The cotyledonary petioles inPisum sativum developing at the start of germination, as well as the cotylaries growing out after decapitation of thePisuin seedlings manifest very often the so-called lateral correlations, since one of them suppresses the opposite primordium when the growth inhibition in the plant coinciding apparently with the growth promotion results necessarily in a normal development only of one of these originally equal primordia. These correlations also seem to be mediated by auxin, being induced by gravity or by corresponding cotyledon and root products, which can be supported by the use of exogenous auxins.

Obwohl auf Grund vieler Untersuchungen vermutet werden konnte, daß die sog. Kakteen-Eiweißspindeln, d. h. die ZelleinschlÜsse des Kakteen-X-Virus (CaXV), aus zahlreichen verlängerten Partikeln des OaXV zusammengesetzt sind, war das dennoch bis jetzt noch nicht bewiesen. Deshalb versuchten wir im Laufe dieser Untersuchungen mittels der fluoreszierenden Antikörper festzustellen, ob die Eiweißspindeln wirklich Aggregate von Viruspartikeln darstellen.
Bei dieser Untersuchung wurde die sog. indirekte Methode angewandt. Dabei haben wir zuerst die spindelhaltigen Zellen mit dem durch Immunisierung der Kaninchen hergestellten homologen Serum gegen CaXV behandelt, und erst nachher dieselben Zellen in eine Lösung von fluoreszierenden Antikörpern gegen das Kaninohen-γ-Globulin eingelegt. Nach dieser Behandlung leuchteten die Eiweißspindeln im Fluoreszenzmikroskop kräftig gelbrÜn (Fluoresce-inisiothiocyanat). Diese Fluoreszenz bewies uns, daß die positive Reaktion eingetreten ist und daß die Eiweißspindeln aus Viruspartikeln aufgebaut sind. Mehrere Kontrollversuche haben die Genauigkeit unserer Grundversuche bestätigt.

The activity of 1-methyl-1-nitrosourea (MNH), 1-ethyl-1-nitrosourea (ENH), 1-methyl-3-nitro-1-nitrosoguanidine (MNG) and 1-ethyl-3-nitro-1-nitrosoguanidine (ENG) was tested on seeds of barley andArabidopsis. The activity of nitrosoamides tested was expressed by the germination and M₁ seedling height reduction of barley and M₁ root length reduction ofArabidopsis.
1) After the action of both nitrosoureas (MNH and ENH) the germination of barley is at the same level as that of controls, even at concentrations, leading to a maximal reduction in the height of seedlings. After the action of both nitrosoguanidines (MNG and ENG) germination decreases in parallel with the decreasing seedling height. InArabidopsis no such differences in the relation germination to root length reduction were observed after nitrosoureas and nitrosoguanidines treatment. The differences in the M₁ generation of barley andArabidopsis after nitrosoguanidines treatment may be the reason for the non-mutagenic action of MNG and ENG in barley.
2) All 4 tested nitrosoamides are active between pH 3 and pH 6 and almost entirely ineffective at pH 7 and in basic solutions.
3) The effectiveness (in relation to M₁ seedling height reduction) of the tested nitrosoamides with a methyl group (MNG and MNH) is higher than of the nitrosoamides with an ethyl group (ENG and ENH).
4) 50% decomposition of aqueous solutions (at 25° C) of MNH and ENH takes about 60 hours, for MNG 120 hours and for ENG 420 hours.
5) Aeration during treatment or a period in the cold (5° C) after treatment improved the germination of MNG treated seeds. Sucrose, KNO₃ and thiourea had no effect.

1. Kinetin at a supra-optimal dose of 1.0 mg/l reduces the growth inhibitory effect of CCC at 5 × 10^-2 M on tobacco callus and increases it on tobacco crown-gall.
2. CCC increases the content of total, acid soluble, protein anti nucleic acid nitrogm in both tissues. Kinetin partially reduces the effects of CCC on nitrogem metabolism in callus tissue, and increases it in crown-gall.
3. It is suggested that (1) CCC affects the synthesis of RNA directing the synthesis of protein, and (2) interaction of kinetin with CCC realizes via the genetic apparatus of the cell.

The enzymatic transamination reactions between aspartic and α-ketoglutaric acid and between aspartic and pyruvic acid were studied in fresh dialysed extracts of young wheat plants cultivated under various trophical conditions, in mineral solution (Knop), in the solution of an soil organic substance (potassium humate) and without nutrients (H₂O). Simultaneously, the level of endogenic aspartic acid, glutamic acid and the growth values were determined. The enzymatic reactions were characterized by determining the optimum pH, the time course, and the effect of coenzyme and of inhibitors.
The activity of the aspartate-glutamate transaminase from the root system of plants was considerably higher than the activity of the overground organs. The enzymatic activity from both parts of the plant was inversely proportional to the growth rate: intensive growth of the plants from the Knop variant was connected with their low enzymatic activity; the level of endogenic glutamic acid was high. The slow growth of the plants without nutrients was connected with a higher enzymatic activity; the level of endogenic glutamic acid was low. The plants from the potassium humate variant had an intermediate position between these two variants from the point of view of growth as well as from that of enzymatic activity. The plants with insufficient nutrition (slow growth, low level of endogenic glutamic acid) apparently have a low capacity for supplementing the glutamic acid deficit, which is essential for the metabolic processes, by increasing the activity of the reactions leading to glutamic acid synthesis (Asp-Glu) and, on the other hand, by decreasing the reactions utilizing it (Glu-Ala). For wheat plants the active aspartate-glutamate reaction is obviously physiologically more important than the direct reaction glutamate-aspartate and the reaction aspartate-alanine which in all cases had a very low activity.

The cytological analysis of 25 Yugoslav rye populations, collected from Slovenia Serbia and Macedonia, showed the presence of B chromosomes in the all populations analysed (100%). The number of B chromosomes present was small, from 1 to 3, while the average number per plant ranged from 0-13 to 0.97. The frequency of rye plants with B chromosomes for Yugoslavia had an average of 27.10%. The frequency of plants with B chromosomes and the average number of that chromosome category per plant were appreciably greater in the arid region of Macedonia than in the humid region of Slovenia, the differences being significant and real biometrically.
Comparing the data of other authors for primitive Asian rye populations, it was established that the B chromosome frequency is lowest in the populations from regions designed as centres of the origin of this plant species (Near East, Asia Minor), with a considerable successive increase of their frequency further as well toward the East (Transbaikal, Korea), as toward the West (Balkan Peninsula, Yugoslavia). Possible causes of the B chromosome frequency increase in the populations out of the centres of rye origin were discussed, and it was pointed out to the importance of their study in primitive West European populations.

U odr. Blenheimská reneta se postřiky α-naftyloctové kyseliny na letorosty strormů bez plodů neprojevily vyšším počtem založených květních pupenů. Autor proto dospěl k názoru, že otázka přímého zapojení a přímého vlivu α-naftyloctové kyseliny na zakládání kvétních pupenů u jabloné je sporná.

The applicability of the microrelief (or reprint) method for stomatal aperture determinations was studied in middle-aged sugar beet leaves. It was found that the picture of the central aperture (CA) of stomata on the reprints could be observed only if their eisoiial aperture (EA) was sufficiently wide. If the width of EA was small (about 1-3 μ), it was impossible to determine the width of CA by means of the reprint method, in view of the proportional dimensions of the upper closing flaps. A lower concentration of the chlorophorm solution of methylmethacrylate used for taking reprints had a favourable influence on the amount of stomata whose width of central aperture was reproduced on the reprints. Simultaneous measurements of the EA-width and of the diffusibility of leaves (determined porometrically) in the course of a day showed, on the whole, fairly corresponding changes. During the wilting of detached leaves their diffusibility fell to zero, where it remained. The width of EA also decreased at first, but at higher water deficits it partly again increased.

A method of calculation for determining the total transpiration (consumption of water for transpiration) of a single woody plant seedling or of their growth during periods of different length (from one day up to the whole vegetative season) is described and critically evaluated; the calculation is performed according to single transpiration intensity measuring results, by the cut-shoot method and weighing at 8, 11, 14 and 17 hours (or more often during the day).

A study of the effect of exogenous sugars (fructose, glucose, arabinose and xylose) on Qo₂ inChioreila pyrenoidosa (A 82) and inScenedesmus obliquus (A 125) showed that the effect of sugars on respiration depends on previous cultivation of the alga. In autotrophically cultivated algae all sugars contribute to the increase of Qo₂, in those cultivated rnixotrophically (with the addition of glucose or together with yeast extract, and with xylose) this occurs only in Scenedesmus when glucose or xylose are applied. The effect of cultivation was apparent in that mixotrophically cultivated algae had larger endogenous reserves of substrates than the autotrophic ones. The exogenous substrate is not preferentially respired and does not affect respiration solely as its substrate. In Chlorella, the effect of different cultivation conditions is more pronounced, the QO₂ being usually higher than inScenedesmes.

The paper deals with the study of morphological differentiation of flower buds in 10 varieties of apple-trees in relation to the growth of summer shoots and the earliness of varieties. The data obtained indicate that in the warmer regions of Slovakia the critical season of transformation of flower buds from vegetative to generative forms takes place, on the average, between July 20 and 29, and, at the same time, the variety Yellow Transparent deviates from the average four week-earlier. According to the author we can speak neither of a positive relation between the onset of morphological differentiation and the active growth of summer shoots nor of the relation between the earliness of the variety in maturing and the onset of differentiation. The morphological differentiation may be classified into five phases: 1^st phase - the formation of the growing point primordium, 2^nd phase - the formation of the cup on sepal primordia, 3^rd phase - the formation of petal primordium, 4^th phase - the formation of carpel and stamen primordia, 6^th phase - completion of the differentiation through substantial enlargement of flower organs before the onset of winter.

Par la température de ľunique journée longue permettant la mise à fleurs chezAnagallis arvensis, il est possible do déterminer la formation do 2 types do boutons, par la suite, en jours courts: les uns évoluent en fleurs normales; les autres on fleurs proliféres - mais dans tune proportion do 50% seulement. Excisés précocement, à un stade de leur dévoloppement oè seuls, les sépales sont initiés, ces 2 types de boutons sont placésin vitro sur un milieu simple. Leur développement s'achéve, sur ce milieu, par la formation, soit de fleurs normales s'épanouissant, soit de fleurs proliféres dans la mêm proportion quein vivo. Ces résultats sont discutés dans le cadre du schéma proposé par Heslop-Harrison comme hypothése ďinterprétation de ľorganogenése florale.

The paper deals with the relationship between the glucose utilization and growth ofPenicillium frequentans. The vegetative growth was scanty and sporulation started at a time when glucose was abundant in the culture medium. Occurrence of autolysis in spite of the presence of glucose in the culture medium is a peculiar phenomenon reported here. The autolysing culture gives rise to conditions which favour the germination of spores and the development of vegetative growth. The citric acid is the major metabolite produced by the fungus and its biochemical origin appears to follow condensation of oxalacetate and acetate. Lastly production of citrmin as another metabolite has also been reported.

Both quantitative and qualitative immunochemical methods were used for studying the mutual relationships of several spocies and the subspecies of the genusPhaseolus: Ph. vulgaris L. ssp.vulgaris, Ph. vulgaris L. ssp.aborigineus Burk.,Ph. coccineus L.,Ph. acutifolius A. Gray,Ph. lunatus L. (American endemites) andPh. aureus L. (a typical Asian bean). Protein characters of cotyledons (i.e., "storage" proteins) of the above species were compared with the aid of antisera prepared against seed (cotyledon) proteins ofPh. vulgaris L. ssp.vulgaris, cv. Veltruská Saxa, using
(a) the whole complex of cotyledon protein,
(b) the albumin fraction of this complex,
(c) the globulin fraction,
(d) crystaline phaseolin.
Our results are in agreement with the morphological and genetic data ofBurkart andBrücher on the close relationship betweenPh. vulgaris L. ssp.vulgaris andPh. vulgaris L. ssp.aborigineus (both contain a character designated asPh. vulgaris protein 1 which is lacking in the others, both contain an identical phaseolin and exhibit only negligible differences in the specificity of proteins). The closest to these two species isPh. coccineus (almost identical phaseolin, small differences in the albumin and globulin fractions, a greater quantitative difference in protein specificity).Ph. acutifolius contains a somewhat different phaseolin, exhibits greater deviations in the albumin and globulin fractions and a greater quantitative difference in protein specificity.Ph. lunatus andPh. aureus are quite different in all the above respects. These data are in good agreement with genetic data (crossability).

In both types of crosses (3n C.G.×4n D 154 and 4n D 154×3n C.G.) pods were found to set. In the first case pods shed within 4 days. In the second case pods were found to persist till maturity. Only a few uppermost ovules were found to be fertilized. Pollen tubes were seen to reach the ovules within 24 hours.
In 4n D 154×3n C.G. fusion of sperm with the egg was not noted to be complete till 3 days but the secondary nucleus is fertilized by other sperm. In 3n C.G.×D 154 fusion of sperm with egg or with polars was not complete within 3 days. Signs of degeneration of ovules were noted on the 5th day in both cases.

Mosaic disease ofAnchusa officinalis found at a ruderal association in Prague-Holešovice in the close proximity of TMV infected cruciferous weedsCardaria draba andSisymbrium loeselii, was identified to be caused by the same agent-the necrotic TMV-strain.

The effects of various cultural factors on the secretion of three pectic enzymes (PP, PG and PE) byAlternaria tenuis on synthetic media were studied. The results can be summarised as follow:
1. No definite correlation between the secretion of pectic enzymes, pH of the medium and the growth of the fungus was observed.
2. The secretion of the enzyme was dependent on the presence of pectin in the medium.
3. While various sugars were found to be equally effective, production of the enzymes was better on a medium without any sugar.
4. After varying the various concentrations and constituents of the medium, the following medium was found to be the best for the enzyme secretion: 1% pectin, 0.2% asparagine, 0.05% magnesium sulphate and 0.3% potassium dihydrogen phosphate.
5. It was established that on the above medium the fungus required four days of incubation at 25°C for the secretion of most active pectic enzymes.

Substances inhibiting local infection with virus X were isolated from leaves of potato cultivars Saphir, Saco, and Blaník by means of ultracentifugation and were concentrated with ammonium sulphate. These inhibitors were effective if rubbed into leaves of some host plants at least 2-4 days prior to infection without using any abrasives.

The calculation and construction of a simple nomogram to be used instead of a set of two equations in a two-wavelength spectrophotometric determination of chlorophyllsa, b, their total amount and ratio is are described. Any pair of equations can be represented nomographically by this construction.

In unseren Versuchen haben wir die Wirkung der 3 isomeren Styrylpyridine und des bekannten Herbizidstoffes 3-Amino-1,2,4-triazols (AT) in der Konzentration 10^-3 m auf die Succinat-dehydrogenase und Succinoxydase-aktivität der Wurzel vonSinapis alba untersucht. Styrylpyridine hommten das SDH-Enzymsystem vollständig, falls sie zum Pflanzenhomogenat noch vor der Messung der Aktivität hinzugefügt wurden. Diese Stoffe zeigten die gleiche Hemmwirkung wie Malonat. In den Versuchen, wo die Pflanzen direkt in den Versuchslösungen kultiviert wurden, zeigte sich 3-Styrylpyridin als das wirksamste; weniger wirksam war 4-Styrylpyridin und am wenigsten wirkte 2-Styrylpyridin. Die gleiche Abstufung der Wirksamkeit lieferten auch die Wachstumsteste und die Untersuchungen der SO-Aktivität. Die Succinoxydase-aktivität war nur wenig beeinflust, falls die Substanzen dem Pflanzenhomogenat beigefügt wurden. Bei den Pflanzen, die in den Versuchslösungen kultiviert wurden, zeigte sich die gleiche Abstufung der Hemmwirkung der SO-Aktivität wie bei dem SDH-System. AT beeinflusste das SO-Enzymsystem überhaupt nicht und das SDH-Enzymsystem wurde im Gegenteil noch stimuliert.

In experiments with fodder cabbage and sugar beet the influences were tested which restrict the finding of a uniform linear dependence between the chlorophyll content and photosynthetic rate. The main factor is most probably the irradiation during the growth of plants and the measuring of photosynthetic rate. Changes in the density and length of irradiation with the proceeding spring season are reflected in the decrease of unit chlorophyll activity in all leaves of the plant. Such differences were not observed in plants grown in winter months at a low greenhouse irradiation density. High irradiation density during the measurement of photosynthesis ensures the finding of high correlation of photosynthetic rate with the chlorophyll amount per unit area of leaf. With a low irradiation density, or in thick leaves, the lower layers of chloroplasts are not saturated with radiation, and hence a higher correlation coefficient is found by relating photosynthetic rate to the percentage of chlorophyll in dry weight than to the quantity of chlorophyll per unit area of leaf blade. In some experiments higher activity of chlorophylls was found in young leaves before they have reached the state of "photosynthetic maturity" than after this turning point. This difference diminished by relating the photosynthetic rate to chlorophylla content instead of the total amount of chlorophylls (a+b). High activity of chlorophylls in very young leaves and great individual variability within the experimental plant groups caused by uneven cultivation conditions are the basis of apparent sigmoid character of average curves for the chlorophyll-photosynthesis relation.

Comparison with the findings in the cells of other plants and animals showed that the endoplasmic reticulum in the root apex ofFagopyrum has the same general character and function as in other biological objects, i.e. in secretory processes and especially in this case in the transport of the substances produced. Detailed studies of the morphology and activity of the endoplasmic reticulum showed some functional differences which are characteristic for this object. The endoplasmic reticulum participates apparently in the transport of the mass of known but functionally and nomenclatorically controversial formations which here are called dense bodies. Dense bodies exist inFagopyrum in a considerable amount as compared to other objects. Frequent contact of the dense bodies with the ends of the endoplasmic reticulum, contact with the endoplasmic retieulum passing through the plasmodesm, accumulation of the dense bodies along the cell wall and in proximal distance of the plasmodesms and intensive staining of some plasmodesms was observed. The dense vacuoles in this object represent dilated spaces of the endoplasmic reticulum which apparently have the function of reservoirs of the dense mass. The endoplasmic reticulum in the calyptra cells appears to participate in the formation of the cell walls. This object differs hereby from others, where the participation of the Golgi apparatus has been observed in this function.

Stimulation and inhibition of photosynthesis inHydrilla verticillata Presl. with quinine sulphate and quinine alkaloid with concentrations ranging between 0.001 and 100 ppm was observed. Quantitative measurements of photosynthesis were done by a microburette (Audus 1940) and qualitative estimations by the modified apparatus byZutshi (1965a). Maximum inhibition of 50% and 34% is obtained with 100 ppm of quinine sulphate and quinine alkaloid respectively. The inhibition is due to the adverse effect on the pigment system particularly on carotene (Zutshi 1963). Forty percent stimulation of photosynthesis is obtained with 0.01 ppm quinine sulphate and 12.5% with 0.001 ppm quinine alkaloid. Difference in the biological activity of these two alkaloids is due to their different chemical structure and purity.

Mycelium of white-rot fungi secretes laccase into the medium. It was found by cultivation on malt-agar plates that the mycelium does not produce laccase equally in all its parts. The youngest hyphae at the margins of the colony represent usually the maximum producers, whereas older hyphae produce less or none at all. An exception here isCollybia velutipes which is the weakest producer of laccase of all the fungi studied and where only the older hyphae begin to secrete it. Manometric estimation of laccase showed that maximum specific activity of laccase is achieved at the boundary between the phases of initial and linear growth and i₁₁ some cases during the first half of linear growth. Ageing of the mycelium characterized by certain changes in its metabolism is reflected in changes of enzyme production by fungal hypha of different age.

The inhibitor of the X virus (Jermoljev, Albrechtová 1965) can be separated from other proteins by 60 min centrifugation at 40000 r.p.m. in the Spinco L centrifuge and by subsequent gel filtration of the supernatant on a Sephadex G-50 column. For the elution it is best to use Tris-maleate buffers and 0.2M Tris-HCl of pH 7.2. The inhibitor is present in the first fractions containing proteins, between 30 and 45 ml. It is most suitable to concentrate the inhibitor by salting out with ammonium sulphate to 30-50% saturation. The inhibitor can be preserved by adding ammonium sulphate to the sap. At 3°C it can be kept in this manner for 2 months. If the pH of the sap drops below 5.5, the inhibitor is inactivated. Complete inactivation of the inhibitor takes place after a 10 min heating at 67.5°C. No substantial difference in the amount of inhibitor in the sap from apical leaves and leaves from middle levels has been found. Keeping the plants in the dark has no effect on the inhibitor level.

The action of zinc on the growth of barley and the biosynthesis of indol compounds and gibberellin-like substances was investigated in a number of concentrations of zinc from doses stimulating growth to toxic doses. The seeds were soaked before sowing in solutions of zinc sulphate (5.10^-5 to 5.10^-1% Zn), and the plants cultivated for 7 days in water. Lower concentrations of zinc increased both plant growth and the biosynthesis of tryptophan and auxins. At the optimum concentration of 5.10^-3% Zn this increase in tryptophan amounted to 241% of the variant without zinc; in substances with an R_F corresponding to indolyacetic acid, the increase determined by the biological test, was 207% as against the variant without zinc. Higher concentrations of zinc inhibited growth, the tryptophan content was decreased to below that of the control without zinc and the auxin content also fell to below the control values. Zinc also influenced the content of gibberellin-like substances in the plants. At a concentration of 5.10^-3% Zn the increase in the growth activity in the gibberellic acid area of the chromatogram was 294% of the variant without zinc. At toxic concentrations of zinc, the content of gibberellin-like substances fell to below that of the controls. The finding that zinc acts simultaneously on the biosynthesis of auxins and gibberellins is also evidence for the common action of growth substances of various chemical types on plant growth.

The author intended here to present a classification of discontinuous, particulate membraneous structures of the plant cell, including (1) dense bodies, (2) vacuoles, (3) vesicles in plastids and mitochondria, (4) vesicles outside the protoplast and (5) vesicles surrounded by a compound (double) membrane. Three types of dense bodies (1) are distinguished: (a)Mühlethaler's spherosomes, including phragmosomes (b) lipoid bodies and (c) classical spherosomes. Type (a) is characterized in particular by being clearly bounded by the unit membrane; the matrix of these structures after ordinary treatment is grey in the positive and shows a more or less visible internal structure, the bodies are round in shape. Types (b) and (c), on the other hand, are frequently described as membrane-less structures, their matrix being very dark in the positive, frequently with a dark fringe and a lighter central part. They show no other structure and are mostly irregular in shape which is apparently an artifact. Bodies of type (a) are undoubtedly the immediate component of active living matter which cannot be said about types (b) and (c).Frey-Wyssling's interpretation of spherosomes need not be generally valid for all dense bodies, other explanations being acceptable. It is thus possible to interprot spherosomes as promitochondria and "preproplastids".
The present manuscript is a torso where only the dense bodies have been treated in greater detail A chronological review of the literature opens the manuscript, dealing mainly with the descriptive morphology of these structures. This section is published in extenso. In the other section-unfinished-the functional morphology of the dense bodies was to be presente d. From this section only the conclusions concerningMühlethaler's spherosomes are published.