Aeschynomene sp. prope villosa (a dalbergioid legume) represents a group of populations with morphological characteristics similar to those of Aeschynomene villosa, but without complete overlap, and whose cytogenetic characteristics subtly differ from both the latter and other related taxa. In this study, conventional surface spread and air-drying techniques, along with Giemsa staining, were used to analyze metaphase chromosome complements and karyotypes of individuals belonging to a population of A. sp. prope villosa, a taxon included in the Americanae series of Aeschynomene. The results confirm a previously obtained karyotypic formula. Differences observed in chromosome sizes do not modify the karyotype or its symmetry. They are interpreted here as a loss of gene flow between populations or adaptations to different ecogeographic conditions. The presence of chromosome stickiness in 7.4% of the nuclei analyzed is noteworthy. This aberration, not previously observed in Aeschynomene, primarily involves areas near the telomeres of apparently homologous and non-homologous chromosomes. This phenomenon, observed mainly in meiosis, has been linked to the tendency of chromosomes to clump together during cellular divisions following plant hybridization events. The same criterion of chromosomal interaction after hybridization could explain the changes in the number and position of satellites recorded in a previous study. Although unexpected, these results should not be surprising, since intergradation between A. villosa and A. americana, species with which it overlaps in its distribution area, has been suspected for at least 70 years. Furthermore, hybridization and allopolyploidy have already been demonstrated in other morphological series of Aeschynomene.
A crucial method for evaluating the potential harm to the genome caused by contaminants at levels exceeding the optimal threshold is the chromosomal plant assay. This paper reports on a study that examined the effects of varying concentrations of manganese (Mn) on the mitotic index (MI), cell kinetics index (CKI), and abnormality index (AI) in Glycine max L. root tip cells. Percentage of mitotic index, abnormality index, cell kinetics index, in root meristems of Glycine max L. at control and varying concentrations of Mn were evaluated. The findings showed that Mn doses that were utilized for seed treatment caused distinct differences in chromosomal activity of Glycine max L. root tip cells, with a decreased mitotic index and cell kinetics, and an increased abnormality index. Treatment was conducted at room temperature for 24 hours, 48 hours, and 72 hours at four different concentrations of Mn: CN (Control), 5μM, 10μM, 15μM, and 20μM. The control group was treated with distilled water. The findings demonstrated that Mn has cytotoxic and genotoxic effects on Glycine max L. root tip cells.
The fertilization of eggs may be delayed during induced fish breeding due to unforeseen circumstances. It is, therefore, necessary to know the optimal delay period and explore short-term storage options that can extend the viability of the eggs in such instances. In two studies, African catfish Clarias gariepinus eggs were obtained from broodstocks induced using ovaprim® hormone at 0.5ml/kg. A batch of the stripped eggs was then exposed in triplicate to atmospheric oxygen for 0, 1, 2, 3, 4, 8 and 12 hours post-stripping (HPS). In contrast, another batch was stored for 8 hours using sole and combined methods of “refrigeration”, “addition of extender” and “aeration”. The eggs were then fertilized using fresh sperm in all instances. In both experiments, egg characteristics, breeding parameters, and biometric parameters of hatched fry were recorded. Results showed a size reduction in the eggs as the time of exposure to atmospheric oxygen increased. Also, the fertilization and hatchability of eggs were similar to 4HPS; beyond this threshold, the value declined significantly to zero. However, the hatched fry’s biometric parameters showed no significant difference among treatments (P<0.05). The second study showed a poor breeding performance of eggs stored in all the different storage methods tested. Meanwhile, egg sizes and biometric parameters of the few hatched fry show no significant difference among the treatments (P<0.05). It was therefore concluded that the fertilization of stripped C. gariepinus eggs should not be later than 4HPS to optimize the breeding performance of the fish.
We investigated the intra-specific relationships between three Solanum species in Egypt: Solanum nigrum, Solanum villosum, and Solanum sinaicum, in addition to the inter-specific relationships among the populations of the three studied species. These species’ taxonomic difficulty is primarily due to its inconsistent infra-specific treatments in various floras. The morphological studies revealed distinguishing characteristics for the three investigated Solanum species mainly fruit and flower characteristics. The morphological differences allowed S. villosum to be divided into two subspecies: subsp. villosum, and subsp. miniatum. The genetic variation between the three Solanum species was clarified using AFLP technique. The ribosomal DNA ITS1-5.8S-ITS2 region of the three studied species was sequenced using the universal primers ITS4 and ITS5. The DNA sequences of Solanum species were counted. The karyotypes of the species under examination were established using the chromosome number and genome size acquired from mitotic chromosomal preparations.
The rapid rise of heavy metals and their extensive industrial use have raised concerns because these metals are released into the environment from both intentional and unintentional sources. When present in the environment in high concentrations, heavy metals may threaten the plant kingdom, particularly staple food crops. Nevertheless, little research has been done to identify the effects of heavy metals. The current study aims to assess the cytological alterations caused by lead (Pb) and copper (Cu) heavy metals on Glycine max Cv-JS-355. For two hours, Glycine max seeds were subjected to different Pb and Cu concentrations (CN, 25, 50, 75, 100, and 125 ppm). They were examined for their effects on chromosomal aberrations (CAs), micronucleus index (MNI), radicle length (RL), mitotic index (MI), cell death (CD), and seed germination (SG). The findings show a dose-dependent rise in MNI, CAs, CD and a substantial decrease in SG, RL, and MI. Furthermore, the percentage of abnormal mitotic cells, including cell nucleic leaking (CNL), Multi-pole division (MPD), Chromosomal bridge at telophase (CBT), chromosome retarded in anaphase (CRA), Dissociate chromosome in metaphase (DCM), increased in the Pb and Cu treated groups.
