Using different explants of in vitro seed grown Scutellaria baicalensis Georgi plantlets, hairy roots were induced following inoculation of Agrobacterium rhizogenes strains A₄GUS, R1000 LBA 9402 and ATCC11325. The A₄GUS proved to be more competent than other strains and the highest transformation rates were observed in cotyledonary leaf explant (42.6 %). The transformed roots appeared after 15-20 d of incubation on hormone free Murashige and Skoog medium. Growth of hairy roots was assessed on the basis of total root elongation, lateral root density and biomass accumulation. Maximum growth rate was recorded in root:medium ratio 1:100 (m/v). Hairy root lines were further established in Gamborg B₅ medium and the biomass increase was maximum from 15 to 30 d. PCR, Southern hybridization and RT-PCR confirmed integration and expression of left and right termini-linked Ri T-DNA fragment of the Ri plasmid from A₄GUS into the genome of Scutellaria baicalensis hairy roots. GUS assay was also performed for further integration and expression. All the clones showed higher growth rate them non-transformed root and accumulated considerable amounts of the root-specific flavonoids. Baicalin content was 14.1-30.0 % of dry root mass which was significantly higher then that of control field grown roots (18 %). The wogonin content varies from 0.08 to 0.18 % among the hairy root clones which was also higher than in non-transformed roots (0.07 %).

The leaf structure and chloroplast ultrastructure of kidney tea (Orthosiphon stamineus Benth.) was studied in in vitro culture on standard MS medium supplemented with or without plant growth regulators (PGRs). The cytokinin N⁶-benzyladenine (BA) negatively affected the structure of the palisade parenchyma and chloroplast ultrastructure and increased the stomatal frequency of the adaxial epidermis. The auxin indole-3-butyric acid (IBA) did not modify the morphology of regenerated leaf tissues as well as the chloroplast ultrastructure. The effect of both PGRs applied in combination was manifested in well-differentiated mesophyll parenchyma, typical chloroplast ultrastructure and increased stomatal frequency on both leaf surfaces. This protocol can be suggested for further ex vitro propagation.

Transgenic Podophyllum peltatum plants were successfully produced by Agrobacterium tumefaciens-mediated transformation. Embryogenic callus was co-cultivated with Agrobacterium tumefaciens harboring a binary vector pBI 121 carrying β-glucuronidase (GUS) and neomycinphosphotransferase (NPT II) gene. GUS-histochemical analysis revealed that, 50 µM acetosyringone treatments during Agrobacterium infection and 3 d co-cultivation with Agrobacterium showed enhanced transformation efficiency. Percentage of GUS positive callus increased rapidly as the subculture time proceeded on selection medium containing 100 mg dm^-3 kanamycin. Kanamycin resistant somatic embryos were formed from embryogenic callus after cultivation with 11.35 µM abscisic acid (ABA) for 3 weeks and then on hormone-free selection medium. Somatic embryos were germinated and converted into plantlets on medium containing 2.89 µM gibberellic acid (GA₃). The integration of GUS and NPT II gene into transgenic plants was confirmed by polymerase chain reaction and Southern analysis.

ALBINO3, a homologue of PPF1 in Arabidopsis, encodes a chloroplast protein, and is essential for chloroplast differentiation. In the present study, ALBINO3(-) transgenic plants exhibited a significant decrease in both the number of rosette leaves at bolting and the days before bolting, suggesting the important roles of ALBINO3 in regulating flowering during non-inductive short-day photoperiods. ALBINO3 mRNA was apparently accumulated in shoot apical meristem and floral meristems around the shoot apical meristem in wild-type plants. ALBINO3 might be predominantly involved in inducing the floral repression pathway by activating the expression of TFL1, and by suppressing the expression of LFY, respectively, in the shoot apical meristem. Moreover, the function of ALBINO3 in regulating flowering transition depended on the expression of CO and GA1, because ALBINO3 might function in the downstream integration of the photoperiod-dependent and the photoperiod-independent pathways. These results suggest that ALBINO3 may have an important integrative function in the flowering process in Arabidopsis.

Tocopherol cyclase (TC, encoded by gene VTE1) catalyzes the penultimate step of tocopherol synthesis. In this study we used wild type and transgenic tobacco plants overexpressing VTE1 from Arabidopsis to examine the role of tocopherol in ozone sensitivity. Wild type plants responded to an 4-h exposure to 300 nmol mol^-1 ozone by severe leaf necrosis while the transgenic lines exhibited limited injury. Compared with the wild type, VTE1-overexpressing plants had lower increase in hydrogen peroxide, malondialdehyde contents and ion leakage, and lower decrease of net photosynthetic rate 48 h following the ozone exposure. Transgenic plants also better maintained the structural integrity of the photosynthetic apparatus.

Morphological, physiological, fruit yield and quality related traits were compared between the seed-grown and tissue-cultured plants of tomato (Lycopersicon esculentum Mill.) cv. Red Coat in a greenhouse. No significant differences were observed for any of the traits studied except for the number of leaves and branches, which were higher in the seed-grown plants than in tissue-cultured plants at the later stages of growth. No phenotypic abnormality of the tissue-cultured plants was observed suggesting that genetic fidelity of tissue cultured plants can be maintained if appropriate plant growth regulators are used with fewer member of subcultures in the multiplication medium.

Comparative studies on rooting and growth performance of cuttings raised from in vitro and in vivo grown plants of Rosa damascena are described. Cuttings were treated with different auxins and upon transfer to soil their growth performance was recorded. Overall, the auxin treated cuttings of in vitro raised plants responded better than the cuttings of in vivo raised plants. Optimal response for percentage of rooting, root number, root length and bottom breaks was observed at 100 mg dm^-3 IBA. The cuttings derived from in vitro raised plants showed a significantly better response for percent rooting, root number, root length and bottom buds in control treatments.

For expression of MRJP1 - the most abundant protein of honeybee royal jelly - in plants, plasmid carrying the expression cassette composed of CaMV 35S RNA promoter, cDNA encoding MRJP1 with its native signal peptide, and nos3' as transcription terminator in binary vector pBin19 was prepared. The plasmid was introduced into tobacco (Nicotiana tabacum L. cv. Wi38) plants by Agrobacterium tumefaciens-mediated transformation. Transgenic F₁ and F₂ generation was grown from the seeds of the primary obtained transgenic tobacco plants. Immunoblot analyses of protein leaf extracts from transgenic plants showed expression of MRJP1.

Utilizing either Agrobacterium-mediated transformation or particle bombardment we obtained transgenic soybean [Glycine max (L.) Merr.] plants expressing the chitinase gene (chi) and the barley ribosome-inactivating protein gene (rip). Six regenerated plants were grown to maturity and set seed. The identification of transgenic soybean plants that co-integrated the two anti-fungal protein genes was determined by polymerase chain reaction (PCR) and Southern blot analysis. Protein detection from the soybean leaves demonstrated the expression of the chitinase (CHI) and the ribosome-inactivating protein (RIP) in the six R₀ transformants. Soybean cotyledonary nodes were transformed using the bivalent plant expression vector pBRC containing chi and rip both driven by the CaMV 35S double promoter. Following vacuum (0.06 MPa) infiltration treatment of the tissue for 5 min, Agrobacterium was co-cultivated with the cotyledonary nodes for 3 d on MSB medium (MS salts and B₅ vitamins) (pH 5.2), the transformation frequency reached a maximum of 1.33 %. The chi and rip genes were present in all the transgenic plants. Co-bombardment of immature cotyledons with plasmids pBchE (encoding chi) and pARIP (encoding rip) resulted in a maximum transformation frequency of 0.52 % with a 50 % co-integration rate. Our results demonstrate efficient co-transformation of multiple genes in soybean.

Tobacco leaf discs were transformed with a plasmid pBIBnNHX1, containing the selectable marker neomycin phosphotransferase gene (nptII) and Na⁺/H⁺ vacuolar antiporter gene from Brassica napus (BnNHX1), via Agrobacterium tumefaciens-mediated transformation. Thirty-two independent transgenic plants were regenerated. Polymerase chain reaction (PCR) and Southern blot analyses confirmed that the BnNHX1 gene had integrated into plant genome and Northern blot analysis revealed the transgene expression at various levels in transgenic plants. Transgenic plants expressing BnNHX1 had enhanced salt tolerance and could grow and produce seeds normally in the presence of 200 mM NaCl. Analysis for the T₁ progenies derived from seven independent transgenic primary transformants expressing BnNHX1 showed that the transgenes in most tested independent T₁ lines were inherited at Mendelian 3:1 segregation ratios. Transgenic T₁ progenies could express _BnNHX1 and had salt tolerance at levels comparable to their T₀ parental lines. This study implicates that the BnNHX1 gene represents a promising candidate in the development of crops for enhanced salt tolerance by genetic engineering.

Fatty acid ω-3 desaturase (FAD) is the key enzyme catalyzing the formation of trienoic fatty acids. We utilized an Arabidopsis FAD7 gene and the seven independent transgenic rice plants harbouring 1 to 3 copies of this gene were generated. The expression of FAD7 mRNA was different among independent transgenic lines regardless of the copy number. The total linolenic acid (18:3) contents reduced by about 7 - 32 % in transgenic rice plants but the linoleic acid (18:2) content increased accordingly. With or without wounding treatments, the jasmonate content was higher in transgenic lines than in wild-type rice plant. The transgenic lines overproducing jasmonate also showed increased expression of PR1b mRNA and allene oxide synthase inresponse to wounding.

Androgenic lines of Brassica juncea cv. PR-45 raised by anther culture, were screen for genetic variation. 393 androgenic plants were transferred to pots to study the R₀ generation. These plants showed substantial variation for different characters. Seed progenies of 27 lines of R₀ plants were sown in the field to study R₁ generation. Androgenic plants within lines were significantly homogeneous for the various agronomic characters studied. Two lines were shorter (18 - 20 %) than the control plants, with a remarkable feature of early maturation. Three lines showed 27 - 31 % higher yield than the parent cultivar.

A cDNA-encoding γ-tocopherol methyltransferase (γ-TMT) from Arabidopsis thaliana was overexpressed in deoduck (Codonopsis lanceolata L.) to improve the tocopherol composition. Deoduck (T₂) containing the γ-TMT transgene was produced by Agrobacterium-mediated transformation. Transgene expression was confirmed by polymerase chain reaction and RNA gel blot analysis. The transgenic plants produced more leaves than control plants. In addition, the transgenic plants showed higher levels of the CSOD, CTRX, CAPX, CNADP ⁺-IDCH, and CSO transcripts and higher SOD-like activity compared with the control plants.

The effects of lead were investigated in bean plants (Phaseolus vulgaris L. cv. Zlota Saxa) grown hydroponically in nutrient solution and exposed to Pb(NO₃)₂ (0.1, 0.5, 1 mM) with or without equimolar concentrations of chelator ethylenediaminetetraacetic acid (EDTA). The roots treated only with Pb(NO₃)₂ accumulated up to 25 g(Pb) kg^-1(d.m.), during 4-d exposure. However, in bean plants exposed to 0.5 mM Pb + 0.5 mM EDTA or 1 mM Pb + 1 mM EDTA 2.5 times less Pb was determined. In bean plants treated only with Pb, less than 6 % of total lead accumulated was transported to the aboveground parts, while in the case of plants grown with Pb + EDTA, around 50 % of total Pb was transported to the shoots.

An AREB gene, designated as AhAREB1, was cloned from peanut (Arachis hypogaea L.). The gene contains a 1 338-bp open reading frame that encodes a putative protein of 445 amino acids. The corresponding genomic DNA containing four exons and three introns was isolated and analyzed. An upstream 1 060-bp DNA promoter fragment of the AhAREB1 gene was also amplified from peanut genomic DNA. Multiple sequence alignment of the deduced amino acids of AREB showed that the AhAREB1 protein shares high sequence homology with GmAREB1, S1AREB and ABF2. Quantitative real-time PCR analysis showed that AhAREB1 was induced by polyethylene glycol, NaCl, gibberellic acid, abscisic acid and salicylic acid. The cloning and characterization of the AhAREB1 gene will be useful for further studies establishing the biological role of AhAREB1 in plants.

Lithium pollution may seriously influence the metabolic and signalling processes of plants. In the present paper, we investigate the effect of lithium chloride on fungal elicitor-triggered H₂O₂ generation in Rubia tinctorum L. cell cultures. Our results show that Li⁺ strongly influences elicitor-induced H₂O₂ formation and time-course in the cells nad culture medium. Neomycin, a phospholipase C inhibitor, and 2-APB, an inositol-1,4,5-triphosphate (IP₃) receptormediated Ca²⁺ release blocker, strongly affected the elicitor-induced H₂O₂ production and had a similar effect on elicitor-triggered H₂O₂ formation as Li⁺. We monitored changes in H₂O₂ location at subcellular level and our observations confirmed the changes measured by quantitative methods. The obtained results enabled us to deduce that the IP₃ pathway might be involved in the early signalling events leading to the moderation of elicitor-induced reactive oxygen species generation.

To examine whether ferulic acid (FA) could protect plants from dehydration stress and to investigate a mechanism for the protection, cucumber seedlings were pretreated with 0.5 mM FA for 2 d and then were exposed to dehydration induced by 10 % polyethylene glycol 6000. After pretreatment with FA, the activities of antioxidant enzymes (catalase, superoxide dismutase, and quaiacol peroxidase) in leaves were higher than under dehydration treatment alone which was in accordance with the increased transcript levels of respective genes. Moreover, the combination of FA pretreatment and dehydration reduced the content of superoxide radical, hydrogen peroxide, and malondialdehyde, and increased the relative water content and content of FA, proline, and soluble sugars in comparison with dehydration alone. We propose that pretreatment with FA protects cucumbers against dehydration stress by decrease of lipid peroxidation due to activation of antioxidant enzymes and by increase of proline and soluble sugar content in leaves.

The role of irradiance on the activity of antioxidant enzymes: superoxide dismutase (SOD) and catalase (CAT) was examined in the leaves of Pisum sativum L. plants grown under low (LL) or high (HL) irradiance (PPFD 50 or 600 µmol m^-2 s^-1) and exposed after detachment to 5 mM Pb (NO₃)₂ for 24 h. The activities of both enzymes increased in response to LL compared with HL and no effect of Pb ions was observed. Photosystem (PS) 1 and PS 2 activities were also investigated in chloroplasts isolated from these leaves. LL lowered PS 1 electron transport rate and changes in photochemical activity of PS 1 induced by Pb²⁺ were visible only in the chloroplasts isolated from leaves of LL grown plants. PS 2 activity was influenced similarly by Pb ions at both PPFD. This study demonstrates that leaves of HL grown plants were less sensitive to lead toxicity than those from LL grown plants. Changes in electron transport rates were the main factors responsible for the generation of reactive oxygen species in the chloroplasts and as a consequence, in induction of antioxidant enzymes.

The use of two Agrobacterium tumefaciens strains for transformation of Triticum aestivum L. cv. Vesna was studied. Immature embryos, isolated 15 d after pollination, were co-cultivated with the super-binary LBA4404/pTOK233 and the binary AGL1/pDM805 vectors. While the transient GUS-intron expression was high (69.9 and 80.0 %), the number of plants regenerated on selective media containing hygromycin or phosphinotricin did not exceed 0.4 and 0.13 %, respectively. Nevertheless, the regenerated plants were fertile and produced seeds. The T₀ plants, as well as the T₁ seedlings, displayed the activity in the β-glucuronidase histochemical assay and a positive signal in PCR analysis for the presence of uidA gene sequences in their genomes. The data suggest that the transformation of wheat cv. Vesna with both Agrobacterium strains is feasible.

We investigated the impact of low pH and aluminum on the metabolism and capacity for Al accumulation in shoots of the plantain species Plantago algarbiensis and P. almogravensis. We found that increasing the concentration of Al in the medium increased accumulation of it in the shoots of both plants (although more in P. almogravensis than in P. algarbiensis). The presence of Al in the medium induced proline and saccharide synthesis in P. almogravensis without affecting lipid peroxidation, but increased proline synthesis and lipid peroxidation in P. algarbiensis without affecting the saccharide content. Lipid peroxidation in P. algarbiensis was also enhanced at pH 4.0. The activity of antioxidant enzymes was increased as a response to low pH and Al in both species. Our data indicate that both species can accumulate high levels of Al but they have different sensitivities to low pH and/or the presence of Al in the growth medium.

Somatic embryogenesis and plant regeneration were successfully established on Nitsch and Nitsch (NN) medium from immature zygotic embryos of six genotypes of grapevine (Vitis vinifera). The optimum hormone combinations were 1.0 mg dm^-3 2,4-dichlorophenoxyacetic acid (2,4-D) for callus induction and 1.0 mg dm^-3 α-naphthalene acetic acid (NAA) + 0.5 mg dm^-3 6-benzyladenine (BA) for embryos production and 0.03 mg dm^-3 NAA + 0.5 mg dm^-3 BA for embryos conversion and plant regeneration. The frequency of somatic embryogenesis varied from 10.5 to 37.5 % among six genotypes and 15.5-42.1 % of somatic embryos converted into normal plantlets. The analysis of DNA content determined by flow cytometry and chromosome counting of the regenerated plantlets clearly indicated that no ploidy changes were induced during somatic embryogenesis and plant regeneration, the nuclear DNA content and ploidy levels of the regenerated plants were stable and homogeneous to those of the donor plants. RAPD markers were also used to evaluate the genetic fidelity of plants regenerated from somatic embryos. All RAPD profiles from regenerated plants were monomorphic and similar to those of the field grown donor plants. We conclude that somaclonal variation is almost absent in our grapevine plant regeneration system.

Benzothiadiazole (BTH) is a structural analogue of salicylic acid (SA) which is widely recognized for its role in elicitation of systemic acquired resistance in a broad range of plant species. Here, BTH was applied to cell cultures of the bulbous ornamental plants Ornithogalum dubium and O. thyrsoides, showing a strong effect on rates of differentiation and morphogenesis. Morphogenic cell clusters in liquid Murashige and Skoog (MS) medium containing 1-naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BAP) were used for all treatments. The calluses were washed thoroughly and activated with increasing concentrations of BTH. Following the induction, calli were grown on a solid MS medium without growth regulators (MS) or on a comparable media with NAA and BAP (M-206). The calli treated with BTH displayed a dose dependent increase in formation of meristematic centres followed by enhanced shoot formation compared to controls. Microscopic analyses revealed increased differentiation to cell organelles and a strengthening of the cell wall. A stronger response to BTH was observed in MS than in M-206 medium. A similar effect on calli differentiation was obtained by three weeks darkness followed by light exposure. The dark/light positive effect on differentiation was further augmented by BTH in a synergistic fashion. It is suggested that BTH enhances the rates of morphogenesis in Ornithogalum cultures by triggering a plant regulator-like activity.

To reveal the allelic differentiations at the two genes for fertility restoration (Rf) on chromosomes 1 (Rf3) and 10 (Rf4), 15 chromosome single segment substitution lines (SSSLs) with the Rf3 locus and 18 SSSLs with the Rf4 locus were crossed with Bobai A (BbA), a cytoplasmic male sterility line with wild abortive type of cytoplasm (WA-CMS), respectively. Based on the pollen and seed fertility of the F₁ hybrids, the Rf3 and Rf4 genes were each classified into four alleles, namely Rf3-1, Rf3-2, Rf3-3, and Rf3-4 for Rf3, and Rf4-1, Rf4-2, Rf4-3, and Rf4-4 for Rf4. Out of the 33 SSSLs, an SSSL W23-19-06-06-11 carrying the genotype Rf3-4Rf3-4/Rf4-4Rf4-4 possessed the strongest restoring ability for BbA. To determine the genetic effects of Rf3 and Rf4 for WA-CMS, one BC₃F₂ population possessing the genetic background of W23-19-06-06-11 was generated from the cross between W23-19-06-06-11 and BbA by backcrossing and marker-assisted selection. In the BC₃F₂ population, the plants carrying the Rf3Rf3/Rf4Rf4, Rf3Rf3/rf4rf4, and rf3rf3/Rf4Rf4 genotypes were selected and their phenotyping for pollen and spikelet fertility were evaluated. The result showed that under the genetic background of SSSL W23-19-06-06-11, the effect of Rf4 appeared to be slightly larger than that of Rf3 and their effects were additive for WA-CMS system. These studies will lead to the transfer of Rf genes into adapted cultivars through marker-assisted selection in active hybrid rice breeding programs.

Lingonberry (Vaccinium vitis-idaea L. ssp. vitis-idaea Britton) cultivars Regal, Splendor, and Erntedank were obtained by conventional softwood cuttings (taken as a control), by in vitro shoot proliferation of node explants, and by adventitious shoot regeneration from excised leaves of micropropagated shoots. In the plants propagated in vitro, the total ascorbate content increased and its pool was more oxidized, the total glutathione content also increased but its pool became more reduced. The leaves of plants obtained from the in vitro culture showed significantly higher antioxidant enzyme activities except for dehydroascorbate reductase which was at a similar level in all plants. Total soluble phenolics, tannins, and flavonoids were enhanced in fruits of in vitro-propagated plants whereas in leaves, the levels of these metabolites (except flavonoids) were higher in ex vitro derived plants. The total radical scavenging capacity was enhanced in berries of the in vitro propagated plants. It is suggested that the active morphogenetic process, characterized by intensive formation and scavenging reactive oxygen species is reflected in the activities of antioxidant enzymes and metabolites. The reduction potential of glutathione is the most important parameter which determines patterns of growth and differentiation in the investigated plants.

In Arabidopsis thaliana in vitro culture, shoots were induced from the shoot apical meristem (SAM) of germinating seeds in the presence of 2,4-dichlorophenoxyacetic acid. Primary shoot primordia developed leaf-like structures, from which secondary shoot primordia were produced. Regenerated shoots were recovered when the material was transferred to a medium lacking auxin. Adventitious roots formed from a callusing basal region of the secondary shoots. The CUC1 transcription factor was expressed at the apex of the primary shoot primordium and at the boundary between the regenerated SAM and the developing leaf primordia. The DR5::GUS transgene was used to localize sites of maximum auxin occurrence. Auxin was firstly detected in the dividing cells beneath the SAM epidermis, which coincided with sites where primary shoot primordia were initiated. In the regenerated shoots, auxin response was not detected in the basal region of the stem, suggesting that the regenerating structures were shoots rather than somatic embryos. Direct shoot regeneration from the A. thaliana SAM requires a localized accumulation of auxin.

Proteins WCS120 and DHN5 are known as the major cold-inducible dehydrins in wheat and barley plants, respectively. WCS120 and DHN5 relative accumulation increased exponentially along with a growth temperature decline in the range from optimum to cold temperatures. Even at optimum growth temperatures, the most frost-tolerant wheat and barley cultivars can be distinguished from the remaining ones according to dehydrin relative accumulation. The highly tolerant wheat and barley cultivars started accumulating dehydrins at higher growth temperatures and reached higher dehydrin amounts than the less tolerant ones. Statistically significant correlations between lethal temperature for 50 % of the samples (LT50) and dehydrin relative accumulation have been found at all growth temperatures (5, 10, 15 and 20 °C) for WCS120 in wheats and at 5 and 10 °C for DHN5 in barleys. Analogous relationships between dehydrin relative accumulation at different growth temperatures and plant acquired frost tolerance have been proved for wheat WCS120 and barley DHN5.

An efficient, rapid, and reproducible plant regeneration protocol was successfully developed for Abrus precatorius L. using mature nodal explants excised from a 5-year-old field grown plant. The highest shoot regeneration frequency (87 %) with maximum number of multiple shoots (15.0) and shoot length (4.8 cm) were recorded on Murashige and Skoog (MS) medium amended with 2.5 μM thidiazuron, 120 mg dm^-3 polyvinylpyrrolidone, and 0.5 μM α-naphthalene acetic acid. The best treatment for maximum root (4.0) induction was half strength MS medium supplemented with 1.5 μM indole-3-butyric acid. The in vitro plantlets with well-developed shoots and roots were successfully transferred into plastic cups with Soilrite and acclimatized in a culture room under photon flux density (PFD) of 150 μmol m^-2 s^-1, thereafter transferred to a greenhouse with PFD of 300 μmol m^-2 s^-1, and finally to a field with 70 % survival rate. During the acclimatization period (0-49 d), leaf chlorophyll and carotenoid content increased whereas malondialdehyde and H₂O₂ content decreased probably due to increasing activities of antioxidant enzymes (catalase, superoxide dismutase, glutathione reductase, and ascorbate peroxidase). Our work suggests that micropropagated plants developed an antioxidant enzymatic protective system to avoid oxidative stress during establishment under ex vitro environment.

Changes in membrane lipid composition is a fundamental strategy for plants to resist low-temperature stress. We compared members of 11 membrane glycerolipid classes in Thellungiella salsuginea and its close relative Arabidopsis thaliana at normal growth temperature, and during cold acclimation (CA), freezing (FR), and post-freezing recovery (PFR). The results showed several properties of T. salsuginea distinct from that in A. thaliana, which included: 1) low relative content of phosphatidic acid (PA) and a rapid increase and decrease of PA during FR and PFR respectively; 2) insensitivity of lyso-phospholipids to freezing; and 3) high ratio of phosphatidylcholine to phosphatidylethanolamine. All these properties were in favour of maintaining membrane integrity and stability and therefore enable T. salsuginea to be more tolerant to freezing than A. thaliana.

The aim of this study was to evaluate the influence of methylglyoxal (MG) on organogenesis and regeneration of tobacco (Nicotiana tabacum L.) plants from callus in media containing glycine or succinate. The best improvement in shoot proliferation and shoot length was obtained in the medium supplemented with 0.1 mM MG and 0.5 mM glycine or 0.25 mM succinate. The histological studies showed vigorous development of corm like structures and shoot organogenesis from callus tissues cultured in MG supplemented media. Biochemical studies also revealed higher content of δ-aminolaevulinic acid (a precursor of chlorophyll) and of chlorophyll.

Rice (Oryza sativa L.) seedlings were grown hydroponically in Hoagland's nutrient solution under controlled conditions to investigate the effects of NaCl pretreatment on their response to subsequent application of cadmium (Cd) alone and Cd + NaCl combination. The Cd stress caused growth retardation in all plants, significantly reduced pigment content, stomatal conductance (g_s), and net photosynthetic rate (P_N). Cd stress significantly increased malondialdehyde and proline content. Compared to Cd treatment alone, combination stress had more detrimental effects on the above parameters. However, the NaCl pretreatment was beneficial in improving the plant growth and plant tolerance to Cd alone or combination stress.