STRUCTURAL AND BIOFUNCTIONAL CHARACTERIZATION OF PLANT MEDIATED GREEN SYNTHESIZED METALLIC NANOPARTICLES
Tez Türü: Bütünleşik Doktora
Tezin Yürütüldüğü Kurum: Marmara Üniversitesi, Mühendislik Fakültesi, Biyomühendislik Bölümü, Türkiye
Tez Danışmanı: Ahu Altinkut Uncuoğlu
Tezin Onay Tarihi: 2025
Tezin Dili: İngilizce
Desteklendiği Program: Diğer
Özet:
Nanoparticles, with their large surface area and high reactivity, offer a promising alternative to traditional fertilizers for improving nutrient uptake in plants. In this study, iron oxide (Fe2O3), zinc (Zn), and titanium dioxide (TiO2) nanoparticles were synthesized using Laurus nobilis (bay leaf) extract through an environmentally friendly, biocompatible, and cost-effective green synthesis method. The synthesized nanoparticles were characterized using Ultraviolet-Visible spectroscopy, Dynamic Light Scattering (DLS), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and Transmission Electron Microscopy (TEM), confirming their nanoscale size and successful formation. After structural characterization, the biofunctionality of green-synthesized NPs as potential biofertilizers were assessed. NPs were applied to sunflower plants via three methods: (1) added to Hoagland medium to examine their effects on morphological, physiological, and biochemical responses under a hydroponic system, (2) incorporated into semi-solid MS medium for in vitro seed germination, and (3) foliar application in field-grown plants to assess seed yield. TEM imaging and ICP-MS analysis demonstrated the uptake and translocation of nanoparticles from roots to leaves. Growth and yield parameters of sunflowers showed significant improvement at specific NP concentrations and application methods, while higher doses resulted in adverse effects, highlighting the importance of dosage optimization. Furthermore, recognizing the complexity of the plant growth environment, which includes interactions with rhizobacteria, a preliminary study was conducted to evaluate the effects of NPs on a plant pathogen (Fusarium oxysporum) and Plant Growth-Promoting Rhizobacteria (PGPR) species, Bacillus cereus and Pseudomonas aeruginosa. The results revealed that the NP synthesis complex inhibited the growth of F. oxysporum at doses starting from 50 ppm, while no inhibitory effects on B. cereus or P. aeruginosa were observed up to 100 ppm. These findings demonstrate the potential of green-synthesized nanoparticles as biofertilizers, offering growth enhancement and pathogen suppression under optimized conditions, contributing to sustainable agriculture.