Plant Hormones Flashcards
What tropisms do plant shoots experience?
Positive phototropism
Negative geotropism/gravitropism
What tropisms do plant roots experience?
Negative phototropism
Positive geotropism/gravitropism
Positive hydrotropism
What is a tropism?
A directional growth response
What is a plant’s response to light?
Phototropism
What is a plant’s response to gravity?
Geotropism/gravitropism
What is a plant’s response to moisture?
Hydrotropism
How do plant hormones travel?
From cell to cell
How do plants use hormones to make adjustments to survive?
Plant hormones are sensitive to their environment
Why does a plant’s shoots need to grow upwards?
To receive light to break the bonds in water during photosynthesis
To receive carbon dioxide for photosynthesis
To lose water through transpiration
Why does a plant’s roots need to grow downwards?
To receive water for photosynthesis
To anchor the plant in the soil
To reach minerals
How do hormones contribute to a plant’s response to stimuli?
They are distributed unequally, causing unequal growth rates
What are auxins?
Plant hormones
What do auxins control?
Cell elongation
What do auxins do in the shoots of plants?
Make cells elongate
What do auxins do in the roots of plants?
Inhibit cell growth
How do auxins move in accordance to light?
They move away from light
How do auxins move in accordance to gravity?
They move towards gravity
What is ethene?
A plant hormone
What does ethene do?
Causes fruit to ripen
How does ethene cause fruit to ripen?
By stimulating the conversion of starch into sugar
What state is ethene in?
A gas
What are gibberellins?
A plant hormone
What do gibberellins do?
End the dormancy period of seeds and buds, meaning flowers open and seeds germinate
Promote growth and development
How are auxins used as weedkillers?
They make the weed grow too quickly, resulting in it dying
What is a use of ethene?
Ripen fruit
How is are auxins used to produce parthenocarpic fruit?
By subjecting the plant to auxins in early ovule development, resulting in the production of fruit without the fertilisation of the ovules to create seedless fruit?
What is parthenocarpic fruit?
Seedless fruit
How are gibberellins used?
To grow seeds all year round
