Domain: Natural Science — Cell & Developmental Biology
Target concept: Observe the germination process of soybean seeds, and verify that the radicle emerges first through the seed coat and grows downward, followed by the growth of the plumule upward.

Video generation prompt: A time-lapse demonstration of soybean seed germination. Soaked soybean seeds were placed on a moist filter paper in a transparent petri dish. The continuous stages are shown: seed imbibition and swelling, rupture of the seed coat, and emergence of the radicle and plumule. Fixed camera position, close-up filming, with the process simplified and accelerated.

Evaluation guide:
(i) Target concept: Epigeal seed germination in dicots, where radicle emergence precedes and enables subsequent plumule development. Minimum mechanism: Water imbibition causes turgor pressure increase → seed coat rupture at weakest point (micropyle) → radicle protrudes due to differential cell elongation → hypocotyl elongation lifts plumule upward. (ii)Storyline: Frame sequence must show: (1) Initial state: dry-appearing but hydrated seeds resting on textured moist filter paper inside transparent petri dish, fixed centered view; (2) Swelling phase: seeds visibly enlarge symmetrically, surface tension increases, seed coat tightens; (3) Rupture phase: localized splitting at micropylar end, often with slight whitish extrusion; (4) Radicle phase: thin white/yellowish structure emerges downward through rupture, elongating steadily with visible tip; (5) Plumule phase: pale yellow-green structure emerges upward from same seed body (above cotyledons), extending with gentle curvature; all phases must be contiguous, unoccluded, and maintain fixed viewpoint; no off-screen emergence or re-entry allowed.

Manual:
Experimental Procedure
1. Soak soybean seeds in water for 12–24 hours until plump.
2. Place 3–5 soaked seeds equidistantly on moist filter paper inside a transparent petri dish.
3. Cover dish loosely; place under consistent ambient light; record with fixed close-up camera.
Observation of Experimental Phenomena
- Seeds swell uniformly within minutes of placement.
- Seed coat ruptures at micropylar end.
- Radicle emerges first through rupture, grows downward.
- Plumule emerges later from above cotyledons, grows upward.
Summary of Experimental Principles
Soybean exhibits epigeal germination: imbibition triggers metabolic reactivation; radicle (embryonic root) is the first organ to emerge, establishing anchorage and water uptake; plumule (embryonic shoot) follows, enabling photosynthesis upon emergence.

Prompt Grounding rubric:
level_1: No soybean seeds appear; no petri dish or filter paper is shown; there is no sign of moisture; no seed coat, radicle, or plumule appears; the camera is not fixed/close-up, or the footage does not read as a time-lapse (e.g., a single static frame or chaotic handheld motion).
level_2: Soybean seeds appear but are not resting on filter paper inside a petri dish (or the dish is empty/holds unrelated items); or the camera is panning/angled rather than fixed and close-up; or only seed swelling is shown with no radicle or plumule of any kind visible.
level_3: Soybean seeds rest on visibly moist filter paper inside a transparent petri dish, filmed with a fixed close-up camera, and the footage has a clear time-lapse rhythm (visible progression across frames); seed swelling is shown and a radicle (thin, tapering, whitish structure) or a plumule (stouter, pale yellow-green, curved structure) emerges from a seed, but only one of the two appears, or the second one appears too briefly or too occluded to identify by shape.
level_4: All conditions of score 3 hold, and both a radicle and a plumule emerge from the same seed body, each remaining visible long enough that its characteristic shape and color (thin/tapering/whitish for the radicle, stouter/curved/pale yellow-green for the plumule) can be told apart from the other; seed-coat rupture is shown before either structure appears; one minor flaw is allowed (e.g., the two structures briefly overlap in the same frame region, or one momentarily exits the frame edge).
level_5: All conditions of score 4 hold with no flaw: the radicle and plumule are unambiguously distinct in shape, texture, and color throughout, seed swelling and coat rupture are both fully visible before either structure appears, the camera frame never loses either structure mid-growth, and no text label or narration is needed to tell the two apart; their appearance alone makes it identifiable.

Scientific and Causal Correctness rubric:
level_1: The radicle and plumule are absent or misidentified (e.g., a root hair mistaken for the radicle, or a cotyledon mistaken for the plumule), the radicle grows upward or the plumule grows downward, the seed coat never ruptures, the seed never visibly swells or instead shrinks, or moisture and germination show no visible connection.
level_2: Both a radicle and a plumule appear, but at least one grows the wrong way (e.g., the radicle extends sideways, or the plumule extends downward), or the seed coat stays intact the whole time even though both structures emerge, or swelling appears only after a structure has already emerged, or different seeds in the same dish show conflicting emergence orders with no consistent pattern.
level_3: The radicle emerges before the plumule and grows downward; the plumule emerges afterward and grows upward; the seed coat is visibly split before the radicle appears; swelling is visible before the coat splits; this pattern holds for the seed(s) shown, but one causal link is broken, such as the radicle appearing without any prior swelling or coat rupture, or the plumule appearing before any sign of the radicle.
level_4: Every causal step is shown in order (swelling, then visible coat rupture, then the radicle emerging through the rupture site and growing downward, then the plumule emerging from the same seed and growing upward), with no contradicting event (no reversed growth, no plumule appearing before any radicle sign), and this pattern is consistent across every seed shown; one non-essential detail may be off, such as the cotyledons staying fully enclosed when they would normally show slight exposure, or the radicle lacking a visibly tapering tip.
level_5: Every step matches soybean epigeal germination with no exceptions: swelling precedes coat rupture; rupture occurs at the pointed (micropylar) end of the seed; the radicle emerges exactly through that rupture site and elongates downward as the dominant growing tip; the plumule emerges later from just above the cotyledons and elongates upward; the cotyledons stay attached and do not detach or unfold prematurely; every stage shown is continuous and consistent with standard soybean developmental biology.

Spatiotemporal Consistency rubric:
level_1: Seeds jump to a new position on the filter paper between frames, the petri dish or filter paper disappears and reappears, the filter paper's texture or color changes abruptly, the frame goes from bright to dark with no lighting event, the radicle or plumule blinks in and out without any growth shown connecting the two states, or the camera view suddenly pans, tilts, or zooms.
level_2: One major break occurs: a seed disappears for two or more consecutive frames then reappears larger, the radicle or plumule appears fully formed with no elongation shown leading up to it, the filter paper looks bone-dry in one frame and soaked in the next with no transition, the shadow cast by a seed swings to a different direction with no light source change to explain it, or the petri-dish rim visibly bends or warps.
level_3: Seeds, dish, and filter paper keep the same relative positions frame to frame, the radicle lengthens without reversing or skipping back, the plumule lengthens without reversing, and no seed, dish, radicle, or plumule is clipped, stretched, or warped, but one small flaw remains, such as a brief flicker in the moisture sheen on the paper or a slight jitter in a seed's outline for a frame or two.
level_4: There is no teleportation, no warping of the dish or paper, no abrupt lighting jump, and no sudden change in zoom or tilt; the radicle's tip visibly lengthens gradually rather than jumping to a longer length, the plumule does the same, and each stays within the petri dish rather than passing through the filter paper; one very minor artifact is tolerable, such as a faint frame-to-frame brightness flicker too small to register as a lighting change.
level_5: All conditions of score 4 hold with none of the tolerated minor flaws: the camera framing, lighting angle, and object placement stay identical in every frame; between the shown frames the radicle and plumule always appear a bit longer than the frame before, never shorter and never stuck at the same length for many consecutive frames, consistent with a deliberately sped-up, simplified time-lapse rather than real-time filming; the moisture sheen on the filter paper changes gradually rather than in a sudden jump; neither structure ever appears to bend back on itself or grow in reverse.