Impact of Foliar Application of ZnO and Fe3O4 Nanoparticles on Seed Yield and Physio-Biochemical Parameters of Cucumber (Cucumis sativus L.) Seed under Open Field and Protected Environment vis a vis during Seed Germination

Nakul Gupta; Sudhir Kumar Jain; Bhoopal Singh Tomar; Anjali Anand; Jogendra Singh; Vidya Sagar; Rajesh Kumar; Vikas Singh; Tribhuvan Chaubey; Kamel A Abd-Elsalam; Awani Kumar Singh

doi:10.3390/plants11233211

Impact of Foliar Application of ZnO and Fe₃O₄ Nanoparticles on Seed Yield and Physio-Biochemical Parameters of Cucumber (Cucumis sativus L.) Seed under Open Field and Protected Environment vis a vis during Seed Germination

Plants (Basel). 2022 Nov 23;11(23):3211. doi: 10.3390/plants11233211.

Authors

Affiliations

¹ ICAR-Indian Institute of Vegetable Research, PB-01, Po-Jakhini (Sahanshahpur), Varanasi 221305, India.
² ICAR-Indian Agricultural Research Institute, New Delhi 110012, India.
³ Plant Pathology Research Institute, Agricultural Research Center, Giza 12619, Egypt.

Abstract

Nutritionally rich cucumber seeds remain in demand in the agricultural, health and cosmetic sectors as they are essential for a successful crop stand establishment and seed-based products. However, the production of cucumber seeds is impeded by source limitation and nutrient deficiency. The foliar application of micronutrients can supplement this deficiency and overcome the physiological setback. An experiment was undertaken to compare the impacts of the foliar application of Fe and Zn, as nanoparticles and fertilizers, on the yield and seed quality of cucumber under open and protected environments. A foliar spray of nano-ZnO (ZnNPs) and nano-Fe₃O₄ (FeNPs) at 100, 200 and 300 mg L^-1, as well as ZnSO₄ and FeSO₄ as fertilizer (0.5%), was conducted at the vegetative stage and pre- and post-flowering stages. The NPs had a greater efficacy in an open field than in the protected (naturally ventilated poly house) environment. The application of both NPs increased seed yield (51.7-52.2%), total chlorophyll content (15.9-17.3%) and concentration of Zn and Fe in the fruit and the seed, by 2.0-58.5% and 5.0-30.5%, respectively. A significant increase in starch, soluble proteins, soluble sugars and oil content was observed in the seeds from the NP treated plants. NP treatment also enhanced the germination-related parameters, such as percent germination (16.8-17.0%), rate of germination (18.0-22.2%) and seedling vigor (59.8-72.6%). The biochemical characterization showed a significant improvement in the seed water uptake and the activity of hydrolytic enzymes (amylase and protease) in the germinating seed. The involvement of reactive oxygen species (superoxide anion and hydrogen peroxide) and antioxidant enzymes (Superoxide dismutase, Catalase and Peroxidase) in the germination process was indicated by an increase in their activities in the seeds from NP treated plants. Hence, the study proposes the potential benefit of the foliar application of 300 mg L^-1 ZnNPs and 200 mg L^-1 FeNPs at crucial stages of plant growth to improve the yield and seed quality in cucumbers.

Keywords: Fe-nanoparticles; Zn-nanoparticles; antioxidant; cucumber; foliar application; seed germination.

Grants and funding

This research received no external funding.