Protoplasts isolated from wild cotton Gossypium davidsonii were cultured in KM₈P medium supplemented with different phytohormones. The most effective combination was 0.45 µM 2,4-dichlorophenoxyacetic acid, 2.68 µM α-naphthaleneacetic acid and 0.93 µM kinetin and the division percentage at the 8^th day was 30.78 ± 3.04 %. The density of protoplasts at 2-10 × 10⁵ cm^-3 was suitable for protoplast division and calli formation, with a division percentage of 32.21 ± 3.64 % and a plating efficiency of 9.12 ± 2.61 % at the 40^th day. The optimal osmotic potential was achieved using 0.5 M glucose or 0.1 M glucose plus 0.5 M mannitol. Protoplasts were cultured in three ways, a double-layer culture system, with liquid over solid medium was proved to be the best way. Embryo induction was further increased by addition of 0.14 µM gibberellic acid.

Cd accumulation, its effects on elongation growth of maize coleoptile segments, pH changes of their incubation medium and the membrane potential of parenchymal cells were studied. The Cd content increased significantly with exposure to increasing cadmium concentrations. Coleoptile segments accumulated the metal more efficiently in the range 10-100 µM Cd, than in the range 100-1000 µM Cd. Cd at concentrations higher than 1.0 µM produced a significant inhibition of both growth and proton extrusion. 100 µM Cd caused depolarization of the plasma membrane (PM) potential in parenchymal cells. The simultaneous treatment of maize coleoptile segments by indole-3-acetic acid (IAA) and Cd, counteracted the toxic effect of Cd on growth. Moreover, our data also showed that 100 µM Cd suppressed the characteristic IAA-induced hyperpolarization of the membrane potential, causing membrane depolarization. These results indicate that the toxic effect of Cd on growth of maize coleoptile segments might be, at least in part, caused via reduced PM H⁺-ATPase activity.

The present paper reports a protocol for minimum growth conservation of Drosophyllum lusitanicum (L.) Link. in vitro. Double-node cuttings were maintained for 4, 8 and 12 months at 5 or 25 °C in the dark. The effects of sucrose either alone at 5, 20, 30, 40 and 60 g dm^-3 or at 20, 40 and 60 g dm^-3 in combination with 20 g dm^-3 mannitol, on survival and post-storage shoot multiplication efficiency were investigated. The cultures could effectively be conserved under minimum growth at 5 °C for 8 months on Murashige and Skoog's medium supplemented with 60 g dm^-3 sucrose, 20 g dm^-3 mannitol and 0.91 µM zeatin. Following extended conservation, the cultures could be successfully regenerated into new shoots, and they were morphologically similar to those of non-stored controls.

Deposition pattern of hydrogen peroxide (H₂O₂) under salt stress (100 mM NaCl) was examined cytochemically in rice (Oryza sativa L. cv. Pokkali) through the reaction of H₂O₂ with cerium chloride (CeCl₃) to produce electron dense precipitates of cerium perhydroxide. The distribution pattern of cerium perhydroxide precipitates in leaf sheath was considerably different from other parts of rice under salinity stress. Cerium perhydroxide precipitates were mainly accumulated on the tonoplast of leaf sheath under salinity, although they were localized on the cell wall and plasma membrane in all other tissues such as leaf blade and root.

Sunflower plants were transformed via co-cultivation of previously bombarded hypocotyl explants with Agrobacterium tumefaciens harboring the plasmid pNGL that contains the human lysozyme gene. The transformed shoots were selected using kanamycin and regenerated plants were analyzed using histochemical β-glucuronidase assay. Southern, Western and Northern blot analyses indicated the transfer, expression and stable integration of the foreign DNA into the sunflower genome. Resistance against the phytopathogenic fungus Sclerotinia sclerotiorum, which causes white mold disease, was confirmed using a phytopathogenic test and microscopic observation of the infection process.

Cassia auriculata L. seedlings were irradiated with ultraviolet B (UV-B) in an environment-control chamber. The two doses assayed (7.5 and 15.0 kJ m^-2) induced oxidative damage with an increase in lipid peroxidation and hydrogen peroxide and a decrease in chlorophyll and total phenol contents. The ascorbate and dehydroascorbate content as well as the reduced glutathione/oxidized glutathione content and ratio were significantly increased. The UV-B stress led to significant increases of the activity of superoxide dismutase, catalase, peroxidase and polyphenol oxidase. It is suggested that Cassia seedlings try to counteract high concentrations of oxygen species produced under UV-B stress through a co-ordinated increase in the contents and activities of antioxidants involved in their detoxification.

Embryogenesis and plant regeneration was achieved from callus cultures derived from unpollinated ovaries of Psoralea corylifolia L. Callus was initiated from unpollinated ovaries on Murashige and Skoog (MS) medium supplemented with 2.2 µM N ⁶-benzyladenine (BA) and various concentrations of α-naphthaleneacetic acid (NAA (2.7 to 10.7 µM) or 2,4-dichlorophenoxyacetic acid (2,4-D (2.3 to 9 µM) alone or in combination. Highly organized embryogenic callus induction, embryo development, proliferation and maturation were achieved on transfer of callus clumps to MS medium supplemented with NAA (0.27 µM) or 2,4-D (0.23 µM) alone or in combination with BA (2.2 to 8.8 µM). Addition of abscisic acid (ABA) (0.95 to 5.8 µM) to the medium enhanced average numbers of cotyledonary stage embryos, the maximum number (34.6 ± 0.7) being obtained on MS medium containing 0.27 µM NAA, 2.2 µM BA and 3.8 µM ABA. Embryos germinated on MS medium supplemented with BA (0 to 8.8 µM). MS medium containing gibberellic acid (GA₃ (0.29 to 5.8 µM) enhanced embryo germination frequency, the highest frequency (66.7 %) occurring on MS medium containing 2.2 µM BA and 4.3 µM GA₃. Effect of several concentrations (3.0 to 6.0 %) of sucrose or maltose was also observed on germination of embryos. MS medium enriched with maltose supported high frequency of embryo germination.

Plant enzymes participating in degradation of nitroaromatic compounds have not been biochemically characterized in details so far. From suspension culture of soapwort (Saponaria officinalis L.) we isolated a novel plant oxidoreductase involved in degradation of trinitrotoluene (TNT). The enzyme catalyses first steps of reduction of TNT nitro groups in the presence of NAD(P)H under anaerobic conditions. The enzyme is monomeric with molecular mass 29 kDa, its two isoforms have pI 4.8 and 5.1. According to the spectral and activation analysis the enzyme contains flavinmono-nucleotide as a prosthetic group. The structure properties suggest an evolutional relationship to oxophytodienoate reductase. The N-terminal amino acid sequence shows homology to family of Old Yellow Enzyme (E.C. 1.6.99.1).

The influence of different sugars (sucrose, maltose, glucose and fructose, 0.05-0.5 M) on embryogenesis and plant regeneration from cultured anthers of niger [Guizotia abyssinica (L. f.) Cass.] have been studied. Among the different sugars tested, 0.2 M sucrose was the best for embryo induction and plant regeneration. Maximum of 57 embryos per 60 anthers were induced on embryo induction medium [Gamborg's B5 medium supplemented with 10 µM 2,4-dichlorophenoxyacetic acid (2,4-D), 2 µM kinetin (KIN)] containing 0.2 M sucrose. Embryo differentiation was achieved on B5 medium supplemented with 0.5 µM benzyladenine (BA) and 0.09 M sucrose. Embryo maturation was on B5 medium containing 10 µM abscisic acid (ABA) and 0.09 M sucrose. Embryo germination was achieved on B5 medium with 0.09 M sucrose. Embryos that were developed on B5 medium supplemented with 0.2 M sucrose showed highest frequency (68 %) of plant regeneration.

The regulatory properties of NADH-dependent nitrate reductase (NR) in desalted root extracts from hydroponically grown cucumber (Cucumis sativus L.) seedlings were examined. The lowest activity of NR was detected in extracts incubated with Mg²⁺ and ATP. An inhibitory effect of Mg-ATP was cancelled in the presence of staurosporine (the protein kinase inhibitor) and completely reversed after addition of ethylenediaminetetraacetate (EDTA) as well as AMP into reaction mixture. Reactivation of enzyme due to AMP presence, contrary to the chelator-dependent NR activation, was sensitive to microcystin LR (the protein phosphatase inhibitor). Above results indicated that the nitrate reductase in cucumber roots was regulated through reversible phosphorylation of enzyme protein. A drop in the activity of NR was also observed after incubation of enzyme at low pH. At low pH, the presence of ATP alone in the incubation medium was sufficient to inactivate NR, indicating that H⁺ can substitute the Mg²⁺ in formation of an inactive complex of enzyme. ATP-dependent inactivation of NR at low pH was prevented by staurosporine and reversed by AMP. However, AMP action was not altered by microcystin LR suggesting that in low pH the nucleotide induced reactivation of NR is not limited to the protein phosphorylation.

Genetic diversity was estimated in 13 accessions of the otherwise self pollinated Mucuna pruriens (L.) DC. (velvetbean) comprising varieties pruriens and utilis collected from tropical humid forest using 15 RAPD primers. Similarity index value of 0.68 based on Nei and Li's similarity coefficient indicated high degree of genetic variability. Analysis of various genetic diversity indices like total heterozygosity, Nei's gene diversity, percentage of polymorphic loci, expected and observed number of alleles and Shannon index strongly suggests that variety pruriens is genetically more diverse than variety utilis. Chemical analysis with respect to 3,4-dihydroxy-L-phenylalanine (L-DOPA) content showed uniform distribution. Cluster analysis showed grouping of accessions into two major clusters and tendency of accessions of variety pruriens to group according to their geographical locations. Bootstrap analysis confirmed the robustness of the phenogram. The putative hybrid MMP6 with relatively low similarity value index and low L-DOPA content was promising as food or fodder.

A cDNA encoding a putative translationally controlled tumor protein (TCTP) was isolated from a cDNA library made with mRNA isolated from red ripe strawberry fruits. This protein is highly conserved in all species analyzed. Expression of strawberry TCTP increased along the ripening of strawberry fruits, and is constitutively expressed in vegetative tissues. The putative function of this protein remains still unknown

Procedures were developed for flow cytometric analysis and sorting of mitotic chromosomes (flow cytogenetics) of common vetch (Vicia sativa L., 2n=12). Suspensions of intact chromosomes were prepared from root tips after cell cycle synchronization, formaldehyde fixation, and mechanical homogenization. On average, 3 × 10⁵ morphologically intact chromosomes could be isolated from 25 root tips. Flow cytometric analysis of DAPI-stained chromosomes resulted in histograms of relative fluorescence intensity (flow karyotypes) containing four peaks, representing particular chromosomes and/or pairs of chromosomes with similar relative DNA content. Peaks I and II were assigned to chromosomes 6 and 5, respectively. These chromosomes could be sorted with a purity exceeding 90 %. The two remaining peaks on the flow karyotype were composite, each of them representing a pair of chromosomes. Chromosomes 1 and 3 were assigned to composite peak III while chromosomes 2 and 4 were assigned to composite peak IV. The chromosomes could be sorted with a purity of 99 % from both composite peaks. Bivariate flow karyotyping after simultaneous staining of chromosomes with DAPI and mithramycin was not found helpful in discriminating additional chromosomes. This study extends the number of legume species for which flow cytogenetics is available and provides a new tool for targeted and effective analysis and mapping of common vetch genome.

Quantitative trait loci (QTLs) for Cu-tolerance were determined in wheat grown in control and Cu-treated soil in greenhouse. In addition, loci having an influence on the shoot Cu-, Fe-, Mn-and Zn-contents under non-stressed and Cu-stressed environments were mapped. One major QTL for Cu-tolerance was found on chromosome 5DL, while slighter effects were determined on the chromosomes 1AL, 2DS, 4AL, 5BL and 7DS. QTLs affecting the shoot Mn-and Zn-contents were found on the chromosomes 3BL and 3AL, respectively. The centromeric region on the chromosome 3B plays a role in the regulation of the shoot Fe-contents in the stressed plants. Under Cu-stress QTL affecting shoot Cu-content was found on chromosome 1BL, while on the chromosome 5AL a QTL influencing the Cu-accumulation ability of wheat from Cu-polluted soil was determined.

The influence of sugars and growth regulators on shoot and root growth of Dactylorhiza species was studied under in vitro conditions. The seedling development was stimulated with the application of glucose and sucrose at concentration of 10 g dm^-3 each. The improvement of shoot growth rate and shoot length was enhanced by cytokinins N ⁶-(2-isopentenyl)adenine or N ⁶-benzyladenine and their combination with auxin indolebutyric acid (IBA). The root growth rate and root length of seedlings increased in the presence of IBA and α-naphthaleneacetic acid. Individual Dactylorhiza species showed statistically significant differences in shoot and root development depending on sugar and growth regulator combinations.

The effect of 24-epibrassinolide (BR₂₇) on cold resistance of rape seedlings was studied by ion leakage and photosynthetic pigment degradation measurements. Aqueous solutions of BR₂₇ were injected into cotyledons or primary leaves of rape plants and these plants were incubated at 2 °C or 20 °C. Cold treatment (2 °C) without BR₂₇ injection elevated the membrane permeability in both primary leaves and cotyledons significantly. Surprisingly, injection of leaves with water or 0.467 % aqueous ethanol solution led to a massive increase in membrane permeability after cold stress at 2 °C. The synergistic effect of leaf infiltration and cold on permeability was abolished by 0.05 and 1.00 µM of BR₂₇ in primary leaves and by 1.00 µM of BR₂₇ in cotyledons. On the other hand, BR₂₇ solutions strongly elevated the membrane permeability at 20 °C, while water and ethanol solutions brought about only negligible increases. Water or ethanol infiltrations strongly reduced the leaf contents of chlorophyll (Chl) a, Chl b and carotenoids at 2 °C but less markedly at 20 °C. However, in seedlings exposed to 2 °C pigments content was significantly higher in BR₂₇-treated leaves as compared to water/ethanol control. There were no differences between pigment contents of leaves injected with BR₂₇ solutions or only water/ethanol at 20 °C. The above data strongly support the stress protecting effect of BR₂₇.

Young plants of a rhizomatous grass Calamagrostis epigejos (L.) Roth were grown from seed in nutrient solutions containing nitrogen in concentrations 0.1, 1.0, and 10 mM. After six weeks of cultivation the plants were defoliated and changes in growth parameters and in content of storage compounds were measured in the course of regrowth under highly reduced nitrogen availability. Plants grown at higher nitrogen supply before defoliation had higher amount of all types of nitrogen storage compounds (nitrates, free amino acids, soluble proteins), which was beneficial for their regrowth rate, in spite of lower content of storage saccharides. Amino acids and soluble proteins from roots and stubble bases were the most important sources of storage compounds for regrowth of the shoot. Faster growth of plants with higher N content was mediated by greater leaf area expansion and greater number of leaves. In plants with lower contents of N compounds number of green leaves decreased after defoliation significantly and senescing leaves presumably served as N source for other growing organs. Results suggest that internal N reserves can support regrowth of plants after defoliation even under fluctuating external N availability. Faster regrowth of C. epigejos with more reserves was mediated mainly by changes in plant morphogenesis.

DNA content was estimated by flow cytometry in seedlings and in vitro clones of six species: Oenothera paradoxa, Inula verbascifolia ssp. aschersoniana, Rubus chamaemorus, Solidago virgaurea, S. graminifolia and Pueraria lobata. With the exception of P. lobata, there was no difference in genome sizes between seedlings and in vitro cultured plants from any species, indicative that they maintain their genetic stability during in vitro culture. This confirms the usefulness of tissue culture for production of certified plant material to obtain herbal medicines.

The effects of 100 and 200 µM methyl jasmonate (MJA) on cell proliferation and paclitaxel and baccatin III production were investigated in free and alginate immobilized cells of Taxus baccata growing in a selected product formation culture medium. The greatest accumulation of paclitaxel (13.20 mg dm^-3) and baccatin III (4.62 mg dm^-3) occurred when 100 µM MJA was added to the culture medium of cells entrapped using a 1.5 and 2.5 % alginate solution. The effects of different treatments on the viability of cultured cells and their capacity to excrete both taxanes into the surrounding medium were considered.

The endosperms of Carthamus tinctorius cv. HUS-305, excised at globular to heart-shaped stages of zygotic embryo development, were cultured on Murashige and Skoog's medium (MS) supplemented with different concentrations of 6-benzylaminopurine (BAP), kinetin, thidiazuron (TDZ), 2,4-dichlorophenoxyacetic acid (2,4-D) or α-naphthalene-acetic acid (NAA). The highest incidence of callusing was on 2,4-D supplemented media. However, embryos differentiated only from the calli developed on media supplemented with BAP, kinetin or TDZ with the last eliciting maximum embryogenic response. The addition of a reduced nitrogen source, casein hydrolysate to MS medium supplemented with BAP and/or NAA, did not stimulate the response. However, adenine sulphate (100 mg dm^-3) promoted the induction of somatic embryos. Upon transfer to MS basal medium or the same supplemented with 0.61 µM gibberellic acid (GA₃), plumular poles of few embryos elongated resulting in the development of shoots.

High efficiency shoot regeneration was achieved through leaflet and cotyledon derived calli in Cassia angustifolia - an important medicinal plant. Dark brown compact callus was induced at the cut ends of the explants on Murashige and Skoog's (MS) medium augmented with 1 µM N⁶-benzyladenine (BA) + 1 µM 2,4-dichlorophenoxyacetic acid (2,4-D). Such callus pieces on transfer to cytokinins (BA or kinetin) supplemented medium differentiated shoots within 10 - 15 d. Of the two cytokinins, 5 µM BA was optimum for eliciting morphogenic response in 83.33 and 70.83 % cultures with an average of 4.16 ± 0.47 and 3.70 ± 0.56 shoots in cotyledon and leaflet derived calli, respectively. The addition of 0.5 µM α-naphthaleneacetic acid (NAA) to MS + 5 µM BA further elevated the maximum average number of shoots to 12.08 ± 1.04 and 5.37 ± 0.52 for cotyledon and leaflet calli, respectively. The excised shoots were transferred to a rooting medium containing either IAA (indole-3-acetic acid), IBA (indole-3-butyric acid) or NAA. Nearly 95 % shoots developed an average of 5.4 ± 0.41 roots on half strength MS medium supplemented with 10 µM IBA.

Multiple shoot buds could be induced directly from internode explants of Celastrus paniculatus inoculated on Murashige and Skoog's (MS) medium containing different growth regulators. The best response was obtained when 4.44 μM 6-benzylaminopurine (BAP) was incorporated in the medium. Incorporation of indole-3-acetic acid (IAA) and α-naphthalene acetic acid (NAA) did not improve response, rather promoted callusing. Adventitious shoot buds could be multiplied and elongated on MS medium containing 2.22 μM BAP. Rooting of shoots (80 %) was obtained when their bases were dipped in pre-autoclaved indole-3-butyric acid (IBA) solution (2.45 mM) for 10 min followed by their implantation on medium containing 1/4 MS salts, 1.0 % sucrose and 0.6 % agar. Out of 500 plantlets subjected to hardening, 410 were successfully hardened under greenhouse conditions. Twenty plants were established in field while remaining of them were transferred to nursery conditions without any mortality.

The effects of drought on growth, protein content, lipid peroxidation, superoxide dismutase (SOD), peroxidase (POX), catalase (CAT) and polyphenol oxidase (PPO) were studied in leaves and roots of Sesamum indicum L. cvs. Darab 14 and Yekta. Four weeks after sowing, plants were grown under soil moisture corresponding to 100, 75, 50 and 25 % field capacity for next four weeks. Fresh and dry masses, and total protein content in leaves and roots decreased obviously under drought. However, several new proteins appeared and content of some proteins was affected. Measurement of malondialdehyde content in leaves and roots showed that lipid peroxidation was lower in Yekta than in Darab 14. Severe stress increased SOD, POX, CAT and PPO activities in leaves and roots, especially in Yekta. According to the present study Yekta is more resistant to drought than Darab 14.

Changes in dry matter accumulation and allocation, abscisic acid content and carbon isotope composition of three wheat cultivars from dry, middle and wet climate regions were recorded at full maturity after exposure to different watering regimes (100, 50 and 25 % field capacity). Compared with the wet climate cultivar, the dry climate cultivar showed lower stem height, total leaf area, total dry biomass and total grain dry mass, and higher root/shoot ratio, abscisic acid content and carbon isotope composition under all watering regimes. Both water-limited treatments significantly reduced leaf growth and increased dry matter allocation into the roots leading to a significant raise of root/shoot ratio in all cultivars tested. In addition, drought affected morphological and physiological properties more in the dry climate cultivar than in the wet climate cultivar.

Histidine-containing phosphotransmitters (AHPs) transfer a phosphoryl group from membrane receptors to effectors in the nucleus. Five AHP genes have been identified in Arabidopsis. Real-time reverse transcription polymerase chain reaction (RT-PCR) was employed to quantify contents of individual transcripts in Arabidopsis leaves, roots, stems, flowers and siliques. High organ specificity of gene expression was found in AHP1, AHP2, AHP4 while expression of AHP3 and AHP5 appears more ubiquitous. We detected two AHP5 specific PCR products (AHP5 and AHP5L). Out of the five AHP5 introns, the second one was retained unspliced in the longer product (AHP5L) while AHP5 corresponded to a completely spliced AHP5 mRNA. The ratio between alternately and completely spliced AHP5 mRNAs was highest in flowers and lowest in siliques and stems. No evidence for alternative splicing in the remaining AHP transcripts was found. Two open reading frames were identified in AHP5L. The conserved part of the phosphotransfer domain remains unaffected in the longer one as the translation initiation at an intron ATG would result in a polypeptide coded by exons 3 to 6 and a short extension encoded by the intron part of the alternative open reading frame. However, the isoelectric point would shift by about 3 units towards neutral.

Transgenic rice plants in which the content of dienoic fatty acids was increased as a result of co-suppression of fatty acid desaturase were more tolerant to high temperatures than untransformed wild-type plants, as judged by growth rate and chlorophyll content. When untransformed wild-type and transgenic rice seedlings were incubated at 35 °C, seedlings of the transgenic rice lines showed approximately 1.6 and 2.1 times the growth of untransformed wild-type seedlings, as assayed by shoot and root mass, respectively. The chlorophyll content of the transgenic leaves after 9 d at 35 °C was also higher than that of wild-type rice. The maximum photochemical efficiency of photosystem 2 was also higher in transgenic plants than in wild-type plants upon high temperature stress.