The transamination activity in five or seven days-old poppy seedlings (Papaver somniferum L. cv "Váhovecký") germinated in darkness or light was studied. The changes in L-phenylalanine:-(E.C.2.6.1.5), aspartic acid:-(E.C.2.6.1.1), and L-ornithine: α-oxoglutarate transaminase (E.C. 2.6.1.13) were followed and correlated with duration and conditions of cultivation.

The authors succeeded in demonstrating accumulation of tyrosine and p-coumaric acid in three day-old roots of maize (Zea mays L.) fed with L-phenylalanine and einnamie acid. Phenylpyruvic acid applied under the same conditions gave rise to phenylalanine, indicating the presence of the corresponding transferase activity. Even simultaneous application of inhibitors of transaminase activity - hydroxylamine and isonicotinic acid hydrazide - did not result in the formation of p-hydroxyphenylpyruvic acid.

The effect of phosphorus deficiency on anthocyanin content in tomato plants was studied from the point of view of pathological anthocyanin formation. Phosphorus deficiency resulted in an evident increase of anthocyanin content in all experiments, independently of the tomato variety and of the cultivation conditions. The anthocyanin amount was five times higher on the average and the differences were statistically significant. The average growth inhibition of tomato plants under phosphorus deficiency was 18%. Accumulation of anthocyanins is limited by the temperature; anthocyanins are not synthesized at temperatures above 30°. The results of the experimental variant with enhanced phosphorus concentration in nutrient solution were not uniform. In some experiments a decrease of anthocyanins accompanied by slight growth stimulation was observed, in others an increase associated with growth inhibition. It seems that cultivation conditions, especially the light intensity, play an important role in these experimental variants.

Populations of theChloretta vulgaris Beijeb. strain Česnokov "V" clones (progenies of single cells) grown up from cells treated by chemical mutagens were cultivated on the surface of solid media. The differentiation of growth types according to their growth rates in the populations originating from the same sample of cells but growing under different conditions was compared. The strain studied exhibited much greater growth rate variability on the complete medium than on the minimal one. Short time changes of light regime during the cultivation for the purpose of inducing reparation processes in the mutagen damaged cells did not manifest themselves significantly in the composition of resulting clonal populations. The possibility of selection of growth types under conditions studied was considered.

The effect of phenolic substances isolated earlier from cabbage, maize and pea on L-tryptophan-3-¹⁴C (L-Try-¹⁴C) metabolism in those plants was investigated. For the sake of comparison the effect of diethyldithiocarbamate (DIECA) on cabbage was also observed. A phenolic substance of unknown structure isolated from cabbage was utilised in a 0.5 mg/ml concentration, p-coumaric acid (PCA) from maize in 0.7 mg/ml concentration and quercetinglucosyl-coumarate (QGC) found in pea in 8 mg/ml concentration were used. The chosen concentrations were on the limit of their inhibitory effect on the growth of the respective plant apical segments. The effect of DIECA was investigated at 0.1 mg/ml concentration. Using non-labelled L-Try as substrate (5×10^-3m) biological tests have shown that QGC and DIECA have a weaker but distinct effect on the increase in auxin level (+17% and +15%, respectively). All phenolic compounds, as well as DIECA increase the intake of L-Try-¹⁴C from the incubation solutions. Phenolic substances decrease the conversion of L-Try-¹⁴C to its metabolites. The changes were studied after a 20 hour period of L-Try-¹⁴C metabolism. On chromatograms changes in the proportion of L-Try-¹⁴C metabolites took place, especially in the areas of substances of complex character from which IAA splits off easily,i.e. in the areas of 3-indolylacetylglucose and 3-indolylacetamide. The radioactivity of these areas is generally decreased (e.g. the decrease of radioactivity in the 3-indolylacetylglucose area under the influence of the phenolic substance ofBrassica plants is -7,4%, under the influence of PCA in maize it is -8.9% and under the influence of QGC in pea it is -17.1%). DIECA also decreased the radioactivity of this zone, by -10,5%. In cabbage a large part of L-Try-¹⁴C was transformed to glucobrassicin; its biosynthesis increases in the presence of the phenolic substance of cabbage by +3%, in the presence of DIECA by +27%. The results are discussed in a working hypothesis based on the key formation of IAA, accompanied by its oxidation and detoxication.

Using electrophoresis in acrylamide gel, fractions of peroxidase, indoleacetic acid oxidase, and o-diphenol oxidase were investigated in extracts from three growth zones ofVicia faba L. roots. Three peroxidase fractions (zones) moving towards the anode were revealed as well as four peroxidase fractions (zones) migrating towards the cathode. Three peroxidase fractions showed detectable indoleacetic acid oxidase activity. The o-diphenol oxidase activity was revealed in all peroxidase fractions moving towards the anode, in those moving towards the cathode the o-diphenol oxidase activity differred according to the substrate used. One fraction with both peroxidase and o-diphenol oxidase activity occurred only in electrophoreograms of extracts from the maturation zone; in this fraction no indoleacetic acid oxidase activity was demonstrable.

Maize caryopses were exposed in moist, sterile sand to temperatures of 24°, 10° and 6°. The amino acid content of embryo, endosperm and pericarp tissues of kernels and amino acid occurence in sand eluates was analysed by paper chromatography.
The lower the temperature to which the seeds were exposed and the greater the delay in start of germination, the greater were the amounts of amino acids exosmosed from the kernel to the surrounding media. The exudation of aspartic acid, proline, alanine, γ-aminobutyric and glutamic acids was especially high.
The time-course of amino acid content in various kernel parts proves that cold does not check the enzymic hydrolysis of reserve nitrogen compounds. There is, however, an inhibition of translocation and use of amino acids in the embryo. Therefore, amino acids diffuse out from the caryopse into the media. Although mainly the peripheral parts of endosperm take part in exosmose, participation of the embryo in the exudation of certain amino acids (proline) can be supposed as well.
In cold resistance of emerging maize kernels the remarkable interaction of microorganisms is causally related to the high amino acid exosmose found in these experiments. The mechanism of amino acid exosmose and its relationship to cold resistance are discussed in detail.

The rate of carbon dioxide evolution, respiration quotient, and the rate of liberation of heat were determined on the 3rd day of germination of wheat seeds. The seeds were germinated with pure water (control) or they were transferred for a 5-hour period to a solution of dinitrophenol, sodium arsenate, sodium phosphate or indole-3-acetic acid. The heat liberated was compared with the total energy released in respiratory processes of the seedlings, calculated from the gas exchange measurements. The amount of heat liberated for 1mm of carbon dioxide evolved and for 1mm of oxygen absorbed was definitely changed in the presence of the compounds used. However, the ratio of heat liberated to the total energy released in respiration of the seedlings changed only slightly.

The seeds, seed covers and leaves, taken after 17, 27, 37, and 47 days after tagging of flowers of soybean, were analysed quantitatively for their contents of different phosphorus fractions. Total phosphorus content increased in seed cover and leaves, there was a gradual decrease during ripening. All the phosphorus fractions i.e. acid soluble-P, lipid-P, nucleic acid-P, and protein-P were found to increase with maturity in seeds whereas in case of seed covers the content of acid soluble-P, nucleic acid-P and protein-P decreased but a marked increase was observed in lipid-P. In leaves during ripening, all the phosphorus fractions decreased except protein-P which was found to be almost constant. In lipid-P an increase was observed during later stages of maturity.

Changes in soluble sugar content in individual parts (embryo, endosperm and pericarp) of maize caryopses exposed to the influence of 24°, 10° and 6° were studied. At the same time the eluates from sand in which the seeds were planted and exposed for various periods were analysed by paper chromatography.
It was found that the lower was the temperature of exposure the greater were the amounts of sucrose, glucose, raffinose and other sugars diffused from the caryopses into the medium before the start of germination. The exosmose course and the changes in sugar content in kernel tissues proved that the hydrolysis of storage polysaccharides is not inhibited by low temperatures but that under such conditions the use of products of hydrolysis for the growth of the embryo is inhibited.
It is concluded that not only surface parts of endosperm but also the embryo participates in exosmose. The relatively high sugar exosmose found from seeds germinated at low temperatures explains the well-known interaction of pathogenic and parasitic microorganism in cold resistance during emergence.

Beet yellows virus was transmitted by wingless aphidsMyzus persicae (Sulz.) after 16 hrs acquisition feeding on leaves covered with a Parafilm M membrane. Effectiveness of the virus transmission was decreased approximately to half of the original value by acquisition of the virus through the membrane. No virus was transmitted to healthy beet seedlings after 6 or 16 hrs continuous feeding on a concentrated suspension of the purified virus or on crude juice extracted from an infected plant (suspensions contained 15% of sucrose).

The paper deals with the effect of mineral nutrition on the content of free flavonoid glycosides (phloridzin, hyperine) free and bound C₆-C₁ aldehydes (vanillin, syringic aldehyde) in the woody parts of apple shoots of the variety 'Antonovka' and on the content of products oxidized by nitrobenzene (vanillin, syringic aldehyde) in connection with the lignification of cell walls.
It was established that the biosynthesis of phenolic compounds is retarded under the influenco of nitrogenous fertilizer while the biosynthesis of proteins is activated, intensifying growth. Contrary to nitric fertilizer, phosphoric with potassic fertilizers promote formation of phenolic compounds and suppress protein synthesis and growth; at the same time phenylalanine is included in the biosynthesis of lignin, but not in the biosynthesis of proteins.

The root cap develops out of the cells of the caliptrodermatogen. The root apex belongs to the first of Haberlandt's histogen types. The velamen usually consists of three layers of cells, and develops out of the protoderm by periclinal divisions. Funnel-shaped cells later divide tangentially into two cells, and in one of these cells a fibrous body develops. Two to four thick-walled cells alternate, usually with one passage cell in the exodermis. The cortex proper consists of approximately ten to twelve layers of parenchymatic cells in the mature root. There are eight to sixteen xylem poles alternating with the same number of phloem poles in the central cylinder.
In the roots ofDendrobium cunninghamii I observed two types of mycorrhizal infection, which can be classified as transitive types between ptyophagus and tolypophagus mycorrhizae. In my opinion, a state of balanced symbiosis exists between the fungus and the plant; a part of the time the plant acts as a parasite on the fungus.

Evidence for the effect of sterols on plant mycoplasma is presented. Two essential sterolsi.e. cholesterol and stigmasterol were applied in the following way: grafts from tomato plants infected with potato witches'broom, wedge-shaped at the base were dusted on the cut surfaces with the corresponding sterol in the amount of 4 mg to one graft, inserted in freshly cut wedges of stock plants and firmly tightened with rubber tubes. Both sterols stimulated growth of diseased grafts and delayed symptom manifestation. The stimulation was more evident with stigmasterol and the delay in symptom manifestation and intensity was more distinct with cholesterol. Supplying tomato plants with sterols externally probably enables additional multiplication of mycoplasma in already infected grafts, and the plants need not provide the grafts with essential metabolites which they themselves need for the development of reproductive organs. Stigmasterol, a metabolite peculiar to the tomato plant, is probably more rapidly consumed than cholesterol which may remain in the plant as a metabolic pool of sterols for mycoplasma propagation.

Tryptophan, tryptamine, or indolepyruvic acid were applied to 2 systems: a bacterial (pea stem sections containing the epiphytic bacteria) and a plant system (pea stem sections under sterile conditions).
In the plant system, the production of indoleacetic acid and indoleethanol (tryptophol) from each applied indole derivative is clearly reduced by the aldehyde reagents bisulfite and dimedon, respectively. Indoleacetaldehyde is chromatographically detected after alkaline liberation from its bisulfite addition product.
In the bacterial system, the production of indoleacetic acid and indoleethanol is likewise reduced by bisulfite and dimedon. However, after tryptophan or tryptamine application, we could not detect indoleacetaldehyde in the described way.
In one case only, namely tryptamine application to the bacterial system, indoleethanol production (contrary to indoleacetic acid production) is scarcely reduced by the aldehyde reagents. This indicates a bacterial pathway tryptamine → indoleethanol which bypasses indoleacetaldehyde.

Kinetin, coumarin and four growth retardants including Phosfon D (2,4-dichlorobenzyltributylphosphonium chloride), CCC [(2-chloroethyl) trimethylammonium chloride], B-Nine (N-dimethylaminosuccinamic acid) and AMO-1618 (2-isopropyl-4-dimethylamino-5-methylphenyl-1-piperidinecarboxylate methyl chloride) arrested chlorophyll, protein and RNA degradation in the leaf discs of maize kept in darkness; GA₃ was without effect. Coumarin and Phosfon D markedly lowered the level of TCA soluble nitrogen compounds in the tissue; other compounds were inactive in this respect. Puromycin, 4-fluorophenylalanine, actinomycin D, 5-diazouracil and 2-thiouracil also retarded the loss of chlorophyll from the leaf discs of maize; chloramphenicol was without effect on yellowing. The inhibitors of RNA and protein synthesis slightly decreased, increased or had no influence on the chlorophyll preserving effect of coumarin and growth retarding chemicals. 2-Thiouracil markedly decreased the loss of protein content from the discs.
Coumarin and growth retardants inhibited the synthesis of chlorophyll in the leaf tissue of etiolated seedlings of maize.
It is suggested that synthesis of some specific protein(s) is required for senescence in the detached leaf tissue. Synthesis of this protein(s) was possibly arrested by the compounds which were under examination.

In the present paper RNA from apple-tree callus tissue labelled with 6-benzyl-minopurine¹⁴) was studied. The RNA isolated from this tissue was prepared as sample for electron microscopic studies and was also used as biochemical control. The electron microscopic autoradiograms obtained showed the labelled structure of RNA, sRNA and rRNA. The incorporation of labelled purine rings was confirmed in all three RNA types by the radioactivity, which was also proved in nucleotides after hydrolysation of RNA fractions. The results were compared with RNA isolated from tissue cultivated on a non-radiactive medium.

The importance of various correlative influences on growth and vegetative or floral development of cotyledonary buds inScrofularia argutaSol. is shown. The terminal bud, on the one hand, inhibits growth of cotyledonary buds and, on the other hand, induces their early flowering. The cotyledon stimulates growth of its axillary bud, but has no action on its floral development. Leaves above the cotyledonary node have the same effect as the cotyledon. Finally, roots stimulate vegetative growth of cotyledonary buds and suppress floral expression, but only when apical dominance has been removed at an early stage of development.

The metabolism of D-and L-tryptophan-3-¹⁴C (Try-3-¹⁴C) was studied and compared for three different plant species, cabbage, maize and pea. Apical segments of the seedlings were incubated for 6 hours in solutions of L- or D-Try-3-¹⁴C (1.5 μc/ml) with the addition of chloramphenicol (10^-4g/ml) and then allowed to stand for another 20 hours in moist chambers. The methanolic extract of the tissues was analyzed radiochromatographically and by paper electrophoresis in combination with biological tests. Chloramphenicol in a concentration of 10^-4 g/ml had little influence on the growth of the segments, though the antibiotic slightly decreased the uptake of L-Try, it did not prevent the formation of IAA from L-Try. In the segments of cabbage the following metabolites were formed from L-Try-3-¹⁴C (accounting for 52% of the activity of the chromatographically separated extract): glucobrassicin (26.0%), neoglucobrassicin (3.6%), a spot corresponding according to its Rf to 3-indolylacetamide (IAAmide-10.9%), β-glucoside of 3-indolylacetic acid (IAGluc-3.3%) and traces of 3-indolylacetonitrile (IAN), IAA and indole-3-carboxylic acid (total 5%). In maize segments L-Try-3-¹⁴C (53.0%) was transformed to several unidentified hydrophilic substances, one of them possessing auxin activity (total amount 6.9%), IAGlue (9.3%) accompanied by a small amount of tryptamine, a spot corresponding according to its Rf to IAAmide (16.5%), IAA and another unidentified hydrophobic substance (4.1%). In pea segments L-Try-3-¹⁴C (66.7%) gave a zone corresponding according to its Rf to IAAmide (20.0%), a substance similar to IAGluc (10.5%) and also hydrophobic substances (3.1%) containing traces of IAA, which could be demonstrated only by bioassay.
D-Try is metabolised in the three plants by the virtually exclusive formation of malonyltryptophan.

The tapetal layer of anthers inCapsicum annuum L. is differentiated from the archesporial complex during the early development stage of the anthers. Further development of tapetum proceeds according to the scheme of the cellular polynuclear type. The high rate of polyploidy is characteristic of the whole layer (from 4n to 8n). Cytokinesis does not follow karyokinesis which conditions the inception of two or three-nuclear cells. The majority of the mononuclear cells show the typical plant endomitosis without the chromosome spiralization, accompanied by the structural nuclear change-over. In other cells chromosome spiralization in the prophase and, after passing through the metaphase, restitution of the cell nuclei were observed. The tapetum development has been studied in 12 cultivars of sweet pepper which did not differ in the course of the karyological processes. The subtle differences during the temporal course of degeneration of the whole layer in the postmeiotic period of development were observed.

The 3-(3-indolyl)-aorylic acid previously found in ether or ethylaoetate extracts of lentil seedlings is proved to be formed during extraction from an indolic precursor.

The author describes the testing method for clonal selections from the original strainScenedesmus quadricaudaGreifswald/15 in biomass production. This method served for testing the clones in greater series. It was applied to clonal cultures selected on a solid medium after treatment of the coenobia with UV-light before their inoculation. The production characteristic of the clones was expressed by the temperature dependence of the constant μ from Simmer's growth equation in the last step of the testing process used. Some significant differences of this kind were found among the evaluated clonal cultures. This way of characterization facilitates a more detailed evaluation of clones in comparison with values obtained by an oneshot testing method under standard conditions.

Values of the water saturation deficit (WSD) for hydroactive stomatal movements of kale leaves were estimated using the method of transpiration curve analysis.
Stomata of young leaves started closing at WSD values of 5 to 6 per cent and were completely closed at 18 to 20 per cent WSD. During maturation and ageing of leaves these WSD values increased to 12.5 and 18 to 23 per cent respectively. Thus the stomatal reaction is more sensitive to changes in WSD in adult leaves than in young ones. After maturation is attained both values decrease. In apparently withering leaves the individual phases of transpiration curves can barely be distinguished, probably for the reason that even under optimal conditions their stomata remain half-closed and at high WSD values an incomplete closing of the aperture occurs. The injured cuticle of withering leaves affects the shape of the transpiration curve as well.

Activities of five enzymes were followed in electrophoreograms of extracts from three growth zones of broad bean root. With ascorbate oxidase (L-ascorbate: oxygen oxidoreductase, E.C. 1.10.3.3) one new fraction was found in the electrophoreograms of extracts from the maturation zone, electrophoreograms of α-glucan phosphorylase (α-l,4-glucan: orthophosphate glucosyltransferase, E.C. 2.4.1.1), amylase (α-l,4-glucan 4-glucanohydrolase, E.C. 3.2.1.1), sucrose glucosyltransferase (disaccharide glucosyltransferase, E.C. 2.4.1.7) and leucine aminopeptidase (L-leucyl-peptide hydrolase, E.C. 3.4.1.1) were identical for all three investigated growth zones. Ascorbate oxidase activity occurred in the same regions of electrophoreograms as peroxidase activity.

Beet yellows virus (BYV) was mechanically transmitted by sap from sugar-beet plants, infected with BYV, to the plants of Chenopodium quinoa Willd. and of Chenopodium foliosum (Moench) Asch. Mechanical transmission of BYV to the plants of Tetragonia expansa Murr. failed. Infectious material was homogenized in phosphate buffer with veronal and EDTA, pH 7-8. Experimental plants were darkened three days before infection and kept at a temperature of 5°C. Plants of C. quinoa Willd. were decapitated. Back transmissions from C. quinoa Willd. and C. foliosum (Moench) Asch. infected with BYV, to sugar-beet plants were carried out by the aveid Myzus persicae Sulz. These transmissions were positive. Filamentous particles of BYV, of an average length 1275 nm, were found in plants of C. quinoa Willd. and C. Foliosum (Moench) Asch., infected with BYV.

The virus origin of a Czechoslovak isolate of potato witches' broom disease is discounted: electron micrographs of ultrathin section of phloem tissues from plants infected with potato witches' broom disease demonstratedMycoplasma-like bodies, spherical or elongated showing binary fission and fragmentation. The minute corpuscles have a diameter of about 50-60 nm, the largest bodies of 1000 nm. The width of elongated filamentous structures is about 200 nm, most oval bodies have a diameter of 250 nm. A weak tetracycline treatment of diseased plants causes a delay of symptom development; a strong dose of tetracycline (applied by means of the wick method into the stem) inhibits symptom appearance completely. Tetracycline produces a phytotoxic effect inhibiting the growth of tomato plants and causing (at higher concentrations) necrosis and death of these plants. There is a note in the paper dealing with the term "mycoplasma". The word mycoplasma in the sense ofEriksson (1897) or ofMereschkowsky (1910) does not correspond to the genus nameMycoplasma Nowak (1929).

A study has been made of the level of naturally-occurring growth substances and inhibitors in acid-soluble fraction of peach leaves and shoots using paper chromatography and bioassay methods.
The content of substances which stimulate growth ofAvena coleoptile sections calculated on a fresh weight basis can be expressed by a one-peak curve with a maximum at 10 a.m. The shoots were higher in growth substances than leaves in all periods of time examined. The extract contained two substances which significantly stimulated the growth of coleoptile (accelerator-2 and-3). High inhibition was found in the area of inhibitor-β and to a lesser extent in the area of inhibitor-α. The changes in the concentration of inhibitors were different in leaves and shoots.

The main epicotyledonary axis inPisum sativum exhibits a very fluctuating either left- or right-handed deflexion of its first-order laterals, but the biserial buds on the laterals of various further order reveal in this respect certain regularities according to their position on the seedling, their deflexion being very often adaxial in the vicinity of cotyledons, however, in more distant and therefore later produced laterals, as a rule, abaxial. The integrant characteristics of these relationships may become clear from their experimental shift with the aid of exogenous auxin increasing inhibitions as well as of triiodobenzoic acid blocking the transport of endogenous auxin participant also in these embryonic-growth correlations.