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Plant Responses, Growth, & Import. Chapter 3 Lessons 5 & 6. 1. Tropism – a plant’s growth in response to a stimulus Positive tropism – growth is toward the stimulus Ex. Plant growing toward the light (phototropism) Negative tropism – growth is away from the stimulus
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Plant Responses, Growth, & Import Chapter 3 Lessons 5 & 6
1. Tropism – a plant’s growth in response to a stimulus • Positive tropism – growth is toward the stimulus • Ex. Plant growing toward the light (phototropism) • Negative tropism – growth is away from the stimulus • Ex. Plant growing away from gravity (gravitropism) What are the stimuli that produce plant responses?
1. Photoperiodism • Short day plants – flower when the days are short • Long day plants – flower when the days are long 2. Dormancy • Helps plants survive freezing temperatures and the lack of liquid water • Ex. Deciduous trees – drop their leaves How do plants respond to Seasonal Changes?
1. Environment • Habitats for animals, food, oxygen, clean water, hold soil in place 2. Humans • Food, clothing, building materials, fuel How are plants important to everyday life?