No abstract

Materials composed of single or a few pure/modified graphitic layers can be easily synthesized using chemical methods. In the present work, nanocomposites of reduced graphene oxide (RGO) with zinc oxide (ZnO) have been prepared via in situ reduction of graphite oxide (GO). X-ray diffraction spectra (XRD) confirmed the coexistence of RGO and ZnO crystal planes. The XRD results were complimented by Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy. Incorporation of ZnO phase into the graphitic layers has been identified with the help of scanning electron microscopy (SEM). Incorporation of ZnO into graphitic layers has enhanced the thermal and optical characteristics of RGO but turned out with the reduced electrical conductivity. These nanocomposites illustrated fascinating antimicrobial activities against human pathogens E. coli and S. aureus.

A study on the effect of various phytohormonal combinations on in vitro propagation of Cocoyam [Xanthosoma sagittifolium (L.) Schott] was conducted to develop an improved and efficient in vitro regeneration protocol for its mass multiplication. Histological analysis to understand the in vitro regeneration pattern and genetic fidelity assessment of regenerated plants were also carried out. Single shoots excised from in vitro established cultures of X. sagittifolium were used as explants. Among the 32 different phytohormonal combinations tested, indirect organogenesis with intervening callus phase was observed on majority of the media combinations. Meristematic clump formation was optimally achieved on all the tested media combinations with maximum 43.54 ± 0.51 shoot primordia on MS medium containing 0.2 mg/L BAP + 0.1 mg/L NAA followed by 36.44 ± 0.76 shoot primordia on MS medium having 2.5 mg/L TDZ. Micro-morphological analysis of different morphogenetic structures revealed that the regeneration of cocoyam is well executed via meristematic nodules, shoot primordia formation that may evolve in to proper shoots. Adventitious shoots (> 2 cm) were successfully (100.00 ± 0.00%) rooted on the half-strength MS medium containing IBA (0.05–1.0 mg/L) and IAA (0.05–0.5 mg/L). The number of roots ranged from 0.78 ± 0.31 on the control half-strength MS medium to 13.94 ± 0.46 on half-strength MS supplemented with 1.0 mg/L IBA. Considering somaclonal variations as a potential restriction to in vitro multiplication of plants, genetic stability was assessed using 40 ISSR primers. The PCR amplification profiles obtained from all the tested propagules (calli, meristematic clumps, regenerated plantlets) were similar to the mother plants indicating the homogeneity of the individuals raised through the regeneration protocol reported here.

At ambient temperature (25–30 oC) and the prevailing atmospheric CO2 levels (380 ppm), installing the C4 photosynthetic machinery in a C3 plant would potentially drive away the photorespiratory process through a carbon concentrating mechanism (CCM), thereby preventing oxygenation reaction of Rubisco. Development of C4 rice is a global research priority, for enhanced water use efficiency (WUE) and yield. At optimal environment, the difference in the solar energy to biomass conversion between C3 and C4 plants is mainly due to photorespiration. So, photorespiratory bypasses are the potential alternatives than conversion to C4. Genetically transformed C3 model plants with photorespiratory bypass had demonstrated higher biomass (under same environmental conditions) than its wild type. Using a transcriptome approach, we report here the differential expression pattern for photorespiratory genes and chloroplastic pyruvate dehydrogenase (plPdc) gene between the leaves, peduncle, and the developing grain tissues in three rice genotypes. In addition to pyruvate, glycolate and glyoxylate also are the substrates for the plPdc gene product and hence a suitable candidate for photorespiratory bypass.