Browsing by Author "Roy, Swarnendu"

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Open Access
Bisphenol A toxicity in aquatic flora: Impacts and possible remediation
(University of North Bengal, 2020-03) Sarkar, Ashis; Roy, Swarnendu
Bisphenol A (BPA), is one of the high volume produced chemical which is extensively used as raw material for polycarbonate and epoxy resin manufacturing. Being one of major used and disposed material from a wide source, traces of BPA have been diagnosed from everywhere. BPA has been identified as an endocrine disruptor compound (EDC) for most of animals, due to structural similarity with hormones, and hinders many physiological functions. This review work focuses on the status of BPA in water bodies of different parts of the world. The review also focuses on the impact of BPA on aquatic plants and its possible remediation. Sub-standardly imposed policies by several countries and failure of water resource governance are rapidly leading towards incautious release of plastics and other BPA associated waste products in environments. BPA pollution affects humans, animals and even plants. Among the aquatic flora, most affected plant groups are the algal groups and macrophytes. At lower BPA concentration, many beneficial bacterial strains also show sensitivity whereas some other strains are known to metabolize or remove BPA from the water bodies. In this connection, several aquatic macrophytes have also been reported to contribute in the removal of BPA from the aquatic ecosystem.
Open Access
Evaluation of silica nanoparticles and their functionalization in the alleviation of salinity stress in two legumes -Lens Culinaris and Glycine Max
(University of North Bengal, 2023) Sarkar, Mahima Misti; Roy, Swarnendu
Soil salinity is one of the major environmental stresses that imparts drastic effects on plant growth and development. The adverse effects of salinity affect the overall plant health, resulting in impaired physiological and biochemical attributes. Poor health ultimately causes a loss in plant production rate and nutritional values. To overcome the negative effects of salinity and to improve the yield of crop plants, major emphasis has been given to the application of several fertilizers, pesticides, and fungicides. Moreover, the development of genetically modified crops has been advocated for the development of salt-tolerant crop plants. However, these have some drawbacks, such as genetic modification being timeconsuming and cost-consuming and applying chemical fertilizers hampering soil fertility. Moreover, the efficiency of fertilizers, considered important for improving crop yield, reduces soil fertility due to over-application, resulting in residual toxicity on crop plants. In this context, in the last decade, nanotechnology has emerged as an alternative strategy for the betterment of plant health as well as environmental stress alleviation. The idea behind using nanoparticles in crop improvement was to improve the efficiency of the bulk materials already used as agrochemicals. Because of having a high surface area to volume ratio, the nanomaterials facilitate easy uptake and render them more interactive with the cellular active components, thereby amplifying their efficiency. Though silica is not an essential element in plants, its deficiency creates various problems; thus, it is considered a semi-essential element. The application of silica nanoparticles (SiNPs) has excellent potential for crop improvement because it increases silica availability to plants. The synthesis of any nanoparticles demands an optimization process through which we can understand the ratios of components that should be used to get the actual shape, size, and surface charge. In this purview, the second chapter presents the synthesis, optimization, and characterization of SiNPs. SiNPs were optimized by varying the three important ingredients (TEOS, ethanol, and ammonia) through ‘Design Expert 13’ based ‘mixture design’, which revealed that the size of the SiNPs can be modified but not the surface charge. Using mixture design, we successfully obtained ~50 nm-sized SiNPs, which was confirmed through several analytical techniques. To study the potential of SiNPs in salinity stress alleviation, four concentrations of NaCl (for seedling and vegetative stage – 0, 100, 200, and 300 mM; for reproductive stage – 0, 200, 400, and 600 mM) in combination with four concentrations of SiNPs (0, 1, 5, and 10 g/L) were applied in two legume crops – lentil, and soybean, respectively (Chapters 3 and 4). The results depicted that both plants had better germination attributes under salinity after the application of SiNPs. In the seedling and vegetative stages, SiNPs were found to improve the plant’s health under salinity through improved plant height, relative water content, photosynthetic pigments, ionic and osmotic balance, antioxidant defense (enzymatic and/ non-enzymatic), membrane stability and reduced ROS accumulation. Similarly, in the reproductive stage of both legumes, applying SiNPs was also observed to reduce the salinity stress impacts through improved plant health, yield, and nutritional aspects of the seeds. The use of bare SiNPs has already been proven to have beneficial attributes for crop plants under salinity. However, very little research has focused on applying functionalized nanoparticles for crop improvement under environmental stresses. Surface functionalization of these nanoparticles with bioactive molecules has the potential to increase their efficiency in this regard. Thus, in chapters 5 and 6, the SiNPs surface was functionalized with two important sugars/osmolytes – glucose (GSiNPs) and trehalose (TSiNPs), respectively. Both surface functionalizations were confirmed using several analytical techniques, including FTIR, XRD, DLS with zeta potential, UV-visible spectroscopy, SEM, EDS, TEM, and AFM. Applying both GSiNPs and TSiNPs improved the health of lentil and soybean seedlings through improved height, photosynthetic pigments, ion balance, and antioxidant defense under salinity stress. In both plants, the improvement was found to be more profound with the use of GSiNPs and TSiNPs compared to the bare SiNPs. The bioassay experiments also proved that the functionalization of the SiNPs surface with glucose/trehalose increased the bioavailability and uptake of both silica and sugars in the seedlings. Thus, these studies can provide ample evidence of the greater efficacy of surface-functionalized nanoparticles in palliating salinity stress in plants. Apart from the morphological, physiological, and biochemical analyses, we performed the molecular and genetic background of the beneficial effects of surface functionalized SiNPs (TSiNPs) by performing the whole transcriptome analysis (RNA-Seq). The results revealed that the TSiNPs have regulatory roles on various genetic expression, which modulates various protein expressions, pathway functions, cellular components, molecular functions, and biological processes to confer progressive health benefits for lentil seedlings under salinity. More specifically, some of the genes involved in the providence of salinity stress tolerance (Sodium hydrogen exchanger, Potassium transporter, Cytochrome b6, sugar transporter, and ABC transporter G family member) were expressed highly in the presence of TSiNPs. Along with their beneficial effects on crop improvement, various nanoparticles have also been found to have toxic effects on plants, animals, and environmental elements. So before proceeding to the filed application and commercialization, the SiNPs must also be checked for their toxicity attributes. In this purview, the cytotoxicity and genotoxicity of the synthesized SiNPs were evaluated on the Allium cepa root tip, considering their applied concentration and size. Further, the toxicity effects of SiNPs were attempted for attenuation using surface functionalization with sugar molecules – GSiNPs and TSiNPs. The results showed that the SiNPs showed toxic effects after the 100 g/L concentration, and the 30 nm and 100 nm sized SiNPs showed more toxic effects than the 50 nm-sized nanoparticles. Further, the GSiNPs and TSiNPs were found to reduce the toxicity level of SiNPs even at higher concentrations (> 100 g/L). A toxicity study was also performed on soil microflora, and the results showed that the SiNPs, GSiNPs, and TSiNPs improved the soil microbial communities (mixed soil bacteria, phosphate solubilizers, nitrogen fixers, and silica solubilizers) in control (0 mM NaCl) as well as 300 mM NaCl stress conditions. Finally, the SiNPs, GSiNPs and TSiNPs were developed into nanoformulations (slowrelease type) using sodium alginate as internalizing polymers. The results of Chapter 9 revealed that the alginate internalization makes the silica and/or sugar release from SiNPs, GSiNPs, and TSiNPs at a slower rate, considering the effect of incubation time, pH, and temperature. These nanoformulations also improved the seedling growth even better than the bare and functionalized SiNPs, even in the presence of NaCl stress. However, the cost of production at the laboratory scale is relatively high, and our future emphasis is to make these nanoformulations cheaper so that they can handed over to the farmers for field application.
Open Access
Morphological and Anatomical Studies on Some Members of Araceae of North Bengal
(University of North Bengal, 2022) Karmakar, Biswanath; Chakraborty, Rakhi; Roy, Swarnendu
present study aimed to characterize eight edible members of the family Araceae on the basis of their morphological and anatomical characteristics. The petiole length, leaf size, and corm size varied widely across the studied members. Significant variations in the stomatal index, stomatal length, and width were observed, although all were of paracytic type with elliptical to circular shapes. Leaf epidermal cells were found to be polygonal or puzzle shaped. Mesophyll cells were non-distinguishable as palisade or spongy parenchyma. The root vascular bundles were found to be exarch, either arranged circularly or remaining scattered in the ground tissue. Pith was also observed, either large, centrally located, or scattered. Petiole anatomy showed scattered vascular bundles with collateral xylem and phloem in almost all the species, except Ol Kochu, Panchmukhi Kochu, and Ghot Kochu. Presence of tannins was observed in the petioles of all the species, whereas calcium oxalate crystals in the form of raphides were found to be present in some members. Water vessels, either large or small were found in the petioles of all the species. The number of parenchyma cells varied from 2 to 6 depending on the species. All the morphological and anatomical characteristics would help identify the eight members of Araceae and provide information for future studies with them.
Open Access
Nutritional and Antioxidant Properties of the Seeds of Vigna unguiculata subsp. sesquipedalis (L.) Verdc. – An Underutilized Legume of West Bengal
(University of North Bengal, 2021-03) Firdousi, Sabnam; Chakraborty, Rakhi; Roy, Swarnendu
The Exploration of the underutilized crops for nutritional benefits is one of the major strategies to feed the ever-increasing population. There are many nutritionally rich leguminous crops (Vigna unguiculata, Cassia hirsuta, Canavalia ensiformis, Dolichos biflorus, etc.) that have remained unexplored for a long time, though could provide a cheap and alternative food source. The present study was conducted to assess the nutritional and antioxidant properties of the seeds of an underutilized legume Vigna unguiculata subsp. sesquipedalis (L.) Verdc. The methanolic seed extract showed concentration-dependent radical scavenging activities against DPPH, ABTS, NO, OH and FRAP. The seed extract also showed the presence of nutritional and antioxidative phytochemicals viz. alkaloids, saponins, tannins, phenolics, flavonoids, ascorbic acid etc. The presence of a considerably high amount of protein and a low amount of total sugar can also be regarded as beneficial for regular consumption. Moreover, HPLC-MS analysis also revealed the presence of several phenolic derivatives (gallic acid, pyrogallol, chlorogenic acid, catechol etc.) that might also contribute to the antioxidative property of the seeds. Further research on the isolation, purification and characterization of the antioxidative phytocompounds would help decipher their mechanism of action as well as increase the sustainable utilization of the nutritionally rich legume crop.