Melih Boydak

Silvicultural characteristics and natural regeneration of Pinus brutia Ten. - a review

Pinus brutia Ten. is a characteristic species of the eastern Mediterranean. P. brutia and P. halepensis Mill. are distinct species; but P. eldarica, P. stankewiczii and P. pityusa are subspecies of P. brutia. Fire is the major disturbance in P. brutia forests, and several adaptations generally contribute to post-fire regeneration of P. brutia; however, P. brutia can also naturally regenerate without fire. Flowering occurs between March and May. Seed distribution occurs throughout the year, with maximum dispersal in August and the great majority of seeds dispersing within the period July-December.P. brutia retains some closed cones and so establishes a natural canopy seed bank. Seed germination occurs in the rainy season with two frequency peaks: the major one in spring and a minor one in autumn. P. brutia seedlings develop rapidly-growing tap roots. Shelterwood, clearcutting and strip clearcut methods can successfully be applied to P. brutia forests, depending on local conditions. Density of P. brutia seedlings was greater and seedlings were more vigorous when the natural regeneration methods were combined with prescribed fire. Clearcutting methods combined with laying cone bearing branches on the surface of the soil and additional seeding increases regeneration success. Ground litter of 2–4 cm creates a medium that reduces evapotranspiration, delays growth of competing vegetation, and increases seedling survival. Successful regeneration must be established by the end of first vegetation period.

Genotype Differencies in Direct Plant Regeneration from Stem Explants of Populus tremula in Turkey

Plant regeneration from 9 clones ofPopulus tremula representing diverse genotypes originated from Turkey, has been studied in different media, such as Murashige and Skoog’s Medium (MS), Aspen Culture Medium (ACM) and Woody Plant Medium (WPM) with appropriate supplements of growth regulators. Regeneration efficiency on WPM containing 1 mg/l zeatin using stem explantsin vitro, was higher than on MS and ACM. In this system, the time required for shoot regeneration was 2 weeks, which was shorter by two weeks than that of previous reports. A strong genotype dependence was observed among the tested nine clones. The regeneration system, we describe here, did not involve the callus phase and thus was less prone to somaclonal variation. When adventitious microshoots were cultured on WPM supplemented with 0.5 mg/l or 2 mg/l indole-3-butyric acid (IBA), root formation was obtained after 1 week of culture. Adaptation of regenerated plantletsin vivo was 100%. This system for micropropagation ofPopulus tremula is expected to be suitable for studies on transformation of genes involved in lignin biosynthesis via modification of lignin content.

The distribution of Phoenix theophrasti in the Datça Peninsula, Turkey

Abstract Phoenix theophrasti was known from only five coastal localities in Crete, until new sites were found in the Datca Peninsula of Turkey. The natural distribution of this species in the Datca Peninsula is on the northern and southern slopes of the main mountain rannge. There are also a few scattered trees and groves. This record is an important addition to the flora of Turkey and it represents the first occurrence in Asia.

Seed crop investigation of Pinus sylvestris, Pinus nigra subsp. pallasiana and Pinus brutia in Turkey

Seed crop investigation of Pinus sylvestris, Pinus nigra subsp. pallasiana and Pinus brutia in Turkey

agrobacterium-Mediated Transformation of Peroxidase Gene to Tissue Culture of populus Tremula

Tissue culture of Populus tremula Dursunbey 2 clone from stem expiants was established. peroxidase gene isolated from Stylosanthes humilis (Shpx6), in antisense orientation was transferred to poplar via Agrobacterium tumefaciens. The effects of Shpx6 gene leads to modification of total peroxidase activity and total lignin amount. A reduction of total peroxidase activity for 50% and total lignin amont for 20% was observed in transgenic plants compared with control plants. The results obtained here, could be useful for utilization of poplar in paper and pulp industry.

Regeneration and Transformation of populus Tremula with Antisense pOMT8 from stylosanthes Humilis

Populus tremula was transformed using Agrobacterium tumefaciens with antisens O-metyltransferase gene from Stylosanthes humilis (pOMT8), which is showing 83% homology with COMT gene from poplar. In four out of ten transgenic plants OMT activity has been downregulated for 30–39%, however peroxidase activity was 100% higher compared with controls. While the lignin amount in transgenic plants was not changed, lignin composition were modified. Results indicate that it is possible to downregulate endogenous OMT activity and modified lignin composition through the introduction of heterologous consract from Stylosanthes humilis in Populus tremula.