plant organs: Roots Flashcards
how much of the plants total dry weight will roots make up
about one-third
what are the four vital functions of roots
absorption, anchorage, food storage, and nitrogen fixation
what do roots absorb
water and dissolved nutrients
why do roots need O2
for respiration
roots must have _____ contact with soil particles
extensive
what simple minerals do roots absorb
N, P, S, K
what other extra things will roots absorb
vitamins, hormones, and other organic substances that leached out of decaying materials
why are anchorage shoots beneficial for photosynthesis
puts the plant in a position that allows it to carry out photosynthesis effectively
what environmental conditions are roots useful for
wind, rain
plants with poorly developed roots are more susceptible too…
lodging-falling over
what are adventitious roots
roots that form from the stem instead of the root tissues
what are prop roots
roots that arise from the stem above the soil surface to provide additional support for the plant
what kinds of plants is storage really important for
biannual, perennial
why is root storage so important for biannuals and perennials
provides a means for surviving the winter and resuming growth in the spring.
why is it important to not cut plants such as alfalfa late into the year
the plant won’t be able to get all the food into the roots. this will increase the chances of a winter kill
what plant species does nitrogen-fixing happen in
legumes (plants that have their seed in a pod)
what bacterial do legumes have a relationship with
rhizobia
where do rhizobia live
in the roots of the legumes plants. in formed colonies called nodules
what is the function of rhizobia
take up nitrogen in the soil and air and fix it for the plant to use. they also use a special enzyme to help with this process
how much nitrogen is in the air
approx. 79%
what kind of relationship do legumes and rhizobia have
symbiotic relationship meaning they both benefit by living together
how do legumes and rhizobia benefit each other
the plant provides the bacteria with food, water, and a safe place for it to live in return for nitrogen
does every plant species have the same kind of rhizobia
No. each species has its own strain of rhizobia that forms a relationship with it
what do we have to do when growing peas, lentils etc..
we have to inoculate the seed whit rhizobia
how are rhizobia usually purchased
in bags mixed with peat
what kind of roots do dicots have
taproot systems. which is a major root with secondary roots grown from the taped root
what kind of roots do monocots have
the radical is replaced by the secondary root system early in the plant growth. it grows rapidly to form the fibrous root system
in monocots where does the secondary root system form from
the crown (just below the soil surface)
what is the tip of the root protected by
the root cap
what does the root cap cover
the apical meristem
what is behind the apical meristem
the area of cell enlargement. the cells grow and expand pushing the root through the soil
what is behind the cell enlargement area
the area of cell maturation. the cells will specialize into specific tissues/organs
what is the function of root hairs
important for absorbtion. they aren’t very long individually but the combined length is huge. they increase surface area allowing more cells to be in contact with the soil
how do root hairs take up water
through osmosis
