Sex‐specific phosphorus acquisition strategies and cycling in dioecious Populus euphratica forests along a natural water availability gradient

Abstract

Soil phosphorus (P) availability affects plant growth and distribution. However, it is still unknown how sex‐specific variation in functional traits affects plants’ P acquisition and soil P transformation. On wet sites, female poplars had a greater specific root length (SRL), and a higher diversity of arbuscular mycorrhizal fungi (AMF) and phosphate‐solubilizing bacteria (PSB). Male poplars living on wet sites increased the abundance of AMF and PSB communities and enhanced moderately labile and highly resistant organic P mineralisation via increased phosphatase activity. In contrast, on the dry site, the abundance and diversity of AMF and PSB communities increased in females, enhancing moderately labile and highly resistant organic P mineralisation via elevating phosphatase activities. Males maintained greater SRL and promoted Ca‐P mobilisation via the release of root carboxylic acids and rhizosphere acidification on the dry site. The AMF community diversity followed a similar pattern as that of the PSB community when altering the P availability of different‐sex plants. Our results indicated that organic P and Ca‐P are the major sources of plant‐available P in natural P. euphratica forests. Seasonal shifts and geographic locations affected the share of organic and inorganic P pools, and AMF and PSB diversities, ultimately altering sex‐specific P acquisition strategies of plants.