Conjunctive and concentration dependent effects of nanoscale zinc and boron on the physiological, biochemical, nutrient uptake, and translocation processes in peanut (Arachis hypogaea L.)

In the present investigation, different concentrations (150, 200, 300, 400, and 500 mg/L) of nanoscale zinc oxide (ZnO) and boron (B) were applied through foliar spray (pot culture) to evaluate their effects on the growth and biochemical parameters of peanut. Nanoscale zinc oxide and nano boron were prepared using modified oxalate decomposition and encapsulation methods, respectively, and were characterized using techniques such as, X-ray diffraction (XRD), dynamic light scattering (DLS), ultraviolet-visible (UV-vis) spectroscopy, and transmission electron microscopy (TEM). The average size (37.2 nm, 53.6 nm) and zeta potential (-37.7 mV, -28.3 mV) of nano ZnO and nano boron were measured, respectively. Fourier transform infrared spectroscopic (FT-IR) studies revealed the functional groups that are present in the hydrosols. Highest germination percentage (98.7% and 96%), seedling vigor index (2359 and 1325) and total chlorophyll content (3.28 and 2.24 mg g(-1)) were recorded at 500 mg/L of nano zinc oxide and nano boron. Significantly higher peroxidase, catalase, superoxide dismutase (SOD) enzymatic activities, pod yield (39.76 g pot(-1) and 38.14 g pot(-1)) and haulm yield (49.56 g pot(-1) and 47.05 g pot(-1)) were also recorded with the application of nano ZnO and boron @ 500 mg/L. Translocation of nanoscale nutrients through stomata was clearly observed. Significant nutrient uptake with the foliar application of nanoscale nutrients has been recorded. The performance of groundnut (in terms of yield, quality and nutrient uptake) was significantly enhanced with the application of nanoscale nutrients and this point to achieving the nutrient bio-fortification with the desired levels for the betterment of human health.