Modern Planting Studies: Productivity performance of peach trees, insecticide and antimicrobial biological activity of leaf extracts are affected by the foliar application of nanofertilizers
1. Brief introduction
Peaches are considered one of the nutritionally and economically important fruits and are known all over the world, with 15,748 hectares cultivated in Egypt. Several studies have reported the importance of nanofertilizers, which can be used in small quantities rather than extensively.
The application of NP stimulates plant growth and crop yields, reduces the use of chemical fertilizers, and therefore requires a lot of interest. In addition, DeRosa et al. reported that nanofertilizers are beneficial in inhibiting the loss of nutrients from the soil.
In addition, these nano-fertilizers can avoid interactions between nutrients, air, water, microorganisms and soil. Foliar applications of nanofertilizers provide efficient and low-waste nutrients because they transfer faster and higher to different parts of the plant. Nanoparticles are characterized by their small size, light weight, and high surface-to-volume ratio.
Ag NP has a great impact on plant growth and progress, such as germination, root-shoot ratio, seed growth, root growth and elongation, and inhibition of senescence. In addition, Sharma et al. mentioned that Ag NP is distinguished by its unmatched physicochemical and biological properties compared to macro-scale NPs.
In addition, 20-60 ppm Ag NPs stimulated plant growth, leaf area, shoot and root length, and seed content of chlorophyll, carbohydrates, protein, and antioxidant enzymes in common beans, corn, and mustard greens.
Ag NPs exhibit powerful biological activity, and they affect plants at many different levels. In addition, a 25 ppm Ag NP significantly improved leaf area and grain yield, while a 75 ppm treatment reduced grain yield.
Therefore, this investigation aims to investigate the effects of spraying commercial nanofertilizers on vegetative growth, pollen grain viability, yield, and fruit quality of the "Prince of Florida" peach variety.
In addition, the biological activity of leaf extracts treated with nanofertilizers as insecticidal or bactericidal activity against some stored cereal insect and plant bacterial pathogens was studied. Phenolic compounds in leaf extracts were determined by high-performance liquid chromatography.
2. Materials and methods
Characterization of Ag NPs First, particle shape and particle distribution were determined using "transport electron microscopy". The stock concentrated solution was centrifuged at 20,000 rpm for 60 min to obtain Ag NPs in powder form. The obtained Ag NPs powder was observed using scanning electron microscopy to examine the morphological characteristics of LINS-MF14.
The experiment was planted in 2020 in sandy clay soils 4×4 meters apart under drip irrigation from a private orchard in the El Omid district of Massamatru Province, Egypt. The physicochemical analyses of the experimental soils were as follows: pH (8.17), EC (2.58 dS/m), Na+ (15.2), K+ (1.6), Ca2+ (5.0), Mg2+ (4.0), Cl− (14.5), HCO3 (5.0), CaCO3 (26.7%) and SO4 (6.0).
Seventy uniform trees were selected for the study with the same vigor possible and received the same agricultural practices in both seasons. The trees were treated three times before flowering, during full bloom, and one month later: water (control), 10, 12.5, and 15 ml/L of Ag NPs, and 2.5, 5, and 7.5 ml/L of zinc NPs. The treatments are arranged in a randomized full-block design, with each treatment consisting of ten replicates/ten trees.
3. Plant growth parameters, percentage of flowers, and fruit yield
The data showed that foliar applications of 10, 12.5, and 15 mL/L Ag NPs and 2.5, 5, and 7.5 mL/L zinc NPs significantly improved bud thickness, leaf area, and total chlorophyll compared to the control group.
The highest value was obtained by using 15 ml/L of Ag NPs, which is superior to treatment compared to other applied treatments and controls. In addition, the use of 12.5 mL/L Ag-NP and 7.5 mL/L Zn NPs also had a positive effect on improving the same vegetative growth parameters compared to other applied treatments and controls.
Compared with the control group, foliar application of Ag and Zn NPs significantly increased flower %, yield (kg/tree) and yield (t/h). The optimal increment was obtained by spraying 12.5 and 15 ml/L of Ag NP and 7.5 ml/L of zinc more than other application treatments and controls. In addition, the superior treatment compared to other treatments is Ag NP of 15 ml/L ppm.
Fourth, the physical characteristics of the fruit
The data showed a significant increase in all treatments when sprayed with Ag NPs 10, 12.5 and 15 mL/L and Zn NPs at 2.5, 52.5 and 7.5 ml/L compared to the control group. Best results were obtained with controlled use of 12.5, 15 mL/L Ag NPs, 7.5 and 5 mL/L Zn NPs.
5. Effect of nanofertilizer on the viability of pollen grains
The results showed that the two commercial nanofertilizers had a significant effect on pollen viability, but different types of pollen distortions were detected, such as the content of viscosity, ultrastructural changes on the outer and inner walls of pollen grains, an increase in ultrastructural changes, partial or complete degradation content, and a decrease in pollen content with large capacity gaps.
On the other hand, in the absence of any distortion, commercial Ag NPs showed a high increase in pollen viability. Commercial Ag NPs greatly increase spore pollen size increases, and spores are also increased and isolated at different locations, looking for eggs for pollination and fertilization, a situation that is important for plant breeding and improvement as well as fruit ripeness and size.
