Showing papers in "Biologia Plantarum in 1973"
TL;DR: In this article, a new method of sap flow rate determination in stems of adult trees is described in which mass flow (the transpiration flux in the present case) is estimated from a heat-transfer measurement.
Abstract: A new method of sap flow rate determination in stems of adult trees is described in which mass flow (the transpiration flux in the present case) is estimated from a heat-transfer measurement. The device used includes a couple of thermometers in a differential connection and plate electrodes, through which a controlled heat input flows into a denned studied segment of the xylem. The present method was tested first with a laboratory simulating system, then with the stem of a living adult treePrunus avium L. The data are registered continually and automatically; continuous measurement of sap flow rate of long duration with a greater number of trees is thus made possible.
252 citations
TL;DR: Local variations in the duration of the mitotic cycle in the apical meristem of broad bean root is determined by means of colchicine-induced polyploidy and the results derived are discussed in connection with the ontogenesis of different types of cells taking part in the primary structure of the root.
Abstract: Mitotic activity does not stop for different meristematic cells of the root apex at the same distance from the initials. The differences are connected with the functional heterogeneity of the apical meristem of the root. The arrangement of vascular bundles,i.e. the alternation of independent xylem and phloem groups, is of major importance. In broad bean roots, the protophloem sieve elements stop dividing first. The centre of the stelei. e. late metaxylem elements stop dividing next. Division in the stele gradually ceases centrifugally, while it ceases centripetally in the peripheral part of the root. The cylindrical region with prolonged cell division includes internal layers of the cortex including endodermis, pericycle and adjoining cells of the stele. Proximally apical meristem is reduced to isolated strands of cells adjacent to the protoxylem poles. Pericycle cells stop dividing last at a distance of approx. 9–10 mm from the initials.
27 citations
TL;DR: Using four independent late mutants, obtained by treatment of the early cultivar Dijon-G with N-methyl-N-nitrosourea, it was found that their delayed flowering has a monogenic genetic basis, the mutant alleles appearing to be incompletely dominant.
Abstract: Using four independent late mutants, obtained by treatment of the early cultivar Dijon-G with N-methyl-N-nitrosourea, it was found that their delayed flowering has a monogenic genetic basis, the mutant alleles appearing to be incompletely dominant. All these mutants display a positive reaction to the graded vernalisation; the vernalisation requirement of the individual mutants is, however, both quantitatively and qualitatively different and hence specific for each of the mutant genotypes. lodoacetic acid is found to inhibit the vernalisation of the mutants to some extent only when the duration of the vernalisation is relatively short (20 days). A hypothesis is advanced, assuming a potential existence of a complete genetic apparatus for vernalisation already in the Dijon-G cultivar, where it is, however, blocked by suppressor or epistatic genes.
17 citations
TL;DR: Minimal diffusive resistances of both leaf epidermes increased during normal and retarded ageing; the later rapid rise in diffusion resistance was induced by the loss of stomata ability to open fully.
Abstract: Minimal diffusive resistances of both leaf epidermes increased during normal and retarded ageing (moving secondary leaves aside, plant decapitation). The retarded ageing of primary leaves slowed down increase in epidermal resistance (rep), and was also reflected in the prolongation of their growth, increase of leaf area, size of epidermal and guard cells and stomatal pores. Decrease of stomata density was to some extent balanced by an increase in the pore size; the later rapid rise in diffusion resistance was induced by the loss of stomata ability to open fully.
17 citations
TL;DR: In this article, a comparison of post and simultaneous azocoupling procedures for β glucosidase localization on unfixed and fixed root tips of Zea mays was made, concerning the time course of enzyme reaction, its pH dependence, the effect of various buffers, the comparison of several diazonium salts and the use of different naphtholic substrates.
Abstract: A comparison was made of post and simultaneous azocoupling procedures for β glucosidase localization on unfixed and fixed root tips ofZea mays. Using this object, more detailed studies of β glucosidase distribution were undertaken, concerning the time course of enzyme reaction, its pH dependence, the effect of various buffers, the comparison of several diazonium salts and the use of different naphtholic substrates. The indigogenic reaction was also applied. Attempts were made by means of azocoupling procedures to localize a and β glucosidase in root tips ofCucurbita pepo, Lupinus albus, Piswm sativum andVicia faba in comparison withZea mays. In addition to certain technical problems, the questions of constitutive and adaptive enzymes, sugar distribution and histogenesis versus function are discussed in relation to the presence and distribution of s glucosidase in the studied objects.
16 citations
TL;DR: The inhibitory effect was found with all the applications during the first two days, whereas a stimulatory one on the third and fourth day was found, assuming this dual effect reflects the differences attained in developmental phase and in the degree of shoot apex differentiation.
Abstract: IAA, NAA and ethrel (1 × 10-4M and 3 × 10-4M) was applied to the plumula of Chenopodium plants at different time after the start of photoperiodic treatment and the flowering response was investigated. The inhibitory effect was found with all the applications during the first two days, whereas a stimulatory one on the third and fourth day. We assume this dual effect reflects the differences attained in developmental phase and in the degree of shoot apex differentiation.
15 citations
TL;DR: By modifying the auxine-cytokinine ratios and with or without the addition of sugar, it is possible to direct neoformation in stem and leaf fragments of Torenia fournieri towards the production of roots only or buds only.
Abstract: By modifying the auxine-cytokinine ratios and with or without the addition of sugar, it is possible to direct neoformation in stem and leaf fragments ofTorenia fournieri towards the production of roots only or buds only; the buds either remain vegetative or become floral according of the treatment.
14 citations
TL;DR: Experimental results show that during differentiation of fruiting bodies and their morphogenesis not only gibberellins and cytokinins are of importance, but also substances of an inhibitory character are secreted into the cultivation medium.
Abstract: The fungusLentinus tigrinus was cultivated in a synthetic medium. During vegetative growth of mycelium and differentiation of fruiting bodies samples serving for determination of endogenous growth regulators were collected. The material was extracted with methanol, separated by chromatography and the isolated fractions were tested. Substances of auxin type were assayed with coleoptile segments of oat plants, gibberellins by measuring the hypocotyl growth in the lettuce and cytokinins from the degree of chlorophyll decomposition in the leaf segments of barley. Very low content of auxins was found in all phases of growth and differentiation of the fungus. The content of gibberellin substances was relatively high during the whole life of the fungus. The highest content is found in the vegetative mycelium and in the differentiated fruiting body, especially in the cap; it decreases during the differentiation of fruiting bodies. The content of cytokinins is equally high and the pattern of its change resembles that of the gibberellins. Its maximum is reached in young vegetative mycelium, it decreases when fruiting bodies are formed and when they are growing. Minimum is reached in the differentiated stalk, where also the amount of inhibitions is the highest. Experimental results show that during differentiation of fruiting bodies and their morphogenesis not only gibberellins and cytokinins are of importance, but also substances of an inhibitory character. A relatively high amounts of these substances was secreted into the cultivation medium. In a synthetic nutrient solution they may be easily demonstrated.
13 citations
TL;DR: A fully normal meiosis was found in Allium sativum L. by means of PMC analysis and evidence for the pollen sterility was given by crossings on sterile types.
Abstract: A fully normal meiosis was found inAllium sativum L. by means of PMC analysis. Quadrivalents were formed only in several cultivars. The cultivation of inflorescence stem (after the exstirpation of bulblets) in a tetracycline solution of 900 i.u. induced a formation of fertile flowers. The first pollen mitosis was studied and the pollen parameters compared with those ofAllium cepa L. Evidence for the pollen sterility was given by crossings on sterile types. A microbiological factor was not isolated.
13 citations
TL;DR: Embryo cultures were carried out in order to test the relative effciency of gibberellins (GA3 and GA4), chilling and leaching, and results are compared with facts already known on mature dormant embryos of other plants.
Abstract: Mature seeds ofTaxus baccata L. andTaxus baccata L.fastigiata Loudon contain embryos which are both immature and dormant. Embryo cultures were carried out in order to test the relative effciency of gibberellins (GA3 and GA4), chilling and leaching. The increase of germination percentages depends on the treatment applied and the tested variety. WithTaxus baccata, the germination of which is very difficult, a double treatment either leaching and gibberellins or leaching and chilling are necessary to obtain a high percentage of germination. Our results are compared with facts already known on mature dormant embryos of other plants.
13 citations
TL;DR: The relationship between the water potential and water saturation deficit in kale and maize leaf tissue was measured during dehydration and resaturation either of leavesin situ or of cut leaves as discussed by the authors, and the curves relating Ψw to ΔWsat were similar in all variants, but at the same values ofΔ Wsat corresponding values of λw were always lower in leaves in situ than in cut leaves and during dehydration than during resaturation.
Abstract: The relationship between the water potential (Ψw) and the water saturation deficit (Δ Wsat) in kale and maize leaf tissue was measured during dehydration and resaturation either of leavesin situ or of cut leaves. The curves relating Ψw toΔWsat were similar in all variants, but at the same values ofΔ Wsat corresponding values of Ψw were always lower in leavesin situ than in cut leaves and during dehydration than during resaturation.
TL;DR: The greatest difference between NA synthesis in induced and non-induced plants was observed at the end of the second (or sometimes third) inductivecycle, and in the subsequent cycles the difference decreased or disappeared eventually.
Abstract: Beginning with the second inductive cycle the rate of nucleic acid (NA) synthesis in cotyledons and apical buds ofChenopodium rubrum is higher at the end of the dark period or 4h following transfer of the plants to light in induced plants than in non-induced ones. This is due to an increase in all NA fractions. The greatest difference between NA synthesis in induced and non-induced plants was observed at the end of the second (or sometimes third) inductivecycle. In the subsequent cycles the difference decreased or disappeared eventually. During photoperiodic induction NA synthesis shows a diurnal rhythm with a peak at the end of the dark and at the beginning of the light period. Rhythmicity of NA synthesis is endogenous. The period length of the endogenous oscillation is about 18 h. Interruption of the dark period by light causea amplitude of the first oscillation to be reduced and delays the appearance of the second peak. NA synthesis did not show rhythmicity in plants grown in continuous light. The significance of the observed phenomena for photoperiodic induction is being discussed.
TL;DR: Using a semiconductor freezing microtome, there is no difficulty in getting an ample supply of quite suitable sections of Ca formol fixed root tips of Vicia faba, but the protoplasts shrink and often fall out from the cells, and no improvement was revealed using — at different concentrations — sucrose and arabic gum alone.
Abstract: Using a semiconductor freezing microtome, there is no difficulty in getting an ample supply of quite suitable sections of Ca formol fixed root tips ofVicia faba, applying Holt’s sirup or plain 0.88 M sucrose as media for keeping the material, getting the sections and treating them after sectioning, but the protoplasts shrink and often fall out from the cells. No improvement in this respect was revealed using — at different concentrations — sucrose and arabic gum alone. The changes in the proportions of the ingredients of the sirup were also ineffective. A series of experiments were therefore performed with plain sucrose, but none of the factors tested was efficient enough to improve the results as compared with the standard procedure, the gradual transfer being the only exception. Since this makes the procedure more laborious and time consuming, certain other media were tested, 0.88 M ethanol and 0.88 M dimethylsulf-oxide yielding the best results. Attempts are being made to understand some points of the present experience in connection with the results of other authors and on the basis of general theory respectively.
TL;DR: It is found that Auxin in the presence of adequate amount of carbon nutrition increases the fresh production of protein and that the magnitude of rooting is determined by the size of protein pool that is available in tissue at the time of root initiation.
Abstract: 2.5 cm long etiolated stem segments ofPopulus nigra did not root at all in water or in IAA alone, but rooted in glucose + IAA. 5-Fluorodeoxyuridine (FUDR), 5-Fluorouracil (FU). actinomycin-D and cycloheximide all inhibited rooting, the inhibitory effect of each increasing with concentration and being more marked in glucose than in glucose + IAA. The inhibitory effect also decreased with the delay in the application of cycloheximide. The DNA, RNA and protein contents of segments grown in IAA + glucose where rooting occurred were higher than in water or in IAA + glucose + cycloheximide/or + aetinomycin-D where rooting did not occur. Auxin in the presence of adequate amount of carbon nutrition increases the fresh production of protein and that the magnitude of rooting is determined by the size of protein pool that is available in tho tissue at the time of root initiation.
TL;DR: The successive staining alcian blue/aluminium lake of nuclear fast red was proved a useful tool for studies on plant root tip and attempts were made to apply spectrophotometry and paper chromatography to overcome the confusions in manufacturers’ labelling of the dye.
Abstract: The successive staining alcian blue/aluminium lake of nuclear fast red was proved a useful tool for studies on plant root tip. A simple and reliable procedure is given resulting in blue cell walls, almost colourless cytoplasm and red nuclei. Attempts were made to apply spectrophotometry and paper chromatography to overcome the confusions in manufacturers’ labelling of the dye and to check the lake formation.
TL;DR: The results are discussed in relation to the previously described changes in the yield of induced mutagenic effects in barley seeds treated with monofunctional alkylating agents and stored at 30% and 20% seed water content.
Abstract: In water soaked barley seeds the respiration rate (QO2) at 25 °C is about 100 times higher at 30% than at 20% water content. The treatment of seeds with mutagenic methyl methanesulphonate led to the depression of the respiration rate in dependence on the applied mutagenic dose. Seed storage at 30% water content resulted in a recovery from the inhibition of seed respiration caused by methyl methanesulphonate. In contrast, at 20% seed water content the respiration rate either slightly decreased or remained unchanged in the course of storage. The results are discussed in relation to the previously described changes in the yield of induced mutagenic effects in barley seeds treated with monofunctional alkylating agents and stored at 30% and 20% seed water content.
TL;DR: In vivo modification and (or) in vivo activation were probably responsible for the increase in NADH2 dependent GDH activity.
Abstract: Both nitrite reductase and nitrate reductase were induced by nitrite, but there were differences in the time course of induction and in the response to different NO2
- concentrations between these enzymes. NH4
+ depressed the induction of nitrite reductase. NADH2 dependent glutamate dehydrogenase activity was enhanced by those NO2-concentrations in the medium at which unmetabolized NO2
- occurred in the roots. NADPH2 and NAD+ dependent GDh activities were not affected. In vivo modification and (or) in vivo activation were probably responsible for the increase in NADH2 dependent GDH activity.
TL;DR: The highest ratios PN/E in young and middle age leaves indicate that the increase of the internal resistance to photosynthesis with leaf age was more rapid than that of ri.
Abstract: CO2 absorption (PAT) and transpiration (E) rates, and leaf diffusion resistance (ri) were individually studied in all leaves of tobacco plants (Nicotiana tabacum L cv Wisconsin 38) before flowering Differences between old, middle age and young leaves were in all characteristics studied and found statistically significant In all three leaf age groups E was closely correlated to ri No similar correlation was discovered between PN and ri The highest ratiosPN/E in young and middle age leaves indicate that the increase of the internal resistance to photosynthesis with leaf age was more rapid than that of ri
TL;DR: The efficiency of the geocontrol system of pea and maize roots was compared and the period of time which elapses between the stimulus and growth response, i.e. the geotropic reaction time, is 4 times shorter in maize roots than in pea roots.
Abstract: The efficiency of the geocontrol system of pea and. maize roots was compared on the basis of their oscillation movements. The rate of elongation of maize roots is 3.6 times higher, the amplitudes of oscillation deviations are 10 times lower and their frequency is 5 times lower than the corresponding values recorded for pea roots. The period of time which elapses between the stimulus and growth response, i.e. the geotropic reaction time, is 4 times shorter in maize roots than in pea roots. The maize root is able to correct the direction of its elongation 3.5 to 5 times more frequently than the root of pea. This characterize the difference between the both compared control systems from the point of view of physiological economy.
TL;DR: Individual leaves on apple shoots treated by pinching and/or ringing were supplied with14CC2 and the rate of photosynthesis and the pattern of photosynthate distribution was studied, finding that assimilates are not located in matured leaves.
Abstract: Individual leaves on apple shoots treated by pinching and/or ringing were supplied with14CC2 and the rate of photosynthesis and the pattern of photosynthate distribution was studied. The ringing of the shoots as well as the ringing and pinching done together reduces the rate of photosynthesis almost by half. Pinching itself had no effect on the rate of photosynthesis. Removing the main sink — the growing shoot apex — by pinching leads to the accumulation of photosynthates in the shoot, mainly in the first internode below the pinching point. Accumulated assimilates were soon used up by the axillary meristems which were stimulated to grow by pinching. Very small amounts of assimilates (about 1 %) were translocated to adjacent shoots which were supplied by their own leaves. When adjacent shoots were defoliated, more assimilates were translocated there (nearly 8%), however, a strong tendency to accumulate the assimilates in the internode below the pinching point was observed. Assimilates are not located in matured leaves. The presence of an active sink located near the donor stimulates the mobilization of assimilates present in the donor leaf.
TL;DR: A definite pattern of DNA synthesis was observed during the transition from a proembryonic mass to the torpedo stage of embryogenesis, and the labeling pattern for both the heart and torpedo stages was found to be coincident with specific morphogenetic events.
Abstract: Embryo development in cultured wild carrot tissue was studied by considering the relationship between DNA biosynthesis and embryo morphogenesis. Autoradiographic data of3H-thymirdine incorporation indicated a higherpercentage of cells undergoing DNA synthesis in adventive embryos than in proembryonic masses. A definite pattern of DNA synthesis was observed during the transition from a proembryonic mass to the torpedo stage of embryogenesis. In particular the labeling pattern for both the heart and torpedo stages was found to be coincident with specific morphogenetic events.
TL;DR: D-Glucose and several other sugars are taken up by slices of callus tissue of Nicotiana tabacum and are both oxidized to CO2 and incorporated into tissue components, the transport process being characterized by lack of specificity, no hyperbolic saturation, no influence of metabolic or transport inhibitors and hardly any dependence on pH.
Abstract: D-Glucose and several other sugars are taken up by slices of callus tissue ofNicotiana tabacum and are both oxidized to CO2 and incorporated into tissue components. The uptake as well as the subsequent metabolism are slow, the transport process being characterized by lack of specificity, no hyperbolic saturation, no influence of metabolic or transport inhibitors and hardly any dependence on pH. The apparent activation energy of the process was about 42 kJ mol-1. It appears that the transport proceeds by simple diffusion through narrow intercellular spaces and possibly hydrophilic pores and that only about 10% of the tissue volume is accessible to the sugars in question.
TL;DR: Changes in the transpiration rate of intact spring barley plants, cv.
Abstract: Changes in the transpiration rate of intact spring barley plants, cv. “Slovensky dunajsky trh”, were studied separately in the light and in the dark under controlled temperature and illumination, after the infection withErysiphe graminis DC, during an 8 day period of the development of the fungus. In the first stage of pathogenesis, the fungus diminishes water output from the host plants in the light. An opposite phenomenon can be observed in the dark; water output from infected plants in the dark increases sharply mainly in the stage of advanced fructification. Thus, the fungus considerably diminishes the ratio of water output from the host plants in the light to that in the dark.
TL;DR: In this article, the formation of starch in excised 3-day-old pea roots was enhanced up to three fold after cultivation for five days in liquid media containing 3% glucose, microelements, and 10-6 M kinetin or 10-7 M naphtaleneacetic acid (NAA).
Abstract: The formation of starch in excised 3-days-old pea roots was enhanced up to three fold after cultivation for five days in liquid media containing 3% glucose, microelements, and 10-6 M kinetin or 10-7 M naphtaleneacetic acid (NAA). A synergistic effect of kinetin and NAA on starch formation was observed when both hormones were applied simultaneously over a wide range of concentrations.
TL;DR: The course of biological curves of accumulation of total, vegetative and grain dry matter in maize was investigated in a field experiment and an asymptotic trend was obtained for the curve of biological yield (Fbiol) in relation to the population density.
Abstract: The course of biological curves of accumulation of total (Ybiol), vegetative (Yveg) and grain dry matter (Ygr) in maize(Zea mays L.)was investigated in a field experiment. The different population densities from 27 777 to 121 418 plants per ha were tested in interaction with increasing fertilizer rates (NPK) ranging from zero to 780 kg of pure nutrients per ha. The grain yield (Fgr) plotted against the population density shows a parabolic trend with a maximum at densities from 64 000 to 79 000 plants per ha. An asymptotic trend was obtained for the curve of biological yield (Fbiol) in relation to the population density. The optimum densities for Ygr and Fbiol were identical in the unfertilized control plot. At optimum and higher population levels the application of optimum rate of pure nutrients was 260 kg per ha. Leaf area index(L) was rising with the increasing stand density. Its value was also increased by increasing mineral nutrition but only at plant densities higher than 64 000 plants per ha. The proportion of Ygr/ Ybiol showed an optimum atL value within 2.03 and 2.68. Its value declined with further increase of both, stand densities and levels of NPK. The optimumL estimated for Ygr was within 2.65 and 3.87 and that for Yol in the control variant was 2.65. Tn fertilized plots even the highestL values (5.17) did not influence neither the biological nor the vegetative dry matter yields. Relative photosynthetic potential for dry matter formation (RPPgr) was decreasing with the increasing stand density.
TL;DR: The main difficulty in the use of the method of stigmatal and placental pollinationin vitro seems to consist in the fact that pollen tubes are not capable of growing from the surface of ovules and placenta into the micropyle.
Abstract: A study was made on certain problems connected with the application of methods of stigmatal and placental pollinationin vitro in the snapdragon. Germinable pollen without microbial contamination could be obtained only from the flowers which were left, after surface sterilization, on the stem till the dehiscence of anthers. The germination of pollen, and especially the growth of pollen tubes was better in a 0.3 M lactose solution with 10−3 per cent H3BO3 than in usual sucrose media. The seedsin vitro could be obtained only after normal pollination and the successive artificial cultivation of the entire pistil (the method of stigmatal pollinationin vitro). The seeds did not differ either in their morphology or in their size from those developed under natural conditions, they were viable and without dormancy. Though the pollinated pistils were cultivated in the medium without growth substances, callus formation from uncovered ovules and placenta was observed in some cases. A dependence was revealed of the proliferation on pollination and on the cultivar employed. When using the method of placental pollinationin vitro we failed to obtain seeds. The main difficulty in the use of this method seems to consist in the fact that pollen tubes are not capable of growing from the surface of ovules and placenta into the micropyle.
TL;DR: Peroxidase activity and isoenzyme pattern were investigated in buds and tubers of Jerusalem artichokes in relation to induction and breaking of dormancy and the role of the cathodic isoperoxidases is discussed in connection to auxin catabolism and the genesis of oxygenation products inhibitory to plant growth.
Abstract: Peroxidase activity and isoenzyme pattern were investigated in buds and tubers of Jerusalem artichokes in relation to induction and breaking of dormancy. Peroxidase activity per unit soluble protein is the highest in the dormant stage. Conditions leading to growth,i.e. release of dormancy by the cold, stimulation of axial growth by gibberellic acid or stimulation of radial growth (tuberization) by kinetin, cause rapid loss of total peroxidase activity together with a decrease of intensity of the most cathodic isoperoxidases. Induction of dormancy by AMO-1618 increases peroxidase activity mainly through the same cathodic isoenzymes. The role of the cathodic isoperoxidases is discussed in relation to auxin catabolism and the genesis of oxygenation products inhibitory to plant growth.
TL;DR: Evidence of a fluctuating expression of mutagen effect in the course of the subculture interval is given and may demonstrate a recovery of the cultures from the mutagen effects.
Abstract: N-Methyl-N-nitrosourea and N-methyl-N-nitrosourethane at concentrations of 0.1 mM to 1 mM inhibited the growth of tissue cultures ofNicotiana tabacum L. The inhibitory effect was proportional to the mutagen concentration applied. The primary expiants (pith slices) and a 3-year tissue culture strain exhibited a different sensitivity to the same mutagen concentrations. The variability in sensitivity of tissue culture inocula to mutagen effects was reduced by previous fractionation of the culture and by standardization of the age and size of inocula. The changes investigated in the ratio of relative growth rates between the controls and treated cultures give evidence of a fluctuating expression of mutagen effect in the course of the subculture interval and may demonstrate a recovery of the cultures from the mutagen effect.
TL;DR: In this paper, L-aspartic and L-glutamic acids were found to enhance glutamate dehydrogenase activity in isolated pea roots, and the results indicated that both ammo acids induce increased GDH synthesis.
Abstract: Exogenous L-aspartic and L-glutamic acids enhance glutamate dehydrogenase activity in isolated pea roots. The results obtained indicate that both ammo acids induce increased GDH synthesis.
TL;DR: The maximum of alcohol dehydrogenase (ADH) activity of germinating pea and broad-bean seeds sediments from 40 to 60% ammonium sulfate saturation, from lentil and kidney-beans seeds between 40 and 50%, was found in this article.
Abstract: The maximum of alcohol dehydrogenase (ADH) activity of germinating pea and broad-bean seeds sediments from 40 to 60% ammonium sulfate saturation, from lentil and kidney-bean seeds between 40 and 50%. This operation increased the specific activity of ADH preparations roughly tenfold. Chromatography on DEAE-eellulose and gel filtration increased the activity of the resulting preparation when compared with the initial preparation 178 times with pea, 334 times with broad-bean, 122 times with lentil and 77 times with kidney-bean. The ADHs resemble each other in coenzyme specificity: the reaction rate with NAD is one hundred times greater than with NADP. The substrate specificity is quite wide: besides ethanol, these enzymes oxidize 2-propene-l-ol (actually faster than ethanol), 2-butene-l-ol (at the rate of one half t h a t of ethanol) and butanol (even more slowly). In general, saturated alcohol analogues are oxidized more slowly than unsaturated ones. Methanol is a substrate for the enzym from pea only. The ADHs of the plants studied did not oxidize diols, sugar alcohols and cyclic alcohols. The enzyme from pea has the widest substrate specificity oxidizing isobutanol, phenylalcohol and mercaptoethanol. ADHs, which are widely encountered in plants, resemble each other to a certain degree — they have identical coenzymes, equal Km values and equal values of the pH optimum, they differ in the purification process and in substrate specificity.