Phenolic acid allelochemicals induced morphological,ultrastructural, and cytological modification on <Emphasis Type="Italic">Cassia sophera</Emphasis> L. and <Emphasis Type="Italic">Allium cepa</Emphasis> L.

The allelopathic potential of leaf aqueous extract (LAE) of Calotropis procera on growth behavior, ultrastructural changes on Cassia sophera L., and cytological changes on Allium cepa L. was investigated. LAE at different concentrations (0.5, 1, 2, and 4 %) significantly reduced the root length, shoot length, and dry biomass of C. sophera. Besides, the ultrastructural changes (through scanning electron microscopy, SEM) induced in epidermal cells of 15-day-old seedlings of Cassia leaf were also noticed. The changes induced were shrinking and contraction of epidermal cells along with the formation of major grooves, canals, and cyst-like structures. The treated samples of epidermal cells no longer seem to be smooth as compared to control. LAE at different concentrations induces chromosomal aberrations and variation in shape of the interphase and prophase nucleus in A. cepa root tip cells when compared with control groups. The mitotic index in treated onion root tips decreased with increasing concentrations of the extracts. The most frequent aberrations were despiralization at prophase with the formation of micronuclei, sticky anaphase with bridges, sticky telophase, C-metaphase, etc. The results also show the induction of ghost cells, cells with membrane damage, and cells with heterochromatic nuclei by extract treatment. Upon HPLC analysis, nine phenolic acids (caffeic acid, gentisic acid, catechol, gallic acid, syringic acid, ellagic acid, resorcinol, p-coumaric acid, and p-hydroxy benzoic acid) were identified. Thus, the phenolic acids are mainly responsible for the allelopathic behavior of C. procera.     

Allium cepa assay based comparative study of selected vegetables and the chromosomal aberrations due to heavy metal accumulation

Irrigation of industrial effluents may end in the bioaccumulation of various toxic metals and consequent genetic changes in contaminated food crops. To test this hypothesis and extent of genetic modifications, Allium cepa test was performed to food crops viz. tomato (Lycopersicum esculentum) and chili (Capsicum annum) as Allium cepa test is a useful tool to assess genetic variations in plants. Prior to A. cepa test, the plants were exposed to various metal concentrations 125–1000 mg/L in the synthetic wastewater. The extracts of harvested plants were used to grow the root of A. cepa following its standard method. The root tips were fixed, stained and examined under compound microscope (almost 300–400 dividing cells) to check the extent of chromosomal variations during various stages of mitosis. The results revealed various chromosomal abnormalities including laggards, stickiness, vagrant chromosomes, binucleated cells, nuclear lesions, giant cells and c-mitosis at different level of treatment. On the whole, aberrations were increasing with the increasing doses along the positive control. In comparison, chili crop had higher level of aberrations depicting the higher chromosomal changes. Lower mitotic index (MI) with increasing level of doses was also describing the hampered cell division due to increased metal stress. The study is showing that the cell division was ceased with increasing metal stress thus increasing the rate of cell aberrations.     

Detection of chemically induced aneuploidy with plant test systems

The utility of plant test systems for detecting chemically induced aneuploidy was evaluated by using papers published in peer-reviewed journals. A total of 147 papers were provided to the group by the Environmental Mutagen Information Center. Based on the criteria established by the Gene-Tox Committee (Waters and Auletta, 1981), 22 papers were selected for in-depth review. Only those papers listing additional, missing, or lagging chromosomes in the meiotic or mitotic cells were included in this review. Although most plant test systems may be developed to utilize either mitotic or meiotic cells for cytogenetic analysis, only a few have been employed for this purpose. In this review, Allium cepa was found to be the most commonly used test system. Other species used less frequently were Vicia faba, Hordeum vulgare, Sorgham vulgare, and Pennisetum americanum. None of the plant test systems have been sufficiently utilized to warrant judgment for its sensitivity and specificity for detecting induced aneuploidy. A suggested protocol for detecting chromosomal malsegregation in meiotic or mitotic cells is presented. Further development and utilization of plant tissue culture techniques and morphological markers identifiable in the seedling stages is recommended for detecting chemically induced aneuploidy.     

Cytogenetic effects of silver and gold nanoparticles on Allium cepa roots

The present study evaluates the cytogenetic effects of both silver and gold nanoparticles on the root cells of Allium cepa. In this study, the root cells of Allium cepa were treated with both gold and silver nanoparticles of different concentrations (1?mg/L, 5?mg/L and 10?mg/L) along with control for 72?h. Experimental results revealed that after 72?h of exposure, a significant decrease in mitotic index (MI) from 68% (control) to 52.4% (1?mg/L), 47.3% (5?mg/L) and 41.4% (10?mg/L) for gold nanoparticles and 57.1% (1?mg/L), 53% (5?mg/l), 55.8% (10?mg/L) for silver nanoparticles. Through minute observation of the photograph, it was recorded that some specific chromosomal abnormalities such as stickiness of chromosome, chromosome breaks, nuclear notch, and clumped chromosome at different exposure conditions. Therefore, present results clearly suggest that Allium cepa root tip assay could be a viable path through which negative impact of both gold and silver nanoparticles can be demonstrated over a wide range of concentrations.     

Genotoxicity of five food preservatives tested on root tips of Allium cepa L.

The effects of the food preservatives sodium benzoate (SB), boric acid (BA), citric acid (CA), potassium citrate (PC) and sodium citrate (SC) have been studied on root tips of Allium cepa L. Roots of A. cepa were treated with a series of concentrations, ranging from 20 to 100 ppm for 5, 10 and 20 h. The results indicate that these food preservatives reduced mitotic division in A. cepa compared with the respective control. Mitotic index values were generally decreased with increasing concentrations and longer treatment times. Additionally, variations in the percentage of mitotic stages were observed. The total percentage of aberrations generally increased with increasing concentrations of these chemicals and the longer period of treatment. Different abnormal mitotic figures were observed in all mitotic phases. Among these abnormalities were anaphase bridges, C-mitosis, micronuclei, lagging, stickiness, breaks and unequal distiribution.     

Genotoxic potential of the latex from cotton-leaf physicnut (Jatropha gossypiifolia L.)

Jatropha gossypiifolia L. (Euphorbiaceae), popularly known as cotton-leaf physicnut, is a milky shrub notable for its medicinal properties. The present study aimed to evaluate the toxic, cytotoxic and genotoxic effects of the latex of J. gossypiifolia, using Allium cepa L. as test system. Seeds of A. cepa were exposed to five concentrations of the latex (1.25; 2.5; 5; 10 and 20 mL/L) in order to evaluate parameters of toxicity (evaluation of root growth), cytotoxicity (mitotic index frequency) and genotoxicity (frequency of chromosome alterations). The latex showed a significant decrease in root mean growth value as well as mitotic index for the tested concentrations, except for 1.25 mL/L, when compared to results from the negative control. The 1.25, 2.5 and 5 mL/L concentrations induced significant chromo-some adherences, C-metaphases and/or chromosome bridges, as genotoxic effects. The significant frequency of chromosome bridges also indicated mutagenic potential for chromosomes of J. gossypiifolia as discussed in the paper. Considering that the latex is used in popular therapies, and that the test system A. cepa presents good correlation with tests carried out in mammals, it can be pointed out that its use for medicinal purposes may be harmful to human health especially if ingested.     

Cytotoxic and genotoxic effects of <Emphasis Type="Italic">Lavandula stoechas</Emphasis> aqueous extracts

Lavandula genus is an important member of Labiatae (Lamiaceae) family. People use commonly Lavandula stoechas as a medicinal plant for various diseases around the world and also in Turkey. The aim of this study was to investigate cytotoxic and genotoxic effects of aqueous extracts (40, 80 and 120 g/L) from L. stoechas flowers on Allium cepa root tip meristem cells. For this purpose, A. cepa onion bulbs were treated with the above-mentioned L. stoechas flower extracts for 72 h. Spring water (pH 7.3) was used as a control. The result of this study sowed that aqueous extracts reduced mitotic index, but induced chromosome aberrations and mitotic aberrations in comparison with control, significantly (p < 0.05). Aqueous extracts induced breaks, stickiness, pole deviations and micronuclei. Furthermore, these effects were related to extract concentrations. These results showed that L. stoechas aqueous extracts have cytotoxic and genotoxic effects.     

Comparison of cytotoxic and genotoxic effects of plutonium-239 alpha particles and mobile phone GSM 900 radiation in the Allium cepa test

The goal of this study was to compare the cytotoxic and genotoxic effects of plutonium-239 alpha particles and GSM 900 modulated mobile phone (model Sony Ericsson K550i) radiation in the Allium cepa test. Three groups of bulbs were exposed to mobile phone radiation during 0 (sham), 3 and 9 h. A positive control group was treated during 20 min with plutonium-239 alpha-radiation. Mitotic abnormalities, chromosome aberrations, micronuclei and mitotic index were analyzed. Exposure to alpha-radiation from plutonium-239 and exposure to modulated radiation from mobile phone during 3 and 9 h significantly increased the mitotic index. GSM 900 mobile phone radiation as well as alpha-radiation from plutonium-239 induced both clastogenic and aneugenic effects. However, the aneugenic activity of mobile phone radiation was more pronounced. After 9 h of exposure to mobile phone radiation, polyploid cells, three-groups metaphases, amitoses and some unspecified abnormalities were detected, which were not registered in the other experimental groups. Importantly, GSM 900 mobile phone radiation increased the mitotic index, the frequency of mitotic and chromosome abnormalities, and the micronucleus frequency in a time-dependent manner. Due to its sensitivity, the A. cepa test can be recommended as a useful cytogenetic assay to assess cytotoxic and genotoxic effects of radiofrequency electromagnetic fields.     

Chromosomal location of rDNA in Allium: in situ hybridization using biotin- and fluorescein-labelled probe

Summary A biotin- and fluorescein-labelled probe of Helianthus argophyllus has been used to map specific repeated rDNA sequences by in situ hybridization on mitotic chromosomes of Alliwn cepa, Allium fistulosum, a diploid interspecific (Allium fistulosum x Allium cepa) F₁ hybrid, and a triploid interspecific (2 x = A. cepa, 1 x = A. fistulosum) shallot. Hybridization sites were restricted to satellited and smallest pairs of chromosomes in both A. cepa and A. fistulosum. The number, size, and position of the hybridization sites distinguish homologous chromosomes and identify the individual chromosomes carrying the nucleolus organizing region (NOR) at the secondary constriction, as well as the individual chromosomes carrying an additional NOR. This in situ hybridization technique is the first reported in a plant species and offers new cytogenetic markers in Allium.     

Physiological and cellular mechanisms of natural herbicide resource from Aglaia odorata Lour. on bioassay plants

A bioassay-guided fractionation of the allelochemicals of the ethyl acetate fraction extracted from Aglaia odorata led to isolation of a bisamide, odorine. The growth inhibitory effects of odorine and ethyl acetate fraction were studied for comparison on Echinochloa crus-galli. Odorine and ethyl acetate fraction of A. odorata could inhibit the germination and seedling growth of E. crus-galli, with ethyl acetate fraction being more potent. Thus, ethyl acetate fraction was selected for further experiment, E. crus-galli seeds were studied the effects of the ethyl acetate fraction from A. odorata leaves in wettable powder formulation on imbibition and ??-amylase activity. It was found that treated seeds showed lower imbibition and ??-amylase activity. The results of cytogenetic bioassay in Allium cepa roots showed that ethyl acetate fraction inhibited cell mitosis and induced mitotic abnormalities resulting from its action on chromatin organization and mitotic spindle in the exposed roots.     

Die ursachen der sterilität vonAllium sativum L.

A fully normal meiosis was found inAllium sativum L. by means of PMC analysis. Quadrivalents were formed only in several cultivars. The cultivation of inflorescence stem (after the exstirpation of bulblets) in a tetracycline solution of 900 i.u. induced a formation of fertile flowers. The first pollen mitosis was studied and the pollen parameters compared with those ofAllium cepa L. Evidence for the pollen sterility was given by crossings on sterile types. A microbiological factor was not isolated.     

Isolation of 24-epibrassinolide from leaves of <Emphasis Type="Italic">Aegle marmelos</Emphasis> and evaluation of its antigenotoxicity employing <Emphasis Type="Italic">Allium cepa</Emphasis> chromosomal aberration assay

Brassinosteroids are of universal occurrence in plants. They have been reported to affect plant growth and development through a spectrum of physiological responses. Recently they are reported to confer resistance in plants against a number of biotic and abiotic stresses. In the present study, a brassinosteroid was isolated from Aegle marmelos Correa. (Rutaceae) which was characterized to be 24-epibrassinolide (EBL) using various spectroscopic techniques (TLC and ESI-MS analysis). It was evaluated for the antigenotoxicity against maleic hydrazide (MH) induced genotoxicity in Allium cepa chromosomal aberration assay. It was shown that the percentage of chromosomal aberrations induced by maleic hydrazide (0.01%) declined significantly with 24-epibrassinolide treatment. EBL (10⁻⁷ M) proved to be the most effective concentration with 91.8% inhibition. This is the first report on the isolation of 24-epibrassinolide from Aegle marmelos and its antigenotoxic effects against MH employing Allium cepa chromosomal aberration assay.     

Induction of polyploidy and C-tumours after treatingAllium cepa root tips with the herbicide “Treflan”

Treflan has the ability to induce polyploidy inAllium cepa root tips. The frequency of polyploidy was reduced after allowing the roots to recover, which indicates that the process of polyploidy is a reversible one, if we apply Treflan for a short time (4 h). As soon as the chemioal is removed from the cells, they go on with their normal way in division. It was found that the concentration 350 × 10^-5 ml Treflan per 100 ml water is an effective concentration in producing polyploidy in the roots ofAllium cepa. Treflan induced C-tumours in root tips ofAllium cepa. Two types of enlargement were noticed, complete swelling along the majority of root tips and complete swelling with a certain enlargement immediately after 2 mm terminal tips. The histological examination of these zones revealed that swellings were due to cell enlargement both in meristematic and in tumour zones. This conclusion was evidenced by the results obtained from the nucleoplasmic index.     

Effect of caffeine on G2 repair and its reversion by adenosine

Chromosome damage induced in root meristems of Allium cepa L. by an 18-h treatment with 5-aminouracil (AU) was enhanced by 2-h pulses with 5 mM caffeine, the most effective pulse being given from the 8th to the 10th h after AU. Chromosome damage was detected by the percentage of anaphases or telophases showing chromosomal aberrations. This caffeine effect was partially reversed by adenosine. We suggest that this caffeine anti-repair effect could be due to a competition between methylxanthine and an adenine-nucleotide derivative (ATP?) required for some step(s) of G₂-prophase repair.     

Cytological effects of papaverine hydrochloride on root tips ofAllium cepa L.

Papaverine hydrochloride, which is an alkaloid found in opium, inducedc-metaphase,c-anaphase, non-congression, diagonal anaphase, chromosome and chromatid bridges, lagging of chromosomes, micronuclei and multinucleated cells in root tips ofAllium cepa. It is the only one amongst the alkaloids of opium which caused a high increase in MI after a long period of treatment with some low concentrations.     

The improved Allium/Vicia root tip micronucleus assay for clastogenicity of environmental pollutants

The meristematic mitotic cells of plant roots are appropriate and efficient cytogenetic materials for the detection of clastogenicity of environmental pollutants, especially for in situ monitoring of water contaminants. Among several cytological endpoints in these fast dividing cells, such as chromosome/chromatid aberrations, sister-chromatid exchanges and micronuclei, the most effective and simplest indicator of cytological damage is micronucleus formation. Although the Allium cepa and Vicia faba root meristem micronucleus assays (Allium/Vicia root MCN) have been used in clastogenicity studies about 12 times by various authors in the last 25 years, there is no report on the comparison of the efficiency of these two plant systems and in different cell populations (meristem and F₁) of the root tip as well as under adequate recovery duration. In order to maximize the efficiency of these bioassays, the current study was designed to compare the Allium and the Vicia root MCN assays on the basis if chromosome length, peak sensitivity of the mitotic cells, and the regions of the root tip where the MCN are formed. The total length of the 2n complement of Allium chromosomes is 14.4 μm and the total length of the 2n complement of Vicia is 9.32 μm. The peak sensitivity determined by serial fixation at 12-h intervals after 100 R of X-irradiation is 44 h. The slope of the X-ray dose-response curve of Allium roots derived from the meristematic regions was lower than that derived from cells in the F₁ region. Higher efficiency was also demonstrated when the MCN frequencies were scored from the F₁ cells in both Allium and Vicia treated with formaldehyde (FA), mitonycin C (MMC), and maleic hydrazide (MH). The results indicated that scoring of MCN frequencies from the F₁ cell region of the root tip was more efficient than scoring from the meristematic region. The X-ray linear regression dose-response curves were established in both Allium and Vicia cell systems and the coefficients of correlations, slope values were used to verify the reliability and efficiency of these two plant cell systems. Based on the dose-response slope value of 0.894 for Allium and 0.643 for Vicia, the Allium root MCN was a more efficient test system. The greater sensitivity of the Allium roots is probably due to the greater total length of the diploid complement and the higher number of metacentric chromosomes. The Allium/Vicia root MCN test system was applied to determine the clastogenicity of saccharin (SC) and wastewater from Rio Queretaro and the Arena canal in the city of Queretaro, Mexico. The minimum effective dose (MED) is 10 R for X-rays, 50 mM for FA, 2.2 mM for MMC, 0.01 mM for MH, and 40 ppm for SC.     

Mutagenic and cytotoxic activities of benfuracarb insecticide

Benfuracarb is a carbamate insecticide used to control insect pests in vegetables and it has anti-acetylcholinesterase activity lower than other carbamates. Cytotoxic effects of benfuracarb were evaluated by using root growth inhibition (EC₅₀), mitotic index (MI), and mitotic phase determinations on the root meristem cells of Allium cepa and mutagenic effects were determined in Salmonella typhymurium Ames test by TA98 and TA100 strains with and without metabolic activation. In Allium test, 1 % DMSO was used as negative control group and 10 ppm MMS was used as positive control group. 75 ppm concentration of benfuracarb was found as EC₅₀. In MI and mitotic phases determination study, 37.5, 75 and 150 ppm doses of benfuracarb were used. Dose-dependent cytotoxic activity was found by root growth inhibition and MI studies. It was identified that mitotic inhibition activity of benfuracarb was higher than 10 ppm MMS. In Ames test, mutagenic activity was not observed and over 200 µg/plate of benfuracarb was determined as cytotoxic to S. typhymurium strains. Benfuracarb can be called as “mitotic inhibitor” but not called as mutagen.     

Synthesis of eco-friendly silver nanoparticles using Allium sp. and their antimicrobial potential on selected vaginal bacteria

Allium cepa and garlic Allium sativa plants were used to evaluate their potential synthesis of silver nanoparticles and their antibacterial effect on Streptococcus pneumoniae and Pseudomonas aeruginosa. Transmission electron microscopy (SEM) was used to distinguish the morphology of the nanoparticles attained from plant extracts. Energy dispersive X-ray (EDX) spectrometer established the existence of elemental sign of the silver and homogenous allocation of silver nanoparticles. Diffraction by using X ray (XRD) analysis for the formed AgNPs revealed spherical plus cubical shapes structure with different planes ranged between 111 and 311 planes. The antibacterial action of AgNPs against vaginal pathogens, Streptococcus pneumoniae and Pseudomonas aeruginosa was recognized. Our work showed a rapid, eco-safety and suitable method for the synthesis of AgNPs from Allium cepa and garlic Allium sativa extracts and can be used in biomedical applications.     

Inhibitory effect of fusicoccin on cell division

Rapid interactions in cell division and cytodifferentiationare induced by hormone treatments in dark-cultured explantsof Jerusalem artichoke. Fusicoccin, at concentrations between10^–6 and 10^–5 M, markedly inhibited the division-promotingactivity induced by plant hormones. Further, fusicoccin-treatedmeristematic root tips of Vicia faba and Allium cepa showeda rapid decrease in the mitotic index. Fusicoccin seems to inhibitsome hormone-sensitive processes required during the inductionand regulation of cell division. (Received March 28, 1979; )