Changes in plant growth, photosynthetic gas exchange, chlorophyll fluorescence and stem diameter of soybean [Glycine max (L.) Merr.] plants under drought stress were studied. Total plant dry mass was reduced by 30 % compared to well-watered control plants. Leaf water potential was slightly decreased by water stress. Water stress induced daytime shrinkage and reduced night-time expansion of stem. Photosynthetic rate, stomatal conductance and transpiration rate were significantly declined by water stress, while the intercellular CO₂ concentration was changed only slightly at the initiation of stress treatment. The maximum photochemical efficiency of photosystem 2 and apparent photosynthetic electron transport rate were not changed by water stress.

To investigate whether exogenous sucrose can protect cucumber from water stress, cucumber (Cucumis sativus L.) seedlings were pretreated with 90 mM sucrose or 90 mM mannitol for 1 d and then were dehydrated with 10 % (m/v) polyethylene glycol (PEG) 6000 for further 1 d. Dehydration inhibited plant growth and decreased osmotic potential and relative water content (RWC) in leaves. The pretreatment with 90 mM sucrose further reduced the osmotic potential but increased the RWC and alleviated the growth inhibition. Compared with the PEG treatment alone, the combination of sucrose + PEG increased the activities of superoxide dismutase, guaiacol peroxidase, glutathione reductase, dehydroascorbate reductase, monodehydroascorbate reductase, ascorbate peroxidase, and glutathione peroxidase, and elevated the content of endogenous sucrose, glucose, and fructose together with the activities of soluble acid invertase and neutral invertase. This was in accordance with the enhanced transcription of genes encoding copper/zinc superoxide dismutase, guaiacol peroxidase, and glutathione reductase. Furthermore, the sucrose pretreatment decreased the content of malondialdehyde and hydrogen peroxide and increased the content of ascorbate, reduced glutathione, and proline under the dehydration. Taken together, the pretreatment with 90 mM sucrose, but much less with mannitol, induced antioxidants, proline, and soluble sugars and thus reduced dehydration-caused damage to the cucumber seedlings.

Gibberellic acid (GA₃) is widely used at different stages of berry development, and to understand the molecular mechanism of its action requires identification of stable reference genes. We sprayed grapevine (Vitis vinifera L.) cv. Thompson Seedless with GA₃ at rachis stage for rachis elongation, at flower cluster stage for flower thinning, and at 3-4 mm berry stage for berry elongation. Tissue samples were collected at different time points after GA₃ application. The expression of 10 candidate reference genes was analyzed using 4 different algorithms to assess their suitability for real time-PCR data normalization. Based on the overall ranking, PP2A, Sutra, and SAND were identified as the most stably expressed genes across all samples. With regard to different stages, tubulin, EF1α, and UBC were the most stable genes during rachis elongation; PP2A, SAND, and Sutra were the most suitable at the flower cluster and berry stages. The expression of GA signaling gene SPINDLY (VvSpy) was analyzed to validate the stable reference genes. After the GA₃ application, the expression of VvSpy was reduced at the rachis stage but did not change at the flower cluster and berry stages. The expression profile of VvSpy was comparable when two or three reference genes were used for data normalization.

The effects of different cadmium concentrations [17 mg(Cd) kg^-1(soil) and 72 mg(Cd) kg^{- 1}(soil)] on Cannabis sativa L. growth and photosynthesis were examined. Hemp roots showed a high tolerance to Cd, i.e. more than 800 mg(Cd) kg^-1(d.m.) in roots had no major effect on hemp growth, whereas in leaves and stems concentrations of 50 - 100 mg(Cd) kg^-1(d.m.) had a strong effect on plant viability and vitality. For control of heavy metal uptake and xylem loading in hemp roots, the soil pH plays a central role. Photosynthetic performance and regulation of light energy consumption were analysed using chlorophyll fluorescence analysis. Seasonal changes in photosynthetic performance were visible in control plants and plants growing on soil with 17 mg(Cd) kg^-1(soil). Energy distribution in photosystem 2 is regulated in low and high energy phases that allow optimal use of light and protect photosystem 2 from overexcitation, respectively. Photosynthesis and energy dissipation were negatively influenced by 72 mg(Cd) kg^-1(soil). Cd had detrimental effects on chlorophyll synthesis, water splitting apparatus, reaction centre, antenna and energy distribution of PS 2. Under moderate cadmium concentrations, i.e. 17 mg(Cd) kg^-1(soil), hemp could preserve growth as well as the photosynthesis apparatus, and long-term acclimation to chronically Cd stress occurred.

Cadmium (100, 400 and 1000 μM CdCl₂) treatments resulted in the inhibition of root dry biomass, root elongation and increased Cd accumulation in wheat (Triticum aestivum L.) roots. Further, these treatments decreased relative water content, chlorophyll content, ¹⁴CO₂-fixation, activities of phosphoenolpyruvate carboxylase and ribulose-1,5-bisphosphate carboxylase and abscisic acid content while increased malondialdehyde, hydrogen peroxide and free proline contents. Chloroplast and root ultrastructure was also changed. Pretreatment of seeds with SA (500 μM) for 20 h resulted in amelioration of these effects.

The effects of NaCl (0, 50, 100, 150 and 200 mM) on growth, water relations, glycinebetaine, free proline, ion contents, stomata number and size of Kochia prostrata (L.) Schard were determined. Shoot and root fresh and dry matter, root and shoot length, relative growth rate, net assimilation rate, relative water content, water use efficiency, soluble sugars and glycinebetaine contents were not changed at low NaCl concentrations, but they were significantly decreased at 200 mM NaCl. The K⁺, Mg²⁺ and Ca²⁺ contents, water potential, chlorophyll a+b and carotenoides contents, and stomata number and size were reduced already at low concentrations of NaCl. In contrast, the Na⁺, Cl^- and proline contents increased several times with increasing NaCl concentration. Kochia prostrata is a salt tolerant species, the optimal growth of this plant occurred up to 150 mM NaCl. The mechanisms of salt tolerance in the plant may be balance among ion accumulation and production of glycinebetaine, proline, soluble sugars for maintenance of pressure potential.

Tomato plants were treated for two weeks with different concentrations of Cr(III) or Cr(VI) compounds to compare their toxic effects. The concentration of total Cr in plant tissues increased linearly with its concentration in the growth medium and Cr accumulated largely in the roots, regardless of the form in which it was supplied to the plant. All measured plant growth parameters were negatively affected by Cr, but Cr(VI) showed much more pronounced toxic effects. Leaf net photosynthetic rate (P_N) was decreased by both Cr forms, and the decrease was also greater for Cr(VI). Cr(III) caused no significant effect on leaf stomatal conductance, whereas Cr(VI) reduced it. Cr(VI) also markedly reduced the variable to maximum chlorophyll a fluorescence ratio, measured in dark-adapted leaves.

Tobacco (Nicotiana tabacum L. cv. Samsun) plantlets were cultured in vitro on Murashige-Skoog medium photoautotrophically (without sucrose) or photomixotrophically (with 3 % sucrose) under two irradiances [70 or 230 µmol m^-2 s^-1]. Significant differences in stomatal density and sizes in leaves of different insertion levels (3^rd, 5^th and 7^th leaves from bottom) in photomixotrophic plantlets but not in photoautotrophic ones were found after 35 d of culture. Stomatal density was higher in upper leaves and on abaxial leaf side. Higher irradiance enhanced stomatal density in photoautotrophic plantlets. Stomatal sizes decreased with leaf insertion level but no significant differences between leaf sides were found. Abaxial stomata were more circular than the adaxial ones. In photomixotrophic plantlets stomata tended to be more elongated in the 3^rd and the 5^th leaves, whereas stomatal elongation in photoautotrophic plantlets was similar in all leaves.

A protocol for in vitro multiplication of Capparis decidua (Forsk.) Edgew. has been developed from cultured leaves procured from multiplying axillary shoots on the cultured nodal explants. The highest efficiency of shoot formation was observed on Murashige and Skoog (MS) medium containing 2 mg dm^-3 benzyladenine (BA) and 0.5 mg dm^-3 1-naphthaleneacetic acid. The regenerated shoots were transferred to MS medium containing 3 mg dm^-3 BA for growth and proliferation. Shoots above 2 cm in length were transferred to MS medium supplemented with 1 mg dm-3 indole-3-butyric acid plus 0.5 mg dm^-3 indole-3-acetic acid for root induction. No variation was detected among the micropropagated plants by randomly amplified polymorphic DNA (RAPD) markers.

The effects of nitrogen [75 and 150 kg (N) ha^-1] and elevated CO₂ on growth, photosynthetic rate, contents of soluble leaf proteins and activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and nitrate reductase (NR) were studied on wheat (Triticum aestivum L. cv. HD-2285) grown in open top chambers under either ambient (AC) or elevated (EC) CO₂ concentration (350 ± 50, 600 ± 50 μmol mol^-1) and analyzed at 40, 60 and 90 d after sowing. Plants grown under EC showed greater photosynthetic rate and were taller and attained greater leaf area along with higher total plant dry mass at all growth stages than those grown under AC. Total soluble and Rubisco protein contents decreased under EC but the activation of Rubisco was higher at EC with higher N supply. Nitrogen increased the NR activity whereas EC reduced it. Thus, EC causes increased growth and P_N ability per unit uptake of N in wheat plants, even if N is limiting.

The role of acetylsalicylic acid (0, 1 and 10 μM) pre-treatment in amelioration of salt and osmotic stress in a wild species of potato (Solanum stoloniferum) was investigated. We compared the effects of iso-osmotic concentrations of polyethylene glycol 6000 (15 %) and NaCl (80 mM) on the physiological responses of this species in explants grown in the liquid Murashige and Skoog medium. Both salt and drought reduced shoot growth parameters, photosynthetic pigment contents and increased lipid peroxidation, electrolyte leakage, H₂O₂ content and lipoxygenase activity. The effect of NaCl was more severe than that of polyethylene glycol. Salinity also increased Na⁺ content and decreased K⁺ content and K⁺/Na⁺ ratio. Under both stresses, the activities of superoxide dismutase, guaiacol peroxidase, ascorbate peroxidase, catalase and glutathione reductase enzymes were increased. Acetylsalicylic acid pre-treatment alleviated the adverse effects of both stresses on all parameters measured.

Seedlings of Sorghum bicolor (L.) Moench were subjected to 180 mM NaCl with or without 0.25 mM spermine (SPM) for 7 d. NaCl treatment resulted in the inhibition of growth and increased the content of free proline, soluble protein and malondialdehyde (MDA). Additionally, it also enhanced the activity of catalase (CAT), peroxidase (POX) in both shoots and roots, while decreased that of glutathione reductase (GR). When exogenous spermine was added to the test solution, the growth of sweet sorghum seedlings was improved, and a smaller increase in the free proline and MDA contents was observed. The addition of spermine also partially increased the activities of POX and GR, but had no effects on soluble protein content or the activity of CAT.

High frequency of shoot formation was achieved from Solanum nigrum L. leaves on Murashige and Skoog (MS) medium without any callusing stage. Shoot forming ability was more pronounced on leaves positioned dorsally. For shoot induction, 2.0 mg dm^-3 benzylaminopurine and 1.5 mg dm^-3 kinetin were observed to be the most effective plant growth regulators (PGRs). The present paper also describes first successful induction of in vitro flowering in S. nigrum. The leaf derived shoots were excised and treated with various root promoting PGRs and 0.25 mg dm^-3 indole-3-butyric acid produced maximum number of roots (15.2 per plant). Plants were later transplanted in field with 100 % survival. Solasodine content was higher in in vitro raised shoots and leaf derived callus, compared to ex vitro grown shoots.

The aim of this work was to investigate the role of the antioxidant enzymes in salt tolerance comparing the salt-sensitive (Pérola) and a salt-tolerant (Pitiúba) cultivar of cowpea [Vigna unguiculata (L.) Walp.]. Salt stress (100 mM NaCl for 8 d) reduced the leaf growth rate more in the sensitive cultivar. The salt-induced decrease in the relative water content, Na⁺ accumulation and increase in leaf electrolyte leakage was similar in both cultivars. Salt stress induced a higher increase in the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and phenol peroxidase (POX) in the tolerant cultivar than in sensitive one.

In previous experiments elevated but sub-symptomatic applications of Zn (0.1 mM and 1 mM) caused impairments in growth parameters and photosynthetic performance of Populus × euramericana (Dode) Guinier clone I-214. The aim of this work was to evaluate leaf morphological and anatomical traits in this clone in response to the same Zn concentrations. The results showed that Zn treatments induced variations in leaf dry mass, area, mesophyll thickness, intercellular spaces, stomatal density and size. Stronger modifications, especially concerning stomata characteristics induced by 1 mM Zn, were consistent with physiological impairments while those induced by 0.1 mM Zn suggested a compensatory strategy for maintaining functional integrity.

Measurements of stem respiration were conducted for a period of four years (1999-2002) in 14-year old Norway spruce (Picea abies [L.] Karst) trees exposed to ambient (CA) and elevated CO₂ concentration (CE; ambient plus 350 μmol mol^-1). Stem respiration measurements of six trees per treatment were carried out 2-3 times per month during the growing season. Stem respiration in CE treatment was higher (up to 16 %) than in CA treatment. Temperature response of stem respiration (Q₁₀) for the whole experimental period ranged between 1.65-2.57 in CA treatment and 2.24-2.56 in CE treatment. The mean stem respiration rate normalized to 10 °C (R₁₀) in CA and CE treatments ranged between 1.67-1.95 and 2.19-2.72 μmol(CO₂) m^-2 s^-1, respectively. Seasonal variations in stem respiration were related to temperature and tree growth.

The effects of photoperiod on the development of in vitro grown plantlets of yam (Dioscorea alata L.), were investigated. Plantlets were transplanted into pots, acclimatizated until they reached vegetative stages V₁ (3 leaves) or V₂ (8 leaves), and then grown under 12-h or 16-h photoperiod. The formation and development of underground tubers was only induced under 12-h photoperiod. Tuber initiation was not related to the initial vegetative stage of plants, and the tubers were visible at about 18 - 24 d. On the contrary, a 16-h photoperiod inhibited tuber formation and stimulated vine and leaf growth. The total dry matter production and the number of leaves per plant of V₁ stage plants were 50 and 30 % lower respectively, after 44 d under 12-h compared to 16-h photoperiod. These parameters were not influenced by photoperiod in V₂ stage plants. Consequently, the effect of 12-h photoperiod on dry matter of V₁ plants was attributed to a source limitation related to the early initiation of tuberization. The transfer of plants grown under 12-h to 16-h photoperiod stopped tuber growth and starch accumulation. On the other hand, it stimulated the shoots and the roots to grow.

Zephyr lily (Zephyranthes grandiflora), an important ornamental plant has been micropropagated in vitro after controlling microbial contamination by a pretreatment with 0.2 % Bavistin and 0.1 % Pantomycin for 4 h before final sterilization with 0.1 % mercuric chloride. In 67 % of the sterile cultures, 11 shoots on average were regenerated directly from basal half of bulb scales in Murashige and Skoog (MS) medium containing 3 % sucrose and 2 mg dm^-3 benzylaminopurine (BAP). Shoots emerged in bunches on a basal achlorophyllous bulbous part. Combination of 2 mg dm^-3 BAP with 1 mg dm^-3 gibberellic acid (GA₃) enhanced shoot growth. Stout roots (maximum of 5-6 per shoot) were developed in presence of 1 mg dm^-3 indole-3-butyric acid (IBA). Micro-bulbs showed potential of regeneration and could be used as secondary explants. The morphologically identical plants derived by in vitro propagation were genetically identical as shown by PCR based ISSR marker analysis of genomic DNA.

Bulbscales of oriental lily hybrid Star Gazer were used as the explants. Bulblets were formed on the basal portion of the excised bulbscales on MS medium supplemented with growth retardants, different sucrose concentrations and exposed to continuous light or dark. ^{Alar, Cycocel} and Paclobutrazol in concentration 1 mg dm^-3 produced higher number of bulblets as compared to the control. The number of bulblets, however, decreased with the increase in concentration of the growth retardants. The number of bulblets was higher at 90 than at 60 g dm^-3 sucrose and when the bulbscales were exposed to continuous light than to darkness. The growth retardants, higher sucrose concentration and continuous dark stimulated fresh mass of bulblets. The number of bulblets having roots and leaves decreased in medium with Alar, Cycocel and Paclobutrazol as compared to the control. A few bulblets produced roots and leaves in medium with 90 g dm^-3 sucrose and none of the regenerated bulblets produced leaves under continuous dark.

VERNALIZATION INSENSITIVE 3 (VIN3) is a chromatin remodelling protein that is induced by low temperatures and is required for the vernalization response in Arabidopsis thaliana. VIN3 is one of the polycomb group (PcG) proteins, which mediates epigenetic repression of FLOWERING LOCUS C (FLC) in A. thaliana. Here, we present cloning, characterization, and expression of a putative SlVIN3 gene in tomato (Solanum lycopersicum L.) by isolating cDNA clones corresponding to SlVIN3 gene using primers designed based on conserved sequences between PcG genes in A. thaliana and tomato. The SlVIN3 cDNAs were cloned into a pBS plasmid and sequenced. Both 5' and 3' RACE were generated and sequenced. The flcDNA of 2 823 bp length for the SlVIN3 gene was composed of 5'UTR (336 bp), ORF (2 217 bp), and 3'UTR (270 bp). The translated ORF encoded a polypeptide of 739 amino acids. Alignment of deduced amino acids indicates that there are highly conserved regions between tomato SlVIN3 predicted protein and plant VIN3 gene family members. Both unrooted phylogenetic trees constructed using the maximum parsimony and maximum likelihood methods indicate that there is a close relationship between SlVIN3 predicted protein and VIN3 protein of Vitis vinifera. The expression of SlVIN3 gene remained high during floral organ differentiation and growth and decreased when the fruit started to develop.

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.

Plant glutathione peroxidases (GPX) catalyze the reduction of H₂O₂ or organic hydroperoxides to water, mitigating the toxicity of these compounds to cells. In rice plants, the GPX gene family is composed of five members that are distributed in a range of sub-cellular compartments including cytosol, mitochondria, chloroplasts, or endoplasmic reticulum. Of these, OsGPX1 and OsGPX4 are located in mitochondria and chloroplasts, respectively. To understand the role of these GPX in rice, the effect of knockdown of OsGPX1 and OsGPX4 in rice plants was evaluated. Our data show that OsGPX4 was essential for in vitro rice regeneration because no plants were obtained from calli carrying a hairpin construct against OsGPX4. Although the knockdown of OsGPX1 did not impair plant regeneration, the plants with silenced OsGPX1 (GPX1s plants) showed reduced shoot length and a reduced number of seeds compared to the non-transformed rice plants. These results indicate that OsGPX1 and OsGPX4 are essential for redox homeostasis which leads to normal growth and development of rice.

Brassinosteroids (BRs) are polyhydroxylated steroidal plant hormones that play pivotal role in the regulation of various plant growth and development processes. BR biosynthetic or signaling mutants clearly indicate that these plant steroids are essential for regulating a variety of physiological processes including cellular expansion and proliferation, vascular differentiation, male fertility, timing senescence, and leaf development. Moreover, BRs regulate the expression of hundreds of genes, affect the activity of numerous metabolic pathways, and help to control overall developmental programs leading to morphogenesis. On the other hand, the potential application of BRs in agriculture to improve growth and yield under various stress conditions including drought, salinity, extreme temperatures, and heavy metal (Cd, Cu, Al, and Ni) toxicity, is of immense significance as these stresses severely hamper the normal metabolism of plants. Keeping in mind the multifaceted role of BRs, an attempt has been made to cover the various aspects mediated by BRs particularly under stress conditions and a possible mechanism of action of BRs has also been suggested.

Low temperature is the main limiting factor for cultivation expansion, fast growth, and high yield of Eucalyptus species. To investigate the mechanism of their cold tolerance, a cDNA subtraction library representing the cold-induced genes of Eucalyptus dunnii was constructed using suppression subtractive hybridization (SSH) technique. A gene encoding a calmodulin-binding protein (CaMBP) was identified from the SSH library, and the expression pattern of CaMBP under cold stress was further evaluated through reverse transcription - quantitative polymerase chain reaction (RT-qPCR). The expressions of EguCBF1a and EdCaMBP increased already after 4 h of the cold stress, supporting the idea that the CaMBP gene may have a function in the survival of Eucalyptus during winter. A full-length mRNA sequence of 1 808 bp was obtained via a rapid amplification of cDNA ends method, and the sequence was subsequently deposited to GenBank (accession No. JX401571). The CaMBP cDNA of E. dunnii contained a single open reading frame of 1 362 bp, a 5t' untranslated region of 175 bp, and a 3t' untranslated region of 268 bp. Multiple sequence alignment and phylogenetic analysis indicated that CaMBP of E. dunnii shared 56 to 84 % identities with the CaMBPs of other plants and was similar to that of Ricinus communis, Medicago truncatula, and Gossypium hirsutum.

The ATP binding cassette B/multidrug-resistance/P-glycoprotein (ABCB/MDR/PGP) subfamily is a member of the ABC protein family. Significant progress has been made in the functional characterization of ABCB genes, particularly in Arabidopsis thaliana. This review evaluates recent advances concerning the plant ABCB subfamilies including their evolution and structure, the involvement and regulation of ABCB-mediated auxin transport, and the roles of ABCBs in plant growth and development. Insights into specific functions of members of the ABCB subfamily and their mediation of various regulatory pathways are also presented.

Expansins, found in the cell wall, have the unique ability to induce immediate cell wall extension. In this study, a β-expansin gene (TaEXPB23) isolated from wheat (Triticum aestivum L.) coleoptiles was transformed to tobacco (Nicotiana tabacum) to investigate its role in plant growth and development. TaEXPB23 was preferentially expressed in wheat coleoptile and a close correlation between TaEXPB23 expression and coleoptile growth was observed. The over-expression of TaEXPB23 in tobacco also resulted in accelerating growth of leaves and internodes at earlier developmental stages, and it was involved in regulating plant development.

Selenium (Se) is essential for health of humans, animals, and plants. Especially wheat is a major source of Se in the terrestrial food chain. In this study, an element analysis was optimized and the content of Ca, Mg, K, S, P, Fe, Se, Mn, Cu, Zn, and Mo in leaves, roots, and seeds were measured during growth of wheat (Triticum aestivum L. cv. Manu) in Hoagland nutrient solution with 5 and 15 μM Na₂SeO₄. Se was transported to all investigated tissues and accumulated in the seeds in proportion to used amounts. The supplementation of Se, independently of concentration, weakly modified the micro- and macro-elements content in the seedlings. In the flag-leaf stage, an increase of the Mo and S content in the shoots and the S and Cu content in the roots was found. Moreover, in the generative phase, a decrease in Ca and Fe in the roots was registered. Increased Se in the nutrient solution strongly stimulated the Se accumulation in the seeds.

A gene encoding Mn-containing superoxide dismutase (Mn-SOD), designated as ThMSD, was cloned from salt cress (Eutrema halophilum) by reverse transcriptase - polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The full length of ThMSD (acc. No. EF413171) is 1 047 bp with an open reading frame (ORF) of 693 bp. The deduced 231-amino acid polypeptide had a predicted molecular mass of 25.5 kDa, an estimated pI of 9.08, and a putative Mn-binding site. Recombinant ThMSD protein was expressed in Escherichia coli and characterized. The SOD activity of ThMSD was inactivated by sodium azide but not by potassium cyanide or hydrogen peroxide confirming that ThMSD is a Mn-SOD. Real-time PCR revealed that ThMSD was expressed in roots, rosette leaves, stems, stem leaves, flowers, and siliques. ThMSD mRNA reached the highest content in roots and its content increased when plants were treated with NaCl (in a concentration dependent manner), ABA, and subjected to drought. ThMSD was transformed into Arabidopsis and the stress tolerance properties of transgenic lines were assayed. The seeds of transgenic lines exhibited significantly higher germination rate under 100 and 150 mM NaCl than the wild type. The root growth of transgenic lines was affected less obviously than the wild type under 100 mM NaCl. The above results indicate that ThMSD played an important role in E. halophilum tolerance to environmental stresses, especially NaCl stress.

Transcription factors play vital roles in stress signal transduction and gene expression modulation. The sequence analysis shows that MdCBF1 from Malus domestica Borkh. cv. Fuji contained an AP2 core domain of 56 amino acids. By comparison of deduced amino acid sequences of CBF related proteins, we deduced that MdCBF1 is a CBF transcription factor gene which belongs to AP2/EREBP family, DREB-A1 subfamily. Further, we reported that transgenic Arabidopsis thaliana plants expressing the MdCBF1 gene exhibited stronger growth than wild type plants under freezing stress. The analysis of RT-PCR for stress-responsive genes implied that MdCBF1 over-expressing plants had a higher expression of COR15a, RD29A, and RD29B genes than wild type plants. Collectively, our results indicate that MdCBF1 might play an important role in the response of transgenic Arabidopsis plants to freezing stress.

Plant regeneration through indirect somatic embryogenesis was attempted from the immature cotyledon-derived explant of Cassia angustifolia Vahl. - a valuable leguminous shrub. The highest frequency (90.5 %) of somatic embryos was obtained on a Murashige and Skoog (MS) medium augmented with 10.0 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.0 μM benzyladenine (BA) with the production of a maximum of 22.8 embryos per explant, of which 35.3 % germinated on the same medium after 6 weeks of culture. A half strength MS medium without plant growth regulators facilitated better conversion of embryos into complete plantlets compared to a full strength MS medium. Regenerated plantlets were successfully acclimatized in sterile Soilrite and transferred to field conditions with a 70 % survival rate. Histological studies performed at different stages of embryogenesis revealed the mode of differentiation of embryos from the callus. The content of chlorophylls (a + b) and carotenoids, and the net photosynthetic rate (P_N) in the regenerated plantlets were tested during different periods of acclimatization.