Kinetin (10^-4 m) is initially more effective than GA (10^-4M) in reversal of the inhibitory effect of Phosfon D (10^-3m) on the germination of kale seed (Fig. 2 and Fig. 3). Kinetin is about 2.5 times more effective than GA in reversal of the synergistic inhibitory effect of coumatin (100 p.p.m.) plus Phosfon D on germination of kale (Fig. 2 and Fig. 4); initially most effective in this respect is a supraoptimal concentration of kinetin, 5 x 10^-4M, which markedly inhibits germination in the control.
It seems that kinetin, Phosphon D and coumarin act specifically on the process of germination. It is suggested that in the germinating seed of kale Phosfon D and coumarin block alternative metabolic pathways, induced by kinetin.

V popsaných pokusech byl vliv letního odlistování na zakládání květních pupenů do značné míry závislý na odrůdě a byl silnější u stromů vykazujíeích bujnější růst.

When the lethal radiomutant chlorina 42 was cultivated on glucose containing and glucose-free medium the cotyledons of the matant sown on glucose medium had a higher chlorophyll content than those of the matant sown on glucose-free madium. In further cultivation of this mitant on glucose medium until flowering the total chlorophyll content is maintained at the same level, it increases slightly in the case of flowering plants. The mutant cultivated on glucose medium differs somewhat with regard to the content of free amino acids from the green control cultivated also on glucose medium over the whole vegetation period. The former has a higher glutamine content than the latter and in some growth phases also a higher content of asparagine. It is assumed that the insufficient photosynthetic activity is apparently not fully compensated by glucose and the plant has to supplement its energy balance by partial oxidative protein catabolism even under the conditions of artificial nutrition.

When compared with the control plants, the increase in dry weight in the growing parts of germinating plants ofPisum sativum L., cultivated in a closed atmosphere in darkness or light is heavily inhibited. The concentration of carbon dioxide in the closed atmosphere increased in 60 mg CO₂/per 1 g of the final dry weight of plants after 10 days. Similar results were obtained with older plants under similar conditions. The Knop solution caused a slight increase of dry weight in the growing parts of plants, but did not change considerably the relations in gas exchange. The results show that even plants which are able to photosynthetize, are only transpiring under the above conditions; first, when the plants were devoid of cotyledons, as storage organs, the changes in their dry weight (but not the changes in the CO₂ and O₂ exchange in a closed atmosphere) seemed to show photosynthetic income of CO₂ (while its concentration increased to 3-6 volume %) when compared with the control.
From the above results follows that quantative relations between photosynthesis respiration cannot be solved by analysing the gas exchange in a closed atmosphere.

Identification trials were carried out to determine a virus-like disease of Impatiene parviflora DC. Two forms of foliar symptoms were observed:
a) Chiorotie and necrotic areas sometimes fallen out, leaving the leaves "shot holed";
b) milder foliar symptoms consisting of slight greenish yellow areas and spots often scarcely visible except by transmitted light.
Results of experiments with the first form of the disease demonstrate the identity of the causal virus with cabbage black ringspot virus; the second type of symptoms was caused by a Strain of cucumber mosaic virus inducing unusual symptoms in tobacco plants.

In der Arbeit wurde die Möglichkeit der allelopathischen Beeinflussung von Folgepflanzen durch Vorkulturen bei der Kultivierung in abgestuften Zeitintervallen nacheinander auf demselben Bodensubstrat bei folgenden Konabinationen von Pflanzen untersucht: Mohn - ZuckerrÜbe, Ackersenf - Gerste, Hanf - Korn, Zwiebel - Raps. Die Versuche wurden in Gefassen mit Komposterde, welche im Laufe des Versuches im Garten in den Boden eingelassen worden waren, durchgefÜhrt. Es wurde das Wachstum der Vorkulturen und der Folgepflanzen in den ersten Wachstumsphasen untersucht. Von der Aussaat der Folgepflanzen wurde in Bodenproben die Respirationsintensität, die aktuelle Feuchtigkeit und der Gehalt an physiologisch zugänglichem Stickstoff, Phosphor und Kalium bestimmt.
In allen untersuchten Kombinationen waren die Folgepflanzen durch die Kultivierung der Vorkultur und die nachfolgende Lagerung des Bodensubstrates beeinflusst. Die Wachstumsveränderungen der Folgepflanzen standen teilweise mit dem Gehalt an physiologisch zugänglichem Stickstoff im Bodensubstrat in Korrelation. Aus dem Charakter der Wachstumsveränderungen ging jedoch auch klar hervor, dass sich hier auch allelopathische Faktoren beteiligt haben. Sehr inhibierend wirkte Mohn auf ZuckerrÜbe, weniger inhibierend wirkte Ackersenf auf Gerste und Zwiebel auf Raps. Die Wirkung von Hanf auf Korn zeigte mit der Lagerungsdauer des Bodensubstrates zusammenhängende Veränderungen.
Veränderungen im Gehalt an physiologisch zugänglichem Stickstoff, Phosphor und Kalium im Versuchsbodensubstrat entsprachen nicht der Menge der angewachsenen Pflanzenmasse der Vorkultur, was durch die angewendete Kultivierungsmethode bedingt war. Die verhältnismässig schnelle Erneuerung der durch die Vorkultur erschöpften Nitrate im Versuchsbodensubstrat in der Zeit der Bodenlagerung wurde wahrscheinlich durch Nitrifikationsprozesse verursacht.
Den festgestellten Veränderungen der Respirationsintensität des Versuchsbodensubstrates nach kann sich auch die Bodenmikroflora an der allelopathischen Beinflussung beteiligen.

1. A number of varieties of cultivated juteGorchorus oHtorius L. andG. capsularis L. were tested in artificially created drought, waterlogging and control conditions.
2. The number of lateral roots with secondary growth was reduced to the minimum inC. capsularis under waterlogged conditions, but the weight of the roots was increased to the maximum, due to the production of numerous spongy and fibrous roots.C. olitorius suffered in both the characters under similar environment and failed to produce fibrous and spongy root. This species gained in root weight and lateral root number in drought under whichC. capsularis suffered in these two characters. These were the main features of adaptation of these two species.
3. Within species among varieties the variations regarding these two characters have been found to be controlled by genotypes. Lateral root number within both the species has been found to be a more strongly heritable character than root weight. Expected genetic advance has revealed the scope of selection for lateral root number.
4. While variations among thé varieties within species have been interpreted as an expression of phenotypic flexibility, the variation between species is an expression of phenotypic plasticity, which is an outcome of basically physiological mechanisms.Corchorus capsularis L. andC. olitorius L. are two cultivated jute species. The most striking distinction between these two species hitherto known is that whileG. capsularis can withstand waterlogging successfully,C. olitorius cannot. This general view formed the basis of testing these species under artificially created environmental stresses to find out the general components contributing to this specific difference.

The redox potential of wilted leaves of cereal seedlings grown in a greenhouse was higher than in the fresh leaves. However, the redox potential in the wilted leaves of plants during the stem extension was lower than in fresh leaves. The reaction of barley leaves var. Japan 2003, which belongs to the dundar-beyi Zhuk.-group, differed materially from the European cereal varieties. The cause of the change of redox potential is discussed in connection with the ontogeny of cereals and resistance against obligate parasites.

Root formation in the etiolated pea stem sections and inhibition of this process is described in the present paper. Sodium fluoride, iodoacetic acid, norvaline, phenylserine, 5-bromuracil and 2-thiouracil did not inhibit the root formation completely. Complete inhibition, however, was observed after treatment of pea stem sections by kinetin, ethionine and chloramphenicol (5 X 10^-5 M, 1 x 10^-2 M, and 1 x 10^-2 16 hours after sectioning). The concentration of kinetin which produced complete inhibition of root formation simultaneously stimulated the growth of the lateral buds.
Root formation under the conditions described below can be divided into two stages. The first stage 64 hours from the beginning of the experiment, the second stage 64 hours later. Further, the first stage includes the formation of the meristematic cells in the pericycle areas. In the second stage are included the growth of roots and differentiation of root-tissues. Roots were formed, first of all, in the short vertical region of the sections near to the basal buds. Secondary xylem formation was also observed during the cultivation of the sections. This process was stimulated by kinetin.

Immediate response of water uptake by intact plants ofPisum sativum L. to the introduction of high concentrations of α-naphtaleneacetic acid (NAA), β-indoleacetic acid (IAA), 2,4-dichlorophenoxyacetic acid (2,4-D), 2-methyl-4-chlorophenoxyacetic acid (MCPA), coumarin was determined by a series of potometric measurements. Growth substances were present in the root medium in two concentrations: 10^-3 m and 10^-2 m; the concentration of coumarin was 5. 10^-4 m and that of EDTA was 10^-3 m.
The response of water uptake to the application of the growth substances and coumarin was always negative. EDTA did not affect immediately the intensity of water uptake. The inhibition of water uptake brought about by the growth substances takes place immediately. Coumarin causes slow, progressively increasing inhibition of water uptake. A coincidence was found as to the time course of the changes in the water uptake intensity in the presence of high concentrations of growth substances and coumarin in the root medium with the time course of changes of transpiration intensity, found under analogous conditions by Allerup (1964). This may be considered as another justification for the hypothesis, according to which the rapid changes of transpiration intensity in the presence of high concentrations of growth substances in the root medium are caused by rapid changes of the intensity of water uptake.

The differentiation of tissues is closely connected with the proteosynthesis. One can therfore assume that tissues with different types of cell growth (meristematic or elongation growth) and with different degrees of differentiation are different in their protein composition. In order to compare the protein composition of different plant organs, the method of disc electrophoresis on a polyacrylamide gel has been used by some authors. As compared with other methods used up to now, e. g. isolating proteins on DEAE cellulose or in Sephadex, this method does not need so much material and its resolution ability seems to be higher. It is also quicker and enables the study of several samples simultaneously. Its disadvantage is that proteins can be identified mainly by means of Rf and their quantity, measured from the intensity of staining of individual fractions in the gel, which may be misleading due to different sorption capacity of different proteins (FričFričová 1967). None the less, it is good for comparison of protein composition of individual parts of the plant body.
Different methods have been used to compare protein composition of individual growth zones in roots.Barsky,Ivanov andPushakova (1965) used luminiscence microscopy and found that in maize roots it is not possible to find substantial differences by this method.Morgan andReith (1954) arrived at similar conclusions. On the other hand,Steward et al. (1965) andMorris (1966) found qualitative differences in protein composition of different parts of pea roots using acrylamide electrophoresis. The results of the last named authors show considerable discrepancies in details, due perhaps to a different method of extraction (buffer, pH, purifying method).
We have used acrylamide gel electrophoresis for investigating proteins in precisely defined growth zones of theVicia faba root.

White-rot fungi causing the white decay of wood, secrete polyphenol oxidase type enzymes which catalyze the oxidation of diphenols to quinones. If the substrate also contains amino acids, they can be oxidized secondarily to a red pigment, the intensity of which depends on the activity of oxidation oxoenzymes. This finding was used for devising a quick test to demonstrate the oxidases secreted into the cultivation medium by wood-rotting fungi. As substrates we used hydroquinone and glycine. We tested a total of 89 species and 131 strains of wood-rotting fungi. Simultaneously, we compared the newly devised test with the most common test for the detection of polyphenoloxidases, with the guaiacol test. It follows from the results that the new test, in which the intensity of the red colour was estimated colorimetrically, permits to divide the wood-rotting fungi into two groups, the positively and the negatively reacting ones. This division does not fully coincide with that obtained by means of the guaiacol test.

Coleoptile and root tips ofTriticum aestivum cv. Arnej 624 and those ofAvena sativa cv. Victory (Svalöf) as well as dry excised embryos ofTriticum aestivum cv. Rival (Svalöf) and those ofArachis hypogaea cv. 34 3A. H. were cultivated in media containing various concentrations of sucrose and growth regulators, like ascorbic acid, indole-3-acetic acid and gibberellin. Growth, differentiation and water uptake of the various explants were determined at regular time intervals. Further, the concentration of the endogenous ascorbic acid in mg./g. fresh weight, as well as the amount of this growth regulator utilized as per cent of the total were determined.
Although all the three growth regulators promote growth in the explants, their effect is best felt when sucrose of a higher concentration (1.0 per cent) is added to the medium. In fact, the response to 1.0 per cent sucrose is sometimes as good as a combination of a growth regulator with sucrose, especially in the case of root explants.
The results clearly indicate that the biosynthesis of ascorbic acid in the explants is catalyzed by the addition of indole-3-acetic acid as well as gibberellin. Simultaneously, the utilization of ascorbic acid is also appreciably increased by the presence of these growth regulators.
Addition of 1.0 per cent sucrose to the medium containing the above mentioned growth regulators augments to a considerable extent not only the concentration of ascorbic acid, but also steps up its utilization. Enhancement of ascorbic acid as well as its increased utilization are correlated with rapid imbibition of water, growth and differentiation.
The role of ascorbic acid in growth is discussed; and on the basis of the data presented here it is postulated that: (1) auxin and gibberellin function in the growth process by catalyzing the biosynthesis of ascorbic acid; and (2) that ascorbic acid not only participates in activation of various enzyme systems, but also stimulates the production of adenosine triphosphate by acting as an electron donor in photosynthetic phosphorylation as well as oxidative phosphorylation; (3) that the above action of ascorbic acid creates a favourable redox balance for synthesis of nucleic acids, proteins, enzymeproteins, and cell-wall constituents, thus enabling the processes of cell division and enlargement to proceed at a fast rate; and (4) that the relative rates of cell division and cell enlargement as well as "ageing" will determine the pattern of plant development.

Schizaphis graminum (Rondani) is proved to be an additional vector of maize mosaic virus (MMV). The pH range for the infectivity of the virus in extracted juice is found to be from 4.4 to 9.0, the optimum being 5.6 to 7.2. Effect of certain chemicals on the virusin vitro has also been studied. Cross protection between MMV and Sugar-cane mosaic virus (SMV) indicated positive results. It has been concluded on the basis of similar physical properties, tolerance towards certain chemicals, host range, symptomatology, aphid vectors and positive immunological tests, that MMV and SMV are related viruses.

The paper deals with the resaturation of water saturation deficit in fourStipa species tested under various ecological conditions. Attention is paid to the relations between the saturation and oversaturation types of curves, on the one hand, and soil moisture on the other. The oversaturation type appears in plants well supplied with soil moisture. The explanation of this phenomenon is discussed.

We compared the occurrence of peroxidase isozymes in protein extract from roots, hypocotyls and cotyledons of 10 dayCucurbita pepo plants and of adult leaves of older plants by means of starch gel and polyacryl amide gel electrophoresis. We reached maximum discrimination by means of starch gel electrophoresis: 11 zones were ascertained on the cathode side and about 2 on the anode side at pH 3.1. Two zones occurred regularly:A and (the latter having a more complicated structure). ZoneD is characteristic for roots, but is it suppressed and seldom found with leaves. On the other hand zonesC ₁ andC ₂ are clearly discernible with leaves but are substantially less evident with roots. The character of anodic zoneZ is discussed later in this paper.

The cytoplasmic components of broad bean (Vicia faba L.) root tip cells were studied light- and electronmicroscopically. Using a light microscope, differences were revealed between cells from the cortex and from the central cylinder. For electron microscope studies the cells near the boundary between the mentioned parts of the root tip were selected at a distance of about 2 mm from the initials. The orientation of objects during embedding made possible fairly accurate localization. No peculiar, strikingly osmiophillic bodies were seen, which could be identified without doubt as osmiophillic platelets. It follows that some of the current cytoplasmic components, perhaps more or less altered were described as osmiophillic platelets. After fixation with KMnO₄, in which case the electronmicrographs are most instructive, the leucoplasts show several inclusions, mostly only partially limited against the matrix; it is not clear whether the true membrane is concerned here. The origin of intravacuolar membraneous formations is discussed.

Die Wirkung steigender Konzentrationen von NaHCO₃ auf die Ausfällung des Eisens in einer Nährlösung sowie die durch das Hydrogenkarbonat bedingte Hemmung des Wachstums der Pflanzen (begleitet von Chlorose) und zugleich die Gegenwirkung des Na-Humats wurden erforscht. Unter der Einwirkung von NaHCO₃ wurde eine Verminderung des Eisengehaltes und eine Erhöhung des Verhältnisses P/Fe in den Sprossen festgestellt; in Anwesenheit von Humat in der Nährlösung blieb dieser Effekt aus.

6-azauracil (AU) and 2-thiouracil (TU) were applied to the short-day plants Pharbitis Nil and Chenopodium rubrum and to the long-day plants Hyoscyamus niger, Lolium temulentum and Triticum aestivum cv. Chlumecká 12 at different times before, during or at the end of floral induction. In wheat the effect of 5-bromouracil, 5-iodouracil and 2-thio-6-azauracil was also tested.With the exception of bromouracil, which slightly stimulated flowering in wheat, all analogues either strongly inhibited or completely blocked flowering when applied in appropriate concentrations a short time prior to induction or at its beginning. Treatments given a longer time before induction or after its termination was less effective. Inhibition of flowering was always associated with damage to the vegetative growth. The effect of TU was reversed by uracil and that of AU by uridine, if these compounds were applied simultaneously with the analogue at a concentration exceeding at least 5 times that of the analogue. Reversal also applied to vegetative growth. Simultaneous application of gibberellin and analogues did not remove the inhibition.

The liberation of phosphoric acid from glucose-1-phosphate, catalyzed by phosphorylase was studied in wheat growing in sand cultures with an addition of humic acid and hymatomelanic acid. It was found that the phosphorylase activity of tissues changes under the influence of humic acid very significantly. The maximum activity is reached at 10 mg humic acid/liter. The overground organs are less sensitive, as a stimulation effect is reached there only at 400 mg/liter. The effect of hymatomelanic acid is negligible in comparison with that of humic acid. The observed phenomenon is related to the effect of humus substances on the equilibrium of saccharides and on the distribution of dry matter in the plant.

Metabolic disturbances inNicotiana glauca, a symptomless carrier of potato witches' broom were studied. The dry weight content of leaves of diseased plants was slightly decreased, that of the stems increased. The ash content in the dry weight of the whole diseased plant was decreased by 11%. Contrary to tomato plants which had shown considerable disproportions in the distribution of metabolites among the individual organs investigated (ULRYCHOVÁ, LIMBERK 1964), the content of the total nitrogen and of the individual nitrogen fractions of both leaves and stems of diseasedNicotiana glauca were decreased. The content of glutamine was increased in both organs in spite of the decrease of ammonia nitrogen by nearly 30% in both cases. The most striking disturbance found in the diseased plants ofNicotiana glauca was the 67% increase of a low-molecular phosphorus fraction (P extractable with 0-2N HCIO₄) in the leaves. This result agrees with that found in diseased tomato plants and may be primarily associated with the virus infection. The content of all other phosphorus fractions of both leaves and stems was decreased.

The purpose of this paper is to determine the sequence of the formation of the lignified cell wall and to confirm the hypothesis expressed previously on the alternate deposition of cellulose and lignin in a 24-hour period. In this connection, the inner surface of the cell wall of the fibre cells from the youngest wood ofPopulus nigra L. 'Italica' taken during a typical summer day in two-hours' intervals was investigated electron microscopically.
The fine structure of the inner surface of the growing secondary cell walls was found to change regularly within 24 hours and to be determined by the structure of the components just being deposited. Cellulose and lignin were identified unambiguously, hemicelluloses could not be identified by their structure. The cellulose was characterised by the parallel microfibrillar structure; lignin was detected as an amorphous deposition.
The identified structural components are being deposited separately in certain intervals of the day cycle: cellulose in the afternoon hours (12 a. m. - 6 p. m.) and lignin after midnight (0 - 4 a.m.); in the morning hours (6-10 a.m.), neither lignin nor cellulose are deposited, however, the structure of the cellulose formed previously rises as a microrelief under the amorphous layer.
The alternate deposition of both structural components corresponds to variations of the biophysical and biochemical condition of the cells observed in the cambial zone during 24 hours. This periodicity appears to be autonomous and affected only partly by environmental factors. The results confirm the presumption that each lamella of the secondary wall consists of a cellulosic and a non-cellulose (lignin) part. Lignin permeates through the cellulosic part formed previously, impregnates it and cements it to the preceding lamella.

Radish seedlings were grown in asymmetric magnetic fields. The number of seeds germinated and the dry weight of the plants were the two criteria by which possible effects were examined. Two experiments were done; in the first the plants were grown for an average of 7.7 days and in the second for 14.1 days. A statistical analysis of the results failed to reveal any significant difference between control plants grown in dummy magnets and those subjected to the magnetic influence.

The course of biosynthesis of fatty acids in the seeds of winter rape (Brassica napus L. ssp.oleifera, f.biennis cv. Třebíčská) was investigated. After the termination of flowering seed samples were taken at five intervals, the seeds were divided into 4 fractions according to size, and their weight, water content, oil content and fatty acid composition were determined. The oil content was found to increase in all size categories with time, with the exception of a minute drop when complete maturity is reached. Larger seeds contained more oil. The fatty acid composition changes with time in the individual size fractions almost continuously. The same holds for differences between seed sizes of the same sample. The main change in oil composition consists in the decrease of C₁₈ acids in favour of C₂₂ acids. Greatest decrements during maturation were found with oleic acid, less with linoleic acid. In absolute amounts the quantity of all synthesized acids rises, the greatest rise being observed with C₂₂ acids (i.e. predominantly erucic acid). It follows from the mean rates of synthesis of the individual groups (C₁₆, C₁₈, C₂₀, C₂₂) of fatty acids that the fraction of C₂₂ rate of synthesis increases, while that of the C₁₈ acids decreases with the same speed. The results indicate that the fatty acid synthesis is most intense during the second half of seed maturation, the main role being played by accelerating the synthesis of higher acids, especially of erucic acid.

The catabolism of specifically¹⁴C-labelled glucose during the root formation and its inhibition by kinetin and ethionine in the etiolated pea stem sections were studied. The formation of root meristematic foci in the pericycle region of sections was accompanied by the decrease of the C₆/C₁ ratio. Such a result and activation of pentose phosphate cycle, which was also checked by another method, suggested increased participation of pentose phosphate cycle in glucose oxidation. The above mentioned changes were also found after the prevention of root formation by ethionine and, therefore, do not seem to be specific for the meristematic foci formation. The growth of newly formed roots was closely connected with the rise of C₆/C₁ values.
The increase of CO₂ release from the first carbon atom of glucose molecule was recorded after the inhibition of root formation by ethionine.
The rise of C₆/C₁ values and decrease of pentose phosphate cycle activity was observed after the treatment of pea stem sections by kinetin in the first 64 hours after sectioning. In this case root formation was prevented and the growth of lateral buds was stimulated. The secondary xylem formation which took place later was accompanied by the activation of the pentose phosphate cycle. These phenomena are discussed in relation to cell division and biosynthesis of lignin-precursors.

A quantitative anatomical study of the stem structure of grasses of various ecological groups: xerophytes, mespohytes, ephemers, hydrophytes and psammophytes (a total of 30 species) was carried out. The proportions of the various tissues in the stem were expressed as a percentage of the cross-sectional area of the stem. Stems of hydrophytes were found to have only small proportion of mechanical (4-8%) and conducting (2-5%) tissues but a large pro. portion of parenchyma (85-93% - primary cortex and basic parenchyma) and air system (38-40% - parenchyma channels or specialized aerenchyma). The stems of xerophytes possess a highly developed sclerenchyma (30-50%) and vessel bundles (6-13%) while the parenchyma is less developed (36-60%). The cells of the stems of hydrophytes are larger than those of xerophytes, but the cell membranes are thinner. The structure of mesophytes is intermediate between that of hydrophytes and xerophytes and the structure of ephemers is very similar to that of mesophytes. Psammophytes differ from xerophytes in having more mesomorphous features.

The effect of different constant soil moisture levels (90, 60, 30% and 90, 60, 40% respectively, of the maximum capillary capacity) on the vegetative growth of maize was studied by the methods of growth analysis. The constant soil moisture in vegetation pots was maintained by means of the injection method. The constantly decreased soil moisture was applied in one experiment just from the sowing of germinated corns and in the other from the phase of 4-6 leaves. In both the cases plants responded to the different soil moisture levels by a progressively lower growth rate of the total dry weight according to the degree of soil moisture lowering. When the constant soil moistures were applied from the sowing, the differences in the relative growth rate (R.G.R.) were caused mainly by lower leaf area ratio (L.A.R.) values. In the case of constantly lowered soil moistures from the phase of 4-6 leaves, the differences in R.G.R. were caused by lower net assimilation rate (N.A.R.). When the constant soil moisture of 40% was applied from the sowing, the changes in N.A.R. showed the characteristic features of adaptation to unfavourable conditions.

The effect of different concentrations of hydrochloric acid on the qualitative an quantitative content of carbohydrates in humus fraction hydrolyzates was investigated. Three humic acid preparations were subjected to the usual procedure for obtaining fractions of humic and hymatomelanic acids. The carbohydrate content of the hydrolyzates was determined after their Chromatographic separation on Whatman 1, using the Partridge system and detection with acid anilin phtalate. The results showed that the qualitative carbohydrate content in the hydrolyzates of most humus fractions of samples used was identical. With increasing acid concentrations the amount of hydrolyzable carbohydrates usually increased, the total amount of carbohydrate in the hydrolyzate not exceeding 4% . The difference in the carbohydrate content as between hydrolysis with 0-9N and 5-3N HC1 was sometimes fourfold. A higher content of hexoses than of pentoses was generally found.

Types of the daily course of transpiration rate were studied in two-year old seedlings ofPinus silvestris L.,Picea excelsa L.,Larix decidua L.,Tilia cordata Mill., andAlnus glu-tinosa (L.) Gaertn. The curves illustrating the daily development of transpiration rate (Figs. 3 - 8) may be grouped in two types, showing a midday maximum (one-peak curves) and a midday depression (two-peak curves). Unlike herbaceous plants, the seedlings ofPinus silvestris L. were found to show, during the night-time, lower but not negligible values for the rate of transpiration (see Figs. 3 and 8). The following times are considered most suitable in determining the rate of transpiration for both herbs and woody species during the daylight: 09.0, 12.0, 14.0, and 17.0 hours. For the forest species seedlings further times are suitable for the night-time, as follows: 23.0, 01.0, and 06.0 hours. The rate of transpiration in the seedlings of Pinus silvestris attained very low levels at 3 and between 6 and 8 a.m. and between 6 and 8 p.m. (see Figs 3 and 8).