Level 4 Guiding Question: What are the phases that a seed goes through to maturity?
Timeline for Days to Seedling Maturity
A three-phase process leading to the emergence of roots and above-ground growth
Phase 1: Imbibition. Rapid initial uptake of water by the dry seed, followed by a brief but gradual continuation of water uptake. This softens and swells the seed coat and occurs even in seeds that are no longer viable.
Phase 2: Interim or lag phase. Water uptake greatly reduced; internal physiological processes begin. From the outside, little appears to be happening, but this is a very active physiological and metabolic period within the seed.
i. Activation of mitochondria within cells of the seed: Supporting increased cellular respiration and energy production
ii. Protein synthesis: Translation of stored RNA to fuel continued germination
iii. Metabolism and use of stored nutrient reserves to fuel development
iv. Enzyme production and synthesis, leading to the loosening of cell walls around the embryo and root radicle, which will ease subsequent cell enlargement, division, and elongation
Phase 3: Root radical emergence. Initially, root radicle emergence results from cell enlargement, but this is rapidly followed by cell division and elongation as the root radicle pushes into the surrounding soil media.
Level 4 Investigation: How the seed develops to maturity.
Speeding up Germination LabIn this lab you will be watching the video and setting up the lab presented. See your instructor for the equipment and supplies to conduct the experiment. While testing scarification techniques we will also being recording the phases of growth see the diagram above entitled, "Timeline for Days to Maturity". Identify all three phases of seed development using the pictures the diagram and the pictures below.
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All three seed developmental phase are demonstrated in this illustration.
Level 3 Videos: Seed development
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Level 4 Elaborate: Identifying the phases of seed development.
While you are conducting the "Speeding up Germination" Lab draw or take pictures of each of the phases and create a powerpoint or timeline with your drawings or pictures with captions explaining each phase in your own words making sure that each step of the development is explained simply but concisely.
Level 4 Review: What do you know?
Read the online chapter from our text and after you have read the chapter complete the google form below.