A group of environmental scientists investigated the potential of a plant growth-promoting bacterium, Pseudomonas putida, to enhance zinc uptake and growth in Vetiver grass (∗Chrysopogonzizanioides∗*Chrysopogon zizanioides*∗Chrysopogonzizanioides∗) grown in zinc-contaminated soils.
Both rhhrhhrhh mutant and WT plants were cultivated in identical, temperature-controlled glasshouse conditions under high zinc concentrations. Half of the plants of each group were inoculated with P. putida, while the remaining half were not. After 45 days, the root dry mass and shoot zinc concentration of the plants were measured.
The results are summarised in the table below:
| Plant type | Pseudomonas putida added | Mean root dry mass (g pot−1\text{g pot}^{-1}g pot−1) | Mean shoot zinc concentration (mg kg−1\text{mg kg}^{-1}mg kg−1) |
|---|---|---|---|
| rhhrhhrhh mutant | No | 0.85±0.080.85 \pm 0.080.85±0.08 | 120±12120 \pm 12120±12 |
| rhhrhhrhh mutant | Yes | 1.65±0.151.65 \pm 0.151.65±0.15 | 240±18240 \pm 18240±18 |
| Wild type (WT) | No | 3.50±0.253.50 \pm 0.253.50±0.25 | 410±30410 \pm 30410±30 |
| Wild type (WT) | Yes | 3.10±0.303.10 \pm 0.303.10±0.30 | 380±35380 \pm 35380±35 |
The researchers concluded that the addition of Pseudomonas putida fully mitigated the genetic root defect in the mutant grass, restoring both growth and zinc remediation capacity to wild-type levels.
Evaluate this conclusion using the data provided.
