The level of RNA in pollen is approximately 20 mg g^-1 and remains constant during 6 h pollen germinationin vitro also in the presence of 2-thiouracil which stimulates pollen tube elongation. The synthesis of RNA in pollen tubes was investigated according to the incorporation of the label from uracil-2-¹⁴C, 2-thiouracil-2-¹⁴C, orotic acid-5-³H, fructose-U-¹⁴C and from³²PO₄^3- into RNA fractions separated by methylated albumine kieselguhr chromatography. The distribution of radioactivity on elution profiles was different according to the radioactivity source, however it was not changed by the presence of 2-thiouracil in cultivation medium. 2-Thiouracil incorporates into pollen tube RNA at about 50% the rate of uracil. It inhibited the incorporation of orotic acid, of fructose and of phosphate into all RNA fractions. It is suggested that the analogue inhibits the enzymes involved in RNA synthesis essentially as 2-thiouridine-5'-phosphate.

Funaria spores must structure their photosynthetic apparatus before germination. A lack of manganese in the culture media affects neither the final structure of chloroplast nor the chlorophyll synthesis. Fixation of CO₂, reducing power of chloroplasts (DPIP) and RPE photo-induced signal S II are modified by this lack of manganese. The study of Mn/Chl and CO₂ fixed/Mn ratios shows that Mn is a limiting factor for CO₂ fixation and that in the spores depleted of Mn the residual Mn is "structural" Mn.

The effect of abscisic acid (ABA), gibberellin A₄₊₇ and benzyladenine on germination of apple embryos which had been stratified for different periods of time was investigated.
The growth stimulators accelerated the germination of non-stratified embryos or those stratified for a short time. After a longer period of stratification, the effect of growth stimulators was visible only when germination of the embryos was artificially inhibited by simultaneous application of synthetic ABA.
The sensitivity of stratified apple embryos to the exogenous ABA diminished with the number of hours elapsed between the imbibiting by the embryos of the water or gibberellin and the application of the ABA.
This was similar to the change in the sensitivity of apple embryos during stratification due to the increasing concentrations of ABA.

Activities of RNasea were studied in cotyledons of dormant and afterripenedAgrostemma githago seeds. Activity of RNase increases during imbibition and germination. This increase in activity cannot be observed in variants which are not able to germinate (dormant seeds and seeds blocked by higher temperature). The development of RNase activities during germination cannot be inhibited by concentrations of cycloheximide or actinomycine D completely preventing phosphatase synthesis. These results may be indicative for the assumption that the increase of RNase during germination is caused by enzyme activation and not by enzyme synthesis. Cytokinins and a combination of cycloheximide and gibberellic acid stimulate the activity of RNase in dormant cotyledons, whereas neither cycloheximide nor gibberellic acid, applicated by themselves, show any effect. Cytokinins and gibberellic acid do not influence the activity of RNase of afterripened cotyledons, abscisic acid inhibits the increase of enzyme activity.
There are characteristic changes in the pattern of RNases during germination revealed by polyacrylamide gel electrophoresis. The increase in RNase activity of dormant cotyledons caused by cytokinins is accompanied by obvious changes in the RNase pattern on polyacrylamide gel. Treating dormant cotyledons with cytokinins dormancy is partially overcome. In consequence of the application of cytokinins the differences in the electrophoretic RNase pattern between dormant and afterripened cotyledons can be nearly balanced.

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.

To study the effect of high altitude cosmic radiation the seed material of 15 species ofAcanthaceae was subjected to 3 types of exposures in balloon flights at an altitude of 30 900 to 38 100 metres. Germination behaviour was recorded and cytological studies were made. In the material subjected to one exposure, no detectable cytological or morphological change could be recorded. Material subjected to two exposures showed a 1 1/2 to 2 fold increase in cellular dimensions. A fragmented chromosome was observed inRostellularia procumbens. Flowering inJusticia betonica was advanced by 3 weeks. Among the species subjected to 3 exposures, two species showed diminution in height, and entered into flowering earlier than the controls. A study of germination behaviour showed, in general, that the decrease in germination percentage was directly proportional to the amount of radiation. The results indicate that the treatment with cosmic radiation may be helpful in reducing the period between sowing and harvesting. Therefore, if similar experiments be conducted on crop plants, they might yiled interesting and important results from the agricultural point of view.

Methyl methanesulphonate (MMS), applied on barley seeds, inhibits the seed respiration and thein vitro activity of cytochrome-oxidase and catalase, whereas doubles the activity of total dehydrogenases and has no influence on the activity of peroxidase.
Storage of MMS-treated seeds for 10 days at 30% seed water content, thus under conditions favouring the recovery from the MMS-induced toxic and genetic effects, resulted in an enhancement of the cytochrome oxidase and catalase activity, which reached or exceeded the activity of the control. The activity of peroxidase, although increasing during storage, did not attain the value of the control and the activity of total dehydrogenases remained two times higher as compared to the control.

Neither the incubation of the flower scapes of garlic (Allium sativum L.) in tetracycline solution nor the extirpation of the bulblets from the inflorescences led to the development of fertile binuclear pollen. Higher tetracycline concentrations than 125 mg per litre showed a clearly phytotoxic effect. The removal of the bulblets from the inflorescences improved the survival of flowers but it enabled only the initial stages of seed development. The seeds obtained were defective and not able to germinate. The hypothesis on infectious nature of the factors causing sterility in garlic is discussed.

The paper aims at verifying the possibility of obtaining seeds following placental pollination in more than 20 species of dicotyledons and monocotyledons. Excised placentae with ovules were cultivated in solid nutrient media in Petri dishes. Pollen was transferred from anthers onto placentae, its germinating capacity being enhanced by a drop of a 5 per cent sucrose in boric acid in certain cases. Fertilization of ovules resulting in the formation of viable seeds was obtained withNicotiana tabacum, Melandrium album andAgrostemma githago. Although withPaeonia officinalis, Viola tricolor, Antirrhinum majus, Galanthus nivalis, Narcissus pseudonarcissus, Clivia miniata andTulipa gesneriana normal seed set occurred, the seeds did not germinate even after being stimulated with GA₃. The results indicate that the findings may be used for further embryological studies. The species are listed in which no seeds were obtained.

In Jerusalem artichoke tuber,in situ RNA synthesis along vegetative cycle shows two maximums. The first one appears during tuberization and installation of dormancy and a growth inhibition is sufficient to bring it about. The second reveals breaking of dormancy and precedes germination.

Wheat embryos floated off from organic solvents have been compared with mechanically isolated embryos. The results of comparative investigations, including germination,in vivo formation of polysomes and efficiency of cell free preparations forin vitro protein synthesis, favour the use of floated embryos for studies of biochemical processes during germination.

The effects of soaking seed in 2-chloroethylphosphonic acid (CEPA) for 24 or for 48 h on the cumulative 5-day seedling growth ofCucumis sativus L. (cucumber) andPisum sativum L. (peas) were studied. Each cucumber seed absorbed an average of 0.015 ml of CEPA solution, while pea seed absorbed 0.365 ml, over a 24 h period.
In cucumber, 240 mg l^-1 CEPA concentration decreased radicle length by 23%, regardless of soaking duration. The same concentration increased radicle weight in a 24 h soaking duration, but decreased radicle weight when soaking was for 48 h. At 48 h, CEPA concentrations of 0.24 and 2.4 mg l^-1 increased plumule growth by 26%. In peas, the 240 mg l^-1 decreased the length and the weight of both the radicle and the plumule in a 48 h soaking duration, but had no significant effect at a 24 h soaking. At the low concentration of 0.24 mg l^-1, seedling growth was stimulated by over 30%.
Cucumber was 3 times more efficient than peas in the utilization of CEPA for seedling growth, in terms of total fresh weight of seedling per microgram of CEPA absorbed: 1 127 and 274 mg μg^-1 CEPA in cucumber and peas respectively. Extrapolative calculation, using cucumber responses as standard, suggests from this seedling study that about 12 mg l^-1 CEPA is likely to stimulate growth and/or yield in sprayed pea plants.

Seeds of the beanPhaseolus vulgaris L. (Veltruská Saxa cultivar) were gathered gradually at different stages of development, starting at fertilization up to full maturity. Seeds were freeze-dried and the dry solid used for preparing extracts which were analyzed by immunoelectrophoresis for the presence of proteins resembling those contained in the cotyledons of a mature seed. Proteins from cotyledons of the first stages of development of bean seedlings were analyzed similarly.
After a preparatory period, approximately from the second-third seed development stage, there is a period of intense protein synthesis that characterizes cotyledons of a mature seed. These proteins increase in quantity and are differentiated in quality up to maturity when a single antiserum detected a total of 12. After germination both the quantity and number of these proteins decreases.
It was found that some proteins are metabolically more active, both during synthesis and cleavage. This holds e.g. for phaseolin during maturation, as well as during germination. In addition, phaseolin changes its electrophoretic mobility, which is apparently due to proteolytic hydrolysis of phaseolin molecules.
During the last phase of maturation, viz. dehydration of seeds, some new proteins suddenly appear, apparently synthesized from pre-formed peptide chains.
In the discussion the possibility is taken up that the beginning on the synthesis of specific proteins characteristic for mature seeds is the cause underlying the disturbances in the embryonal development of distant hybrids.

Whole seeds, excised embryos, and excised endosperm ofSantalum album were aseptically cultured with a view to studying seed germination in isolation from the host species, and to establishing callus cultures from both embryo and endosperm for comparative studies et their morphogenesis. Seed germination and seedling formation occurred normally only on modified White's medium supplemented with casein hydrolysate or coconut milk, or with both substances. Neither the excised embryo nor the endosperm grew on any of the culture media tested. However in about 17 per cent seed cultures on White's medium supplemented with 2,4-D, kinetin, and yeast extract, the endosperm degenerated, whereas the embryo callused and subsequently differentiated into innumerable embryoids; eventually the embryoids developed into normal plantlets. Callusing of the endosperm occurred also in seed cultures on four media supplemented variously with 2,4-D, kinetin, and yeast extract. Although the endosperm tissue grew through several passages no organ fornation was observed.

The dynamics of the germination and formation of lateral roots under constant conditions were studied in pea Pisum sativum L., cv. Pyram. Various parameters of the above processes were evaluated statistically. The time at which the germination proceeds at the maximum rate was found to be 24.9 h from the start of the imbibition of seeds. The standard deviation of the germination time of an individual seed from the time corresponding to the maximum of germinated seeds was found to be 4.0 h. The formation of the lateral root primordia took place at 54.2 ± 2.9 h. At 73.5 ± 5.5 h from the beginning of the experiment, laterals on the surfaces of primary roots of seedlings became apparent. Differential curves of the distribution of the above processes were plotted graphically. The data obtained are valid for the given conditions and given experimental procedure. The methods described can be used in studies of primary root branching in various plant species.

Grains ofTriticum monococcum L. var.sofianum Körn. were treated with 0.1mm, 0.2mm and 0.3mm solutions of N-nitroso-N-methylurea (MNH), with 0.03m solution of buthylmethane sulphonate (BMS) and with X-rays in doses of 5 000r and 10 000r. The germination and development of individual colors of chlorophyl mutants were observed by the system developed byLamprecht (1960). All the mutants induced were classified according to their color changes into three main categories-homogenous unicolor, homogenous multicolor and heterogenous multicolor. In the last type the colors of individual leaves of the same plant varied. Anthocyanin mutations "albina" and "albino-transvirgata" sometimes coincided with the chlorophyll mutations. Some chlorophyll mutations showing complicated groups of colors appeared which were beyond the scale of classification by ordinary systems. The largest proportion in the spectrum of chlorophyll mutations, induced by MNH and X-rays was occupied by mutations of thealbina type. The broadest mutation spectrum in our experiments was induced by the application of 0.3mm MNH. The doses of X-rays used induced relatively higher numbers ofalbina-type chlorophyll mutations than MNH and BMS. In our experiments we succeeded in inducing on medium size samples ofTriticum monococcum L. var.sofianum Körn not only almost all types of chlorophyll mutations, induced byFujii (1960, 1962) andMatsumura (1960), but in addition also a great number of other even more complicated chlorophyll mutations, which have never been previously described inTriticum monococcum. L.

Grains ofTriticum monococcum L. var.sofianum Körn. were treated with O.1 mM, 0.2 mM and 0.3 mM solutions of N-nitroso-N-methylurea (MNtt), with 0.03 M solution of buthylmethane sulphonate (BMS) and with X-rays in doses of 5 000r and 10 000r. The germination and development of individual colors of chlorophyl mutants were observed by the system developed byLamprecht (1960). All the mutants induced were classified according to their color changes into three main categories-homogenous unicolor, homogenous multieolor and heterogenous multieolor. In the last type the colors of individual leaves of the same plant varied. Anthocyanin mutations "albina" and "albino-transvirgata" sometimes coincided with the chlorophyll mutations. Some chlorophyll mutations showing complicated groups of colors appeared which were beyond the scale of classification by ordinary systems. The largest proportion in the spectrum of chlorophyll mutations, induced by MNH and X-rays was occupied by mutations of thealbina type. The broadest mutation spectrum in our experiments was induced by the application of 0.3 mM MNH. The doses of X-rays used induced relatively higher numbers of albina-type chlorophyll mutations than MNH and BMS. In our experiments we succeeded in inducing on medium size samples ofTriticum monococcum L. var.sofianum Körn not only almost all types of chlorophyll mutations, induced byFuji (1960, 1962) andMatsumura (1960), but in addition also a great number of other even more complicated chlorophyll mutations, which have never been previously described inTriticum monococcum. L.

It was shown that in the horse bean seeds (Vicia faba) the cotyledon proteins are identical, from an immunochemical standpoint, with those coming from the extracotyledon parts (radicle, young stem and embryonal leaves, in totality). However, the beginning of the germinative process exerts a different influence on the antigenic properties of the constitutive parts of the seed. The modification of the antigenic structure in cotyledons takes place slowly. On the contrary, in the extracotyledon parts a rapid decrease was found of the number of antigens present in the non-germinated seed. As the organs become differentiated, the hydrolysis process of these antigens goes on until their almost complete exhaustion. However, it appears that three of the initial antigens remain in the newly arisen leaves. Besides these antigens there are also specific-organ antigens which appear as the respective organs become morphologically differentiated. It was found that in the growing leaves the process of photosynthesis induces the synthesis of antigens characteristic for the mature leaves. The organ-specific antigens occur during plant development at the time when the leaf attains the morphological structure and the functional specialization characteristic for maturity.

Spraying the growth retardant (B-9) ranging from 500 to 4000 ppm, on caraway and fennel plants reduced stem height, whereas increased the umbel number per plant. There was a slight increase in seed-yield as well as weight of 1000 seeds of the two umbelliferae plants, induced by B-9. The largest values of volatile oil, crude fat, and carbohydrate in the seeds of the two plants resulted from 4000 ppm B-9. Whereas, the crude protein was not affected by B-9 treatments in both plants.

Lactate as well as ethanol is formed in seeds of soybean, maize, pea, bean, lentil and broad-bean in the course of germination during the so-called natural anaerobiosis. After 0 to 30 h of germination a concentration peak of lactate appears. Maximum in ethanol content is found after 40 h. The amount of ethanol is higher big more than one order of magnitude as compared to the amount of lactate. Both products of anaerobiosis occur in germinating seeds irrespective of the type of reserve substances.
In contrast to alcohol dehydrogenase lactate dehydrogenase (EC 1. 1. 1. 27) is present in the dry seeds too. Its activity decreases during the first 12 h of germination. It is in this stage that its substrate, lactate, is usually present at a maximal concentration. During the later stages of germination the amount of lactate decreases and enzyme activity rises. There exists a reciprocal relationship between enzyme activity and substrate concentration. In the case of alcohol dehydrogenases (EC 1. 1. 1. 1) the maximum concentration of ethanol precedes the peak of enzyme activity.

The effect of Zn²⁺ ions (in the form of ZnCl₂) in the ceoncentration range 10^-3 to 10^-6 M on the content and biosynthesis of indole glucosinolates glucobrassicin and neoglucobrassicin has been studied on etiolated seedlings of rape (Brassica napus var.arvensis(Lam.) Thell). In the "long-term" experiment zine ions influenced the seedlings during eight days of germination, whereas in the "short-term" experiment zinc ions acted only 72 h on seven days old intact seedlings. The biosynthesis of indole glucosinolates has been followed by the incorporation of³⁵S from Na₂³⁵SO₄ into both glucosinolates in experiments with, hypocotyl segments of the rape seedlings.
Zinc ions at chronic "long-term" application increased the glucobrassicin and neoglucobrassicin level in the seedlings. The neoglucobrassicin content especially was increased. A "short-term" application of zinc ions increased the level of both glucosinolates at higher and lower concentrations, whereas medium concentrations (10^-4 and 10^-5 M) lowered their level.
Zn²⁺ ions lowered absorption of³⁵SO₄^-2 ions by hypocotyl segments and simultaneously lowered the incorporation of³⁵S into glucobrassicin. On the contrary, the incorporation of³⁵S into neoglucobrassicin and proteins was stimulated.
Zinc ions do exhibit a specific effect on neoglucobrassicin biosynthesis, on membrane permeability as against sulphate ions and on the incorporation of sulphur into proteins.

The substrate specificity of apple seeds phenol oxidases was investigated in polyacrylamide gel electropherograms. The nonspecifico-diphenol oxidases were distinguished as well as fractions showing the specificity for some structural elements of substrate molecule. The role of particular oxidases in phloridzin transformations in apple seed was discussed.

The development of excised flax embryos of different age was followed in nutrient media with different osmotic values. Sucrose media with the osmotic value 4.0 bar. (5%) sucrose were the most suitable for the cultivation of excised 7 and 14 days old flax embryos. Nutrient media with the osmotic potential 1.7 bar (2% sucrose) were optimal for 28 days old embryos. The most convenient osmotic potential for optimal root growth was 4.0 bar and for hypocotyls and stems 1.7 bar. High osmotic value of the cultivation media prevented the germination of the embryos and lower osmotic value promoted the germination. Mannitol, when compared with sucrose, inhibited the development and germination of the embryos. Different abnormalities often occurred on the media with mannitol. Agar media were superior to liquid media for the cultivation of explanted embryos.

The influence of Cu²⁺ ions (in the form of CuCl₂) in the concentration range 10^-3 to 10^-6 M on the content and biosynthesis of indole glucosinolates glucobrassicin and neoglucobrassicin has been studied on etiolated seedlings of rape (Brassica napus var.arvensis(Lam.) Thell.). Ions Cu²⁺ acted on the seedlings either chronically from the beginning of the germination or acutely, during 3 to 72 h, on seven days old seedlings. The biosynthesis of both glucosinolates was followed by the incorporation of³⁵S from Na₂³⁵SO₄ into them in hypocotyl segments from seven days old intact etiolated seedlings. After the entry of small amounts of Cu²⁺ ions into the plants, stimulation of the glucosinolates formation occurs, as was found after three h action of Cu²⁺ ions. After the entry of a greater amount of Cu²⁺ ions into the plant, harmful effects appear, as was found after chronic two days action or after 24 and 48 hours acute action of Cu²⁺ ions. Later further stimulation of glucosinolate formation occurs, probably due to enhanced metabolism during reparation processes, as was manifested after chronic action of Cu²⁺ ions lasting four and eight days. The optimal effect of copper was found mainly in the concentration range 5×10^-4 M to 10^-5 M.
Ions Cu²⁺ in higher concentration increased the uptake of sulphate ions by hypocotyl segments, and in lower concentrations increased the incorporation of³⁵S from³⁵SO₄^2- into the proteins.

Three protein fractions (albumins, globulins and glutelins) of cotyledons of ripe and dormant soybean seeds were analysed by a modified polyacrylamide disc electrophoresis method. All fractions were shown to be multicomponent and easily characterized by their "protein electrophoresis spectra". A method of characterizing proteins by their relative electrophoretic mobility (R.E.M.) by comparison with a new nontoxic dye as a tracer is employed for a preliminary identification of proteins. Specificity of protein complement was investigated in view of the autors, further studies on dynamics of specific proteins in the course of ripening and germination of soybean seeds.

13 strains of imperfect fungi have been studied in Lyon according to a biochemical criteria or growth of the studied species in a minimum but nitrogenous medium containing carbon elements. The inoculation is achieved by Api System ensemencement. The germination of the spores showing the carbon assimilation involves the appearance of a trouble. The intensity of this growth is coded by + or -.
The table of the characteristics for the various strains is studied thanks to a taxonomic method based on a relation of proximity by the Euclidean distance. Every strain is represented mathematically by a point in the characteristics-space. The strains are gathered into classes with regard to their proximity, every class being characterized by its centre of gravity. The similar characteristics are studied thanks to a classification tree or dendrogram.
The programme has regrouped the two species pathogenic fungi on the one hand and the ten strains taken in the atmosphere on the other hand, the telluric one having to be set apart.

Ascorbic acid (AA) turnover, and levels of RNA and protein were determined during germination ofCicer arietinum cv. Chafa under-(i) normal watering; (ii) water stress of six days; and (iii) revival upto next stage of seedling growth after water stress. Water stress lowered significantly AA, ascorbigen, ascorbic acid-macromolecule complex, RNA and protein content in embryo axis while a reverse trend was seen after revival. In the cotyledon, AA, RNA and protein contents were higher during water stress. However on revival only AA and protein contents decreased, whereas the RNA content showed further enhancement. It is suggested that increased synthesis of AA in the cotyledon during water stress may trigger enhanced synthesis of RNA and consequently of enzymic proteins, thus bringing about rapid mobilization of reserve materials during revival.

Using the time-lapse cinematography technique, activity of the growing centres of the pea seed hypocotyl (Pisum sativum L.) was followed in the course of the early phases between 15 and 60 hours of germination under standard experimental conditions. The resulting data were plotted in a summary graph with conjugates scales (Fig. 4) indicating time-space limits for further biochemical analysis and the interpretation of mechanism of hypocotyl elongation concerning the dependence of the IAA and RNA content, growth rate, localization of growing zones, transport of substances from the swollen cotyledons into the embryo etc. The most important results are as follows: Between 15 and 20 hours of seed swelling, activity is manifested in two growing centres of the hypocotyl (Fig. 5); between 30 and 36 hours only one zone becomes localized, with a maximum elongation in the region which was originally at a distance of 2.5 mm. from the hypocotyl base. The greatest elongation of the hypocotyl-0.77 mm./hour- was observed between 30 and 48 hours in the zone which was originally at a distance of 2.75 mm. from the hypocotyl base. The zone of maximum growth did not become localized by the termination of the experiment (60 hours) in the presumed zone close to the apex, but was displaced further to the zone which was originally at a distance of 4.0 mm. from the hypocotyl base.

The content and distribution of nitrogen substances in wheat, pumpkin and pea seedlings in complete (NS) or deficient ( - Ca²⁺ or - K⁺) nutrient solutions were studied with the aim of establishing whether impairments in the synthesis of nitrogen substances in vegetative tissues due to the deficiencies may be compensated for by storage nitrogenous substances. Pumpkin and pea seedlings were found to accumulate nitrogen mainly from depots of the seed stores. Both the accumulation and the synthesis of nitrogen substances were inhibited by the cation deficiencies, especially by that of calcium. Concomitant morphological deformations were probably the direct cause of the impairments in the mobilization and hence also in the utilization of the substances. With wheat, on the other hand, no morphological changes resulted from the deficiences and nitrogen was accumulated intensively even from the cultivation solution. Still, the rate of the synthesis of the nitrogenous substances was significantly reduced. Under the conditions of calcium or potassium deficiency in the outer nutrient solution the possibility or utilizing the ions from the storage tissues according to the requirements of the plant appeared to be decisive. The extent of the disproportion of the two factors was the original cause of the early morphological changes which, in their turn, impaired the natural circulation of substancs inside the organism, including the substances containing nitrogen.

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.