Plant structure Flashcards
what is translocation?
long-distanced transportation that occurs through the vascular system (xylem and phloem)
why is transportation in plants needed?
- to move substances from where they are absorbed to where they are needed
- to move substances from where they are produced to where they are needed for metabolism
- to move substances to a different part for storage
how is water absorbed?
water is absorbed along with minerals by root hairs by diffusion through pathways
what are the 2 types of absorption pathways?
apoplast and symplast
what is the difference between apoplast and symplast pathways?
- apoplast pathways consist of non-living parts such as the cell walls and intercellular spaces. It is also faster because the metabolic state of the root does not affect it.
- symplast pathways consist of living parts of the plant such as the protoplast connected to the plasmodesmata. it is slightly slower because it is affected by the metabolic state of the roots
explain how apoplast pathways work
water enters the cell walls and moves through the cell walls or intercellular spaces.
explain how symplast pathways work
water enters the cytoplasm by osmosis through the semipermeable cell surface membrane. the water moves into the sap in the vacuole through the tonoplast and moves through the plasmodesmata.
what is a Casparian strip?
the casparian strip is a thick ring that forces water and minerals to pass through it as the semipermeable membrane filters
what are plants transport systems?
xylem and phloem
what is xylem?
xylem is a one-way system that carries mainly water and inorganic ions from the roots to other parts of the plants.
composed of the tracheid, xylem fibers, and xylem parenchyma
what is phloem?
phloem is a two-way system that carries substances made by photosynthesis to other areas of the plant.
composed of phloem fibers, sieve cells, and phloem parenchyma
name the parts of a dicot stem (6)
epidermis, cortex, fibers, phloem, cambium, xylem
name the parts of a dicot leaf (9)
- upper epidermis
- palisade mesophyll
- spongy mesophyll
- collenchyma
- xylem
- phloem
- compact parenchyma
- parenchyma
- lower epidermis
what are the functions of the epidermis?
prevent water loss and protection
what are the characteristics of the epidermis?
- tights cells
- large vacuoles can contain anthocyanin
- is a living cytoplasm and contains salt crystals, silicate crystals, and oil salts
what are the functions of the parenchyma?
- support the plant
- prevent wilting
- food storage like starch
what are the characteristics of the parenchyma?
- metabolically active
- forms cortex in the roots and stems
- contains chloroplasts to be modified into the palisade and spongy mesophyll
- in aquatic plants, connects to air spaces
what are the functions of the collenchyma?
provides strength
what are the characteristics of the collenchyma?
- meristematic - living cells
2. can be found along the periphery of stems and below vascular bundles
what are the functions of the sclerenchyma?
- strengthen adult parts of the plants or soft organs
what are the characteristics of the sclerenchyma?
- found scattered between other cells
- made up of dead cells
- cell walls contain lignin
- stronger and more rigid than collenchyma
what is the endodermis?
a thick cell that surrounds the vascular tissue in stems and roots and is found between the cortex and the vascular tissues to prevent water and other dissolved minerals from going through the apoplast
what is the mesophyll?
the mesophyll is specialized for photosynthesis and contains chloroplasts.
its 2 types are the spongy mesophyll and the palisade mesophyll.
what are the differences between spongy mesophyll and palisade mesophyll?
the spongy mesophyll is where carbon dioxide and oxygen is diffused out of while the palisade mesophyll contains more chloroplasts
what is the pericycle?
a thick cell where new roots can grow inside the endodermis and next to the vascular tissue. in stems, it is formed from a tissue called sclerenchyma
what are the types of meristem?
- apical - roots and stems
- lateral - roots and stems
- intercalary - base of internodes (where leaves are attached)
what are the major parts of a plant?
- leaves
- seeds
- flowers
- stems
- roots
what are the characteristics of monocots?
- seed only has one cotyledon
- flower petals in multiples of three
- leaves with parallel primary veins
- fibrous roots
what are the characteristics of dicots?
- seed has two cotyledons
- flower petals in multiples of four or five
- leaves have distinct vein work
- broadleaved
true or false: food storage tissue that nourishes the embryo is called cotyledon
false. (endosperm)
what are the stomata?
pores in leaves that allow entry of carbon dioxide for photosynethesis
true or false: sclerenchyma is found scattered between other cells and is composed of living cells?
false. sclerenchyma is composed of dead cells.
the layer that encloses the vascular tissue in the central region of a root is the…
endodermis
what is the most important force that pulls water up in the xylem?
transpiration pull
what is the characteristic of the cell walls in mature xylem vessels?
heavily lignified
what is the function of the pith?
to store food obtained from the phloem
what are the characteristics of a meristematic tissue?
- has large vacuole cells
- has plastids
- has protoplasm
- has thin-walled cells
what are the two types of cells in phloem tissue transport?
- sieve tubes
2. companion tubes
in plants, the tissues that function to support the stem are?
collenchyma and sclerenchyma
