It was shown that in the horse bean seeds (Vicia faba) the cotyledon proteins are identical, from an immunochemical standpoint, with those coming from the extracotyledon parts (radicle, young stem and embryonal leaves, in totality). However, the beginning of the germinative process exerts a different influence on the antigenic properties of the constitutive parts of the seed. The modification of the antigenic structure in cotyledons takes place slowly. On the contrary, in the extracotyledon parts a rapid decrease was found of the number of antigens present in the non-germinated seed. As the organs become differentiated, the hydrolysis process of these antigens goes on until their almost complete exhaustion. However, it appears that three of the initial antigens remain in the newly arisen leaves. Besides these antigens there are also specific-organ antigens which appear as the respective organs become morphologically differentiated. It was found that in the growing leaves the process of photosynthesis induces the synthesis of antigens characteristic for the mature leaves. The organ-specific antigens occur during plant development at the time when the leaf attains the morphological structure and the functional specialization characteristic for maturity.

The stomata closure in Begonia semperflorens by alpha - rays was studied. Complete closure of the stomata was used as indication of the reaction. The minimal doses with significant results was 2-2. 10⁶ α. cm^-2, the maximum at the dose of approx. 9. 10⁶ α. cm^-2 was found.

Experiments with sunflower and fodder cabbage showed that reversion of the leaf disks lower side upwards (towards the radiation source) decreased the photosynthetic rate by as much as 26% both at full (2. 10⁵ erg. cm^-2. sec.^-1) and half density of irradiation. On placing two disks one on another the photosynthetic rate was decreased in the upper disk in a similar way as it was on reversion even if it were placed in the normal position (upper side upwards). But assimilation in the lower disk was only a fraction (0-40%) of that of the upper disk and in thick leaves was within the limits of the compensation point. The sum of the increase in dry weight in both disks due to photosynthesis exceeds the increment in one normally placed disk only in thin leaves and at high density of radiation. On the basis of the differences found it is advised to discard experimental samples where a quarter of the disks were reversed during exposure. On evaluating samples in which some of the disks were duplicated in error, it is most accurate to deduct the weight of one control disk from the weight obtained. The decrease in photosynthetic rate found in reversed and duplicated disks is evidently due to the simultaneous effect of differences in the supply of CO₂ and radiation energy to the assimilating tissue and apparatus and also to differences in the photosynthetic capacity of different leaf tissues.

In der vorliegenden Arbeit wird die Einwirkung der Humusstoffe durch Besprühen der Zuskerrübenblätter untersucht. Gleichzeitig ist auch die Eignung der Kombination von Humusstoffen und Minerallösung bei der Blattdüngung überprüft worden. Die Versuchsergebnisse lassen sich folgendermassen zusammenfassen: Die Blattdüngung mit Humusstoffen, insbesondere in Kombination mit Mineralnährstoffen beeinflusst das Wachstum der Zuckerrübe günstig. Das Gewicht der Rübenblätter und der Wurzel, sowie der Zuckergehalt werden erhöht. Bei den in Wasserkultur gezogenen und mit einer Nährlösung von vollständigerer Zusammensetzung der Mineralstoffe besprühten Pflanzen ist die Wirksamkeit des Besprühens grösser, als bei den Vergleichsversuchen, deren Pflanzen in Sand mit Nährlösung kultiviert wurden. Bei einer Anwendung am Blatte rufen die Humusstoffe ähnliche Veränderungen des anatomischen Baues der Gewebe und der Organe hervor wie nach ihrer Zugabe in die Nährlösung zu den Wurzeln. Die Humusstoffe, insbesondere in Kombination mit einer Minerallösung erhöhen den Chlorophyllgehalt und die Intensität der Photosynthese in den Zuckerrübenblättern. Die Blattdüngung mit Humusstoffen erhöht gleichzeitig auch die Transpiration der Zuckerrübe.

When the epicotyl and one cotyledon is cut off from pea seedlings, only the axillary of the amputated cotyledon is known to grow. When³²P is applied to the roots of such plants, then a higher radioactivity appears in the axillary of the amputated cotyledon already 24 hrs. after amputation of one cotyledon, although this axillary is of the same size at this time as that of the remaining cotyledon. This fact indicates a more extensive material transport to the axillary bud of the amputated cotyledon already during the first day after amputation
The effect of individual regulators on the³²P transport was investigated in an experiment where pea seedlings cultivated in the dark were decapitated and a 0.5% paste, containing the regulatory compounds was placed either on the cutting surface in the apical part of the epicotyl stump or in its central part. After a week the plant roots were supplied with³²P and its transport to the upper part of the epicotyl stump was followed. This transport increased about 10-fold in the case of a paste, containing indolyl acetic acid, when the paste was spread on the apical cutting surface of the stump. However, the transport was inhibited when the paste was applied in the central part of the stump. These results indicate that only the transport of³²P towards the paste with indolyl acetic acid is accelerated, whereas it is decelerated above this paste. A paste, containing triodobenzoic acid inhibited³²P transport only when applied to the apical cutting surface of the epicotyl stump and not when spread over the middle part. In this case³²P transport was more rapid above the paste than towards the paste. The situation was similar in the case of gibberellin and kinetin.

Die vorgelegte Arbeit befasst sich mit der gegenseitigen Beziehung zwischen Roggen und Hanf in Wasserkultur bei ergänzter Mineralernährung. Nach 24tägiger Kultivierung wurden keine beweiskräftigen Unterschiede des Wachstums der Kontrollpflanzen und der Mischkultur gefunden. Beweiskräftige Unterschiede wurden jedoch in der H₂PO₄-Ionensorption bei Anwendung des Radioisotops³²P festgestellt. Beeinflusst wurde auch der Wasserbedarf der Pflanzen in der Mischung. Die festgestellten Unterschiede wurden durch die Wirkung von spezifischen Stoffen in den Wurzelausscheidungen der beteiligten Pflanzen erklärt.

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 "injection method" is recommended for maintaining a constant soil moisture at values lower than maximum capillary capacity in pot experiments. The appropriate amount of water is injected into the soil by means of a puncture needle connected with a syringe. The reliability of the above method in relation to the uniformity of the vertical and horizontal distribution of soil moisture was tested in pot experiments with maize. The fortuity of the changes in the soil moisture distribution within the scope of the given variability restricts the "growth of roots towards the water".

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.

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

1. Treatment with high to sublethal doses of streptomycin (1 m Mol, 0.5 m Mol) did not induce any significant increase in chromosome aberrations at the metaphase and at the ana- and telophase. The only significant increase in aberrant ana- and telophases was observed as a consequence of treatment with 1 m Mol streptomycin (30 °C, 48 hrs recovery). This increase was mainly caused by the presence of lagging chromosomes and was therefore the result of spindle damage and not of chromosome aberrations. This fact was verified by the nonsignificance of the increase in aberrant metaphases under the same treatment. The disadvantages of evaluation of chromosome aberrations in ana- and telophase are stressed in the discussion.
2. Simultaneous treatment with low doses of streptomycin (0.005, 0.0005 m Mol) and ethanol showed a decrease in the frequency of chromosome aberrations compared with their frequency after ethanol treatment alone.
3. Pretreatment with 0.05 m Mol streptomycin for 2 hrs reduced the number of chromosome aberrations, induced by ethanol.

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).