Carboxylate exudation and reproductive effort are associated with leaf phosphorus-resorption efficiency in chickpea

Efficient leaf phosphorus (P) resorption is a key process that enhances internal P-use efficiency in plants. However, the interactions among leaf P resorption, senescence dynamics, and seed P accumulation remain poorly understood. We evaluated 266 chickpea accessions with diverse genetic backgrounds in a temperature-controlled glasshouse experiment. Measurements included leaf P-resorption efficiency (PRE), reproductive allocation, phenology, canopy senescence traits, and biomass distribution, along with rhizosheath carboxylates, which is an indicator of root P-acquisition strategy. Accessions with higher leaf P concentrations exhibited greater PRE, initiated canopy senescence earlier, and maintained a faster canopy P translocation rate. These combined traits significantly increased aboveground productivity and enhanced P-use efficiency. We also identified a non-linear relationship between carboxylate exudation and PRE: resorption efficiency rose with increased exudation before reaching a plateau. Structural equation modelling revealed that greater carboxylate exudation and reproductive allocation were positively associated with enhanced P resorption. Substantial variation in PRE was observed across accessions, ranging from 70% to 89%. This study is the first to systematically integrate leaf P resorption, root P acquisition, reproductive investment, biomass partitioning, and senescence dynamics. Our findings provide new insights into P-use strategies in chickpea and highlight potential pathways for improving crop P-use efficiency.