The role of root phene interactions in zinc and copper uptake efficiency in maize under NPK fertilization

The role of root phene (s) and root phene modules in micronutrient uptake under a regular supply of NPK are least understood in Zea mays L. (maize). Exploration of collective and individual root behavior under different treatments of excessive macronutrients (N, P, K) or NPK and their impact on the uptake of micronutrients (Zn and Cu) was compared. The positive impact of N fertilizer on Zn and Cu uptake efficiency was associated with Lateral root weight (LRW) x Root cortical aerenchyma (RCA) root phene module (M1, R² 0.079 and 0.906). The negative impact of P on Zn uptake efficiency was attributed to the M2 module (LRW x RCA x Nodal root number (NRN)) and the M1 module (R² 0.209) for Cu uptake. Similarly, the negative impact of K fertilizer on Zn and Cu uptake efficiencies was associated with M2 modules respectively. Furthermore, root phene module behavior for positive or negative impact on Zn and Cu uptake was correlated with up-regulation or down-regulation of Zn and Cu transporters in all the root types. The maximum reduction in root exploration cost was observed for N alone followed by NPK and K. The findings are important in understanding the root exploration cost and root phene module management to control the impact of N, P, K, and NPK fertilizers on Zn and Cu uptake efficiencies in maize.