Plant genetic transformation — Which method can directly deliver DNA into plant cells to obtain stable transformants?

Introduction:
Stable plant transformation requires delivering DNA across the cell wall and membrane into the nucleus, followed by integration and expression. Multiple techniques exist, but only a few reliably produce stable transformants in diverse species and tissues.

Given Data / Assumptions:

• Plant cell walls present a barrier to naked DNA uptake.
• Agrobacterium tumefaciens is a common biological vector (not Escherichia coli).
• Physical methods such as particle bombardment can work across many plant taxa.

Concept / Approach:
Evaluate each method for proven ability to yield stable integration. Particle bombardment propels DNA-coated microprojectiles through the cell wall into cells, where DNA can integrate and be expressed. This approach complements Agrobacterium-mediated transformation and is useful for monocots or recalcitrant tissues.

Step-by-Step Solution:

Verification / Alternative check:
Successful transformation is confirmed by selectable marker expression, PCR/Southern blot for integration, and inheritance of the transgene in progeny.

Why Other Options Are Wrong:

Common Pitfalls:
Assuming any bacterium can deliver plant genes; confusing transient viral expression with genomic transformation.

Final Answer:
Particle bombardment (gene gun).