Overview
This field experiment studied the effect of Acinetobacter schindleri SR-5-1 bacterial inoculation on pea (Pisum sativum L.) growth and cadmium accumulation in Cd-contaminated soils. The study measured cadmium concentrations in pea roots and leaves under two cadmium (Cd) stress levels (120 and 240 mg/kg soil), providing data on cadmium uptake and tissue distribution. It is a bioremediation experiment, not a food survey.
Key numbers
Soil Cd concentrations applied: 120 and 240 mg/kg, as verified by post-application soil analysis (p.4).
Cadmium accumulation in pea leaves (non-inoculated plants, relative to control, p.10):
- At 120 mg/kg soil Cd: leaf Cd content increased by approximately 58.10% above control.
- At 240 mg/kg soil Cd: leaf Cd content increased by approximately 77.59% above control.
Cadmium accumulation in pea roots (non-inoculated plants, relative to control, p.10):
- At 120 mg/kg soil Cd: root Cd content increased by approximately 64.42% above control.
- At 240 mg/kg soil Cd: root Cd content increased by approximately 80.98% above control.
Exact concentrations are shown in Figure 4 (panels B and H); the paper reports these as relative changes rather than absolute mg/kg values in the text.
Shoot length reduction at 120 mg/kg Cd (non-inoculated): 10.39% below control; at 500 uM (approximately 240 mg/kg based on soil analysis): 58.47% below control (p.6).
Nutrients in leaves at 120 mg/kg Cd (non-inoculated, relative to control): nitrogen decreased 31.11%, iron 51.21%, zinc 36.90%, potassium 31.34%, magnesium 25.18% (p.9). At 240 mg/kg Cd: nitrogen decreased 141.6%, iron 135.31%, zinc 123.28%, potassium 79.66%, magnesium 85.82% (p.9).
Inoculation with A. schindleri SR-5-1 reduced leaf Cd content by approximately 7.21% (120 mg/kg Cd) and 10.85% (240 mg/kg Cd) relative to non-inoculated stressed plants (p.10).
Methods (brief)
Field experiment, Faisalabad, Pakistan, 65-day growing cycle. Certified pea seeds from Ayub Agricultural Research Institute. Randomized complete block design, 4 replicates, 16 plots (4 treatments x 4 replicates), 3 m x 3 m plots. Cadmium applied as CdCl2 solution, twice during early vegetative stage (5 L per plot per application). Soil analysis confirmed Cd concentrations. Cadmium and mineral elements (Fe, Zn, Cd, Mg) measured by ICP-MS (Thermo Scientific, USA) on dry plant material after tri-acid (HNO3, H2SO4, HClO4, 10:1:4) digestion. Nitrogen by spectrophotometric method; potassium by flame photometer. Data analyzed by two-way ANOVA, Tukey’s HSD at p < 0.05 (Minitab 21.2). The cadmium concentrations applied (120-240 mg/kg soil) far exceed typical agricultural soil background levels; this study characterizes pathological exposure conditions.
Implications
Relevant to the frozen peas pathway section as direct evidence that cadmium applied to soil enters pea roots and translocates to leaves in a dose-dependent manner. At soil concentrations of 120-240 mg/kg Cd, leaves accumulated cadmium increases of 58-78% above control levels. The study also shows that high Cd stress disrupts uptake of iron, zinc, nitrogen, potassium, and magnesium, demonstrating the competitive interference of cadmium with essential micronutrients. The applied Cd concentrations are extreme (typical EU agricultural soil contamination limits are 1-3 mg/kg Cd); the study quantifies worst-case pathway behavior, not typical supply-chain concentrations.
Related evidence
Update history
No substantive edit history is available in this build. The full commit record is available in git.