Engin Tilkat

Current status and conservation of Pistacia germplasm.

The genetic erosion of Pistacia germplasm has been highlighted in many reports. In order to emphasize this and to focus more attention on this subject, national and international (especially IPGRI and IFAR) institutions have initiated projects proposing to characterize, collect and conserve Pistacia germplasm. Therefore, this paper reviews recent research concerning conventional (in situ and ex situ) and unconventional biotechnological conservation strategies applied to the preservation of Pistacia germplasm. As regards conventional conservation, the majority of germplasm collections of Pistacia species are preserved on farms (in situ) and in seed and field genebanks (ex situ), as well as in the wild, where they are vulnerable to unexpected weather conditions and/or diseases. Hence, complementary successful unconventional in vitro methods (organogenesis, somatic embryogenesis and micrografting) and slow-growth storage conditions for medium-term preservation of Pistacia are presented together with the morphological and molecular studies carried out for the characterization of its species in this review. Moreover, special attention is additionally focused on cryopreservation (dehydration- and vitrification-based one-step freezing techniques) for the long-term preservation of Pistacia species. Possible basic principles concerning the establishment of a cryobank for the successful conservation of Pistacia germplasm are also discussed.

Micropropagation of mature male pistachio Pistacia vera L.

Summary Factors affecting the successful rapid proliferation and rooting of male pistachio (Pistacia vera L.) cv. Atlı, were studied. The most suitable type of cytokinin [6 benzyladenine (BA), kinetin (Kin), or thidiazuron (TDZ)], and the effect of eight different concentrations of BA (0.0675, 0.125, 0.25, 0.5, 1.0, 2.0, 4.0, or 8.0 mg l–1) were evaluated to optimise shoot proliferation. The auxins -naphthaleneacetic acid (NAA), indole-3-acetic acid (IAA), and indole-3-butyric acid (IBA), each at 2.0 mg l–1, or different concentrations (0.5, 1.0, 2.0, 4.0, or 8.0 mg l–1) of IBA, and the effect of explant size (1.0, 2.0, 3.0, or 4.0 cm) were assessed for root induction. The highest number of new microshoots per explant (5.64 ± 0.07) was obtained 4 weeks after culturing on Murashige and Skoog (MS) medium supplemented with 1.0 mg l–1 BA. Again, shoot length was highest in 1.0 mg l–1 BA, and decreased as the BA concentration increased. IBA was most effective in promoting root formation. The highest rooting frequency (73%) of microshoots was recorded for explants 4.0 cm in length, 4 weeks after culturing. In vitro-rooted plantlets were transferred to polyethylene pots filled with a 1:1:1 (v/v/v) mixture of soil, sand and peat.This treatment resulted in 90% survival of plantlets, which were acclimatised in a greenhouse.

Somatic embryogenesis of pistachio from female flowers

Summary Induction of somatic embryogenesis from the flower buds of pistachio (Pistacia vera L.) was studied with respect to growth regulators. Sixty-five percent of cultures formed embryogenic calli when placed on modified Murashige and Skoog medium containing 1 mg l–1 benzylaminopurine. In contrast, thidiazuron and α-naphthalene acetic acid reduced embryogenesis. Some of the somatic embryos had fused hypocotyls or multiple cotyledons. Abscisic acid was not necessary for maturation. Fewer somatic embryos germinated with 0.5 mg l–1 abscisic acid, but more converted into plantlets. Separate, morphologically normal, somatic embryos germinated on semi-solid germination medium, and developed into plantlets. Cytological analysis revealed a chromosome number of 2n = 2x = 30, similar to seedlings. The protocol described in this paper, for the induction of somatic embryos indirectly from female flowers of pistachio, represents a first step towards the production of clonal stocks.

Novel Methods in Micropropagation of Pistachio

The focus of this paper is to describe the novel methods developed for the different stages of micropropagation: installation of mature apical shoot tips and elimination of browning exudates; forcing hardwood shoots from the lignified stem sections; forcing axenic leaves; initiation of embryogenic masses (EMS); encapsulation of somatic embryos and cryopreservation of axillary buds for storage, and the facilitation of rooting. These developed methods are not being used by commercial micropropagation laboratories yet. Exudation of phenolics is inhibited when the disinfested and rinsed explants are cut at the base of the shoot tips and washed twice for 1 h by shaking them in sterile distilled water on a shaker at 100 rpm. For shoot initiation, 15–20 cm long terminal stem sections are cut into 3–4 cm sections and placed in pots filled with peat, perlite and soil. Two or three weeks later, the developed softwood shoots are excised; or freshly harvested three to nine apical tips of 1–2 cm are disinfested and used as explants. Leaves excised from axenic shoot cultures were also used to induce organogenesis on a Murashige and Skoog (MS) medium with Gamborg vitamins supplemented with combinations of different concentrations of 6-benzylaminopurine (BA) and indole-3-asetic acid (IAA). Calcium alginate gel was used to encapsulate somatic embryos to produce synthetic seeds. The encapsulated somatic embryos can be stored under refrigerated conditions for short-term conservation. For long-term conservation, some axillary buds can also be stored by using vitrification and one-step freezing technique; however, other cryogenic techniques should also be tested. With these improved stages, application of Pistachio vera L. micropropagation in commercial clonal orchards will be feasible as an alternative to traditional propagation in the near future.

Determination of the Fatty Acid Composition of the Fruits and Different Organs of Lentisk (Pistacia lentiscus L.)

Abstract This paper reports the fatty acid composition of the oil extracts from seeds and in vivo and in vitro grown organs of Pistacia lentiscus L. were determined by using gas chromatography. The main fatty acids were linoleic (LA), palmitic (PALM), oleic (OLA) and linolenic (ALA) acids in the fruits, resins and in both in vivo and in vitro grown root, leaf and stem sections of male or female tree. The major fatty acids were represented by polyunsaturated fatty acids (PUFA) accounting for 56.94 %, 64.44 % and 55.57 % in root, leaf and stem part of male tree grown in vivo, respectively. The prominent class of fatty acid composition of different male organs of P. lentiscus L. regenerated in vitro was represented by PUFA accounting for 63.24 %. The monounsaturated fatty acid (MUFA), OLA and PUFA, LA were determined in the oils of the two genotypes studied.