Wurzelspitzen von Pisum sativum wurden zwischen zwei konvergenten Gläschen gequetscht und der weiteren Entwicklung überlassen. Sohon nach 48 Stunden waren alle um das Plerom herum entstandenen Risse durch kallos vergrösserte Perikambiumzellen dort, wo das Perikambium differenziert war, gefüllt. Soweit das Plerom in Verbindung mit der Initialzone verbunden blieb, wuchs es gleichmässig mit dem Periblem weiter. Wurde es jedoch von den Initialen abgerissen, so hörte es auf zu wachsen. Wenn die Spitze des Pleroms abgerissen wurde, differenzierte sie sich nicht weiter, sondern verblieb als schwach wucherndes Gewebehöckerehen ohne Differenzierung. Die grösste prospektive Potenz besitzt das Plerom, die geringste das Periblem. Sofern das Plerom mit der Initialzone in Verbindung bleibt, beginnt die Spitze am dritten oder vierten Tage normal weiter zu wachsen, wurde es jedoch beim Quetschen von den Initialen abgerissen, so entstehen an der Keimwurzel Seitenwurzeln. Zur völligen Isolierung lebender Zellen und ihre Mischung kommt es in den gequetschten Wurzelspitzen nicht.

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.

Vorkommen und Erscheinungsformen von Kallose wurden an den Zystolithen von 23 Ficus. und 16 weiteren Pflanzenarten aus den Familien der Moraceae, Acanthaceae, Combretaceae, Oleaceae und Urtieaceae untersucht. Zystolithen-Kallose wurde im wesentlichen nur bei der Gattung Ficus gefunden.
In der Zystolithen-Entwicklung vonFicus elastica bestehen die zuerst angelegten Teile des Stieles aus Zellulose. Bei einer Länge von etwa 30 μ werden am Stiel erste Kalloseabscheidungen in Form dünner Überzüge am freien Ende gebildet. In der Folge kommt es häufig zu schichtweise alternierender Anlagerung von Zellulose und Kallose, die neben- und miteinander das Mittelstück des Zystolithen aufbauen. Die äusseren Teile der entkalkten Zystolithen werden stets von einem Mantel aus überwiegend reiner Kallose gebildet.
Das Problem einer Funktion der Zystolithen-Kallose wird diskutiert. Kallose wird-übereinstimmend mit früher vorgebrachten Auffassungen-als Begleiterscheinung des sich während der Entwicklung der Löthozysten verändernden Zellwand-Baustoffwechsels gedeutet.

Soyabean extract contains an activator which passes through parchment paper. The increase in the activity of a mixture of urease and papain with increasing amount of papain in the mixture is due to the increase in the non-dialysable fraction of papain.

The work is concerned with the question of the effect of humic acids on the biological action of agropyrene, the effective substance from the rootstock of Agropyron repens (L.) P. BEAUV. The test organism was the alga Scenedesmus obliquus (TURP.) KRÜGER, cultivated in
mineral solution. The basic biological test was the determination of the number and size of the cells of this alga. It was found that the way in which agropyrene acts on combined application with humus acids depends on which humus fraction is used. It can display a synergic action if humic acid is used, since this substance probably facilitates the penetration of agropyrene into the cells. On the other hand, fulvic acid counteracts the activity of agropyrene and this most probably by mutual binding and blocking of active groups and links.

Bei der Untersuchung von Zellen des Keimsacks von Lilium und des Vegetations-punktes von Triticum wurden plasmatische Einstülpungen und Elemente im Innern der Vakuolen gefunden. Die Plasmaelemente entstehen offenbar durch Abschnüren der Einstülpungen. Die Ursache ihres Entstehens und ihre Bedeutung für die pflanzliche Zelle wurden diskutiert.

Bei den submersen WasserpflanzenPotamogeton perfoliatus L. undP. lucens L. wurde die Anzahl der Epidermalzellen pro Blattflächeneinheit (mit Hilfe der Abdruckmethode) und die Dichte der Blattnervatur (curvimetrisch bei in Lacto-Phenol aufgehellten Blatteilen gemessen) bei oberen, mittleren und unteren Blättern, deren Blattbasis, -mitte, -rand und -spitze untersucht wurden, festgestellt.
Bei beiden Laichkrautarten sind die Unterschiede in der Anzahl der Epidermalzellen pro Blattflächeneinheit bei Blättern verschiedener Insertionshöhe nur am Anfang der Vegetationsperiodo statistisch gesichert, später bei ausgewachsenen Blättern nicht mehr. Die Unterschiede zwischen verschiedenen Blattstellen sind meist nicht signifikant. Die Unterschiede zwischen der Ober- und Unterseite des Blattes sind wohl beiP. perfoliatus, aber beiP. lucens nicht signifikant. Die Unterschiede in der Dichte der Blattnervatur zwischen Blättern verschiedener Insertionshöhe sind mit Ausnahme des Anfanges der Vegetationsperiode und einiger Unterschiede zwischen den mittleren und oberen Blättern beiP. perfoliatus auch nicht statistisch gesichert. Die Unterschiede zwischen verschiedenen Blattstellen sind bei beiden Arten statistisch hoch gesichert.
Dort wo der Einfluss der Wasserumgebung nicht durch die Einwirkung anderer Umwelt-faktoren kompliziert wird, wurde bei erwachsenen Pflanzen von P. perfoliatus und P. lucens nur ein unbedeutender oder kein xeromorphischer nach oben gerichteter Gradient bei den angeführten Merkmalen festgestellt.

A conductometric apparatus for determining the photosynthetic rate suitable predominantly for field measurements is described. In contrast with the hitherto described and applied instruments 3 samples of air can be analyzed here simultaneously, the data are temperature-independent and the entire electronic part of the apparatus is transistorized. The absorbers (300×30×30mm.) and the leaf chambers (140×100×10 mm.) are made of plexiglass. The membrane pump is hand-operated by means of a crank. The conductivity of the absorption solution (0.02N-KOH+0.5% isoamylalcohol+saponin) is measured in a special measuring cell into which the solution is transferred from the individual absorbers. The error of the photosynthetic rate determination is about 10-20% of the value obtained for intensities of 10-20 mg. CO₂ dm.-²h.-¹.

On incubation of the callus tissue ofDaucus carota L. in solutions of glucose-6-¹⁴C and -1-¹⁴C the distribution of radioactivity in the molecule of endogenous glucose will change and the ratio of activities of liberated¹⁴CO₂ (C₆/C₁) will rise The limits of possible changes of specific activity of¹⁴CO₂ and of the C₆/C₁ ratio were calculated with respect to the observed randomization and it was shown that the mutual exchange of carbon atoms in the molecules is not the decisive cause of the rise of the ratio.
The specific radioactivity of¹⁴C in CO₂ is as much as 12 times higher than that of endogenous glucose and fructose and about twice as high as the theoretical maximum. This might indicate that in addition to the cytoplasmic fraction of glucose the callus cells contain a fraction of low metabolic activity, most likely in the vacuoles, that could account for some of the increase of the C₆/C₁ value.
The main reason for the changes in the C₆/C₁ ratio is envisaged in the establishment of isotopic equilibrium between the pentose cycle and glycolysis and other metabolic systems, in particular via triose phosphates, the radioactivity of which can greatly affect the C₆/C₁ ratio, as was shown in a model experiment.

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.

Transpiration rates of leaf blades of irrigated and not irrigated spring wheat plants were studied in relation to the water content and growth changes in the test plants during their development. The applied irrigation stimulated the growth and slightly delayed the development of the test plants. It increased chiefly the water content and to a lesser degree the dry solid weight in the plant body. The quantitative and qualitative properties of the water content in the plant affected not only transpiration rates, but also the development of new and the dying off of old organs and tissues, especially of leaf blades. Transpiration rates in irrigated plants were markedly higher than in not irrigated plants. Mean transpiration rates of different leaf blades varied and were typical for each leaf blade. From the static aspect it was possible to express and even to explain some of the relationships and the heterogenity of the leaf blades on the same stem by the "Law of Zalensky". This involved mainly the mean values of growth characteristics and the investigated features of the water regime. On the other hand, from the dynamic viewpoint it was possible to divide the different leaf blades according to their transpiration changes into two groups. The first group includes the blades of the first to third leaf, the second group the blades of the fourth to sixth leaf and the ear. The capacity to control the water regime in the different blades is greatest at the stage of tillering, shooting and milk ripeness. During these developmental stages the marked decrease in transpiration, caused in the first place by a number of internal and not only external factors, was explained.

A method suitable for serial determinations in genetic experiments is described. Colorimetric determination of HCN (by 1-phenyl-3-methyl-5-pyra-zolone and pyridine, phenolphthalin or sodium picrate) facilitates processing of samples releasing 0.2 μg to 20 μg of HCN. Before hydrolysis of the glycoside the oil content in the seeds can be determined. Variance analysis of the cyanogenic properties of the particular seeds of two sorts of flax with an average HCN content of 0.4 and 0.9 μg shows that the differences between plants and between capsulae of the same plant can be determined.

The cytological effects of the insecticide Systox on the primary roots of Vicia faba and possible mutagenic effects on Arabidopsis thaliana have been studied. It was found that a 0.02% watery solution of Systox after a testing period of 3,6 and 9 hours under partially anaerobic conditions gives the following results:
a) no inhibition of mitosis was produced;
b) inhibition of the spindle was produced independently of the duration of action of Systox;
c) the occurrence of chromosomal aberrations increased significantly after 3 and 6 hours without restitution and after 3 hours with restitution for 24 hours. The frequency of these aberrations may depend on the isomeration of Systox in water since in older Systox solutions-where, according to data in the literature the concentration of isomer II increases-the frequency of chromosomal aberration increases significantly after 24 hours restitution. This influence of isomeration, was not found to affect the inhibition of the spindle, mentioned above.
Partial anaerobiosis itself produces a significant increase in inhibition of mitosis after 6 and 9 hours, an inhibition of spindle formation and an increased occurrence of chromosomal aberrations as against 3 hours testing.
After the action of a 0.2% and 1% concentration of Systox for 6,48 and 72 hours on seeds of Arabidopsis thaliana no chlorophyll or other mutations in the M₁ and M₂ generation were found.