Foliar Application of Nano-NPK in Combination with Nano-Micronutrients for Growth, and Flowering of Tecoma stans L. Plants

Abstract

Eco-friendly, cost-effective, and long-term solutions for agricultural systems should be explored, such as nano fertilizers, which can be employed as controlled-release or slow-release fertilizers. Therefore, pot experiments were conducted to investigate foliar application of nano-NPK and nano-micronutrients at different concentration on growth, flowering and chemical constituents of Tecoma stans plants compared to the traditional mineral fertilization (NPK) at a private nursery in Mansoura city, Dakahlia Governorate, Egypt over the course of two consecutive 2021 and 2022 seasons. The examined treatments included; 3 g L-1 of mineral NPK fertilizer as control, nano-NPK at 1, 2 and 3 ml L-1 and nano-NPK at 2 ml L-1 + nano-micronutrients at 0.5, 1, 1.5 ml L-1 for each. Results demonstrated that all treatments with nanofertilizers enhanced vegetative growth (plant height, branches number/plant, aerial fresh and dry weights/plant, leaves number and leaf area), root growth (length, fresh and dry weight), membrane stability index, relative water content, and flowering parameters (inflorescence number, and floret number/inflorescence). Additionally, chemical components such as total carotenoids in flowers; leaves chlorophyll a and b, total carotenoids, mineral N, P, and K, and peroxidase and catalase activity in leaves were all enhanced by all nano treatments. Treatment with 2 ml L-1 of nano NPK + 1.5 ml L-1 of nano-micronutrients produced the most statistically significant results for these characteristics. The same treatment exhibited the highest reduction in the period from planting date until emergence the first inflorescence. It could be concluded that applying mixture of nano-NPK fertilizer (2 ml L-1) and nano-micronutrient (1.5 ml L-1) at intervals of 15 days during the growth season achieved the most favorable results in terms of morphological, biochemical, and physiological parameters.