ICACT–2021

Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/24483

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Author: search.filters.author.Wijenayaka, Lahiru

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    Impact of ZnO NPs on In Vitro Germination and Growth Characteristics of Rice (Oryza sativa)
    (Faculty of Computing and Technology (FCT), University of Kelaniya, Sri Lanka, 2021) Perera, Sujani; Rupasinghe, Thilini; Wijenayaka, Lahiru
    A key feature of contemporary nanotechnology is the successful utilization of nanotechnological concepts in agriculture, for applications such as enhancement of the efficiency of crop production through improved seed germination & growth, smart fertilizers, smart pesticides etc. Effect of different nanoparticles (NPs) such as TiO2, Ag, Si, Au, Cu, Zn and ZnO on seed germination have been studied in literature for crops such as canola, mung beans, onions, fenugreek and watermelon. Current study focuses on investigating the impact of ZnO NPs on the seed germination and growth of rice (Oryza Sativa). ZnO is a non-toxic NP and has the potential to boost the yield and growth of food crops. According to literature, ZnO NPs have been used to enhance the seed germination in different plants such as mung beans, peanut and black gram. Herein, ZnO NPs were synthesized by a wet chemical method by mixing ethanolic solutions of NaOH and Zn (CH3COO)2·2H2O.The morphology of the synthesized ZnO NPs was studied using Scanning Electron Microscopy (SEM) and synthesized ZnO NPs exhibited a spherical shape with a diameter ranging from 65 nm to 95 nm, with an average diameter of (73±2) nm. The impact of ZnO NPs on germination and growth of rice was studied under different NP concentrations (0- 2000 mg/L) for Sudu samba and traditional rice varieties, Suwandel and Madathawalu. Further, the growth characteristics were investigated by measuring the root length and the shoot length of rice seeds. A significant enhancement of seed germination was observed in all three rice varieties after treating with ZnO NPs. Sudu Samba seeds showed a 7.3 % enhancement of seed germination (at 500 mg/L ZnO) while Suwandel and Madathawalu showed an enhancement of 20 % and 17% respectively. This can be attributed to the ability of ZnO NPs to penetrate through the cell wall and release targeting genes to specific cellular organelles to boost the cell division. As Zinc is an enzymatic component, it has the ability to influence secretion of indole acetic acid (IAA) which important to regulate plant growth and when the level of IAA is increased, it causes an effective response in seed germination. Interestingly, no significant difference in root length and shoot length was observed for Madathawalu while, a negative effect was observed for Sudu samba and Suwandel at 7 days. Further investigations with varying ZnO concentrations and other types of traditional Sri Lankan rice varieties are currently ongoing to gain more insight into the phenomena observed above.
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    Waste to Value through Rice Hull to Nano-silica: A Novel Paradigm of Sustainable Agronomy
    (Faculty of Computing and Technology (FCT), University of Kelaniya, Sri Lanka, 2021) Anuththara, Imasha K.; Kumara, Hasanka; Wijenayaka, Lahiru; Weerahewa, Darshani
    Although Silicon (Si) in its bulk phases has long been used as a fertilizer in agriculture, specifically for those in the Poaceae family, the unique role their nanoscale counterparts may adopt in modern day agriculture remains mostly unknown. Oryza sativa (rice) is among the main agricultural crops in Sri Lanka. The rice plants accumulate and greatly benefit from Si, where it is deposited beneath the cuticle as cuticle-Si double layer in the form of silicic acid. Further, Si may also interact favorably with other applied nutrients, hence improving the agronomic performance, crop yield, as well as the tolerance of rice plants to abiotic and biotic stresses, thus making Si essential in sustainable rice production. The hull, or the hard protective layer of the rice grain, is mostly regarded as a bulk-scale waste produced during the post-harvest processing of rice. Nevertheless, it is notable that Si is a prominent constituent in rice hull. Hence, there have been recent attempts to utilize rice hull as a precursor for producing Si nanoparticles. However, such approaches, still being in their infancy, requires further systematic investigations to optimize the nanoparticle preparation, in terms of the ensuing nanoparticle properties (i.e., size, morphology, and porosity etc.) as well as the process economies themselves. Hence, in this study, a novel, facile, efficient, and scalable strategy was systematically developed for the preparation of Si nanoparticles from waste rice hull. Notably, preprocessing conditions, synthetic parameters, and the chemical usages were optimized to allow scalability and sustainability to ensue. Initial characterization of the nanoparticles synthesized under aptly optimized conditions indicated the ability of this novel approach to synthesize nanoparticles of smaller dimension that could be stably suspended in aqueous media for prolonged durations without any signs of instability. Further investigations are ongoing in terms of creating and controlling the porosity of these nanomaterials, which will further enhance their carrier properties and thus the applicability as an effective nano-fertilizer. Overall, the knowledge imparted by this study will be significant in intensifying agricultural practices, specifically in many developing parts of the world, where rice remains to be a prominent crop, thus indicating a novel paradigm of sustainable agronomy.