Examine the impact of green-synthesized nanomaterials on the germination rates and seedling characteristics of African Marigold (Tagetes erecta L. var. Pusa Narangi Ganda and Pusa Basanti Ganda)

Abstract

Background: West Bengal is key to India's flower industry, contributing 10.61 % of total production, with marigolds valued at 63.44 thousand tonnes. To achieve good yields, many farmers heavily use chemical fertilizers and insecticides. Marigold seeds typically germinate in about 14 days, but farmers often face issues with uneven germination and poor seedling quality.

Materials and methods: This study was conducted at ICAR-AICRP on Floriculture and Landscape Architecture, HRS, Mandouri, Bidhan Chandra Krishi Vishwavidyalaya, West Bengal, India. We synthesized nanoparticles from Tulsi, Doob grass, and Hibiscus extracts in the lab and analyzed them using XRD, SEM, FTIR, and DLS-Zeta methods. We prepared different concentrations of TiO₂ NP, SiO₂ NP, and AgNPs to test their effects on two marigold varieties: Pusa Basanti Ganda and Pusa Narangi Ganda.

Findings: Recent trial results showed that treatments T₄ and T₅ achieved the highest germination percentages, between 90.33 % and 96.67 %, due to increased titanium dioxide nanoparticles (TiO₂ NP). The Vigor Index (VI) was lowest in T₁₀ with silver nanoparticles at 521.67, compared to 609.33 for the control group (T₀) in Pusa Basanti Ganda. Seeds treated with silver NPs had longer germination times of 4.5-6.4 days, while silica nanoparticles (SiO₂ NP) had mean germination times ranging from 4.6 to 5.2 days. The root/shoot ratio positively correlated with shoot dry weight (0.501 at p = 0.05). In Pusa Basanti Ganda, final germination percentage correlated positively with the Germination Rate Index (GRI), Mean Germination Rate (MGR), and Coefficient of Variation (COV) at values of 0.866, 0.756, and 0.743 respectively, all significant at p = 0.01.

Conclusion: The experiment showed that titanium dioxide (TiO₂) nanoparticles at high concentrations enhance seed germination, while silver nanoparticles (AgNPs) hinder it. Silicon dioxide (SiO₂) NPs at moderate concentrations support seedling growth. Tested salts at specific concentrations can be recommended to farmers for better crop production.

Keywords: Germination; Green synthesis; Marigold; Nanoparticles; Seedling vigour.

Graphical abstract

Fig. 1

(a) Diagrammatical representation of the effects of nanoparticle seed priming (b) Role of nanoparticles in ROS level optimization.

Fig. 2

Effects of nanoparticles on the plant after the seed treatment with NPs.

Fig. 3

Absorption and Translocation pathway of Nanoparticles Created in Biorender

Fig. 4

Flowchart for the Process of Synthesizing Silver Nanoparticles Using Extract from Ocimum tenuiflorum. This scheme outlines the chemical reactions involved in the reduction of silver ions to form silver nanoparticles with the help of phytochemicals present in Ocimum tenuiflorum, commonly known as holy basil. Created in KingDraw and MS Office.

Fig. 5

The schematic provides a detailed illustration of the chemical reaction that leads to the synthesis of silicon dioxide (SiO₂) nanoparticles utilizing an extract from the plant C. dactylon. This process highlights the interaction between the extract and the precursor materials, showcasing how the nanoparticles are formed. Created in KingDraw and MS Office.

Fig. 6

Detailed Scheme of the Chemical Reaction for the Synthesis of Titanium Dioxide Nanoparticles Utilizing Extracts from Hibiscus rosa-sinensis. This process involves the extraction of natural compounds from Hibiscus rosa-sinensis, which serve as precursors in the formation of titanium dioxide nanoparticles through a series of chemical reactions. Created in KingDraw and MS Office.

Fig. 7

SEM and EDS of Plant-mediated nano particles: AgNPs (a, b); TiO₂ NPs (c, d); SiO₂ NPs (e, f).

Fig. 8

Fourier-transform infrared spectroscopy (FTIR) of a. AgNPs b. TiO₂ NPs c. SiO₂ NPs (created by Origin Pro).

Fig. 9

X-ray diffraction (XRD) of a. AgNPs b. TiO₂ NPs c. SiO₂ NPs (created by Origin Pro).

Fig. 10

DLS size and Zeta Potential of Plant-mediated nano particles: AgNPs (a, b); TiO₂ NPs (c, d); SiO₂ NPs (e, f).

Fig. 11

Correlations Metrix of (a) Seedling attributes (b) Germination attributes of Pusa Basanti Ganda.

Fig. 12

Correlations Metrix of (a) Seedling attributes (b) Germination attributes of Pusa Narangi Ganda.

Fig. 13

a. The effect of different concentrations of TiO₂ nanoparticles on African marigold seedlings. b. Seed without treatment (Control) c. Seedling growth of seeds treated with silver nanoparticles was restricted at high concentrations (40–60 ppm). d. Healthy marigold seedlings treated with various concentrations of SiO₂ nanoparticles showed improved growth quality with increasing concentration (5–50 ppm).