Using various transformation methods, T-DNA constructions for insertional mutagenesis were introduced into Arabidopsis thaliana and the pattern of segregation of hygromycin resistance selectable marker was followed in succeeding generations in individual transgenic lines up to T₄ generation. Despite the low frequency of transformation, T-DNA was often inserted in two or more independent sites. Mendelian segregation ratios 3:1, 15:1, and irregular segregation ratios were observed. We have also shown continuous decrease of the expression of the resident hygromycin resistance transgenic trait in some lines.

The protein profile of cells of control somatic embryos was compared to that of embryos that have become selected and maintained on 200 mM NaCl in order to detect salt inducible proteins. Two proteins (60 and 51.5 kDa) were more abundant in the selected embryos and one protein with molecular mass 18 kDa was unique to the selected embryos. Enhanced content of 27 kDa protein was observed in all somatic embryos indicating its involvement in the embryonal state. Similar pattern of salt inducible proteins in selected somatic embryos and the plantlets regenerated from such embryos was found.

Ultrastructure of leaf mesophyll and two-layer trap wall of Utricularia vulgaris L. was studied after 24-h and 48-h treatment with different concentrations of cadmium. The treatment of plants with 0.25 g(Cd²⁺) m^-3 caused different changes in the chloroplasts of the two organs. The thylakoids swelled in chloroplasts of leaf and the starch content increased in chloroplasts of traps. Higher concentrations of Cd (0.5 and 1.5 g m^-3) caused osmiophilisation of thylakoids in the chloroplasts of both studied organs. The secretory cells in the trap wall was resistant to Cd.

Total chlorophyll (Chl) content, leaf mass per area (LMA), and net photosynthetic rate (P_N) were studied in four cultivars of mango (Mangifera indica L.) from September to May. Maximum Chl contents were found in September and December, the period considered to be crucial for flowering in mango. P_N was maximum during October and maintained almost steady during the fruit growth period. However, LMA varied significantly in all cultivars. Mean Chl content, P_N and LMA were lower in cv. Malaviyabhog than in other cultivars.

Treatment of excised marrow (Cucurbita pepo L., zucchini) cotyledons with methyl ester of jasmonic acid (MeJA) had no effect on their growth in darkness. On the other hand, MeJA induced the synthesis of three polypeptides (69, 60 and 43 kDa) and stimulated the accumulation of other polypeptides (97.4 and 53 kDa). These changes in the polypeptide profile were accompanied by a suppression of total protein and RNA synthesis as well as the activity of nuclear RNA polymerases. In contrast to MeJA, N⁶-benzylaminopurine (BAP) significantly enhanced cotyledon growth and stimulated protein and RNA synthesis. Furthermore, BAP, when applied together with MeJA, was able to counteract some effects of MeJA including the appearance of specific MeJA-induced polypeptide bands.

Root growth of Sinapis alba seedlings was used to determine the interactions (antagonism, synergism, and indifference) among Cu²⁺, Ni²⁺, Mo⁶⁺, Mn²⁺ and V⁵⁺ (each to each). For majority of combinations the antagonistic or indifferent effect was observed. The synergism was confirmed only between Ni and V, Mo and V, and Cu and V. V and Mn had reciprocal antagonistic effect each other, and Mn was like as Mo and Cu the antagonist to Ni. Molybdenum came up reciprocal indifference with regard to Cu and Mn, Mn and Ni did not influence unfavourable effect of Cu on S. alba root growth.

Shoots of Bacopa monniera exhibited 100 % regeneration on Murashige and Skoog medium with 2 % sucrose, 0.2 mg dm^-3 1-naphthaleneacetic acid, 0.5 mg dm^-3 6-benzylaminopurine and 50 mg dm^-3 glutamine. When the medium was supplied with various concentrations (5 - 15 g dm^-3) of sodium chloride, proline content in regenerants was six times higher than in the control. With increasing NaCl concentration photosynthetic rate decreased and fresh mass and root length of regenerants declined. NaCl also induced formation of new proteins.

The effect of indole-3-acetic acid (IAA) and gibberellic acid (GA₃) applications on parthenocarpic fruit set in Rosa canina and Diospyros lotus was investigated. GA₃ induced parthenocarpic fruit set in both plants, but IAA only in D. lotus. Maturation of seedless fruits was earlier than the seeded fruits. GA₃ caused a decrease in the fresh mass and size of both fruits. IAA induced an increase in the fresh mass and size in parthenocarpic fruit of D. lotus.

Growth and structural responses of primary roots of Zea mays L. to aluminium chloride were studied. The treatment of seedlings with 50 µM AlCl₃ resulted in high accumulation of Al, partial inhibition of root growth, occurrence of surface lesions in peripheral tissues, root thickening caused by expansion of inner cortical cells, reduced root cap length, extensive vacuolation, cell distortion, and increased synthesis of callose within 24 h.

The in vitro regeneration of three flax (Linum usitatissimum L.) breeding lines (cv. Jitka, cv. Areco and NLN 245) and selection of transgenic plants were studied. A. tumefaciens derived binary vector GV3101 (pPM90RK)(pPCVRN4) bearing tetramer of 35S promoter enhancer was used in transformation experiments. Following 3 weeks of cultivation on shoot inducing Murashige and Skoog agar medium containing BAP (0.1 µM) and NAA (0.005 µM) from 82.6 % to 98 % of hypocotyl segments formed shoots. While ticarcillin (500 mg dm^-3) used to eliminate Agrobacterium following the transformation decreased the organogenic response by about 10 % only, the addition of 20 mg dm^-3 hygromycin to ticarcillin efficiently suppressed the regeneration of untransformed control plants. To look up for genomic mutations caused by T-DNA insertion from Agrobacterium transformation or originated from somaclonal variation over 500 regenerated plants have been cloned, transferred into soil and evaluated especially for their morphological characteristics. Up to now among plants of cv. Areco-background at least 8 genotypes showed changes either in flower or filament and stigma colour and one clone of plants with pollen sterility was identified. Among fifty four plant clones evaluated in 7 clones the presence of transgene specific sequence hpt was detected and simultaneously Agrobacterium contamination of tissues was firmly excluded.

Micropropagation and Agrobacterium-mediated transformation were developed in Kalmia latifolia cv. Ostbo Red. The transformation of Kalmia latifolia plants was carried out by an Agrobacterium tumefaciens strain containing the nptII and gusA genes in its T-DNA. Shoots were regenerated on kanamycin selection medium and the expression of the gusA reporter gene was verified by fluorogenic β-glucuronidase (GUS) assay in a few vegetative generations after regeneration. The presence of the gusA gene in regenerated kanamycin resistant plants was detected by polymerase chain reaction.

The isolation and characterisation of cotyledonary ribonucleases (RNase; EC 3.1.27.1), are basic steps to understand the physiology and biochemistry of RNA turnover and mobilisation during seed germination and seedling establishment, as well as how environmental stresses affect them. RNase was isolated and purified 928-fold, to apparent electrophoretic homogeneity from 5-d-old seedlings of Vigna unguiculata. It is a protein with an apparent molecular mass of 16 kDa having three major isoforms. Its optimum pH is 5.8, which decreases to 5.2 in presence of KCl. It has an apparent K_m of 0.80 mg RNA cm^-3 and retains 40 % of its activity when heated to 80 °C. It is completely inhibited by Cu²⁺, Hg²⁺ and Zn²⁺ and is almost insensitive to Mg²⁺, Ca^2+- and EDTA. Urea, Fe²⁺, Co²⁺ and 2-mercaptoethanol partially inhibit its activity. Its amino acid composition shows a resem lance to that of other plant RNases.

An endopolygalacturonase (endo-PG), was purified from the culture medium of a local isolate of Sclerotinia sclerotiorum with ammonium sulphate precipitation, cation exchange chromatography and gel filtration. The purified endo-PG had a molecular mass of approximately 18 kDa estimated by gel filtration. The isoelectric point was determined by isoelectric focusing to be approximately 8, suggesting that PG II possesses a net positive charge at physiological pHs. The pH optimum for the enzyme was at pH 4.5. The endo-PG showed essentially the same affinity for pectin and polygalacturonic acid as substrates.

Exposure of Helianthus annuus L. seedlings to Al³⁺, Cd²⁺ or Zn²⁺ resulted in a marked decrease of fresh and dry masses of the shoots and the roots. The increase of Al³⁺, Cd²⁺ or Zn²⁺ uptake was accompanied by a significant decrease of nitrate, phosphorus and K⁺ uptake. There was a significant increase of malic and citric acid contents in the shoots and roots of heavy metal-treated seedlings whereas the change in fumaric acid was insignificant. Al³⁺ and Zn²⁺ alone stimulated excretion of malic and citric acids to the rhizosphere. Addition of high concentrations of malic or citric acid alleviate to some extent the inhibitory effect of Al³⁺ and Zn²⁺ on plant growth.

The responses of Brassica juncea cv. Pusa Bold to elevated CO₂ was studied under water stress. Carbon accumulation in leaves, stem and roots was significantly higher at elevated CO₂ concentration. The water stress decreased the carbon content in these plant parts and this adverse effect was reduced by CO₂ enrichment. On the contrary nitrogen content of leaves, stem and roots was significantly reduced at elevated CO₂. Water stress caused reduction in nitrogen content in these plant parts, similar at ambient as well as elevated CO₂ concentration.

The influence of phosphate deficiency on the sugar accumulation and sugar partitioning in the root cells of bean (Phaseolus vulgaris L.) was studied. Bean plants were cultured 17 - 19 d on a phosphate-sufficient and phosphate-deficient nutrient medium. Phosphate deficit in the growth medium resulted in increased sugar concentration for about 30 % in the apoplastic and cytoplasmic compartments as well as in the vacuoles of root cells. However, the distribution of sugars between apoplast and cytoplasm compartment and vacuole was not affected by decreased phosphate concentration. About 20 % of sugars were found in the apoplast and cytoplasm, about 80 % in the vacuole. Low phosphate concentration enhanced influx of exogenous ¹⁴C-sucrose into meristematic and elongation zones of root. The ¹⁴C-labelled sugar content in the root tips increased for about 60 % as compared to control plants. Phosphate deficiency increased also ¹⁴C-glucose uptake and content in the root tips. However, the amount of ¹⁴CO₂ liberated during respiration of P-deficient roots (after feeding with uniformly labelled ¹⁴C-glucose) was lower than ¹⁴CO₂ respired by control plants, thus a large part of accumulated sugars seems to be metabolically inactive.

This paper describes the effect of agar, MS basal medium strength, sucrose and polyamines on the in vitro rooting of Syzygium alternifolium realized by a two step procedure involving root initiation (RI) and root elongation (RE). RI was carried out on solidified MS medium supplemented with 1.0 mg dm^-3 indole-3-butyric acid (IBA) for 3 weeks, and RE following transfer to half-strength MS medium devoid of growth regulators for another 3 weeks. Agar and MS basal medium concentrations played important role on rooting response as well as on health of rooted shoots. Sucrose concentration was positively correlated with the rooting percentage, root number per shoot and root length. The combination of polyamines and 1.0 mg dm^-3 IBA increases rooting percentage compared to media containing only 1.0 mg dm^-3 IBA. Optimum rooting was attained with half-strength MS medium containing 1.0 mg dm^-3 IBA, 2 % sucrose, 10 µM spermine and 0.8 % agar.

Eight-day-old bean plants, grown in a nutrient solution, were sprayed with 10^-5, 10^-4, 10^-3, and 10^-2 M atrazine. The lipid changes in primary and trifoliate leaves were studied 6 d after the herbicide application. The atrazine treatment inhibited the growth of the trifoliate leaves, and decreased photosynthetic and transpiration rates, the stomatal conductance, and the total lipid content. Atrazine treatment increased 16:0 and 18:3 acids and decreased trans-3-hexadecenoic and 18:2 acids in the phospholipids. The herbicide also increased 16:0 and 18:1 acids in glycolipids and decreased 18:3 acid in monogalactosyl diacylglycerols and digalactosyl diacylglycerols. In most cases the marked changes in fatty acid composition of the main lipid classes were observed at 10^-4 and 10^-3 M atrazine.

To induce somatic embryogenesis in Quercus robur L. immature zygotic embryos at different developmental stages were collected in weekly intervals from June until September in three consecutive years from four open pollinated trees at two Vienna sites. Acorns were surface sterilised and cultured firstly on P24 medium with 5μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 μM 6-benzylaminopurine (BAP) or on hormone-free P24 medium and secondly on P24 medium with 0.9 μM BAP. The formation of white-yellow globular structures of somatic embryos started during the fourth week after the induction treatment. High induction frequencies of 30 - 80 % were achieved on 2,4-D/BAP medium, whereas rates on hormone-free medium were below 20 %. The initiation of somatic embryogenesis was favoured in the heartshaped and early cotyledonary stage of the zygotic embryo in all three years and lasted until the acorns reached maximum size in August.

Previous results with potato tuber discs showed that a treatment with abscisic acid stimulated K⁺ uptake. In this investigation, we determine the relationship between increased K' uptake and H⁺extrusion, and Ca²⁺ fluxes by treating tissues with specific Ca²⁺ channel blocker (La³⁺), calmodulin (CaM) inhibitors (chlorpromazine and W₇), and with Ca²⁺ ionophore (A23187). K⁺ uptake increased with increasing external pH whether tissues were treated with ABA or not. Treatment of tissues with La³⁺ inhibited K⁺ uptake, whereas CaM inhibitors have no effect. By contrast ABA and A23187 produced a synergistic effect, suggesting that ABA may act in part, on K⁺ uptake, like a Ca²⁺ agonist, in accord with Huddart's hypothesis.

Whole sugar beet (Beta vulgaris L. cv. Ras poly) plants were grown in the greenhouse from the same seed stock used for an in vitro shoot tip culture. In vitro produced sugar beet plants exhibited a high content of chlorophylls a and b, carotene, and total and soluble sugars. On the other hand, total protein content of in vivo plants was higher than that of in vitro plants. No differences were found by SDS-PAGE analysis in the nature and contents of soluble proteins of in vitro propagated plants and greenhouse-grown plants. Surfaces of epidermal cells were larger and palisade and spongy paranchyma tissues were thicker in leaves of regenerants than in leaves of seedlings. Vascular tissues in leaf petioles in regenerants were flat and more differentiated than in seedlings. Closed and undeveloped stomata were found on the abaxial leaf surface of regenerants, whereas in seedlings the stomata were open.

The effects of 1 mM cadmium, lead and nickel on dry mass, Cd, Pb, and Ni contents, and changes in leaf structure in young wheat plants were studied. In leaves, Cd content was highest, followed by Pb and Ni, in roots Cd content was also highest, but followed by Ni and Pb. Roots accumulated considerably larger amounts of the three heavy metals than leaves. Largest reductions of leaf and root mass were obtained with Cd. Pb and Ni effects were almost equal. Ni excess had a strong negative effect on mesophyll thickness, while Cd mostly reduced the number and size of vascular bundles and vessel diameter. High Pb reduced the diameter of vessels causing their different deformations.

New modifications of the method for pea starch and amylose/amylopectin analysis were tested with small samples size of smooth and wrinkled peas. The milling process of the sample and preliminary extraction with 40 % ethanol were very important and affected markedly the standard deviation.

Activities of alcohol dehydrogenase, hexokinase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase were significantly inhibited by cadmium in germinating pea (Pisum sativum L. cv. Bonneville) seeds. The effect was concentration dependent in the range of 0.25 to 1.0 mM CdCl₂. The magnitude of detrimental effect on these enzymes was reduced during later stage of germination (9 d) largely because of fall in the activities of these enzymes in the control seeds germinated in water. In vitro, activities of hexokinase, glucose-6-phosphate dehydrogenase, and alcohol dehydrogenase were inhibited at 0.5 mM Cd²⁺ in the reaction mixture by 62, 67, and 36 %, respectively, however, 6-phosphogluconate dehydrogenase was insensitive to Cd²⁺.

The effect of acute ozone exposure on the stomatal conductance and leaf water content during rapid desiccation was examined in leaves of two tobacco cultivars, ozone sensitive cv. BelW3 and ozone tolerant cv. Samsun. The relative rate of stomatal closure was constant during leaf desiccation in cv. Samsun but decreased in cv. BelW3 in both ozonated and control plants. Ozone exposure increased the relative rate of stomatal closure and transpiration rate (measured on the following day) in cv. Samsun, but reduced the respective parameters in cv. BelW3. As a result, the plants of ozone-sensitive cultivar, treated with ozone, lost more water during desiccation than control plants.