Morphological Adaptation and Cd Translocation/Excretion Pathways in Oryza meyeriana Baill. Under Cd Stress
Year: 2026
Type: article
Abstract: Elucidating the transfer and accumulation mechanisms of Cd in wild rice resources is crucial for breeding low-Cd rice varieties. This study investigated the physiological responses and Cd distribution characteristics of Oryza meyeriana Baill. under 5 and 15 mg/kg Cd treatments. A pot experiment was conducted using O. meyeriana, along with the low-Cd and high-Cd cultivar for comparison. Scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDX) and non-invasive micro-test technology (NMT) were employed to investigate Cd transfer in roots. Under Cd stress, O. meyeriana adopted morphological adaptations, including decreased root hair density and length, alongside a thickened root endodermis. NMT revealed a net Cd2+ influx at the root surface that intensified with increases in external Cd concentration, with negligible root efflux. Combined with the tissue Cd distribution gradient (root > stem > leaf), these physiological kinetics demonstrate that O. meyeriana has a prominent root Cd retention strategy, with roots sequestering 52–59% of total plant Cd. O. meyeriana exhibited lower Cd translocation in both the xylem and phloem. Furthermore, Cd excretion was detected on the leaf surface of O. meyeriana, functioning as an additional detoxification pathway, with excretion amounts reaching 13.77 μg/kg under 15 mg/kg Cd treatment. O. meyeriana exhibits physiological sensitivity to Cd but copes with the stress through distinct morphological adaptations. Collectively, O. meyeriana responds to Cd stress through a coordinated regulatory pathway of root retention—restricted stem to leaf translocation—and leaf excretion, thereby exhibiting strong low Cd accumulation capacity and highlighting its valuable application potential in low-Cd rice breeding.
Source: Plants
Language: English
Topic: Heavy metals in environment
Subfield: Pollution
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,258
OpenAlex ID: W7225797855