The response of Brassica carinata hybrids and their parents to moisture stress at different growth stages was studied. B. carinata 226 was found to be susceptible to stress at pre-flowering and post-flowering stages while B. carinata 241 at flowering stage. Neither the changes in stomatal conductance nor in chlorophyll content could fully explain the reduction in net photosynthetic rate (P_N) induced by stress. B. carinata 241 had higher leaf water potential (ψ_w) although, it had lower P_N compared to B. carinata 226. Both the parents had lower P_N as well as leaf ψ_w. The stress response of PN in hybrids followed that in their respective female parents.

During the germination, wheat and sorghum plants tolerated salinity up to 10 mM NaCl. Seedling growth and dry matter production remained more or less unchanged up to 10 mM NaCl in case of wheat and up to 5 mM NaCl in case of sorghum. The water content of test plant species exhibited nearly constant values irrespective of the salinity level applied. The proline and carbohydrate content increased with elevating NaCl, while free amino acids content decreased. Irrigating of seedlings with tryptophan had non significant effect at all salinity levels used.

In vitro cultures of Calathea ornata Koern. cv. Sanderiana shoots were maintained on modified medium of Murashige and Skoog. With the aim to find effective micropropagation method the effects of cytokinins, paclobutrazol, saccharose, mineral salts and shoot-tip damage on the shoot growth and quality were studied. The highest number of shoots was obtained on a medium containing 2.5 mg dm-3 benzylaminopurine, 2.5 mg dm-3 kinetin, 4.5 % saccharose and raised concentrations of Ca, Mg, Fe and Mn. Shoot branching was markedly stimulated by the shoot-tip damage.

Mutagenesis provoked by exposure to increased concentration of antibiotics of five indigenous Rhizobium galegae strains resulted in the generation of several antibiotic-resistant mutants. The mutants differed from the wild type and one from another in respect to the nodulation capacity, the nitrogenase activity, the nodule ultrastructure, and the plant growth response. Galega plants inoculated with mutants resistant to streptomycin and rifampicin formed nodules with higher nitrogenase activity and accumulated more shoot dry biomass than plants inoculated with the parent strains. Resistance to kanamycin and nalidixic acid was associated with significant decrease of nitrogenase activity. A correlation between nitrogen-fixing efficiency and nodule infected cell ultrastructure was found. When the bacteroids occupied about 10 times higher area in infected cells of nodule than peribacteroid spaces and host cytosol had electron dense and homogenous structure, the nitrogenase activity was the highest.

A field experiment was conducted to investigate the effects of presoaking the wheat grains (Triticum aestivum L.) in different levels of salinity (33 or 66 mM) and in growth regulators (indolyl-3-acetic acid, IAA at SO g m^-3, gibberellic acid, GA₃ at 100 g m^-3, or kinetin at 100 g m_-3) on the shoot growth and pigment content of the developing wheat flag leaf. Salinity at 33 or 66 mM led to an insignificant increase in the fresh and dry masses as well as in the shoot diameter and shoot length, but it attenuated the flag leaf area. In the majority of cases, salinity increased the chlorophyll (Chla, Chlb) and carotenoid contents as well as the number of chloroplasts per a mesophyll cell. The growth in the wheat shoot of the saline-treated plants was, in general, stimulated in response to presoaking the grains in kinetin or GA₃. On the other hand, IAA + salinity led to a negligible effect on the growth in the wheat plants particularly at the early stages of growth. The presoaking of grains in NaCl at 33 mM + IAA or 66 mM + kinetin induced a marked increase in the pigment content of the wheat flag leaf particularly at the early stages of growth. The interaction between salinity and phytohormones increased the number of chloroplasts; kinetin was the most effective.

Five sets of synthetic oligonucleotide (20-to 24-mers containing no intenal repeats) primers of known gene sequences [yellow lupin nodule specific (hydroxyl) proline-rich protein, pearl millet alcohol dehydrogenase, Pisum sativum heat shock proteins, Drosophila homeobox, and tRNA] were used to differentiate 73 soybean accessions, including 56 Glycine max (L.) Merr. and 17 G. soja Zucc. & Sieb. The amplified genetic markers revealed polymorphic bands for most genotypes studied. The χ²-analyses of the results showed that several fragments produced with these gene primers were associated non-randomly with resistance to Phytophothora, maturity, seed size, flower colour, seed coat colour, seed hilum colour, growth type, and leaf shape. These markers appear to be valuable for differentiation of G. max and G. soja species and genotypes within these species.

The ontogenetic changes in source-sink relation associated with the manipulation of reproductive sink at different positions on the plant in two okra cultivars (Arka Anamika and Pusa Makhamali) with distinct branching habit (cv. Arka Anamika tends to branch at the middle nodes unlike cv. Pusa Makhamali) were analysed. The cultivar differences for extension growth were nonsignificant except at treatment where all flowers and flower buds upto 8th mode were removed. The reproductive sink reductions resulted in a decrease of total dry matter accumulation per plant to an extent of 13 to 46% in Arka Anamika and 18 to 34 % in Pusa Makhamali. Fruits on the middle nodes appear to be prominent sinks for photo assimilates in cv. Arka Anamika. The reproductive sink manipulation did not result in any particular change in the trend of photosynthesis, but brought about a significant change in the partitioning of dry matter.

A concentration dependent decrease in root nitrate reductase (E.C.1.6.6.1) activity (NRA) by 0.1 to 2.0 mM lead acetate was noticed in three cultivars of Vigna radiata (L.) Wilczek (K851, MH8320 and ML337). Leaf NRA, on the other hand, increased significantly with increasing lead concentration which was more pronounced in cvs. MH8320 and ML337 than in cv. K851. Total nitrogen content of root and shoot was generally increased due to supply of the lead acetate, whereas the total nitrogen content of the colyledons was hardly affected in cvs. MH8320 and ML337 and decreased in cv. K851 during the early growth phase. The inhibition of root NRA could be alleviated by addition of inorganic salts (K2HPO4 and KNO3, but not CaCl2) or 6-benzylaminopurine (BAP) in the incubation medium. Lead mediated inhibition of root NRA was similar in light and dark grown seedlings, but lead induced increase in leaf NRA was more pronounced in the light than in the dark.

We studied the influence of ethephon (2-chloroethylphosphonic acid) on the first stages of development of the main apex of Liatris spicata cv. Callilepis and its relation to the mobilization of soluble saccharides in the corm. Ethephon enhanced cell expansion during the first weeks of cultivation but did not affect the timing of flower initiation. Soluble saccharide concentration in the corm reached a maximum after sprouting, probably due to rapid growth of the shoot. There was no change in the concentrations of soluble saccharides immediately prior to flower initiation, which suggested that quantitative changes in these saccharides were not responsible for activating flower initiation. When corms were treated with ethephon there was a greater degree of soluble saccharide mobilization during the first weeks of cultivation than in untreated corms. However, this did not seem to be the direct result of the addition of this phytohormone and was more probably the consequence of cell growth being encouraged.

Eleven species of nitrogen-fixing cyanobacteria belonging to six genera (Cylindrospermum, Anabaena, Nostoc, Calothrix, Scytonema, and Westiellopsis) tolerate different concentrations of NaCl (from 0.05 to 0.35 M). Wide variation in the chlorophyll (Chl) a content of the species of the same genus and between genera in presence of NaCl was observed. The least tolerant (Cylindrospermum sp., Cy 6), the maximum tolerant (Westiellopsis sp., We 1), and the intermediate tolerant (Westiellopsis sp., We 6) species of cyanobacteria were selected, and their response to various concentrations of NaCl (growth, nitrogen-fixing capacity, and production of extracellular substances) was studied. Nitrogen fixing capacity of both the We 1 and We 6 was greatly impaired in comparison to the decrease in their Chl a content in the NaCl containing media. Cellular and extracellular saccharide and extracellular amino acid contents of the cyanobacteria species in the NaCl supplemented cultures were increased suggesting that presence of saccharides and amino acids enabled the cyanobacterial species to thrive under salt stress. Further, the We 1 did not adapt to the salt whereas Cy 6 showed adaptation to low concentrations of NaCl suggesting that the species which tolerate high concentrations of the salt may not possess the ability to adapt to NaCl.

Photosynthetic parameters were compared in three types of transgenic tobacco plants: ipt-transgenic plants with slightly elevated endogenous cytokinin (CK) content, Pssu-ipt-transgenic plants with markedly increased CK content, and zmp-transgenic plants with slightly elevated CK content accompanied by elevated auxin content. Slightly increased CK content promoted net photosynthetic rate (P_N) in both ipt- and zmp-transgenic plants, and chlorophyll (Chl) and carotenoid contents in zmp-transgenic plants. Morphology, growth characteristics, stomatal conductance, and parameters of Chl a fluorescence kinetics were similar in control and transgenic plants with slightly higher CK content. No significant effect of increased level of endogenous auxin (indole-3-acetic acid) on development of zmp-transgenic plants and measured parameters was found. Pssu-ipt-transgenic plants with highly increased CK content revealed suppressed root development, wilting of plants, and depression of P_N and stomatal conductance; however, Chl content was slightly increased and parameters of Chl a fluorescence kinetics did not indicate damage to photosynthetic apparatus.

Calli of soybean (Glycine max Merr.) cv. Maple Arrow grew better and accumulated more proline when cultured for 5 d on 70 mM NaCl under darkness than at light. This rapid proline accumulation in salinized soybean calli appeared to play a protective role rather than to be a cause of growth failure. Throughout a 28 d-culture cycle (in control and NaCl-treated calli exposed to light or darkness), we followed the possible relationships between the proline contents and the activities of enzymes of proline biosynthesis [ornithine transaminase; NAD(P)H-pyrroline-5-carboxylate reductase], of proline catabolism [NAD(P) proline dehydrogenase], and of NAD kinase responsible of variations in NADP(H) contents. Enzyme activities of proline metabolism and NAD kinase were clearly light- and NaCl-regulated; nevertheless, relationships between enzyme activities and proline content existed only in calli grown for short-term under darkness and in presence of NaCl. The ornithine transaminase route, which was particularly enhanced in these calli during the first days of salt application, seemed to be involved in the initial proline accumulation in soybean.

Eichhornia crassipes plants brought from the River Nile were cultured in jars containing river water supplemented with various concentrations of Cd, Pb, and Sr (0 to 100 μg cm-3), added simultaneously. Treatment continued for 20 d during which each cultivation solution was being replaced with fresh one every 3 d. The growth of Eichhornia was drastically retarded at heavy metal concentrations higher than 15 μg cm-3. At concentrations 15 or 25 μg cm-3, the accumulation of Cd and Pb to levels several times higher than those in control plants was found. More than 50 % of the uptaken metals were retained by roots alone. Leaves and leaf petiols received around 30 and 20 % of the accumulated metals, respectively. X-ray microanalysis indicated the presence of the three heavy metals in Ca oxalate crystals. Content of metals in the crystals increased progressively over time of exposure in a way similar to those in whole plant tissues. These results suggest a possible role for Ca oxalate crystalization in toxic heavy metal deposition and thus tolerance by Eichhornia.

Tobacco and carnation plantlets were grown in vitro on Murashige and Skoog's medium with 2 % saccharose. Carnation plantlets were also grown fully photoautotrophically on a medium without saccharose. The ambient CO2 concentration was increased from 0.6 to 10 or 40 g m-3 during the last 3 weeks of in vitro cultivation or during the first 3 weeks of acclimation to ex vitro condition (plantlets transplanted to pots with sand and nutrient solution) or during both growth phases. CO2 enrichment during in vitro cultivation markedly stimulated growth of tobacco plantlets, and also of carnation plantlets, both with and without saccharose. CO2 enrichment during the acclimation period promoted plant growth more effectively in plantlets grown in vitro at a CO2 concentration of 0.6 g m-3 than in plantlets grown in either growth phase at higher CO2 concentrations.

The effect of five Azotobacter chroococcum strains and nitrogen content in nutrient media on callus growth of two Beta vulgaris L. cultivars were investigated, as well as the activity of nitrate reductase (NR), glutamine synthetase (GS) and glutamate dehydrogenase (GDH) in inoculated callus tissue. On medium with full nitrogen content (1 N) the inoculation with A. chroococcum strain A2 resulted in the highest calli mass, while strains A8 and A14 maximally increased NR activity. On media with 1/8 N the highest effect on calli growth, GS and GDH activity had the strain A8. The strain A2/1 significantly increased callus proliferation on medium without N. Asymbiotic association between sugar beet calli and Azotobacter depended on genotype/strain interaction and was realised in presence of different nitrogen levels.

A continuous propagation of juvenile larch in vitro was based on adventitious bud formation and different cytokinin combinations were tested concerning their effectiveness to induce elongation of adventitious buds. Zeatin (1.5 mg dm-3) combined with kinetin (0.15 mg dm-3) was found to be the best. Development and elongation of buds was achieved on a modified LP-medium. Using this system it was possible to propagate different larchspecies (Larix decidua, L. gmelinii and L. sukaczewii f. multiramosus) continuously. Shoots were successfully rooted and transferred to the soil.

Thidiazuron incorporated into MS medium stimulated rosettes formation only in some treatments. This effect was more pronounced in cultures ofMorus alba thanPrunus sp. Mulberry cultures responded to the optimal concentration of thidiazuron (0.2 mg I^-1) not only with shoot formation but also, with growth of large leaves and poor development of callus tissue. In cultures of both investigated genera the shoot elongation was inhibited. Shoots of mulberry cultures growing on proliferation medium supplemented with thidiazuron formed roots, in many cases.

The influence of salinity, given at germination (stage I) or 75 d after sowing (stage II), on flower production and characteristic features of male reproductive structures was studied in three promising genotypes of chickpea (Cicer arietinum L. cv. ICCV 88102, H 82-2 and C-235). In ICCV 88102 and H 82-2 salinity 20 meq 1^-1 increased the number of flowers when applied at both stages whereas in C-235 only when applied at the later stage. The salinity also delayed flowering; the higher salinity the greater was delay in flowering. In H 82-2 and C-235 salinity treatment given at stage II (when few flower buds appeared) hastened the flowering. The salinity curtailed pollen production; the reduction being minimum in C-235 and maximum in H 82-2. Germination was not significantly affected in C-235 pollen collected from plants grown under salinity conditions upto 60 meq 1^-1 applied at stage I but the tube elongation was inhibited. The inhibition of tube elongation was greatest in C-235. Salinity treatment administered at stage II did not affect significantly pollen germination excepting C-235 in which a consistent decline with increasing salinity was evident. Salinity stimulated tube growth in ICCV 88102. Na₂SO₄ in the germination medium was more detrimental for both pollen germination and tube growth than NaCl.

The variations in length and fresh and dry mass of etiolated hypocotyls of lupin during the growth have been studied. The growth exhibited by the different zones delimited along the hypocotyl was dependent on the localization of the zone as well as on the age of seedlings, but in both cases the pattern of growth was similar. During the period of growth studied (seedlings 7 to 21 d old), the growth of hypocotyl was basically due to cell elongation, since the relative elongation of cells was positively correlated with the relative elongation of the hypocotyl.

Coleoptile removal-induced ethylene production was investigated in light-grown winter rye seedlings. Removal of the coleoptile induced 1-aminocyclopropane-l-carboxylic acid (ACC) synthesis and ethylene production by primary leaves and caused an inhibition of elongation growth of the leaves. The activity of ethylene-forming enzyme (EFE) was associated with the increase in ethylene evolution. Both rise in ethylene and ACC production, as well as EFE activity were inhibited by cycloheximide. Wounding the tissue 40 min after the initial treatment resulted in the second increase in ethylene evolution. Derooting of the seedlings without coleoptile removal did not induce ethylene production. It is suggested that the coleoptile represents a barrier for wound-induced ethylene production from actively growing leaf tissue.

Decrease in leaf irradiance to 50 % due to shading of plants in glasshouse only during clear summer days did not induce significant changes in growth parameters, characteristics of water relations and epidermal conductance of two cyclamen cultivars. Thus the possibility of acclimation of plants to non-stable changes in environmental conditions was not proved.

The effect of NaCI stress on the activities of nitrate reductase (NR), glutamate dehydrogenase (GDH) and glutamate synthase (GOGAT) in callus lines ofVigna radiata which differ in salt resistance, was studied at weekly intervals upto 28 d of growth. After 28 d, the NaCI resistant callus (selected at 300 mM NaCI) at NaCI concentrations higher than 200 mM maintained higher NR activity than non-selected line. NaCI stress also affects aminating and deaminating activities of GDH. The NADH-GDH activity in the presence of NaCI was higher in the resistant than non-selected line. On the other hand, NAD-GDH activity in both the lines was completely inhibited after 7 d of growth. The increased activity of NADH-GDH in resistant calli may play a vital role in protecting the cells from toxic effect of increased endogenous level of ammonia which probably accumulates due to efficient NO₃ ^- reduction. NADH-GOGAT activity was found to decrease under salt stress in both the callus lines. Nitrogen assimilation in salt-resistant calli under salt stress was found to be characterized by high NR and NADH-GDH activities, concomitantly with low GOGAT activity.

Lead chloride (10^-5 M) inhibited the growth of the main root, the duration of development, the number and growth of lateral roots, primary and trifoliate leaves, and also the mitotic index in root apical meristems. Lead strongly inhibited root growth rate, mainly by reducing the number of dividing cells. Other mechanisms of this inhibition are discussed.

Tobacco plantlets were grownin vitro on Murashige and Skoog's medium with2 % of saccharose. Addition of 0.01 mM abscisic acid (ABA) into the medium decreased stomatal conductance of the adaxial epidermis and especially the abaxial epidermis without negative effects on growth parameters. As a result the rate of water loss from ABA-treated plantlets taken out of cultivation vessels was slower than that of control plantlets. This could help their acclimation after transplantation toex vitro conditions.

Embryogenic callus cultures were established from immature cucumber(Cucumis sativus L.) embryos on E20A (Dumas de Vaulxet al. 1981) or MS (Murashige and Skoog 1962) media supplemented with 6-benzylaminopurine (BAP), α-naphthylacetic acid (NAA) and/or 2,4-dichlorophenoxyacetic acid (2,4-D). Regeneration of plants was observed after a transfer to culture media either without growth regulators or supplemented with kinetin and NAA. Flow cytometry was employed to estimate DNA ploidy levels. Most of cell nuclei in young leaf tissues were found in G₁ phase with 2C DNA content. Callus cultures were mixoploid with DNA content ranging from 2C to 32C. The frequency of polyploid cells was increasing with the age of culture and the polyploidization was accompanied by a gradual loss of regeneration ability. Plants regenerated from callus cultures were classified as diploid (57 %), tetraploid (18 %), octoploid (4 %) and mixoploid (2n/4n, 4 %) and (4n/8n, 17 %). The results of this study confirmed a close link between the polyploidization and the loss of totipotencyin vitro. Tetraploid plants obtained in this study have a potential to be used in interspecific crosses where their tetraploid status could help in overcoming existing breeding barriers due to differences in chromosome number.

Methods for testing equality of horizontal distances of subsequent parallel or common lines are suggested in this paper. Possibilities of using these methods are given on data concerning spring barley leaf growth.

Wounding both cotyledons ofBidens pilosa (var.radiatus) induces the inhibition of hypocotyl growth. The wound signal is transmitted very rapidly from cotyledon to hypocotyl and can be visualized by the change in nucleotide pools. First we have shown that the irradiance of the plant can change the ATP level without plant wounding. Therefore, plants were harvested at the start of the light period. Under these conditions, we have determined in hypocotyl the levels of adenosine triphosphate (ATP), guanosine triphosphate (GTP) and non adenylic triphosphates (NTP), and adenylate energy charge (AEC) after wounding. We have observed a transient (2 min) increase in the ATP level followed by a decrease 5 to 30 min later. A similar result was obtained for the GTP level but with some delay. The GTP level increased in 5 min and then decreased after 60 min. For the NTP level the decrease is effective from 5 to 60 min after wounding. The calculation of AEC has shown that a very tight control in the level of ATP may be involved in response to wounding.

Vegetation experiments were conducted under greenhouse conditions in which long-term effects of simulated acid rain on the shoots, and short-term effects of acidified root medium on the roots of two maple species (Acer pseudoplatanus L. andAcer negundo L.) were studied. Both alternatives of the acidification stress were studied with respect to exogenous applications of auxins and gibberellins. Changes in seedling growth caused by acid rain were not marked, but changes in the levels of endogenous growth regulators were detected, both the long-term exposure ofAcer pseudoplatanus L. seedling shoots to acid rain and the short-term acidification of root environment resulted in enhanced cytokinin activity and in decreased gibberellin activity. But when A.pseudoplatanus L. seedlings were pretreated with gibberellins, their activity was further increased by increased acidity.Acer negundo L. seedlings responded to the acidification of their root environment with enhanced cytokinin activity only when pretreated with exogenous auxins. The differences in the responses ofA. pseudoplatanus L. and A.negundo L. to the acidification can be explained in terms of their distinct physiological properties, including changes recorded in chlorophyll content. The results obtained show that a pretreatment of maple seedlings with exogenous growth regulators can modify the effects of increased acidity in the environment on their physiological status as characterized by the level of endogenous cytokinins and gibberellins.

Paclobutrazol (PB), a triazole growth retardant and an inhibitor of gibberellin biosynthesis, reduced at 17 μM concentration the adventitious root formation of bean primary leaf cuttings. Treatments with 5 μM ABA or 4 μM Ethrel, an ethylenereleasing compound, restored the rooting of PB-treated cuttings. Ethylene production and the content of the precursor 1-aminocyclopropane-l-carboxylic acid (ACC) were enhanced in root-forming tissues of PB-treated petioles 48 h after ABA application. The effect of ABA could be abolished by 10 μM CoCl₂, an inhibitor of ACC oxidase. Thus, ABA might stimulate rooting through its effect on ethylene release. 2 mM silver thiosulphate, an inhibitor of ethylene action, decreased the rooting of PB-treated cuttings similarly to Co²⁺, but failed to negate the ABA effect. These data indicate that the effect of PB on rhizogenesis is not associated directly with the inhibition of the biosynthesis of gibberellins