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Background: Many genotoxicity tests allow us to understand the mechanism of damages on genetic material occurring in living organisms against various physical and chemical agents. One of them is the Comet test. The current study aimed to evaluate genotoxic caused by picloram and dicamba to root meristems of Allium cepa utilizing comet assay. Methods: Two different protocols were used for rooting and auxin/pesticide application. (i) A. cepa bulbs were rooted in MS medium and then treated with Murashige and Skoog (MS) medium (control) and 0.67, 1.34, 2.01, 2.68, 3.35, 4.02, and 8.04 mg/L of picloram and dicamba using aseptic tissue culture techniques. (ii) A. cepa bulbs were then rooted in bidistilled water and treated with 0 (control), 0.67, 1.34, 2.01, 2.68, 3.35, 4.02, and 8.04 mg/L of picloram and dicamba in distilled water. The A. cepa root tip cells in both treatment groups were examined using comet test to find the possible DNA damaging effects of picloram and dicamba. Results The results obtained at all the concentrations were statistically compared with their control groups. Almost at all the concentrations of Picloram and dicamba increased comet tail intensity (%) and tail moment in roots treated in MS medium. Two highest concentrations revealed toxic effect. On the other hand, DNA damaging effect of both auxins was only noted on the highest (> 4.02 mg/L) in roots treated in distilled water. Conclusions This study approve and confirm genotoxic effects of how growth regulators on plants. These findings give an evidence of DNA damage in A. cepa. Therefore, both picloram and dicamba should only be used in appropriate and recommended concentrations in agriculture to conserve ecosystem and to pose minimum threat to life.

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.

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.