucht und ist vergessen worden. Erst im Jahre 1962 veröffentlichte AUDUS neue Angaben über dieselbe und zwar auf Grund von elektromikroskopischer Untersuchung der Statozyten in Wurzelhauben.
Die vorliegende Mitteilung bringt zum ersten Mal mikrophotographische Aufnahmen der zytologischen Georeaktion und erwähnt neue Versuche, welehe zu Gunsten der Ansicht sprechen, dass die zytologische Georeaktion durch Druck der Statolithen auf die äussere Zytoplasmahaut der Statozyten ausgelöst wird. Es wird auch darauf hingewiesen, dass nicht nur spezifisch schwerere, sondern auch spezifisch leichtere Körperchen als Statolithen, welche eine Georeaktion auszulösen fähig sind, fungieren könnten.

A water-soluble germination- and growth-inhibitor present in plants of Brassica genus was studied. Aqueous eluates from chromatograms of methanolic extracts of Savoy cabbage, cabbage and Brussels' sprouts leaves, and of Brussels' sprouts roots, inhibited the growth of wheat; the chromatographic behaviour of this inhibitor was similar to that of the thioglycoside glucobrassicin (GLUBR). GLUBRat 10^-3 m, and the supposed product of its enzymatic degradation, 3-indolylacetonitrile (IAN) at 10^-4 m, inhibited the growth of wheat and clover in a similar manner. At lower concentrations, both substances gradually enhanced growth. In contrast to IAN, GLUBR did not appreciably influence the growth of Savoy cabbage. Other products of GLUBR degradation, such as thiocyanate ion and ascorbigen, influenced the growth to a lesser extent and in a different way. At higher concentrations GLUBR and IAN also inhibited the germination of clover seeds. The biological effect of GLUBR is dependent on the presence of the indole nucleus in its molecule; the thioglycoside glucoiberin, which is not of indolic character, does not influence growth. The presence of free myrosinase was shown in intact wheat seedlings. Hence, GLUBR taken in by the germinating plants must undergo enzymatic cleavage. The in vitro activity of myrosinase in wheat and clover was lower than in Savoy cabbage, but the quantity of IAN formed at a pH corresponding to the natural pH was higher in wheat and clover than in Savoy cabbage, where the formation of the growth-inactive ascorbigen prevailed. On the basis of these results the hypothesis was formulated that GLUBR, the indolic complex from the generaBrassica, Raphanus, Cochleria, Nasturtium, Barbarea andSisymbrium, is a representative of a class of potential inhibitors of growth and germination, whose activity can be explained by the liberation of large amounts of growth-affecting substances during their specific enzymatic cleavage.

An investigation was made of the anatomical structure of the shoot apex ofSenecio vulgaris L. a photoperiodically neutral plant, and compared with the formation of successive leaf primordia along the axis up to the initiation of the terminal inflorescence. In the shoot apex of a germinating plant a central zone can first be distinguished from the peripheral zone which is composed of small and intensely stained cells. Later, a rib meristem appears. At the time of the initiation of the middle (the largest) leaves, the shoot apex has a distinct small central zone and a well developed peripheral zone and rib meristem. Between these zones there is a group of cells dividing in all directions, the subcentral zone. At the time of initiation of the last leaves, the central zone extends to the flanks and gradually ceases to be distinguishable. At the same time, the subcentral zone increases in size. This is caused first by cell division and later, with the initiation of the last, most reduced leaves, by enlargement of the cells. Vacuolization in the inner part of the apex and the arrangement of the superficial cells in rows parallel to the surface of the apex, is a preparatory step to the initiation of the inflorescence.

A very low, for the most part unmeasurable glutamic-aspartio transminase activity and a very high glutamic-alanine transaminase activity was found in the overground parts and roots of young wheat plants. The roots had a higher glutamic-alanine transaminase activity than the overground parts in the first and second leaf stage.
Plants cultivated in Knop's nutrient solution (variant with humate and without) showed a higher glutamic-alanine transaminase activity than poorly growing plants, cultivated in distilled water (with humate and without). In plants cultivated in nutrient solutions, transaminase activity increased with the age of the wheat plants.
As in the previous experiments, the effect of humate was only significant, in the roots of plants cultivated in distilled water with humate, where transamination activity was greater than in the control without humate. The roots of this variant with a stimulatory growth effect showed a large accumulation of free sugars in the previous experiments.
The connection between these effects of humate on the roots of young winter wheat plants is discussed.

A study was made of the effect of substituting a short day for vernalization as a varietal characteristic of winter wheat. Varieties representing certain ecotypes were vernalized for different lengths of time and it was studied how a short day can replace or accelerate vernalization. At the same time data were obtained on the effect of a short day on individual criteria of growth. The results showed that there are ecotypes in which a short day does not replace vernalization (the varieties San Pastora and other Italian varietis). In this case growth inhibition did not occur either. Otherwise it usually accompanies the substituting affect of a short day. This finding permits the interpretation of varietal differences observed in association with short day growth inhibition and changes in carbohydrate metabolism conditioned by it. Growth inhibition produced by a short day is a general reaction which is not only associated with vernalization. The author found varieties (Chlumecká 12) in which growth was inhibited by short day without accelerated development occuring (alternative types).

The seeds contain such a high percentage of phosphoric acid that it interferes with the obtaining of correct results in analysis. Its prior removal from the solution of ash is therefore necessary. A new method is suggested for the entire analysis which is a combination of percolation through an ionexchanger column and colorimetric and gravimetric determination.
The oxide values and the average content of ash per 100 g. dry weight of seeds ascertained by analysis were used to calculate the weight of each determined element per 100 g. of dried substance.
The analysis showed that traces of tin are present in the ash of the seeds tested.
Under the given conditions each species maintains its characteristic way of storing ash constituents in the seeds and this is not obviously affected by the affinity of the plants or the influence of the soil.