In order to develop somatic embryogenesis for genetic manipulation process of Populus deltoides Bartrex Marsh eastern, isolated leaf disk explants were cultured on MS medium supplemented with 2,4-D (2,4-dichlorophenoxyacetic acid), BA(benzyladenine) and glutamine. High number of somatic embryos formed on both the midveins and secondary veins. MS medium containing 2 mg/l 2,4-D and 0.1 mg/l BA with 20 J.LM glutamine showed highest number of globular-shaped embryo (11.6). Most of the embryogenic CALLI were formed on the cut edges of the leaf disks in MS medium containing 5 mg/12,4-D and 0.1 mg/1 BA for all glutamine concentrations. MS plant regeneration media supplemented with 2 mg/l BA and 0.1 mg/1 NAA (Naphtalene Accetic Acid) produced high percentage (72.5%) of plantlets on callused leaf disks explants. Rooted plantlets in WPM basal medium were successfully acclimatized on soil medium (1:1:1 peat, perlit and vermiculite) and transferred to the field.

Non-embryogenic callus was produced with sweet lime (Citrns limettoides Tan) and Mexican lime (Citrus aurantifolias) flaveado explants on MS 1 (Murashige and Skoog) medium containing 1 mg I-1 2,4-0, (2,4-dichlorophenoxyacetic acid), 0.1 mg I-1  NAA (naphthalene acetic acid) and 0.25 mg I-1  kinetin. Growth and cell division were not stimulate when the CALLI were subcultured on various media. In addition, nonembryogelllc callus did not grow in suspension culture. Whereas, emberyogenic callus derived from unfertilized ovules of Mexican lime showed growth and cell division in MT (Murashige and Tucker) suspension medium supplemented with 1550 mg I-1 glutamine and 500 mg I-1 malt extract. Mean of counting’s in 3 replicated cultures at the beginning was 0.04±0.002 x 104 and reached to 0.65±0.03 x 104 after 21 d. In order to control internal bacterial contamination, flavedo explants were preculture or media treated by streptomycin and gentamycin. Antibiotics were not effective for disinfection, singly.Streptomycin (1000 mg I-1]) + gentamycin (125 mg I-1) mixture was the most effective treatment for disinfection in 60% of explants. Seventy percent of explants were clean when streptomycin (500 mg I-1) + gentamycin (500 mg I-1]) mixture was used, but more than 50% of explants died due to antibiotic high concentration. Browning of explants increased with the presence of antibiotics in the media.

Opium poppy (Papaver somniferum) is one of the oldest and most important medicinal plants due to biosynthesis and storage of Benzylisoquinoline alkaloids. For more biotechnology exploitation of this plant, optimization of tissue culture and genetic transformation is necessary. Among different factors affecting on genetic transformation, selectable marker and it's interaction with other factors is important. In order to optimization of gene transformation by agrobacterium to the plant, three separate experiments were designed for callus induction from hypocotyl, cotyledon and root explants. The factorial experiments were designed for callus induction with two factors based on completely randomized design with 8 replicates. First factor was basal medium (B5 and MS) and second factor was plant growth regulation (1mg/l 2, 4-D and 0.5 2, 4-D mg/l+0.5 BA mg/l). Analysis of variance and mean comparisons revealed that the highest percentage of callugenesis was observed in B5 Medium. At somatic embryogenesis stage, factorial experiments (with tree factors including medium, hormones and kanamycin) were performed based on completely randomized design with 8 replicates. Results indicated that the most embrygenesis and regeneration of somatic embryonic obtained from hypocotyl explants on B5 medium supplemented with 1 mg/l 2, 4-D and 25 mg/l Kanamaycin.

Induction and selection for salt stress tolerance in plants by synchronized application of tissue culture and mutation is a most useful approach for creation of salt stress tolerant plant. In order to study the effect salt stress tolerance of irradiated CALLI in soybean, an experiment was conducted in 2001 in tissue culture laboratory of NRCAM in a completely randomized design as factorial experiment. In this study we found some salt tolerant cells among cultured CALLI of three soybean cultivars (KW 506, RP. and L. 17), using this approach. We selected those cells after irradiation of CALLI with Gamma ray and various concentration of salt in callus weight increase (W2-W1), callus weight increase ratio [(W2-W1)/W1)] and the percentage of necrotic CALLI percentage. Among different doses of Gamma ray, "10 Guy" was the best, and decreased necrotic CALLI percentage. Despite of somaclonal variation, irradiation treatments affected the creation of tolerance trait in CALLI, so that a few tolerant calluses obtained up to 1% of salt (NaCl).

Alfalfa (Medicago sativa L.) is one of the important forage crops in arid and semi-arid region. Drought as environmental stress reduce plant growth specially alfalfa. In order to study of alfalfa (Medicago sativa L.) CALLI and in vitro selection for drought tolerance a factorial trial as completely randomized design with 9 treatments and 10 replications was done. The comparison was made on variety CUF 101 and soma clones 7R1 and 7R2 in the stage of callus initiation, from view of wet weight, dry weight, dry to wet weight ratio and accumulation of proline in the callus and finally evaluation of regeneration in the presence of different mannitol concentrations (0, 0.4 and 0.7 molar). Results showed that there is a significant difference between alfalfa genotypes in terms of wet weight, dry weight, dry to wet weight ratio, praline accumulation and regeneration percentage in different mannitol concentrations. By increasing drought stress (mannitol concentrations) amounts of dry weight, dry to wet weight ratio and accumulation of proline were increased while the callus wet weight and regeneration percentage were decreased. Shoot formed on high concentrations of mannitol (0.4 molar) were transferred to root induction medium for root induction and shoot elongation. The resulting plantlets were potted into a soil-sand-peat moss mixture for adaptation then transferred to soil to set seed.

Dianthus barbatus is an important ornamental bedding plant in temperate regions with traditional medicinal applications. Water shortage and drought stress are major limitations for landscape development and plant medicine production. Callogenesis is the key step for modern plant breeding techniques and in vitro drought stress study defines the mechanisms of plant response to stress. Therefore this research focused on a) callogenesis optimization by different explants (leaf, stem and root) and plant growth regulators (BAP, NAA and 2, 4-D) and b) effect of osmotic stress (-1,-3,-6,-9 and-12 bar) induced by polyethylene glycol on D. barbatus CALLI. For callogenesis optimization, various criteria such as callogenesis percentage, CALLI colour, tissue type and growth besides chlorosis and necrosis were observed. In the second part, total protein and glycine-betaine content besides the activity of some free radical scavenger enzymes such as superoxide dismutase, catalase, peroxidase were also measured during stress at various levels. Results indicate leaf as the most suitable explant and both 2µ M BAP + 4µ M NAA and 2µ M BAP + 6µ M NAA as the most suitable media supplements for callogenesis. As CALLI were subjected to osmotic stress, growth and weight of stressed CALLI decreased by osmotic stress increment. As osmotic pressure decreased (osmotic stress increased), total protein content decreased while glycine-betaine osmolyte increased. The activity of some free radical scavenger enzymes such as superoxide dismutase, catalase, peroxidase also increased by osmotic stress increment.

To establish a dynamic and fine suspension culture, four different methods of tomato cell suspension culture were compared. Hypocotyl explants of the tomato cultivar Jina were used for callus induction on Murashige and Skoog (MS) Medium supplemented with three different phytohormone combinations. Then, one gram of each type of CALLI was transferred to 50 mL of liquid MS medium with four combinations of auxins and cytokinins to produce cell suspensions. The growth rate, judged by cell turbidity, cell fresh weight, and cell viability was evaluated. The best suspension culture was obtained by using friable CALLI formed on MS medium containing 1 mg L-1 NAA and 0. 1 mg L-1 kinetin, transferred to the liquid MS supplemented with 2 mg L-1 NAA, 0. 2 mg L-1 2, 4-D and 0. 2 mg L-1 zeatin.

Studies show that Oryza sativa L. contains a structure named b-glucan with anti-cancer properties. In the present study, a tissue culture for rice was carried out and b-glucan content was measured under various sugar and vitamin levels in basic MS medium. Seeds of Hashemi cultivar were cultured on MS medium. Two plant hormones, namely, 2, 4-D (0, 1, 1.5, 2 and 3 mg/l) and kinetin (0, 0.5, 1, and 1.5 mg/l) were used to form callus after one week. To extract b-glucan, calluses were incubated by three different sugar treatments with concentrations 15, 30, and 45 g/l and by three vitamin treatments with concentrations 2.5, 5, and 10 cc. After 30 days, those calluses treated with sucrose 45 g/l had a deeper yellow color than other calluses. In fact, higher concentrations of sugar led to deeper color of calluses which were more rigid and dry and, at the same time, more fragile and less bright in color. The calluses were then dried in an oven, and soluble and insoluble sugars were extracted. Results indicated that highest levels of soluble and insoluble sugars (including b-glucan) were achieved in medium containing 3% sucrose. Increase in vitamins did not generally affect soluble and insoluble sugars levels, and just in the medium containing 5cc vitamin, insoluble sugars increased.