Monopotassium phosphate seed priming improves phosphorus deficiency tolerance in Chenopodium quinoa

Phosphorus (P) deficiency is a major factor limiting crop productivity in many soils worldwide. This study aimed to investigate the potential of seed priming with monopotassium phosphate (200 mmol L^-1) to alleviate the adverse effects of P deficiency in Chenopodium quinoa Willd. Seedlings issued from unprimed and primed seeds were cultivated in plastic pots filled with inert sand under P deficient or P sufficient conditions.

In plants from unprimed seeds, P deficiency decreased shoot and root growth, leaf P and potassium ion (K⁺) content, leaf water content, gas-exchange performance, and photosynthetic pigment concentrations, while increasing lipid peroxidation and leaf acid phosphatase activity. Interestingly, monopotassium phosphate (KH₂PO₄) seed priming alleviated P deficiency stress in quinoa, resulting in significant improvement in shoot (9.9-fold) and root (8.1-fold) growth, as well as photosynthetic activity (five-fold and four-fold increases in net assimilation rate (A) and stomatal conductance (g_s), respectively). Chlorophyll content increased four-fold, while carotenoids content increased by 70%, together with an overall improvement in plant nutritional status. This beneficial effect was associated with lower levels of leaf malondialdehyde. However, no significant differences were observed in leaf osmotic potential, anthocyanin content, or acid phosphatase activity between plants derived from primed and unprimed seeds.

KH₂PO₄ seed priming enhances quinoa tolerance to P deficiency through improved photosynthetic integrity, root growth, nutritional status, and strengthened antioxidant defence. Hence, KH₂PO₄ seed priming appears to be a promising strategy for improving quinoa productivity in calcareous soils. © 2026 Society of Chemical Industry.