Leaf Tissue‐Specific Phosphorus Allocation Is Linked to Leaf Lifespan in Chickpea Accessions

ABSTRACT

Plants strategically allocate phosphorus (P) among leaf tissues to support physiological functions. However, there is limited understanding of contrasting leaf cellular P‐allocation patterns and their physiological consequences. We quantified leaf P fractions, photosynthetic P‐use efficiency (PPUE), and P‐remobilisation efficiency (PRE) in five chickpea accessions exhibiting contrasting cellular P‐allocation patterns. Leaf lifespan and concentrations of key phytohormones were also measured, including abscisic acid (ABA), salicylic acid (SA) and jasmonates. Cellular P‐allocation patterns were more strongly associated with leaf lifespan than with PPUE or PRE. Accessions allocating a greater proportion of P to the mesophyll exhibited longer leaf lifespan, which was associated with lower jasmonate concentrations, rather than ABA. Surprisingly, greater P allocation to the epidermis was driven by a higher proportion of metabolite P. At the cellular level, we primarily observed a significant negative correlation between P and calcium concentrations in mesophyll cells, but not in the epidermis. Our findings provide the first evidence that leaf tissue‐specific P‐allocation patterns vary among chickpea accessions. Preferential allocation of P to photosynthetically active cells was associated with longer leaf lifespan. Differences in jasmonate concentrations accompanied these patterns. Collectively, these findings highlight new opportunities to enhance P‐use efficiency in crop breeding programs.