Barium chloride at 0.1 mM concentration inhibited elongation of mungbean (Phaseolus aureus) roots more strongly than elongation of hypocotyls. Root growth was completely inhibited at 80 mM and there was no germination at 100 mM. Respiration rates which were directly proportional to seedling vigour declined at varying degrees at the growth-inhibitory concentrations of BaCl₂. Barium retarded senescence in isolated leaf discs ofCephalandra indica by maintaining the chlorophyll level in darkness. The carotenes were similarly protected from degradation by Ba in darkness whereas xanthophylls were retained both in darkness and light. Ba also protected anthocyanin pigments in the staminode discs ofCanna indica flowers and reduced to a variable extent the leakage of betacyanin pigment fromBeta vulgaris root discs caused by various membrane active chemicals. Applied either alone or in combination with IAA, Ba inhibited cell enlargement in wheat (Triticum aestivum) coleoptile sections. Barium-induced inhibition of lettuce (Lactuca sativa) hypocotyl elongation was largely overcome by GA₃.

The effects of salt stress on nitrogenase (N2-ase) activity, growth and nitrogen content ofVicia faba (L.),Medicago sativa (L.) Merrill,Glycine max andVigna sinensis (L.) were investigated. Four levels of salinity were applied and salt treatments were imposed on inoculated and N-fertilized plants.M. sativa tolerated mild levels of salinity but higher salt concentrations depressed N₂-ase activity of this species. The other three legumes were considerably affected by salt treatments, and N₂-ase activity was significantly reduced by salinity.
Vicia faba, carrying elongate nodules, could restore a partial N₂-ase activity upon recovery from salt stress whereasG. max andV. sinesis, both with spherical nodules, could not regain significant activity when salinity was removed.
Salt stress retarded growth of both inoculated and N-fertilized plants. The nitrogen content of both treatments was also affected by salinity and the effect was more severe for inoculated than N-fertilized plants.

Intact maize seedlings were examined for the uptake and leakage of labelled sulphate and phosphate anions affected by temperature. Control plants, grown at 25 °C were compared from the aspects of uptake capacity and leakage with plants incubated in nutrient solutions cooled to 15 °C and 5 °C, respectively. Short time intervals as well as 1-7 d exposure to cooling were used. Already after 1 h exposure at 5 °C and 5 h cooling at 15 °C and at 5 °C, considerable changes were manifested in anion uptake and leakage.
The uptake of³²P declined more than that of³⁵S. So, after a 30 min uptake interval the uptake of³⁵S decreased at 15 °C to 49.84% and at 5 °C to 6.05% comparing with the uptake at 25 °C, while the uptake of³²P declined to 28.64% at 15 °C and to 4.45% at 5 °C. The leakage of both anions was the highest at 25 °C in absolute rates, but relatively most of the uptaken³⁵S and³²P was released at 5 °C. Longer exposure to a chilling temperature of 5 °C (1-7 days) resulted in two patterns of sulphate and phosphate uptake.

The effect of high concentrations of the simplest polyphenols on extension growth of maize (Zea mays L.) shoot ooleoptile segments, lettuce (Lactuca sativa L.) roots, and on radish (Raphanus sativus L.) seed germination, was studied. Quinone formation in the process of plant incubation in polyphenol solutions was proved. The data obtained are presumably explained by the important part that is played by the quinoid products of phenol oxidation in the ability ofo- andp-biatomic phenols to inhibit growth.

Chlorflurenol (morphactin) EMD 7301 W (60, 120 and 240 mg I^-1) when applied at five to seven leaf and 10-12 leaf stage induced hermaphrodite flowers in the inflorescences ofRicinus communis. The hermaphrodite flowers were mostly apical in position unlike the apical female flower in the control. With an increase in the time gap between sowing and emergence of the inflorescence there was a reduction of the female structures in the hermaphrodite flowers. The last formed inflorescences had an apical male flower in place of a female. The largest number of inflorescences with an apical male or hermaphrodite flower were produced with 60 mg 1^-1 applied at five to seven leaf stage. The hermaphrodite flowers failed to set fruits.

The adaptation of Marmur's method, suitable for DNA isolation from plant cell culture, is described.

The effects of different osmotic stresses (from 0 to -8× 10⁵ Pa) obtained with NaC or polyethylene glycol 6000 solutions on the germination of flax, sesame and onion seeds were investigated. The effect of presoaking with gibberellic acid (GA³) on the germination of the above mentioned seeds was also studied.
It was found that the rate of seed germination and the final germination percentages as well as the amount of water absorbed by the seeds were considerably lowered with the rise of osmotic stress levels whatever the stress agent used, more considerable reduction was obtained under polyethylene glycol 6000 than under NaCl.
Presoaking with gibberellic acid increased the rate and the final germination percentage of osmotically stressed flax and sesame seeds, while those of stressed onion seeds were slightly retarded.

Chloramphenicol has been found to inhibit nitrate reductase activity in black-gram leaves. It inhibitsin vivo nitrate reductase activity up to 50-67%, and the catalytic property of the enzyme up to a maximum of 70-98%. Modulators, such as KNO₃, NADH and HCO₃ could not protect enzyme inhibition by chloramphenicol. It is suggested that the chloramphenicol inhibition is mainly through its effect on the catalytic process of the enzyme.

Fifteen soybean cultivars were evaluated in two water supply conditions, inducing or not a drought stress. Main canopy traits were measured several times during the reproductive period and, at maturity date, the yield components were estimated. Using principal components analysis, the main physiological functions involved in soybean drought tolerance are described: leaf cells enlargement and assimilates transport. These processes could be a good basis on which to define new selection criteria for soybean drought tolerance.

Effects of Na₂CO₃ and NaHCO₃ at equal conductivities (2, 4 and 6 S cm^-1) on germination, seedling growth and some metabolites were studied in two cultivars of green gram (Phaseolus aureus Roxb. cv. Varsha and cv. Pusa Baiskhi) in Petri dishes and sand culture. With increasing conductivity both the salts depressed germination, length of shoot and root and their mass. NaHCO₃ was more depressiv than Na₂CO₃. The contents of chlorophyll, RNA, protein and free amino acids were higher and affected to a lesser extent under salt stress in leaves of cv. Varsha than cv. Pusa Baiskhi. Cv. Pusa Baiskhi was generally more susceptible to salt stress than cv. Varsha.

The stomata and their behaviour towards neutral red uptake in a few arid zone plant species under stress conditions have been inve stigated. Variable patterns of accumulation or non-accumulation and retention of this vital dye, by various cells of leaf epidermis have been observed. The neutral red uptake by the cells of the epidermal strip, coalescence of particles and their movement appear to be connected with the open/closed condition of the stomata.

The inhibitive growth-correlative effect of cotyledons of pea seedlings decreases during their ontogenesis till the age of 14 days. This decrease is associated with an increase in the level of endogenous cytokinins on the one hand and a decrease of endogenous IAA on the other. This is in harmony with the fact that the correlative-inhibiting effect of pea cotyledon upon the growth of its axillary bud can be weakened by exogenous cytokinin and amplified by exogenous IAA.

The action of light on protein synthesis was examined in the cabbage seedlings, a system extensively used in the studies of anthocyanin synthesis. Continuous red and far red light have no effect on total protein content while they cause a marked decrease in the level of free amino acids in cabbage seedlings. The rate of protein synthesis, measured as incorporation of radioaetively-labelled amino acids into proteins, is clearly stimulated by light. Phytochrome involvement in the light stimulation of the incorporation is also demonstrated by the red-far red reversibility of the response. The relative effectiveness of continuous red and far red light upon the incorporation of amino acids into proteins is affected by the nature of the system used to study the incorporation process. When excised cotyledons and short period of incorporation were used, continuous far red was more effective than red. However, when whole seedlings and long period of incorporation were used, red and far red were equally effective. Streptomycin causes a 10- 15% decrease in the rate of incorporation of amino acids into proteins of all cellular fractions, except the plastid fraction where a much higher inhibition (30%) was observed.

Macromolecule syntheses, especially incorporation of radioactive labelled precursors into proteins, RNA and DNA were investigated. Some results on the action of phytohormones applied to dormant seeds and on the influence on water stress conditions by interruption of imbibition even before the radicle protrudes, on germination as well as on RNA and DNA synthesis were analysed. Benzylaminopurine and ethylene, applied in combination, could break dormancy of dormant seeds; a process which is correlated with the onset of DNA synthesis. Interruption of the imbibition during the time of onset of DNA synthesis (after 16 h of imbibition) did not impair the germination, and the protein, RNA and DNA syntheses started after reimbibition at that level which was reached at the interruption point. Only after a break in later phases (after 22 h of imbibition) a weak impairment of germination could be observed.

In the present paper we deal with the possibility of morphogenesis induction in callus tissue cultures of some representatives ofMatricaria andAchillea species. Shoot regeneration from calli ofMatricaria chamomilla andM. inodora has been induced by 0.1 mg l^-1 kinetin or by combination of 0.5 mg l^-1 kinetin and 0.5 mg l^-1 NAA added to Murashige-Skoog culture medium. Rhizogenesis took place without any other addition of auxin. In callus tissue cultures ofAchillea ptarmica cultivated on Murashige-Skoog medium with 1 mg l^-1 2,4-D after a year long cultivation the whole plant has been regenerated without any change of nutrient requirements. In callus tissue ofA. nobilis under the same conditions only roots wore regenerated.

Two isolectins were isolated from the albumin fraction ofArtocarpus integrifolia L. seeds, by precipitation with ammonium sulfate, and DEAE-cellulose and SP-Sephadex C-50 chromatography. The isolectins, when passed through Sephadex G-100 at pH 7.4, had a molecular mass of 43 000 and when subjected to SDS electrophoresis in the presence of β-mercaptoethanol consisted of two subunits with molecular mass of 11 250 and 15 000. When they were tested with human erythrocytes of all the groups of the ABO system there was no blood specificity. The isolectins formed interference arcs by Ouchterlony double diffusion in agarose gel.

It was found that the greatest dehydration rate of detached leaves indicates theTriticum monococcum L. v.vulgare (2n = 14). The indol-3-Acetic acid distinctly decreases the dehydration rate of detached leaves of examined wheat with a different ploidy level (Triticum monococcum, Triticum dicoccum, Triticum spelta andTriticum aestivum).

Two cultivars ofCicer arietinum L. with contrasting sensitivities to water stress, cv. C 214 (relatively resistant) and cv. 130 (susceptible) were compared for their protein content and soluble nitrogen (sol-N) under water stress. During water stress shoots of the cv. C 214 showed an increase (over the control) in both protein and sol-N content. The total nitrogen (total-N) also increased in the cv. C 214 while remaining almost unaffected in the cv. G 130. Cultivar C 214 shoots recorded lower protein/sol-N ratios. The results have been discussed in relation to resistance to water stress.

Complexes of water soluble proteins (albumins) were investigated in three cultivarsof Phaseolus vulgaris, viz: Yeltruská Saxa, Vainica Saavegra B, and Krupnaya sakharnaya. The first two cultivars exhibit haemagglutinating activity against rabbit erythrocytes, but have different elution profiles on Sephadex G-100. Their individual peaks have a different subunit composition, as revealed by SDS gel electrophoresis, as well as a different immunoelectrophoretic pattern, although proteins I and II of the specificity Veltruská Saxa are present in both cultivars. The cultivar Krupnaya sakharnaya expressively differs from the preceding lectin cultivars; it has no erythroagglutinating activity, its albumin complex has a high-molecular component, absent in the preceding ones, and has no lectin peak in the region of molecular mass of 100 000 to 200 000. Immunoelectrophoresis gave no evidence of protein I and II of the specificity Veltruská Saxa.

Esterase variation in shoot and root systems of ten-days seedlings of spring barley mutant lines was investigated. By an electrofocusing method it was found that some regions of the esterase activity were specific for the first leaf and for the root system of seedlings. Results showed the absence of close relationships between the morphological and esterase variation. Low negative correlations were only obtained for the root system parameters.

Both root and hypocotyl growths of lettuce, tomato, red cabbage and cucumber were inhibited when the seedlings were grown in Petri dishes together with 1 to 6 fruits ofWashingtonia filifera. This inhibition, in the case of lettuce hypocotyl, was not reversed completely even after the addition of 50 mg l^t-1 GAs. Effect ofW. filifera fruits on the light-induced synthesis of anthocyanin in red cabbage seedlings revealed that the presence of one fruit was enough to reduce the production of anthocyanin three times less than that of control. Water-soluble extract of the fruits when subjected to high temperature increased its growth inhibiting ability several times that of the untreated control.