Growth in Plants Flashcards
what does indeterminate growth mean
plants can grow to any size
Meristems have cells that are totipotent.
Totipotent 🡪 the ability of a
single cell to divide and produce
all of the differentiated cells in an
organism
and you can locate them in the meristems that are responsible for plant growth
When cells divide in the meristem believe what happens to both cells
one remains in the meristem while the other increases in size, differentiates and then pushed away from meristem
Each apical meristem can give rise to an additional type of tissue such as
protoderm (gives rise to epidermis)
procambium ( gives rise to vascular tissue)
ground meristem (gives rise to the pith)
types of meristems
Apical Meristem – meristems responsible for shoot and root tip growth
lateral meristem – meristems in other plants parts (DICTOS ONLY) T
types of meristems
Apical Meristem – meristems responsible for shoot and root tip growth
lateral meristem – meristems in other plants parts (DICTOS ONLY) that form cylinders of tissue to increase stem/root diameter
What is an Hormone
chemical messanger which is produced and released in one part of an organism to have an effect on another part of an organism
What are Auxins
and what is the most abundant type of Auxin
Plant hormones that have a broad range of functions ex ) starting root growth, development of fruits** mostly responsible for growth
IAA which promotes growth of cells in stems but can also be an inhibitor if high concentration
usually found in the shoot (above ground) while cytokinin’s are below groound
explain tropism
Tropism is the directional growth of plants in response to a external stimuli (ex sunlight)
What controls the rate and direction of growth in Tropism
and how can stem growth be affected in Tropism
Auxins!!!!!!!!!!\
Light and gravity affect stem growth
why does a plant grow towards sunlight
when phototroph ins in tip of growing stem detect a greater light intensity on one side, auxin is transported laterally causing greater growth on the opposite side side, which angles the stem towards the light source. this allows more light to be received for photosynthesis
explain gravatropism
it will grow on its side, gravity causes cell organelles called statolatry to accumulate in lower sides of all which causes PIN3 to direct high concentrations of auxins to inhibit growth on bottom cells so top cells will grow at a higher rate causing downwards growth
Apical dominance explain apical dominance and why its important
and then the important part that i didnt mention on the test
how do the axillary buds then grow after
Apical dominance occurs when the Apical shoot meristem is close to the axillary buds and therefore auxins inhibits the growth of axillary buds so that the plant may grow vertically instead of diagonally in another direction.
which is why the further the node is from the shoot apical meristem, the less likely it will be inhibited
once the shoot grows then the auxin levels decrease allowing for the axillary bud to grow
and then cytokinins are in control for growth of axillary buds
what hormone promotes axillary bud growth
cytokinin’s
