Zinc-Supported Multiwalled Carbon Nanotube Nanocomposite: A Synergism to Micronutrient Release and a Smart Distributor To Promote the Growth of Onion Seeds in Arid Conditions

Abstract

In the current scenario, nanotechnological applications in the agriculture sector showing potential impacts on the improvement of plant growth in terms of protection and safety are at a very nascent stage. The present study deals with the synergistic role of zinc (Zn) and multiwalled carbon nanotubes (MWCNTs) synthesized as a zinc oxide (ZnO)/MWCNT nanocomposite, a prospective applicant to modulate the micronutrient supply and enhance the growth of onion seeds, thereby replacing harmful, unsafe chemical fertilizers. To the best of our knowledge, this is the first report wherein MWCNTs have been envisaged as a micronutrient distributor and a nutrient stabilizer enhancing the growth of onion plant under arid conditions. The growth trend of onion seeds was evaluated in an aqueous medium with varied concentrations of (i) MWCNTs, (ii) zinc oxide nanoparticles, and (iii) ZnO/MWCNT nanocomposites. ZnO/MWCNT nanocomposites with 15 μg/mL concentration displayed the best seedling growth with the maximum number of cells in telophase. A significant growth trend with increased concentration of ZnO/MWCNTs displayed no negative impact on plant growth in contrast to that with the use of MWCNTs. The synergistic impact of Zn nanoparticles and MWCNTs in ZnO/MWCNT nanocomposites on the rate of germination was explained via a mechanism supported by scanning transmission electron microscopy.

Nanomaterials in Plants: A Review of Hazard and Applications in the Agri-Food Sector

“…In the case of seed treatments [21,62,70,71,72,73,74,75,76] and early-stage root treatments in hydroponic media [56], ENM transfer into edible plant segments and to the environment is limited. In view of their reported benefits, their use appears to be justified.…”

“…In view of their reported benefits, their use appears to be justified. Relatively few studies investigated the addition of ENMs to soil, however, tested materials include those which are already used in outdoor settings (i.e., CB and hydroxyapatite) [55,77] and those which are prone to dissolution and are commonly used in conventional agriculture in dissolved form (i.e., Cu and Zn) [27,62,70,72,78]. This suggests that such uses are also justified from a nanosafety perspective.…”

Nanoparticles in Agroindustry: Applications, Toxicity, Challenges, and Trends

“…Stevia rebaudiana callus was treated with ZnO NPs, where plants treated with 100 mg∙L −1 showed increased phenolic and flavonoid content. ZnO NPs generate reactive oxygen species enhancing antioxidant responses [ 143 ]; also, ZnO NPs with 34 nm in size (1 mg∙L −1 ) almost doubled the steviol glycosides content in Stevia rebaudiana , while the secondary metabolites content showed a decline after crossing 1 mg∙L −1 [ 186 ]. The germination stage can also be promoted via nanoparticle interaction; Capsicum annuum L .…”

Multi-Walled Carbon Nanotubes Can Promote Brassica napus L. and Arabidopsis thaliana L. Root Hair Development through Nitric Oxide and Ethylene Pathways

“…Previous research on the relationship between CNTs and plants mainly focused on seed germination [9,10], primary root growth [11][12][13], lateral root development [14][15][16], flowering [17,18], and stress tolerance [19,20]. However, except for the studies of Joshi et al [21] and García-Sánchez et al [22], few investigations have been completed on the functions of multi-walled carbon nanotube (MWCNTs; one kind of CNTs) on root hairs and their corresponding mechanisms, and their phenotypes were controversial.…”