Plant responses Flashcards
What is abscission?
A process where a plant sheds parts, particularly leaves, fruit and seeds when their loss is beneficial to the plant.
What is an autotroph?
An organism that is able to produce complex organic molecules from molecules found in its environment, using an external energy source.
What is critical day length?
A period of day length that when exceeded triggers flowering in long-day plants or inhibits flowering in short-day plants
What is ethylene?
A plant hormone that promotes the ripening of fruit
What is gravitropism?
Growth towards or away from a gravitational attraction
What is hydrotropism?
Growth towards or away from water
What is a long-day plant?
A plant that is triggered into flowering when nights become shorter than a critical day length. Early summer and late spring.
What is a nastic response?
A nastic response is a fast and reversible turgor movement. They rely on changes in turgor pressure within certain plant cells.
What is nyctinasty?
A circadian rhythmic movement of plants in response to the onset of darkness
What is photoperiod?
The period of time each day which an organism receives sunlight.
What is photosynthesis?
The process by which plants and some bacteria use the energy from sunlight to produce glucose from carbon dioxide and water.
What is photoperiodism?
The response of an organism to seasonal changes in the photoperiod.
What is phototropism?
Growth towards or away from a source of light
What is a thigmotropism?
A thigmotropism is movement in which a plant moves or grows in response to touch or contact stimulu. Commonly seen in climbing plants with coil-like structures called tendrils.
What is phytohormone?
Any of a range of chemicals that regulate plant growth
What is phytochrome?
A blue-green pigment found in many plants that regulate various developmental processes, particularly flowering
What is a thigmonastic response?
A nastic response triggered by touch.
What is a short-day plant?
A plant that is triggered into flowering when nights become longer than a critical length. Autumn/Winter.
How does the ability of stems and leaves to change their orientation towards a moving light source give plants an adaptive advantage?
Able to receive maximum light intensity to optimise the rate of photosynthesis.
What is a tropism?
A tropism is a long term, slow growth movement toward or away from a stimulus. They result in permanent changes in the size of some cells.
How does the ability to time flowering with other members of the species give plants an adaptive advantage?
Synchronous flowering increases chance of cross fertilisation and reduces wastage of gametes and nectar. It may also allow plant to synchronise with its pollinator.
How is the ability to change the direction of root growth toward a source of water an adaptive advantage for plants?
Maintain photosynthesis and turgor pressure despite changes in location of water supply.
How does the ability of stems and leaves to grow upwards towards sunlight give plants an adaptive advantage?
The plant is able to compete successfully with other plants for sunlight and avoid over-shading.
How does the ability to grow roots in a downward direction give plants an adaptive advantage?
Access to water for photosynthesis
