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Difficulty: HardInferences and Implicit Meaning

In the late nineteenth century, German botanist Wilhelm Pfeffer investigated the mechanism governing rapid leaf movements in Mimosa pudica, challenging the prevalent physiological assumption that such movements were mediated by electrical impulses analogous to animal nerve transmission. Pfeffer demonstrated that the rapid drooping of Mimosa pinnules in response to tactile stimuli was primarily driven by hydrostatic changes—specifically, the sudden efflux of water from pulvinar cells following a localized alteration in cell membrane permeability. While earlier researchers had detected weak, transient action potentials accompanying the movement, Pfeffer insisted that these bioelectric phenomena were merely ancillary byproducts of cellular osmotic shifts rather than the primary propulsive trigger. Subsequent twentieth-century electrophysiology partially vindicated Pfeffer’s contemporaries by confirming that electrical action potentials do indeed propagate along the vascular bundles of plants to trigger pulvinar turgor loss. However, Pfeffer’s insistence on the decisive role of turgor-driven fluid dynamics prevented plant physiologists from prematurely reducing botanical signaling to a simple mirror of animal neurobiology, forcing subsequent investigators to account for the unique hydraulic architecture of plant tissue.

The passage implies which of the following regarding the "earlier researchers" mentioned in the text?

  1. They observed a genuine physiological phenomenon associated with leaf movement, even if they misconstrued its precise causal function in the response.Answer
  2. B
    They argued that hydrostatic pressure changes were entirely absent during the motor responses of Mimosa pudica leaves.
  3. C
    They were the first investigators to elucidate the complete hydraulic architecture of plant vascular tissues.
  4. D
    They rejected any analytical parallels between the physiological signaling of plants and animal neurobiology.
  5. E
    They disproved Pfeffer's model by proving that pulvinar cells do not undergo changes in membrane permeability.

Answer

The passage implies that the earlier researchers observed a genuine physiological phenomenon associated with leaf movement, even if they misconstrued its precise causal function in the response.
The passage states that earlier researchers 'had detected weak, transient action potentials accompanying the movement,' and later notes that twentieth-century science 'partially vindicated Pfeffer's contemporaries by confirming that electrical action potentials do indeed propagate.' This indicates that the electrical phenomena observed by the earlier researchers were real, even though their understanding of how these signals interacted with hydraulic turgor loss was incomplete or misattributed relative to Pfeffer's hydrostatic model.

Step-by-Step Solution

1
Identify the target reference in the passage
Located the sentence: 'While earlier researchers had detected weak, transient action potentials accompanying the movement, Pfeffer insisted that these bioelectric phenomena were merely ancillary byproducts...'
The question specifically asks for an inference regarding the earlier researchers.
2
Analyze what the passage directly asserts about their findings
Earlier researchers detected action potentials (electrical impulses) that actually accompany the leaf movement.
Evaluating facts directly linked to the earlier researchers establishes the factual baseline.
3
Evaluate the synthesized view of twentieth-century electrophysiology
Twentieth-century findings 'partially vindicated' these contemporaries by confirming electrical signals do propagate to trigger turgor loss.
Inference requires combining their initial observation of electrical impulses with the passage's explanation of how their understanding differed from the physical mechanism.
4
Synthesize the valid inference
The electrical action potentials detected by earlier researchers were real (partially vindicated), but their exact role relative to hydraulic changes was not fully or accurately framed at the time.
Directly supports the statement that they observed a real phenomenon but misconstrued its exact structural role.

Key Concept

Inferences and Implicit Meaning
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Inferences and Implicit Meaning

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