Chitosan and silver nanoparticles are attractive auxin carriers: A comparative study on the adventitious rooting of microcuttings in apple rootstocks

Abstract

Nanocarriers for encapsulation and sustained release of agrochemicals such as auxins have emerged as an attractive strategy to provide enhanced bioavailability and efficacy for improved crop yields and nutrition quality. Here, a comparative study was conducted on the effectiveness of chitosan‐as a biopolymeric nanocarrier‐ and silver‐as a metallic nanocarrier‐ on in vitro adventitious rooting potential of microcuttings in apple rootstocks, for the first time. Auxins indole‐3‐acetic acid (IAA) and indole‐3‐butyric acid (IBA) loaded silver (nAg) or chitosan nanoparticles (nChi) were synthesized. Scanning electron microscopy and transmission electron microscopy studies showed the spherical shape of the nanoparticles. The average particle size of IAA‐nChi was 167.5 ± 0.1 nm while that of IBA‐nChi was 123.2 ± 2.6 nm. The hydrodynamic diameter of the nAg‐IAA and nAg‐IBA particles were measured as 93.66 ± 5 nm and 71.41 ± 3 nm, respectively. Fourier transform infrared spectroscopy analyses confirmed the encapsulation of IAA or IBA in the chitosan nanoparticles. Meanwhile, the characteristic peaks of IAA or IBA were detected on silver nanoparticles. In‐vitro adventitious rooting of microcuttings of Malling Merton 106 (MM 106) was significantly higher both in chitosan and silver nanoparticles loaded with IAA or IBA (91.7%–62.5%) compared to free IAA or IBA applications (50.0%–33.3%), except for 2.0 mg L–1 IBA (66.7%). However, the application of 2 mg L–1 IBA and IBA‐nChi at all concentrations caused an undesirable large callus development.

Synthesis and Characterization of Ionically Cross-Linked Chitosan Nanoparticles

“…Due to its favorable physicochemical characteristics, including its excellent biocompatibility, low toxicity, biodegradability, and good solubility in water, this polymer has received a great deal of attention [7,8]. Additionally, the abundance of hydroxyl and amino groups in chitosan makes it possible to create nanoparticles through both chemical and physical crosslinking [9]. The pharmaceutical industry has shown a particular interest in chitosan and chitosan nanoparticles (Cs-NPs), notably for application in drug delivery systems that target specific delivery sites because they possess mucoadhesive properties [10].…”

Synthesis of Chitosan Microparticles Encapsulating Bacterial Cell-Free Supernatants and Indole Acetic Acid, and Their Effects on Germination and Seedling Growth in Tomato (Solanum lycopersicum)

“…EN-IAA containing 15.88 and 166 μ g/mL of the IAA standard showed average sizes of 3.98 ± 0.160 μ m ( Figure 6(d) ) and 4.65 ± 0.076 μ m ( Figure 6(e) ), respectively. Several studies have shown that the increase in particle size is a consequence of IAA addition and effective encapsulation of this metabolite [ 24 , 51 ]. In addition, several clusters were observed, possibly related to a flocculation effect by the interaction of the charges because of the addition of the positive charge of IAA [ 52 ].…”

Carrier‐based delivery system of phytohormones in plants: stepping outside of the ordinary

“…To evaluate the efficiency of metallic carrier and polymer-based carrier for the delivery of auxins, IAA/indole butyric acid (IBA)-loaded silver NPs and chitosan NPs were synthesized via thermal reduction and ionic gelation methods, respectively. It was found that a nano-carrier system composed of AgNPs and chitosan can be an attractive carrier for auxin delivery (Korpayev et al, 2021).…”