Storage proteins of the seeds (cotyledons) of the South-American speciesPhaseolus caracalla were compared by means of immunoelectrophoretic methods with other representatives of the genusPhaseolus. These proteins most resemble the proteins of the co-called tropical group (i.e. Ph. atropurpureus, Ph. geophilus, Ph. bracteatus, Ph. semierectus) and least the so-called American endemites (Ph. vulgaris, Ph. coccineus, Ph. acutifolius, Ph. lunatus), the main globulin of which is of a completely different specificity. The proteins ofPh. caracalla are less similar to the group of the so-called Asiatic species (Ph. aureus, Ph. calcaratus, Ph. angularis, Ph. aconitifolius, Ph. trilobus) including the analyzed representatives ofVigna sinensis; their main globulin is only partly similar to that ofPh. caracalla. Some considerations on the relationship ofPh. caracalla with the so-called tropical species is presented.

A protease activity was detected in rice (Oryza sativa L. cv. Ratna) leaves that hydrolysed hemoglobin more efficiently than bovine serum albumin. The activity was high when the enzyme was extracted and assayed with tris-maleate buffer [tris (hydroxymethyl) methyl amino-maleate] pH 7.0 rather than with water or with citrate-phosphate buffer pH 7.0. The enzyme had a strong dependence on sulfhydryl groups for its activity without which it was inaotive. The pH optimum was 7.0 and the temperature optimum was 40 °C. Protease activity expressed per unit leaf fresh weight (absolute activity) increased only little during senescence of detached rice leaves while the same activity expressed per unit soluble protein content (specific activity) increased by a greater factor (about 5 times) than absolute activity. Total and soluble protein content decreased during the senescence of detached leaves. Benzimidazole (10-3M) and kinetin (0.5xl0-5M) treatment arrested the increase of the protease activity and the deorease in the protein content during detached leaf senescence. It was indicative that protease protein was more stable than the bulk of other proteins in senescing leaves.

¹⁴CO₂ assimilation, RuBP earboxylase and PEP carboxylase activities show cyclic changes during the development of barley leaves. Cyclic changes, but in phase opposition with respect to carboxylating enzymes, are shown by RuBP oxygenase, phosphoglycolate phosphatase, glycolate oxidase and nitrate reductase activities. The oxygenase function of RuBP carboxylase appears to be the primary source of glycolate in young leaves, whereas in old ones glycolate could be supplied from some source in addition to RuBP oxygenase activity.

Applications of various amounts of GA₃ onto the shoot apex of biennial rosette-plantHyoscyamus niger L., exposed to long days and non vernalized, caused internodes formation and stem elongation. The stem length was proportional to the amount of GA₃ applied. Number and length of developed internodes and the whole length of the shoot were maximal in plants treated with a greater amount of GA₃. In the end, stem elongation stopped and plants formed perchedrosettes without flowering. Hence, gibberellic acid participates in mechanisms of flowering only by indirect effect on stem elongation and not directly on flower formation itself.

During the period of the highest multiplication of TMV in tobacco tissues (on the 6th to l0th daya after inoeulation) the activities of NADP-glyceraldehyde-3-phosphate dehydrogenase, fructose diphosphatase, and phosphoglucoisomerase increase,i.e. the 3-phospho-glycerate is broken down more intensely, being the primer of photosynthesis via glycolysis. Products of this metabolic pathway, which are not employed directly for virus synthesis, are stored during this period as free saccharides and starch. The breaking-down rate of these substances increases during this period as well, as shown by increased activities of amylophosphorylase, phosphoglucomutase and saccharase. The increased aetivity of glucose-6-phosphate dehydrogenase is proportional to the rate of TMV multiplication; its high value (more than twice as with the control) insinuates that the virus reproduction deereases contents of some intermediates of the Calvin cycle (especiaily NADPH and ribulose-l,5-diphosphate) which act as inhibitors of the photosynthetic regulative system.

Stomata on the cotyledons of Morphactin EMD 7301 and EMD 7311 treated seedlings may be anisocytic, anomocytic, paracytic, diacytio, transitional forms and haplocytic. In spite of this diversity, the most frequent type is anisocytic on both surfaces. The stomatal ontogeny may bo perigenous, mesogenous and mesoperigenous. Morphactin EMD 7301 and EMD 7311 increase the size of cotyledons in all concentrations accompanied by an increase in the number of stomata on the adaxial surface in 100, 150, 250 ppm of EMD 7301. The effect of morphactin is promotive to the size of stomata in all concentrations, but it retards the stomatal density and number of epidermal cells. This may be due to an increase in the size of the epidermal cells. The substrates, however, have no effect on the morphology and ontogeny of the stomata; probably they are inherent chracters.

Studies performed on winter rape plants(Brassica nnpus var.oleifera, cv. 'Gór-czański') revealed that cold treatment affected the cell membranes and led to the temporary increase in electrolytic leakage from a tissue. This was followed by the marked decrease of the electrolytic leakage in the course of hardening. Changes in membrane properties were accompanied by the promotion of soluble protein accumulation. Inhibition of protein accumulation by the cycloheximide treatment brought about wilting of plants under cold conditions. Possible role of soluble protein in protection of cells against secondary water stress caused by the coldinduced changes in membrane properties is suggested. Cold-induced changes in the electrophoretic pattern of soluble protein are described and discussed.

The rise in soil salinity level tended to decrease shoot dry weight, and, grain yield per plant and, to some extent, weight of I grain. This effect was usually more pronounced in the presence of CCC. On the other hand, the shoot dry weight was increased by CCC in salinity absence but the reverse at 0.8 % salinization degree. The grain yield per plant was raised by CCC in the presence or absence of salinity, particularly in the latter case. The dry matter accumulation in the shoot system (at earing stage) rather than grain yield tended to be much more affected, whether regarding the negative response to salinity or the positive one to CCC.

This paper reports experiments performed to investigate the influence of various concentrations of streptomycin sulphate on a few parameters of importance in the metabolism of rice (Oryza sativa L.) seedlings. It was shown that respiration rate was accelerated by streptomycin. The specific activities of catalase and peroxidase decreased whereas IAA oxidase increased with increasing streptomycin concentrations. Increased activities of all these enzymes were apparent on a dry weight basis suggesting increased succulence caused by streptomycin treatment. There was a considerable rise in the water soluble protein content following streptomycin application. It may be suggested that growth inhibition by streptomycin results from reduction in the auxin level owing to enhanced auxin destruction.

The fruit pitting symptoms on cherries, plums and prunes were investigated from the standpoint of their etiology. Tomato bushy stunt virus (TBSV) was isolated from pitted fruits of these plants and from their leaves and identified by means of biological and serological methods. Both isolates reacted with antisera againstPetunia and artichoke strain of this virus. In addition, the etiology of pseudopox disease of plum and that of cherry detrimental canker is discussed.

For the detection of starch in paraffin sections of FAA fixed root tipa of pea and maize the Lugol's solution of suitable constitution and proper dilution was tried. JJK containing solution of arabic gum was proved as a mounting medium preserving the resulting colour. A procedure is given combining the application of JJK with alcian blue staining.

Starch was determined by means of IKI reaction in shoot apices ofChenopodium rubrum plants induced to flowering by two short days and in non-induced plants. Small starch grains were already observed in the meristematic cells at an age of four days after sowing. Larger grains were found in the subapical region of the apex. Heterogeneity increases during further growth of the plants in induced, as well as in non-induced vegetative plants. Starch disappears from the cells potentially giving rise to axillary buds, while the number and size of starch grains increase in cells from which leaf primordia will be formed. This metabolic specifity of leaf and bud primordia is preserved during morphological differentiation and applies to vegetative, as well as to prefloral apices of photoperiodically induced plants. The amount of starch in the different regions of the apex is linked rather with organogenesis than with the quantitative growth in the apex.

During the first 24 h of germination of wheat seeds, starch is hydrolysed by free β-amylase. In the next 24 h, some amount of inactive form of β-amylase is converted into active form and this together with α-amylase synthesizedde novo brings about the hydrolysis of starch. The amount of α-amylase is greater in seeds with embryo intact than with embryo excised after 24 h hydration. However, at later stages of seed germination α-amylase becomes predominant and the activity of β-amylase steadily diminishes.

0.25 % ammonium oxalate in a mixture of ethyl alcohol, chloroform, formaldehyde, acetic acid and hydrochloric acid works as a very fast and efficient macerating fixative for the root meristems ofAllium cepa, Allium sativum, Ornithogalum thyrsoides, Pisum sativum andVicia faba. Slicing the tip region of excised meristems hastens spindle poison pretreatment, fixation and staining. Owing to the dissolution of the middle lamella and eliminating a physical barrier to permeability an extremely rapid fixation and staining schedule involving several stains has thus been developed.

The content of endogenous auxins was examined in apical buds ofChenopodium rubrum plants induced by a photoperiodic cycle of 16h darkness and 8h light followed by a dark period of various duration so as to correspond with either maximal or minimal flowering response in the endogenous rhythm in capacity to flower initiated by the photoperiodic treatment. Apical buds of potentially generative plants contained less auxins than apical buds of plants which remained in the vegetative state. Apical buds from plants treated with kinetin (1. 10^-3 M) and therefore remaining in the vegetative state showed an auxin level comparable to that of untreated plants exhibiting minimal flowering response irrespective of the duration of the second dark period. Plants cultivated on a sucrose solution (0.6 M) during the second dark period became generative even at the normal minimum of flowering. The auxin content of the apical buds was low, similarly as in untreated plants induced for a period leading to maximal flowering response. On the other hand, apical buds from plants grown on sucrose solution during a dark period leading to the manifestation of maximal flowering response showed a relatively high auxin content comparable to that found in untreated plants which had obtained a more extended induction by three photoperiodic cycles. The results are discussed with respect to the possible role of endogenous auxins in the regulation of the changes in growth correlations occurring in the shoot apex during photoperiodic induction and in the expression of the competence to flower.

1. Ethyl methanesulphonate (BMS)-treated barley seeds stored at 30 % water content for 1 - 4 weeks are capable of recovering from the mutagen induced injury. The level and speed of the recovery depends on the EMS dose and storage period. Seeds treated with extremely severe EMS doses reducing the% of germination to 5 - 10 % cannot recover from the induced injury. 2. Due to a 1 to 6 weeks storage of EMS-treated seeds with 20 % water content the amount of induced injury increases in dependence on the applied EMS dose and storage period. Doses of EMS, reducing the seedling height in the M₁ generation to 90 - 95 % of the control reveal no storage after-effects. 3. Storage of X-ray exposed seeds at 20 % or 30 % water content did not result in any significant changes in the yield of induced genetic damage.

The seeds ofFraxinus excelsior L. were stratified at 17-20 °C (warm stratification), at 4-6 °C (cold stratification) and at alternating temperature (warm - cold stratification). The seeds subjected to warm stratification only, remained dormant. The seeds stratified only at 4-6 °C germinated gradually during a long period of time. The seeds subjected to warm - cold stratification, however, germinated with great intensity within a relatively short period of time.
GA₃ was shown to stimulate the growth of embryos markedly, and its effect on the germination of seeds depended on the temperature of stratification. GA₃ applied during the cold stratification accelerated the removal of dormancy by shortening the period of stratification and by influencing the germination of seeds. The results obtained indicate a similarity between the effect of temperature 17-20 °C during the warm stratification and that of gibberellic acid. Both those factors applied separately affect favourably after-ripening of the embryos and accelerate the germination of seeds.

In contrast to their soil counterparts, algal fulvic acids were more inhibitory than the corresponding humic acids. Fulvic and humic acids fromFucus vesiculosus were more efficient than the correspondingLaminaria digitata acids in inactivating the enzyme.Laminaria humic acids, which have no phenolic hydroxyls, showed a concentration dependent inhibition hardly in accordance with the presumed role played by these groups in the activity of oxidases.

Time-lapse microcinecmatography showed that the negative prototactic response of the chloroplast lasted 11-19 min and was completed 40 min after the beginning of irradiation; the contraction reached 11% in 60 min.

A propagation method for someFreesia cultivars usingin vitro cultures is described. Bud and root formation was evoked in callus tissue culture on a modified Murashige and Skoog's medium. Reconstituted plants were transferred into soil and cultivated in the glasshouse.

The tips of the rhizomorphs ofSphaerostilbe repens transferred on agar medium regenerate some aggregated organs without an intermediate mycelium stage. Each extremity of the drawn rhizomorphs can give rise to eoremia on its air face and to rhizomorphs on the contact with tho culture medium. These heterogeneous environmental factors impose polarized regeneration, easily inverted, upon the rhizomorphs. Nevertheless, a residual and stable polarity remains; it is attributed to the apex which is more capable of bearing new organs than the other extremity. Tho efficiency to regenerate depends on the ago of collulos and on tho size of tho rhizomorph tip; howover it is very difficult to provent the formation of new aggregated organs.

Uridine-³H incorporation and RNA concentration were investigated in different parts of the shoot apical meristem ofChenopodium rubrum using autoradiography and cytophotometry. A single inductive cycle was sufficient to bring about postinductive first events in the shoot apex but not for complete flower differentiation. The initial activation of RNA synthesis manifested itself in all zones of the apex. The first increase was more conspicuous in the peripheral than in the central zone. The indications of the first events in the apices after a single inductive cycle disappear prior to morphological reversal to the vegetative state. Induction by three short days led to rapid flower differentiation. The increase in RNA synthesis and concentration was most conspicuous in the central zone in this case. The ratio of RNA synthesis and content between bud and leaf primordia (B/L) also change in relation to photoperiodic induction. In vegetative plants the B/L ratio was low while after induction it increased.
The shifts in activity of RNA synthesis observed in the shoot apical meristem are related to the changes in growth activity of the different parts of the apex. The growth ratios in the apices bear the character of growth correlations. The change in the growth correlations following photoperiodic induction together with the total activation of RNA synthesis are considered to represent one of the first events of the transition to the reproductive state.