IRANIAN JOURNAL OF HORTICULTURAL SCIENCE AND TECHNOLOGY
Year:2000 | Volume:1 | Issue:1-2|Papers Count:9

Experiments were conducted to micropropagate sweet lime from shoot- tip (5 mm long) and single-node (5-10 mm long) explants. The explants were surface sterilized and cultured on basic MS medium supplement with various concentrations of benzyladenin (BA) in combination with different concentrations of kinetin (Kin) and naphthaleneacetic acid (NAA). A combination of 1.25 mg I-1 BA with 0.5 mg I-1, NAA and 0.5 mg I-1 Kin was the most suitable, treatment for shoot proliferation using both explants. Shoots obtained from in vitro culture were subcultured four times, each with a 4-week interval, on a fresh medium. Effects of some other variables, such as explant source and adding gibberellic acid (GA3) to the medium, on shoot proliferation rate, were also studied. Single-node, explants, compared to shoot-, tip explants had a better response to in vitro conditions. For rooting, basic MS medium with half or full concentrations of salts plus vitamins, 1.5 or 3%, sucrose and 6 g I-1 agar were used. A five-second quick-dip in sterilized 500 mg I-1 NAA solution before inserting the explants on the medium or direct transferring of the explants on a medium containing 0.25 mg I-1 BA and 0.25 mg I-1 NAA resulted to a good rooting after 4 weeks. The rooted plantlets were successfully acclimatized in a sterilized vermiculite mixture which was superior to quartz, peat moss or mixtures of the three rooting media. Plantlets irrigated with one-eight-concentration of MS salt solution in first week, were easily acclimatized.

Plant regeneration via somatic embryogenesis from different parts of flowers in some genotypes of petunia and ornamental tobacco was investigated. Also the effects of cold treatments, light, darkness and culture medium with different combinations of growth regulators were studied. After sterilization, explants were cultured aseptically. The results showed that the genotypes and different explants from the same genotype affected differently the callus and plant regeneration. Maximum regenerated plants from pedicel culture in petunia (Pc 622 genotype) and in tobacco (N. glutinosa Linn. genotype) were 16% and 179%, respectively. The best culture medium was Murashage and Skoog (MS) with 3 mg 1-1 BAP and 0.2 mg 1-1 NAA. On this medium, the two mentioned genotypes regenerated 90 and 562 % plants from pedicel culture, respectively. No regeneration was obtained from different explants without cold treatment and a period of 7 to 9 days cold treatment increased the rate of regeneration in different genotypes of petunia and tobacco. The effects of light and dark treatments on the rate of regeneration in N. glutinosa were depended to explants. In N. glutinosa regenerated plants from ovary was 10% in darkness and 2.4% in light, while for explants obtained from pedicel, adversely, there were 226% and 112.5% in light and dark, respectively.

An experiment was conducted in Nough Rafsanjan to evaluate the effects of heading back and pinching on latent bud growth, yield and return bloom of pistachio cultivars. In this experiment, 13 to15 years old trees "Kalleh-ghuchi" and "Owhadi" cultivars on Pistacia vera L rootstock were used to evaluate the above parameters. Heading back of 1, 2 and 3-years old wood was performed before bud break and pinching was done at the beginning of new growth prior to the "off" and "on" year of both cultivars. The results of heading back treatment showed that cutting back of branches of both cultivars in both conditions of "off" and "on" induced lateral branch formation, but their effects were different in each cultivar. Pinching of apical bud in "Owhadi" cultivar had no significant effect on latent bud growth, but pinching in "Kalleh-ghuchi" induced lateral breaching. Heading back of 2-years old wood in "Kalleh-ghuchi" and 3-years old wood in "Owhadi" in "on" year reduced yield in the year of treatment, but increased the yield in later year.

Flower induction is the first and major step in grape production. This phenomenon is affected by environmental and internal growth regulators. The present study was carried out to study the effect of kinetin and gibberellic acid at concentrations, of 25, 50 and 100 mg I-1 at the time of induction on flower and fruit production in grape cv. Siah Shiraz., both under irrigated and dry farming conditions. Results of ringing and defoliation indicated that flowers are induced during May in both locations. Statistical analysis indicated that kinetin at the concentration of 50 m g 1-1 increased flower primordial (anlagen) formation, whereas GA caused elongation of flower base and stopped further flower development. Necrotic tissues were observed when buds were sectioned and viewed under the microscope. Although positive effect of kinetin on fruit characteristics was not significant, however, GA3 at 50 and 100 mg 1-1 reduced yield, rachis length weight and berry number per cluster. The effect was more pronounced on dry farming vines than irrigated ones.

Molecular markers as a quick and certain means for research were used for identification of seven local olive cultivars in Gorgan province. Results showed that among three buffer solutions were used for pollen protein extraction. The best result was obtained by using Tris-HCL buffer (pH=8), containing 0.1 M Tirs and 10% (v/w) glycerol. The rich amount of phenols, lipids, pigments made the extraction of proteins from leaves very difficult and observed bands faked enough clarity. The best result was obtained from Tris- HCL buffer (pH=7.6) containing 0.1 M tris, 7% (v/w) succorse, 1% (v/w) BSA, 5 mM sodium metabisulfite, 3%,(v/w) PEG 2000, 1% PVP 40 and 2.5% (v/w) 2-mercaptoethanol. No reaction was observed as an evidence for PX and ACP. In spite of the activity of SOD and CAT no polymorphism was observed in these enzymes. Among seven examined enzyme, merely EST, MDH and ADH showed polymorphisme. According the final dendrogram, UPGAM separates the cultivars into three main groups. The first group included three cultivars (Zard, G2 and H2), second group included two cultivars (M2 and M1) and third group included two cultivars (I2 and H3).

Individual sealing and liner of orange (Citrus sinensis (L.) Osbeck cv. Valencia) with heat-shrinkable films of low-density polyethylene (LDPE), high-density polyethylene (HDPE), oriented polyethylene(OPP)  and polyvinyl chloride (PVC) were compared with cooling for periods up to 4 months. Individual sealing and liner fruit with LDPE, HDPE and OPP films at ambient storage (20.6-33 °C and 49-64.4% RH) had similar weight-loss and marketability up to 1 month when compared with non-packaged fruits at cold storage (5°C and 60-85% RH). However, PVC had not such effect. The percentage of peel moisture of liner and individual seal-packaging fruits with LDPE and HDPE remained as non-packaged, fruits in cold storage but were softer.Regardless of film thickness, two methods of packaging in LDPE, HDPE, OPP and PVC inhibited fruit weight loss at maximum and minimum rates, respectively. However, films permeability to water vapor were probably influenced by chemical composition of the films as well as by films thickness. Liners at cold storage and up to 2 months at ambient storage had more weight loss than individual sealing fruits. No significant differences in percentage of peel moisture and firmness were found between liner and individual seal-packaging fruits. Liner packaging effect was probably due to the water saturated atmosphere in the liner enclosure around the fruits. It was observed that the liner technique as individual sealing maintained the freshness of fruits.

To determine the effects of three constant temperatures (5, 15 and 20°C) on in vitro pollen germination in three apricot cultivars, a factorial experiment was carried out based on RCB with three replications. Branches with flower buds of 'Dorosht-e-Malayer', 'Shastemy-e-Yek' and 'Ghermez-e-Shahroodi' cultivars in Sahand Horticultural Research Station were cut at Fleckinger's D stage. After collecting and culturing the pollen grains, the process of germination was observed under a microscope. The results revealed that the effects of temperature and cultivar on percentages of pollen germination were significant. The interaction between temperature and cultivar was also significant. The percentage of pollen germination in all three cultivars at 5°C was low, so that they showed a significant difference with those at 15 and 20°C. The maximum germination potential was found in 'Dorosht-e-Malayer' whilst the minimum was noticed in Shastemy-e-Yek'. However, at 15°C 'Ghermeze-Shahroodi' had a high germination percentage in comparison with the 'Dorosht-e-Malayer', having no significant difference.