Work

Layered phosphorus application regulates wheat source–sink structure and photosynthetic carbon assimilation capacity for promoting floret development to grain and increasing yield

Year: 2026

Type: article

Abstract: Context Layered phosphorus application can promote crop growth and optimize root system architecture, but the mechanisms by which regulates wheat floret development and grain formation, thereby alleviating drought effects, remain unclear. Objective This study investigates how layered phosphorus application modulates wheat plant architecture and carbon metabolism to promote floret development and grain formation, thereby mitigating drought stress and achieving stable yield. Methodology Field experiments were conducted from 2023 to 2025 using two winter wheat varieties (the large-spike Zhoumai 22, V1, and the multi-spike Xinmai 58, V2) under two soil water conditions (no irrigation, W0; and irrigation at jointing and booting stages, W1) and three phosphorus application methods: shallow application at 10 cm (P1), layered application at 10 and 30 cm (P2), and deep application at 30 cm (P3). This study systematically investigated the effects of layered phosphorus on fertile floret development, leaf-stem-floret structural traits, leaf photosynthetic performance, and carbon metabolism. Results Drought stress impaired organ structure integrity, reduced photosynthetic capacity, and suppressed activities of carbon metabolism enzymes, limiting soluble sugar accumulation, ultimately reducing fertile floret number and grain number per spike. Layered phosphorus application improved wheat plant architecture under both water conditions, increased leaf chlorophyll content and net photosynthetic rate (Pn), enhanced sucrose synthase (SS) and sucrose phosphate synthase (SPS) activities. P2 treatment increased spike number, grain number per spike, thousand-grain weight, and yield in both wheat varieties compared with P1 and P3. Grain number per spike increased by 17.40–26.60% and 6.92–11.99% in V1, and by 15.28–23.42% and 5.34–9.80% in V2, while yield increased by 25.46–34.70% and 7.24–18.62% in V1, and by 23.44–30.79% and 5.21–15.18% in V2, indicating that V1 responded more strongly to layered phosphorus application than V2. Structural equation modeling revealed that both layered phosphorus application and irrigation significantly increased fertile floret number but via distinct pathways: phosphorus application promoted fertile floret number by enhancing leaf structure and chlorophyll content, whereas irrigation primarily exerted its effect by increasing chlorophyll content and the area of small vascular bundles. Conclusion Layered phosphorus application regulated winter wheat source-sink structure, enhanced photosynthetic capacity, and optimized carbon metabolism, thereby reducing fertile floret degeneration and abortion, promoting grain formation, and mitigating drought-induced yield losses. Implications or significance These findings provided a theoretical basis and technical guidance for promoting floret development, increasing grain number, mitigating drought stress and achieving stable yield in winter wheat through layered phosphorus application under field conditions.

Source: Field Crops Research

DOI: 10.1016/j.fcr.2026.110508