Effect of foliar nano-minerals (zinc sulfate) and ground biofertilizers (rhizobacteria) on vegetative growth and flowers yied in Matthiola incana L.

• Zahraa Madhloom Mezher and Sulaiman A. Mashkoor

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This study was conducted during the 2025–2026 growing season in a greenhouse covered with 75% shade at the University of Kufa nursery to investigate the effect of foliar application of nano zinc sulfate and soil inoculation with plant growth-promoting rhizobacteria (PGPR) on the vegetative growth and flowering characteristics of stock (Matthiola incana L.) cv. Cinderella Purple. The experiment was arranged as a factorial experiment RCBD with three replicates. Four concentrations of nano zinc sulfate (0, 3, 6, and 9 mg L⁻¹) were combined with four bacterial treatments including an uninoculated control, Bacillus subtilis, Pseudomonas fluorescens, and Azotobacter chroococcum. The results demonstrated significant improvements in both vegetative growth and flowering traits due to the application of nano-fertilizers and beneficial bacteria. Foliar spraying with 9 mg L⁻¹ nano zinc sulfate increased plant height to 27.67 cm compared with 24.58 cm in the control treatment. The same concentration also enhanced leaf area to 30.32 cm² compared with 25.52 cm² in untreated plants. Inoculation with P. fluorescens produced the highest plant height (27.50 cm), whereas the greatest number of leaves (33.00 leaves plant⁻¹) was also obtained with the same bacterial treatment. Flowering was significantly accelerated by nano-fertilization, reducing the number of days to flowering from 125.42 days in the control treatment to 120.96 days at 9 mg L⁻¹. Furthermore, the number of florets increased from 54.50 florets plant⁻¹ in the control to 75.75 florets plant⁻¹ at the highest nano-fertilizer concentration. Inflorescence length was similarly improved, reaching 12.14 cm compared with 10.61 cm in untreated plants, while flowering duration increased from 8.08 to 9.98 days. The interaction between nano zinc sulfate and PGPR inoculation produced the most favorable responses. The combination of 9 mg L⁻¹ nano-fertilizer and P. fluorescens achieved the highest plant height (30.67 cm) and inflorescence length (13.89 cm), whereas 9 mg L⁻¹ combined with A. chroococcum produced the highest number of florets (84.00 florets plant⁻¹). These findings indicate that integrating nano-fertilization with beneficial rhizobacteria can effectively enhance vegetative growth, flowering performance, and ornamental quality of stock plants, providing a sustainable approach for improving commercial cut-flower production.

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