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What are the three tissue systems of a plant?
dermal
ground
vascular
What is the difference between parenchyma, sclerenchyma, and collenchyma? Whichis undifferentiated? Which is dead a maturity? Which provides flexible support?
parenchyma- generic, variable
collenchyma- provides flexible support
schlerenchyma- cell wall, rigid support, dead at maturity
Where might you find parenchyma, sclerenchyma and collenchyma tissue?
ground tissuexylem
What is the function of xylem? What is the function of phloem? Which of these twotissue types is dead at maturity?Structural Adaptations
xylem- dead at maturity, moves water up
phloem- moves sugar around
Why might many plants be phenotypically plastic?
grow different depending on the environment
What are several morphological differences between a sun and shade leaf?
sun leaves are thicker with more pallisade parenchyma
What is lignification and how does it lead to sturdy plants?
lignin makes plants tough
Often when you submerse a plant stem it becomes thicker yet less sturdy, explainwhy?
less lignin, more air space
Where do you commonly find the stomata on floating leaves and how is that different from where stomata are generally found on emergent leaves?
floating- on top
terrestrial- on bottom
submersed- absent
Why might chloroplasts occur in the epidermal layer of submerged leaves but not emergent leaves?
light is less common underwater
What are several characteristics that are common to floating leaves?Note floating leaves are generally thicker than terrestrial leaves and submerged leaves are among the thinnest leaves (of course these are generalization).
stomata typically adaxial
chloroplast-rich upper palisade layer
regularly arranged spongy layer withcolumnar supports to produce a largenetwork of air-spaces
support of chambers by branching sclereids
phloem better differentiated than xylem
both epidermal layers cutinized and may possess chloroplasts
What are several characteristics of submersed leaves?
lack mechanical tissue (supported by water)
cuticle thin or absent; lack of epicuticular (surface)wax layers
stomata lacking or functionless
mesophyll reduced; often a single cell layer or absent
more chloroplasts in epidermis
xylem greatly reduced or absent
Why are submergent dicots typically dissected, while submergent monocots are ribbon-like?
convergent evolution
Why is a high surface area to volume ratio important underwater?
more light and CO2 uptake
Why is the xylem of submerged plants often reduced or absent?
they do not need to take up water
Why is the cuticle reduced or absent in submerged plants?
to suck in CO2
Why might a broad flat submerged aquarium plant start to develop small pits on itsupper surface?
limited CO2
