The use of dyes is one of the most controversial advances for the food industry because from a health point of view, such dyes, mainly the artificial dyes are not recommended. The objective of this study is to evaluate the cytotoxic effects of the food dyes sunset yellow and Tartrazine on the cellular cycle of Foeniculum vulgare Mill. Germinated root tips were treated with graded concentrations (viz. 0.5, 1, 1.5 and 2%) of sunset yellow and Tartrazine dyes along with a control set (roots dipped in distilled water) for duration of three hours. Roots were then fixed in Carnoy’s fixative and preserved in 90% alcohol. Slides were prepared and cells were analyzed during the whole cell cycle for evaluation effect of food dyes. Mitotic analysis clearly revealed that the azo dye induced endpoint deviation like reduction in the frequency of normal divisions in a dose dependent manner. The results showed that the two dyes used under the evaluated concentration were cytotoxic to the cells of the system used. Mitosis was found to be quite normal in control plants. An inverse relationship between the active mitotic index (AMI) and concentration of food dyes was scored. However, as a result of the treatment on root tip cells, various chromosomal anomalies were induced such as stickiness, fragmentation, precocious movement, C-metaphase, bridges and unorientation and so on. The stickiness was found to be predominant abnormality in both the treatments. These irregularities were more at the higher concentration of Sunset yellow and Tartrazine i.e. 2%. The result concluded that Tartrazine was more cytotoxic than Sunset yellow.
Controlling combining chromosomes in meiosis is necessary to maintain genome constitutions. The Dryopteirs varia complex is one of the apogamous fern groups which perform recurrent hybridization with unequal meiosis, and produce spores after meiosis of the genome doubling in spore mother cells. We analyzed five low-copy nuclear markers (AK1, EST, GapCp, G6PD, and PgiC) and three regions of plastid DNA (rbL, ndhF and trnL-F). The genetic constitution of the five nuclear markers was the same in the D. varia complex. Therefore, recurrent hybridization seemed to be occurred without homoeologous chromosome paring.
The accession showed the tetraploid chromosome number of 2n=28 and irregular meiotic course due to the presence of multivalents, univalents, scattered and unequal distribution of chromosomes, chromatin bridges and laggards. Besides, a few PMCs showed cytomixis and cell fusion resulting into syncytes. Meiotic course in syncytes was also irregular. Consequent to these aberrations, abnormal sporads and sterile pollen grains were resulted. Total pollen sterility in the accession seems to be under the control of genetic factors as reported by different workers. Complete pollen sterility leads to failure in seed set resulting into restricted/poor distribution of species.
Three mutants isolated according to differed morphological traits were isolated from the M2 progeny of gamma ray-irradiated Solanum melongena L. var. PPL, viz. PPL-j3 (5kR), PPL-k3-1 (15 kR), and PPL-k3-2 (15 kR). The seeds of selected mutants of M2 generation were collected individually and grown in M3 generation, separately and data on various quantitative traits, such as plant height (cm), number of branches per plant, number of fruits per plant, fruit weight (g), fruit size (cm), 1000-seed weight (g), and yield (kg) per plant, were recorded for all three mutants. The mutants were morphologically quite distinct, as compared to the control and to each other. The average performance of different quantitative traits was better in a high yielding mutant (PPL-j3) as compared to the control, while in other two mutants (PPL-k3-1 and PPL-k3-2), poor yield was observed. Cytological analysis revealed almost normal chromosomal set in mutant screened from 5 kR irradiated population, except for a few chromosomal aberrations. The higher frequency of meiotic aberrations was recorded in mutants isolated from 15 kR irradiated population. However, the frequency of these chromosomal irregularities decreased at anaphase, exhibiting recovery at later stages. A reduction in pollen fertility was also recorded in mutants isolated from 15 kR, indicating low fruit set.
The databases of chromosome number play significant role in research as they are useful for different areas, such as genetics, plant breeding, phytogeography, documenting intraspecific variation, endemism, plant systematics, origin of flora biodiversity and taxonomic relationship studies in diverse group of plants. The present database includes 702 unpublished and published records of the plants collected from 14 states of the India, which are preserved in our herbarium. These 702 records are distributued over 390 species, 272 genera and 71 famalies. The most explored family was Asteraceae (46 genus and 60 species) followed by Solanaceae (27 genera and 42 species). Intraspecific variations in chromosome number of 37 species has been recorded. In the database, chromosome count of seven species are reported first time in the science: Chassalia staintonii (H. Hara) Deb. et Mondal (n=11), Hygrophila erecta (Burm. f.) Hochr. (2n=29), Polygonum assamicum Meisn. (n=11), Salacca wallichiana Mart. (n=22), Salacca zalacca (Gaertn.) Voss (n=14), Sigesbeckia orientalis L. (n=12) and Stephania elegans Hook. f. et Thomson (n=18). In addition, new chromosome number in 60 species are also documented.