Cengiz Sancak

Cytological effects of the herbicide racer “flurochloridone” on Allium cepa

Abstract The present investigation was carried out to study the cytological effects of the herbicide racer “flurochloridone” (3-chloro-4-(chloromethyl)-1-[3-(trifluoromethyl)= phenyl]-2-pyrrolidinone) on Allium cepa with respect to the cell response, mitotic index, mitotic abnormalities and chromosome aberrations. The roots of bulbs were treated with the following concentrations depending on the root growth inhibition test: 80 ppm (LD50), 40 ppm (LD50/2) and 20 ppm (LD50/4). The results indicated that flurochloridone herbicide reduced the mitotic division in A. cepa as compared to their control groups. The reduction in mitotic activity was more significant when the concentration of the herbicide increased and the exposure time was prolonged. The treatment conducted with flurochloridone induced a significant percentage of abnormal mitosis. Seven types of abnormalities were recorded: C-metaphase, laggards, stickiness, bridges, fragments, multipolarity and poliploidy. Micronucleated cells were also observed at interphase. In additon, in pretreated root tips, chromosome breaks, fragments and sister union were detected.

Influence of different co-cultivation temperatures, periods and media on Agrobacterium tumefaciens-mediated gene transfer

Tobacco leaf disc explants were inoculated with Agrobacterum tumefaciens strain GV2260 carrying p35S GUS-INT to determine the influence of different co-cultivation temperatures (18 – 26 °C), periods (24 – 96 h) and media (solid and liquid) on transformation efficiency. Kanamycin-resistant shoots developed on leaf discs inoculated with Agrobacterium after 4 weeks of culture initiation. Regenerated shoots were excised and rooted in the basal medium supplemented with 100 mg dm −3 kanamycin and 250 mg dm −3 augmentin. The rooted plantlets were finally transferred to compost and confirmed by GUS assay and PCR analysis. The highest transformation frequency was achieved from the explants co-cultivated with A. tumefaciens in liquid medium for 48 h at 22 or 24 °C.

Efficient in vitro bulblet regeneration from immature embryos of endangered Sternbergia fischeriana

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.

In vitro shoot regeneration of fenugreek (Trigonella foenum-graecum L.) using different cytokinins

Although the delayed-type hypersensitivity (DTH) skin reaction to tuberculin is used worldwide for tuberculosis (TB) detection, it has poor diagnostic specificity due to the presence of common antigens in tuberculin shared by many mycobacterial species. The problem is noticed, especially in countries where the Bacillus Calmette-Gue´rin (BCG) vaccination is widely practiced. Thus, a new skin test antigen specific for the diagnosis of Mycobacterium tuberculosis (MTB) infection is urgently needed. CFP-10, a mycobacterial secretary protein that is absent in Mycobacterium bovis BCG and most other mycobacterial species including Mycobacterium avium, Mycobacterium intracellulare, has been shown to elicit cellular immune responses in MTB infected individuals and can be a good candidate for MTB specific diagnosis. We prepared recombinant MTB CFP-10, rCFP-10, and its utility as specific antigen for TB diagnosis was evaluated by skin testing in guinea pigs sensitized with M . tuberculosis, M. bovis, and M. bovis BCG. Our results show that the purified MTB rCFP-10 antigen elicits a positive skin response only in the guinea pigs sensitized with M. tuberculosis and M. bovis , and not in the animals sensitized with M. bovis BCG vaccine. The data presented in this study supports further testing of the use rCFP-10 as the specific antigen in the skin test for the diagnosis of MTB infection in humans. Key words : Recombinant CFP-10 protein, skin test, delayed-type hypersensitivity, tuberculosis infection, Mycobacterium tuberculosis, Mycobacterium bovis, Bacillus Calmette-Gue´rin.

Prolific shoot regeneration from immature embryo explants of sainfoin (Onobrychis viciifolia Scop.)

SummaryImmature cotyledons and embryo axes of sainfoin were cultured on Murashige and Skoog (MS) media supplemented with various concentrations of 6-benzylaminopurine (BAP) and a-naphthaleneacetic acid (NAA) to induce adventitious shoot regeneration. The highest frequency of shoot regeneration occurred following an initial callus growth on a MS medium containing 0.5 mg/l BAP and 2 mg/l NAA. Immature embryo axes showed higher regeneration capacity than immature cotyledons, however, shoot elongation was best achieved on immature cotyledons. Regenerated shoots were excised and rooted in half strength MS medium with 1 mg/l indole-butyric acid (IBA) or 1 mg/l NAA. The rooted plantlets were finally transferred to compost.

High frequency adventitious shoot regeneration in sainfoin

A procedure is described for the rapid and efficient adventitious shoot regeneration from leaflets, petioles and stems of field-grown sainfoin plants. All explants formed shoots on a range of media supplemented with 6-benzyladenine (BA) and α-naphthaleneacetic acid (NAA). Stem explants appeared to have better regeneration capacity than leaflet and petiole explants in most media tested. The highest frequency of shoot regeneration was achieved from stem segments on a medium containing 20 μM BA and 0.5 μM NAA. Regenerated shoots rooted in half-strength Murashige and Skoog medium containing 5 μM indole-3-butyric acid and later established well under greenhouse conditions.

High frequency shoot regeneration from immature embryo explants of Hungarian vetch

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.

In vitro crown galls induced by Agrobacterium tumefaciens strain A281 (pTiBo542) in Trigonella foenum-graecum

Transformation of fenugreek (Trigonella foenumgraecum) was carried out with A281 oncogenic strain of Agrobacterium tumefaciens using root, cotyledon and hypocotyl explants excised from 1-week-old seedlings, which showed that the plant was highly susceptible to transformation. Tumors (calli) were selected on 50 mg dm−3 kanamycin. They were analyzed for β-glucuronidase (GUS) expression. Presence of uidA (gus) gene, was confirmed by polymerase chain reaction (PCR) amplification.

Efficient Adventitious Shoot Regeneration in Cicer Milkvetch

ABSTRACT A procedure has been developed for high frequency adventitious shoot regeneration from hypocotyls, cotyledon, stem and petiole explants of cicer milkvetch. All explants isolated from in vitro seedlings were cultured on Murashige and Skoog (MS) media supplemented with various concentrations of 6-benzylaminopurine (BA) and α-naphthaleneacetic acid (NAA) to induce adventitious shoot regeneration. Hypocotyl explants appeared to have better regeneration capacity than stem, cotyledon and petiole explants in most of the media tested. The highest frequency of shoot regeneration was achieved from hypocotyl segments through an initial callus growth on MS medium containing 10 μM BA and 0.1 μM NAA. Regenerated shoots were excised and rooted in half-strength MS medium supplemented with 5.4 μM NAA. Rooted plantlets were acclimatized to ambient conditions and later established under greenhouse conditions.

Powdery mildews observed on Onobrychis spp. in Turkey

Erysiphe trifolii and Leveillula taurica on Onobrychis spp. in Turkey, are described and illustrated.