Pomegranate peel powder (PPP) is increasingly used as a bioadsorbent to decontaminate
wastewaters due to its adsorptive characteristics. The application of nutrient-fortified
bioadsorbents as alternatives to chemical fertilizers can provide an innovative and
eco-friendly approach for sustainable waste management. Nevertheless, there is extremely
limited information regarding their effects on the growth of agricultural crops. We
investigated the effects of raw and nutrient-fortified PPPs on oilseed rape ( Brassica
napus ). Our results showed that the concentration-dependent in vitro phytotoxicity
of high PPP doses (germination indices were 109.6%, 63.9%, and 8.9% at the applied
concentrations of 0.05%, 0.5%, and 5%) was diminished by the application of nutrient-fortified
PPPs (germination indices were 66.0–83.4% even at the highest doses). In pot experiments,
most PPP treatments (especially Raw-PPP and the mixture of N- and P-fortified PPPs)
promoted the development of aboveground plant parts. Reorganization of the pattern
of protein tyrosine nitration in the root tissues indicated that the plants were acclimated
to the presence of PPPs, and thus, PPP treatment induced no or low-level stress. Our
findings confirmed that several doses of PPP supplementation were beneficial for the
model crop plant when applied in soil. We anticipate that our study will be a foundation
for future investigations involving more plant species and soil types, which can contribute
to the introduction of nutrient-fortified PPPs as sustainable biofertilizers.
