Domain: Natural Science — Cell & Developmental Biology
Target concept: Time-lapse photography of plant seed germination leading to root, stem, and leaf formation

Video generation prompt: A legume seed was placed in a container filled with clear soil, pressed against the transparent wall, and recorded with a fixed camera over time as it germinated.

Evaluation guide:
(i) Target concept: Time-lapse visualization of post-imbibition embryonic development in dicot seeds, requiring intact seed coat, viable embryo, and permissive environment (moisture, temperature, oxygen). Minimum mechanism: Radicle emergence must precede hypocotyl elongation, which must precede leaf primordium expansion. This tripartite sequence is non-negotiable and driven by differential auxin distribution and cell wall loosening.
(ii)Storyline: Frame 1–2s: Intact legume seed pressed against transparent wall in clear soil; no growth visible. Frame 3–4s: Radicle tip breaches seed coat and begins downward extension: continuous, tapered, white/yellowish. Frame 5–6s: Hypocotyl becomes visible as pale green cylinder rising vertically from cotyledon node; radicle continues elongating. Frame 7–8s: Leaf primordium appears as small folded bump at stem apex. Frame 9–10s: Primordium unfolds into symmetrical, green lamina with visible midvein; all three structures maintain fixed spatial relationship to seed and wall. Perspective constraint: Fixed side-on view ensures seed-wall contact, soil depth, and vertical/horizontal axes remain invariant; no top-down or oblique angles permitted.

Manual:
Experimental Procedure
1. Select a dry legume seed (e.g., mung bean or kidney bean) with intact hilum and bilateral symmetry.
2. Fill a transparent-walled container with clear, moist soil (visually granular and translucent).
3. Press the seed firmly against the inner surface of the transparent wall so its outline is fully visible.
4. Mount camera in fixed side-on position to record uninterrupted time-lapse.
Observation of Experimental Phenomena
- First: White/yellowish radicle emerges downward from seed hilum region.
- Second: Pale green hypocotyl-stem axis elongates upward, lifting cotyledons.
- Third: First true leaf unfolds from apical meristem as symmetrical, veined lamina.
Summary of Experimental Principles
Germination is triggered by water uptake; radicle (embryonic root) emerges first for anchorage and absorption; hypocotyl elongation enables seedling emergence; apical meristem produces leaves through cell division and differentiation — all observable due to transparent wall and clear soil.

Prompt Grounding rubric:
level_1: No legume seed is visible; no transparent-walled container is shown; no soil is present; the camera is not fixed side-on; no root, stem, or leaf structure appears at any point.
level_2: A seed-like object and a container are visible, but the seed is not legume-shaped (e.g., it is spherical, conical, or irregular), is not pressed against a transparent wall, and the soil is absent or opaque; no root, stem, or leaf morphology appears across the sequence.
level_3: A legume seed (bilaterally symmetric, oval-oblong, with a visible hilum) sits in a container of clear soil, visibly pressed against a transparent wall; the camera viewpoint is fixed and side-on; a root emerges first, then a stem, then a leaf-like structure, appearing in that order even if their shapes or spatial placement are imperfect.
level_4: Everything required for a 3-level score is present, and every element is also correctly arranged: the legume seed (correct shape, size relative to the soil, hilum visible), the clear soil (translucent, granular texture), and the seed's flush contact with the transparent wall (no visible gap) are all present; the camera stays fixed and side-on; root, then stem, then leaf appear in strict order with correct relative positions - root growing downward, stem growing upward, leaf emerging from the top of the stem.
level_5: Everything required for a 4-level score is present, and every element is rendered with high fidelity: the legume seed is clearly identifiable by shape, hilum, and surface texture, sitting flush against the transparent wall with no gap; the soil shows a granular, translucent texture with visible depth; the camera framing and viewing angle stay identical across the whole sequence; the root grows continuously downward from the radicle tip, the stem grows continuously upward from the cotyledonary node, and the first true leaf visibly unfolds from the shoot tip - all three structures keep correct orientation and proportion throughout.

Scientific and Causal Correctness rubric:
level_1: No biologically plausible germination event occurs, e.g., the seed dissolves, floats away, or turns into a non-plant shape; no root, stem, or leaf differentiates; colors change in ways that violate plant biology (e.g., the seed turns blue, or roots appear to glow).
level_2: A growth-like motion occurs but violates core developmental order: the stem appears before the root; a leaf emerges directly from the seed coat with no stem in between; the root grows upward or sideways with no downward bias; the root, stem, and leaf all share the same color and texture with no differentiation between them.
level_3: The root appears first and grows downward; the stem appears second and grows upward; the leaf appears third; but structural detail is weak: the root lacks a visible root cap or root hairs, the stem lacks nodes, and the leaf lacks visible venation or symmetry; colors stay flat across stages (e.g., everything pale yellow) or change in ways that don't match plant biology (e.g., the seed turns green before any leaf appears).
level_4: The causal sequence and morphology are both correct: the root emerges from the radicle with a visible tapered tip and grows downward; the stem emerges from the hypocotyl/cotyledon region and extends upward with a slight curve; the first leaf emerges as a folded primordium that then unfurls; the colors progress as expected - tan/brown seed coat, whitish-yellow radicle, pale green stem, and a green leaf with a visible midvein - with no abrupt, biologically implausible color jump.
level_5: Every stage of development is biologically consistent: the radicle emerges continuously with no interruption; the root shows progressive elongation with a visible root cap and the beginning of lateral root growth; the hypocotyl lifts the cotyledons as it elongates, followed by the first true leaf unfurling with a symmetric lamina and a defined midvein; green coloration appears only in the photosynthetic tissue (stem and leaf), not in the root or seed coat; no developmental stage is skipped, reversed, or merged with another.

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal rupture: the seed teleports between frames; the soil disappears and reappears; the transparent wall flickers or warps; the scene's brightness swings suddenly from full daylight to near-black within a single frame; a root, stem, or leaf pops in fully formed with no growth motion leading up to it.
level_2: Major discontinuities: the seed changes position or orientation with no visible motion; the soil level shifts inconsistently between frames; the wall's transparency varies frame to frame, opaque one moment and clear the next; the root's length or position jumps discontinuously; the stem bends in opposite directions in consecutive frames.
level_3: Minor but noticeable breaks: a brief freeze of two or more identical frames; a subtle, uncaused shift in shadow position; root or stem growth pauses and then resumes at a visibly different speed; the seed-to-soil contact margin wobbles slightly but stays essentially adjacent.
level_4: Every spatial relationship stays continuous: the seed stays fixed against the transparent wall; the soil's surface and depth stay stable; the wall keeps uniform transparency and flatness; the root extends smoothly downward with no jump or reversal; the stem rises smoothly upward with a consistent curve; the leaf unfolds through a continuous rotating/folding motion with no duplicated, skipped, or jittery frames.
level_5: Every condition for a 4-level score is met, and the growth reads as fully continuous to the eye: no frame is duplicated or skipped; the shadow's shape and intensity never shift on their own; the seed, soil grains, and wall never drift out of place; the root lengthens smoothly with no visible stutter or overshoot; the stem's curvature develops organically with no sudden kinks or resets; the leaf unfolds in one steady, symmetric hinge-like motion with no tearing, flipping, or see-through glitches.