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Geophytes are widely used for perfume and in the pharmaceutical industry as well as for ornamental flowers. Two million dollars is earned annually through the export of geophytes in Turkey. Because of their economic importance bulbs are frequently collected from their natural habitats. Their collection from the wild has resulted in some problems for many plant species. Iris stenophylla Hausskn & Siehe ex Baker subsp. allisonii B. Mathew is a critically endangered geophyte. In vitro production is an alternative method for the protection of this plant. In this study immature embryo and bulb scale explants were isolated and cultured on Murashige-Skoog (MS) medium supplemented with various combinations of 6-benzylaminopurin (BA) and alpha- naphthaleneacetic acid (NAA). The best result were obtained from MS medium supplemented with 1 mg/L BA and 0.25 mg/L NAA.

Habitat destruction has resulted in the extinction of many plant species from the earth, and many more face extinction. Likely, the annual endemic Mediterranean knapweed (Centaurea tchihatcheffii) growing in the Golbasi district of Ankara, Turkey is facing extinction and needs urgent conservation. Plant tissue culture, a potentially useful technique for ex situ multiplication, was used for the restoration of this ill-fated plant through seed germination, micropropagation from stem nodes, and adventitious shoot regeneration from immature zygotic embryos. The seeds were highly dormant and very difficult to germinate. No results were obtained from the micropropagation of stem nodes. However, immature zygotic embryos showed the highest adventitious shoot regeneration on Murashige and Skoog (MS) medium, containing 1 mg l(-1) kinetin and 0.25 mg l(-1) NAA. Regenerated shoots were best rooted on MS medium containing 1 mg l(-1) IBA and transferred to the greenhouse for flowering and seed set. As such, the present work is the first record of in vitro propagation of critically endangered C. tchihatcheffii, using immature zygotic embryos, and is a step forward towards conservation of this indigenous species.

Sternbergia fischeriana is an endangered geophyte and therefore in vitro micropropagation of this plant will have great importance for germplasm conservation and commercial production. Bulb scale and immature embryo explants of S. fischeriana were cultured on different nutrient media supplemented with various concentrations of plant growth regulators. Immature embryos produced higher number of bulblets than bulb scales. Large numbers of bulblets were regenerated (over 80 bulblets/explants) from immature embryos on Murashige and Skoog (MS) medium supplemented with 4 mg l−1 6-benzylaminopurine (BA) and 0.25 mg l−1α-naphthaleneacetic (NAA) or 2 mg l−12,4-dichlorophenoxyacetic acid (2,4-D) after 14 months of culture initiation. Regenerated bulblets were kept at 5 °C for 5 weeks and then transplanted to a potting mixture.

A protocol for in vitro propagation of Muscari mirum Speta, an endangered geophyte of the family Hyacinthaceae, was developed. Bulb scale, scape, leaf, and immature embryo explants were cultured on different nutrient media compositions supplemented with various concentrations of plant growth regulators (BAP, NAA, TDZ, Picloram, 2,4-D). Scape explants produced callus only. Higher numbers of bulblets were obtained from bulb scale explants than embryo explants. The highest percentage of the bulb formation (23.50 per explant) were obtained from bulb scale explants consisting of 4 scale segments cultured on Murashige and Skoog (MS) medium supplemented with 4 mg L-1 6-benzylaminopurine (BAP) and 0.25 mg L-1 alpha- naphthaleneacetic acid (NAA) after 5 months of culture initiation. Rooted bulblets which were more than 5 mm in diameter were transplanted into potting mixture of soil, vermiculite and perlite (1:1:1). The chromosome number of the root cells of in vitro induced bulblets was diploid 2n = 18.

SUMMARYIn this study, mitotic effects of gamma rays on Ekiz 1 variety belonging to Helianthus annuus L. (2n= 34) in the M0 (first irradiated seeds), M1 and M2 generations have been investigated. Seeds (M0) were irradiated with gamma rays at 10, 20, 30, 40 and 50 kR doses. Percentage of total abnormalities in the M0, M1 and M2 generations increased parallel to the increasing dose of radiation. These abnormalites have been observed as C-metaphase, chromosome stickiness, laggards and bridges with or without fragment. Mitotic index (M.I.) in the M0, M1 and M2 generations has decreased parallel to the dose increase. When the generations are compared, both the amounts of decrease in mitotic index and in the percentage of mitotic abnormalities were mostly observed in M0.

Efficient and reproducible shoot regeneration has been established from immature cotyledons and embryo axes of Hungarian vetch. Immature embryo axes showed higher regeneration capacity than immature cotyledons in most media tested. Immature cotyledons appeared to produce the highest frequency of shoot regeneration on 20 μM 6-benzylaminopurine (BA) and 2.5 μM α-naphthaleneacetic acid (NAA)-containing medium; whereas, shoot regeneration on immature embryo axes was best achieved on a medium supplemented with 5 μM each of BA and NAA. Regenerated shoots were excised and rooted in half-strength MS medium supplemented with 5 μM indole-3-butyric acid (IBA). Rooted plantlets were acclimatized to ambient conditions and later established under greenhouse conditions.

An efficient in vitro bulblet production procedure from immature zygotic embryos of endemic and endangered Muscari muscarimi Medik. was described in the current study. Zygotic embryos were first isolated from immature seeds and cultured on different nutrient media compositions supplemented with various combinations of ?-naphthalene acetic acid (NAA), picloram, dicamba, 6-benzylaminopurine (BAP), and thidiazuron (TDZ). The best bulblet regeneration (59 bulblets per explant) was achieved in Murashige and Skoog (MS) medium containing 4 mg/L BAP and 0.5 mg/L NAA after 1 year of culture initiation. Regenerated bulblets were then transferred into MS medium without plant growth regulators for rooting. Bulblets produced well-developed root systems and increased their size on this medium after 2 months. All rooted bulblets were successfully transplanted into a potting mixture and acclimatized to ambient conditions. © TÜBİTAK.