Context: Comparison between a wild type strain Rhizobium spp. (RCA-220) and a genetically modified strain E. coli BL21 in context of growth features.Objective: To observe the comparative growth characteristics of a genetically modified E. coli BL21 and an isolated wild type strain Rhizobium spp. (RCA-220). Materials and Methods:Different kinds of investigations were accomplished in both Luria-Bertani (LB) liquid and semi-solid media to observe the growth and maintenance of these strains. For the isolation of Rhizobium spp. selective Yeast Extract Manitol Agar (YEMA) was used. Colony morphology, pH, temperature, carbon source, salt concentration and light were taken under consideration and optimized for growth characteristics.Results: For the strain E. coli BL21, the maximum growth rate was 1.9 at incubation time 72 h, pH 7.2, temperature 37°C (optimized) while for Rhizobium spp. the growth rate was significantly higher (OD 2) at pH 6.8, temperature 28°C (optimized). Among all used carbon sources, strains grown in the medium supplemented with peptone showed rapid and good performance. So, peptone was proved as the best carbon source for both strains. The maximum growths of these strains were observed at 0g/100ml NaCl salt concentration. RCA-220 strain was comparatively more tolerable to salt than E. coli BL21 strain. In this work, E. coli BL21 showed rapid and good performance in presence of light while Rhizobium spp. showed better performance in absence of light. Statistical analysis showed that the growth rate of Rhizobium spp. was significantly higher than E. coli BL21. Conclusion:From the experimental results, it can be concluded that naturally obtained microbial strains were stable and could tolerate any stress condition where the modified strains lose their growth capability and the overall growth performances were reduced or slowed down than the wild type strain.

Context: In order to control weeds many chemicals are being used which may change the morphological and cytological constitution of plant. Objectives: To study the morphological and cytological effects of herbicides on tetraploid wheat. Materials and Methods: Two herbicides namely, Topstar and Fielder with three different concentrations of each were used along with control in the present study. Seeds of tetraploid wheat were treated for 6 hours with each concentration and some of the treated seeds were allowed to germinate in the petri dishes, while some were sown in the earthen pot. Morphological study was done for both laboratory and pot grown plants. In case of cytological study, mitotic data was recorded using the root tip cells and meiotic data was collected from inflorescence at pre-mature stage of pot grown plant. Results: In this experiment, data on morphological study such as germination percentage, days required in germination, coleoptile length, root length, plant height, ear length, tiller-number/pot, seed/ear, grain-weight/ear and 100 grain-weight indicated that treatment with Fielder decreased these characters with the increase of doses. In case of plant height, Topstar showed increased result than Fielder and control. Moreover, characters like ear length and seed/ear showed little variation among the doses of Topstar compared to control. Similarly, data on cytological study such as interphase chromosome volume (ICV), mitotic index (MI), % of pollen sterility, mitotic and meiotic abnormalities were found to be increased with increasing concentration of both herbicides. Main chromosomal irregularities were chromosome fragments, bridges, laggards, single and multiple chromatid bridges with laggard or fragment, stickiness etc. Conclusion: From the study of morphological and cytological effects of two herbicides along with control it can be concluded that these chemicals had adverse impacts which reduced the yield of wheat.