plant responses to the environment Flashcards
what is an abiotic component
components of an ecosystem that are non-living
what is a biotic component
living components of a ecosystem
what are the three types of chemical defences
tannins- toxic to microorganisms and herbivores, make the leaf taste bad and prevent infiltration of pathogens
alkaloid- animal feeding deterrent make the plant taste bitter
pheromone- chemical released by one individuals which effect the behaviour or physiology of another
what is a tropism
directional growth response of a plant
what is a phototropism
response to light
what is a geotropism
response to gravitational pull
plant roots grow towards the direction of gravity
what is chemotropism
on a flower, pollen tubes grow down the style, attracted by chemicals, towards the ovary where fertilisation occurs.
what is thigmotropism
shoots of climbing plants, such as ivy wind around other plants or solid structures to gain support.
what is a positive response
when a plant responds towards a stimulus. FOr example, positive phototropism, plant grow towards the light.
what is a nastic response
a non directional response to external stimuli
what is a cytokinin
promote cell division
delay leaf senescence
overcome apical dominance
promote cell expansion
what is abscisic acid
inhibit seed germination and growth
causes stomatal closure when plant is stressed by low water availability
what is an auxin
promote cell elongation
inhibit growth of side shoots
inhibit leaf fall
what is a giberellin
promote seed germination and growth of stems
what is ethene
promote fruit ripening
