In dieser Arbeit wurde die Wachstumswirksamkeit von zwanzig, meist neu synthetisierten und an Pflanzen bis jetzt noch nicht geprüften Derivaten VII bis XXVI der Phenoxyessigsäure verfolgt. Es handelte sich um Substitutionsderivate und auch um Derivate, die durch Umwandlung der Karboxylgruppe hergestellt wurden. Die Struktur und die Wirkung der 2,4-Dichlorphenoxyessigsäure (I) Wurde bei diesen Versuchen als Standard verwendet. Die Wirkungslosigkeit der geprüften Substanzen in der Koncentration 10^-6 (1 mg pro Liter) auf keimende Senfpflanzen(Sinapis alba L.) wird infolge Strukturänderungen, auf die Struktur von 2,4-D (I) bezogen, besonders was die Art und Zahl der Substituenten am Phenylrest betrifft, erklärt.

The authors have studied the anatomy of the apical meristem in axils of the highest pair of leaves in chickweed [Stellaria media (L.) Vill.]. The shoot apices in the axils of highest leaves start to grow at different times; this is one of the causes of the unequal development (different length and thickness) of the branches. This unequal development is repeated also in branches of the second, third orders etc.

The present paper is concerned with inheritance of the development of lateral florets in crosses of two-rowed forms of barley of the distichon type with the six-rowed forms of types vulgare and brachyurum.
The character can be employed for identification of true hybrids as early as in the F₁ generation in crosses of two and six-rowed forms when the two-rowed character is dominant. Unsuccessful crosses can thus be eliminated in time. The character can also be useful for the determination of linkage ratios in higher hybrid generations.
1. Heredity of the development of lateral florets in spikelets of barley spike was investigated during hybridization of two-rowed and six-rowed forms by means of the method for continually variable characters.
2. The results obtained indicate that in the manifestation of the character, nuclear factors of two types take part, i. e. the more numerous factors of lesser effect, (here apparently also belong the pleiotropic effects of factors for other characters), and the less numerous factors of greater effect which appear to be fairly independent of the alleles for the number of rows in the spike.
3. It seems that extranuclear factors participate in addition to the nuclear as suggested by the inequality of reciprocal crosses in the same combination.
4. The modifiability of the degree of character manifestation due to external factors is great in hybrid plants.

The test for cold survival in two lines of maize on alternately changing the sterility of grains and soil revealed that for the given type of seeds the death in cold soil is mostly due to epiphytic pathogenic microflora, followed in importance by soil pathogenic microflora and finally by the direct influence of cold.

Experimental investigations on the course of yellows-type virus infections in plantsTrifolium repens L. gave the following results:
During 24 and 48 hours after the completion of the test feeding period the clover phyllody and clover dwarf viruses spread in the plant maximally up to 5 cm. from the point of inoculation.
In the infected plants, the reproduced clover phyllody and clover dwarf viruses appeared on the average 5-6 days earlier than disease symptoms.
Acquisition feeding of leafhoppers onT. repens plants infected with the clover dwarf virus for different periods of time, revealed a decline in the virus concentration in the plants after 45 days from the appearance of disease symptoms. In plants infected with the parastolbur virus, this decline was not found.

One of the criteria employed for evaluating the resistance of plants to drought is their ability to endure the effects of water deficit with no irreversible changes in their tissues. This ability was investigated by means of a method described in this paper. The leaves of some xerophilous grasses (species of the genusStipa, Melica, etc.) were left to dry up under precisely defined experimental conditions so that they reached various degrees of water saturation deficit. Then they were cut up into segments and-mounted in a special frame-were saturated with water. The initial deficit and its compensation were investigated gravimetrically. The resultant values were plotted on a graph. Whereas in some instances the water loss from the leaves during desiccation was linear, the compensation curve exhibited a characteristic breaking point which indicated the degree to which the water loss could be compensated, and when the changes became irreversible. It was found that the studied series of plants of typical continental species have the capacity to supplement their water content ad integrum even in the case of considerable water deficit. Plants living in regions of a more oceanic type do not exhibit this property. It is probable that this property will also be of much value in the explanation of causal phytogeography.

Some constructional adjustments of leaf chambers for photosynthetic rate measurements of leaves and spikes of cereals are described.

In Vegetationskegeln vonTriticum aestivum von verschiedenem Entwicklungsalter wurden die organischen Säuren und der Einfluss von Malonat auf sie, wieauch auf den Qo₂ untersucht.
In der 3. und 4. Etappe der Organogenese wurden Akonitin-, Citronen-, Wein, und Phosphorsäure gefunden und ausserdem eine Ketosäure, wahrscheinlich α-Ketoglutarsäure. In der 2. Etappe der Organogenese traten Phosphor- und Milchsäure auf. Malonat beeinflusste den Qo₂ in der 2. Btappe der Organogenese nicht. In den höheren Entwicklungsetappen bewirkte es eine vollständige Atmungshemmung. Nach 2-3 Studen begannen aber die Vegetationskegel wieder normal zu atmen. Unter dem Einfluss von Malonat trat auf den Chromatogrammen von Vegetationskegeln dieses Entwicklungsalters Milchsäure und bei kurzfristiger Einwirkung des Inhibitors auch Spuren von Bernsteinsäure auf.
Die Versuchsergebnisse wurden in Hinblick auf den Ablauf des Citronensäurezyklus in Vegetationskegeln, sowie auch auf die Möglichkeit der Entstehung einer aeroben Gärung unter dem Einfluss von Malonat und dessen Abbau in den untersuchten Organen diskutiert.

Potassium humate stimulated growth of wheat, increased the activity of phosphatase in the leaves and roots and and the activity of catalase in the roots.
A higher temperature (30° C) during cultivation caused a decline in the activity of phosphatase in the roots and leaves and a decline in the activity of catalase in the leaves. Anaesthetization of the embryos with chloroform retarded growth, increased the activity of the phosphatase only during the first days and increased the activity of the catalase. Similarly, removal of the endosperm caused growth to slow down. Wheat cultivated in this way had increased activity of catalase and phosphatase. The activity of phosphatase in the leaves of all variants and controls, was substantially lower than in the roots as compared with catalase, which was several times as active in the leaves as in the roots. Activity of catalase in both leaves and roots declined, in most cases, with age. Catalase activity declined with age only in the roots while it increased in the leaves.
The activity of the catalase is probably less dependent on the growth rate and depends rather on nutrition, the formation of chlorophyl, photosynthetic activity and like that. From both sources of reference and our experimental results, it can be seen that no simple relation exists between the activity of observed enzymes and the growth rate; the relationship is more complicated.

An investigation was made as to whether the cultivation conditions of algae affect their respiratory metabolism. Chlorella pyrenoidosa (82), Scenedesmus obliquus (125) and Euglena gracilis (259) were cultivated both in a static and shaken culture.
It was found that shaking considerably affects the respiratory metabolism of algae. The shaken cultures, in contrast to the static ones, display a higher O₂ consumption and have mostly a different RQ. It is possible that the differences observed are due to accelerated development and ageing of the shaken cultures.
It thus appears that shaking is an important factor in cultivation which must be taken into account during growth of experimental material. The values of RQ found here to be about 1-3 point to the fact that anaerobic glycolytic processes can proceed even under fully aerobic conditions. The culture of Scenedesmus obliquus (125) appears to have a less adaptable metabolism and does not respond to environmental changes as readily as Euglena gracilis or Chlorella pyrenoidosa.

The authors submit the results of a chromatographic determination of free amino acids and protein fractions, soluble in ethanol and alkali, and insoluble, in the flower and vegetative buds of two almond varieties showing a different frost-resistance i.e. Non-plus-ultra and Vochtchaberdi. The buds were removed at different times between autumn (20.9.59) and spring (31.3.60). The Chromatographie determination of amino acids in buds showed the following:
1. During the autumn-winter season there is a clearly perceptible difference in the content and pattern of amino acids of almost all fractions in flower and vegetative buds. The sharpest difference is found in the content and pattern of free amino acids and protein fractions soluble in ethanol, while in those soluble in alkali and insoluble, it is less.
2. The difference in the amino acid content in the buds disappears during the spring when they are bursting and growing.
3. In the almond Vochtchaberdi which is highly frost-resistant, preparation for the winter begins earlier than in the Non-plus-ultra, a variety with a weak frost-resistance. An earlier increase of the number of amino acids and total amino-acid content of the buds is indicative of this fact.

Two techniques recently described for the demonstration of protein SH in animal material were appllied to plant objects in this work: the technique with β-oxynaphthylmercurichloride and that with p-nitrobromacetophenone. These techniques together with DDD¹ and RSR¹ usually produced more intense staining in plant cell nuclei than in the cytoplasm. When reactions for protein carboxyls and tyrosine were used, similar differences in the intensity of staining the nuclei and cytoplasm were observed. It appears that the differences in the intensity of reactions for protein SH groups correspond to the differences in the concentration of total protein in plant meristematic cell nuclei and cytoplasm.

Leaf cells of healthy cucumber and cucumber infected with Cucumber virus 4 were studied living and fixed, using optical and electron microscopy. Under the electron microscope the infected leaves displayed changes in the structure of the ergastoplasm, Golgi apparatus, mitochondria, bodies with an osmiophil matrix and chloroplasts. The chloroplasts exhibit symptoms of fatty degeneration which affects above all the lamellar systems of grana and intergrana. Weakly osmiophil globules, abundant in damaged chloroplasts, are probably formed through degeneration of grana. Chloroplasts of infected plants resemble some transitional stages of plastids observed during chromoplast formation. The problems of localization of viruses in the cell and degeneration are discussed.

Auf Grund morphologischer Versuche mit Syringa vulgaris, Ligustrum ovalifolium, Philadelphus coronarius, Aesculus hippocastanum, Acer negundo und Bryophyllum crenatum wurde in dieser Arbeit die Abhängigkeit der Erhaltung entspreiteter Blattstiele von den korrelativen Einflüssen anderer Teile der Pflanze untersucht und die Möglichkeit der Nachahmung dieser Korrelationen mittels synthetischer Wuchsstoffe geprüft. Es zeigte sich, dass die Ganzheit der Pflanze, die vor allem durch die Regulationswirkungen der Wurzeln und Blätter bedingt ist, aus dem Verhalten der entspreiteten Stiele klarer hervorgeht als aus dem der ganzen Blätter. Dabei kommen Kompensationen, Polaritätsverhältnisse und embryonale Determinationen zur Geltung.

It was the objective of the present communication to establish the effect of short-term aeration with air alone or air enriched with 5% carbon dioxide on growth and oxidative metabolism of Chlorella pyrenoidosa. An organic medium was used to permit the investigation of the effect of aeration (one hour a day) both under illumination and in continual darkness.
Short-term aeration with air either alone or enriched with carbon dioxide increases dry-weight production both in the light and darkness. We are thus not dealing here with a mere effect on photosynthesis. This treatment affects the oxidative metabolism of the alga: oxygen uptake was always higher in those cultures which were more aerobic during cultivation (aerated cultures in the dark and non-aerated, or only with pure air cultures in light). Cultures in the individual variants display different endogenous respiration when measured manometrically.

The buds remowed from the fruit-bearing cluster bases of trees with fruit had a higher concentration of free asparagine and of some free amino-acids than the buds taken from trees without fruit. The quantitative relationship between amino acids in the hydrolyzates of the buds from the trees with and without fruit was very similar.

The sequence of intensities with which pollen tubes utilize tested sugars from their 0.3 M solutions, is the following: sucrose >glucose >invert sugar > >fructose. The same sequence is maintained in sugar-agar media with the exception of the first two hours of incubation when sucrose, glucose and fructose are all utilized at a practically equal rate. During this period no pollen tubes were formed in the presence of fructose, in common with the sugar-free control, while in the presence of sucrose they reached a length of up to 450 µ. If sucrose was used as carrier for radioactive sugars, fructose-¹⁴C was utilized up to 12 times and glucose-¹⁴C as much as 6 times more actively than sucrose-¹⁴C. When sucrose + glucose or sucrose + fructose (in molar ratio 1 : 1) were used the pollen tubes utilized sucrose-¹⁴C at a slower rate than the corresponding monosaccharide and also at a slower rate than observed with sucrose alone. When glucose or fructose was used as carrier for sucrose-¹⁴C . the carbon dioxide-¹⁴C production by the pollen tubes was (during several time intervals of the experiment) several tens per cent higher than when sucrose served as carrier. Fructose is utilized preferentially from a medium with invert sugar.
It thus appears that the capacity of the pollen enzymic systems for incorporating the sugars tested into their respiratory pathways is as follows: fructose >glucose > sucrose, this sequence being the opposite to that found for the intensity of their growth effect and to that established for the rate of their utilization, unless present in combination. The specific growth effect of sucrose cannot thus be due primarily to the rate of its absorption or to the intensty of its utilization. The rapid rate of utilization of sucrose alone is due to the more intense growth in the presence of sucrose. The results obtained further suggest that sucrose is utilized above all via its inversion when the fructose component is respired preferentially.

From photoperiodic experiments and an anatomic study of the shoot apex in the facultative short-day plantsPerilla ocimoides L. it was shown in all cases that gibberellic acid (GA) application did not accelerate flower induction. Between the development grades 2 and 4, GA caused a certain temporary acceleration which, however, completely equalised in a short period and plants of both variants SD and SD+GA flowered at the same time. Long day plants (LDand LD+GA) also flowered simultaneously with a certain delay. GA caused the total length of the plant to increase in both cases by more than a double, while preserving practically the same number of leaf pairs in variants under the same photoperiodic regime.

Analyses of free amino acids and amides in the axial parts of apple-trees with and without flower-bud initiation were carried out. The results obtained mostly on the basis of investigations carried out during a single vegetation season, indicate that the ratio and content of free amino acids and amides in the axial parts of apple-trees are influenced primarily by the growth of the axial parts and by nitrogen supply to the roots. These findings are in agreement with the results of Oland (1959). In fruit-bearing trees a high content of free amino acids and amides could be demonstrated, together with an increased ratio of soluble to insoluble nitrogenous compounds solely in the fruit-bearing new cluster bases (bourses). This finding is in accord with the results of Haeley and co-workers (1942). No apparent relationship could be established between the content and ratio of free amino acids and amides, and the ratio between soluble and insoluble nitrogen compounds on the one hand, and flower-bud initiation, on the other. The investigation is being continued.

The influence of 6-benzylaminopurine on the respiration of apple buds of the Boskoop variety for 5 days after application of kinine was observed. It was discovered that the consumption of oxygen determined by the direct method of Warburg is higher from the first day after application of 6-benzyl-amonipurine and the increase is continually more marked up to the fifth day, when the consumption of oxygen in stimulated buds is 75 per cent higher than in the control buds.

Wenn wir die Keimwurzeln der Puffbohne (Vicia faba L.) chloralisieren und später die Seitenwurzeln untersuchen, die in ihren chloralisierten Zonen entstanden, sehen wir, dass sich alle in einem verschiedenen Grade der Mixoploidie befinden (Němec 1961). Nach einer fünffachen Chloralisierung enthielten sie allermeist etwa bis zu einem Drittel polyploide Zellen, doch gibt es auch Vegetationsspitzen, die bis zu vier Fünftel polyploide Zellen enthalten. Die Zellen der Wurzelspitzen der Puffbohne ertragen unter dem Einfluss der Chloralisierung eine Erhöhung der Chromosomenzahl nur etwa auf 32n; solche Zellen können sich noch einigemale teilen, dann aber sterben sie früher oder später ab. Eine Restitution der mixoploiden Wurzelspitzen, sei es nun nach einer Dekapitierung oder nach einem Längsschnitt in die Vegetationsspitzen, geht normal vor sich und es beteiligen sich an ihr harmonisch diploide wie polyploide Zellen. Es ist nicht beobachtet worden, dass die polyploiden Zellen vielleicht aus dem Restitutionsvorgang ausgeschlossen worden wären oder dass es zu unregelmässigen Wucherungen gekommen wäre. Die mixoploide Spitze verhält sich bei der Restitution wie ein ganzes, einheitliches, lebendes Organ.

The cluster bases (bourses) in each case had a higher content of total nitrogen and both absolute and relative soluble organic nitrogen than the new secondary growth of cluster bases on trees both with fruit and without fruit than new spurs on trees with fruit. This higher content of total and soluble nitrogen is primarily a feature of the organ and has no connection with the initiation of flower buds. The secondary growth of cluster bases on the trees with fruit never had a significantly higher content of soluble nitrogen than the new secondary growth of cluster bases and new growth of spurs on trees without fruit. In all apple varieties observed the same qualitative pattern of free amino acids and amides was determined and a similar ratio of free amino acids and amides in the corresponding axial parts. The highest amount of free amino acids and amides-especially asparagine and arginine-was determined in the cluster bases. Arginine was accumulated in large quantities in the cluster bases much earlier than in the secondary growth of cluster bases or in the new growth of spurs. An accumulation of arginine and asparagine occurred in the cluster bases even when the supply of nitrogen was insufficient, in the secondary growths of cluster bases, however, their content was very low during nitrogen deficiency. The content of glutamine and sometimes threonine in cluster bases with fruit was also considerably increased. There was more glutamic acid, glutamine and sometimes threonine too in younger axils than in older ones already lignified.
From results given in this work it can be concluded that there is no obvious relation between the content and proportion of soluble and insoluble nitrogen in the spurs of apple trees on the one hand and the initiating of flower buds on the other. Neither was any obvious relation determined between the content of free amino acids and amides in the axillary parts of apple trees under observation and the initiating of flower buds.

The results are discussed of a quantitative and qualitative analysis of the protein characters of seed-enclosed cotyledons and of hypocotyls + roots (of the primary root) of germinated seeds of the following species:Phaseolus vulgaris L.,Phaseolus coccineus L.,Phaseolus lunatus L.,Phaseolus aureus Roxb.
1. A practically identical phaseolin was found in the cotyledonsof Phaseolus vulgaris L. andPhaseolus coccineus L., being absent inPhaseolus lunatus L. andPhaseolus aureus ROXB.
2. A protein component described as Phaseolus protein III was found in the hypocotyl + root ofPhaseolus vulgaris L.,Phaseolus coccineus L. andPhaseolus lunatus L.; it was absent inPhaseolus aureus Roxb.
3. The inequality of breadth of taxonic (group) specificity of the protein characters has been confirmed anew. This fact is discussed in connection with the relative phylogenetic age of the characters, On the basis of the results obtained a developmental scheme of the studied species is proposed.

The indirect influence of irradiation on the production of anthocyanins in the blossoms of red balsam (Impatiens balsamina L.) was investigated. After 18 hrs. of swelling, seeds were irradiated with 4560 r and then changes in the anthocyanin content of blossoms were examined. In X₀ three out of four lines tested displayed a marked increase in anthocyanin content by 18%, 18% and 29%. In X₁ the quantitative content of anthocyanins either equalled that of the controls or was lower, in X₂ a significant decrease in anthocyanin content in all the lines was observed. We are apparently dealing here with a physiological effect of the type of "prolonged modifications".
In X₁ several plants with pink flowers appeared (3.4%). It is assumed that this is not due to a segregation caused by heterozygous material (the controls did not show this effect) but rather to a recessive mutation brought about by irradiation, which became apparent only in X₁.

1. Suppressors were found in reciprocal crosses of some varieties of barley for the manifestation of recessive and dominant alternatives of the following characters: number of rows of the spike, presence or absence of glumes, character of awns and formation of the spike basis.
2. A proof of the existence of suppressors is presented merely statistically on the basis of segregation ratios in the F₂ generation, in the total F₃ generation and in the individual segregating progenies of plants from the F₂ generation and in the back crosses.
3. It was confirmed that the inheritance of the characters investigated is independent in spite of the fact that the segregation ratios are complicated by the participation of suppressors.
4. Separated cultivation of individual progenies from hybrid seeds formed on the mother plant was shown to be very suitable and efficient in hybridization experiments of this type.
5. The significance of the participation of the suppressors in the inheritance of the characters studied is pointed out with respect to the practical breeding of barley.

The reaction ofSolanum tuberosum L. after the irradiation of isolated sprouts was examined. A dose causing marked changes was sought. After a dose of 1,000 r, deformations began to appear in the tuber and stem, which increased with higher doses. Deformations of the tuber were observed after a dose of 250 r. In hybrids 4/50, nests of red-skinned potatoes were found. This property is partly preserved during the subsequent generation. The material is being further examined.

The effect of CO₂ on the plasmatic structure of root-hairs of wheat and barley and the epidermal cells of onion was observed. The results were evaluated on living material with the aid of phase contrast. The root-hairs of barley and the epidermis of onion react to short exposure to an atmosphere of CO₂ by a cessation in the flow of plasma, a lengthening of the mitochondria and a rounding of the plastids.
When the influence of CO₂ lasts longer, it causes fragmentation of the mitochondria. In this phase the cells recover most quickly from the shock caused by their exposure to CO₂. When the plant is under the influence of CO₂ for too long a time, the effect is lethal. The root-hairs of wheat, which have mainly granulated mitochondria, reacted after only 40 minutes in CO₂ by a rolling-up of all the plasmatic particles.
This observation agrees with the results obtained on permanent preparations in the former work and leads to the conjecture, that by fragmentation of the mitochondria, the cell adapts itself to inhibited respiratory conditions.

1. The differences in the dynamics of the origin and further development of the water saturation deficit (WSD) in leaves of different age from 100- to 120-day-old plants of fodder cabbage and rape were investigated.
2. WSD in leaves of different age detached from plants and wilting without water supply develops most quickly in young and most slowly in old leaves. This is in basic agreement with differences in transpiration rate.
3. When entire plants are cut off, leaves of different age wilt at the same rate. In the later phases of wilting, (i.e. at a WSD value of over 20 to 30%) slightly higher WSD values were found in old leaves.
4. During slow wilting of plantsin situ, induced by decreasing soil moisture, a definite preference of young leaves in water supply was determined commencing from medium WSD values, i.e. on an average from 8 to 20%. During total lack of water in the plant, old and adult leaves wilt markedly and die off; the WSD of young leaves remains for a long time at comparatively low values.
5. In the observed preference of young leaves, the translocation of water to young leaves from the wilting older leaves takes a part.