Radish Seed Germination

Warm-up What stimuli (triggers) do plants respond to?

What stimuli do plants respond to? Light Water Temperature Length of day Touch Gravity

Notes: Tropism- growth towards or away from a stimulus How do roots know to grow down? Tropism to gravity=geotropism How do stems know to grow up? Tropism to light=phototropism

Notes continued… Vines growing up the side of a house Tropism to touch=thigmotropism A plant’s ability to bend and grow the root towards a source of moisture Tropism to water= hydrotropism Plants grow towards moist soils to avoid drought stress. Once a root cap has sensed water it bends and then the root grows towards it.

Focus Questions: 1: How will light and dark affect the germination (growth) of a radish plant? 2: How will gravity affect the growth of a radish plant?

Radish seed Lab: Problem: How does light and dark affect the germination of the radish seed plants? Hypothesis: If radish seeds are germinated in the light/dark, then they will germinate faster/slower. If the seedlings are turned upside down, then the roots will grow up/down and the stems will grow up/down.

Continued… Follow procedures given by Ms. Kasem to set up your seeds. Record your data in the table you are making **this investigation will take several days ** Once your group has completed this please complete the analysis questions- you may use your textbook pages for assistance.

Day 1 Observations (Geotropism) Describe what you see…. --how many have sprouted? --how many look healthy? --which way are the roots growing, generally speaking? --any other observation you may have ***Avoid words like: yucky, smelly, ugly, horrible, etc

Radish Seed Germination Opening Assignment (OA): Please get your Science notebook and open it to your Radish Seed Germination lab. Please sit down with your group. Be prepared to answer this question: The property of plants that explains the direction a plant grows is know as: Osmosis? Buoyancy? Geotropism? Turgor Pressure?

Procedure for today: You will get into your groups and one person will get your seeds. Together you will examine you seeds, discuss what has changed and then write out observations. Together we’ll discuss what you’ve observed.

Day 2 Observation (you have 10 minutes to examine & record) Describe what you see… --how many have sprouted now? --how healthy do they look now? --which way are the roots growing, generally speaking now? --write any other observations you may have ***avoid using words like- yucky, smelly, horrible, etc.

Now …. We’ll review over p. 490-493 (tropisms) Recall previous focus questions (objectives) and recall the answers Answer the questions that bridges what we’ve done with where we’re going…external & internal stimuli

How are plants affected by gravity? Geotropism: in response to gravity, roots grow down Is gravity an external or internal stimuli? Now that we have reviewed, please use the remaining class time to complete the Analysis and Conclusions of this investigation. Please be sure you are formulating your own responses!!!