plants lab quiz Flashcards
xylem
- vascular tissue reponsible for transport of water and dissolved substances
- forms continuous pathway through roots, stem, and leaves
- cells have thick cell walls and are dead at maturity
- thicker-walled xylem strengthened by presence of lignin, important for support
phloem
- vascular tissue responsible for transport of organic materials (ex: carbohydrates and amino acids)
- transports from organic molecules from leaves to stem and roots for storage; or to growing points of cell for immediate use
- cells are thin-walled with cytoplasm but lack nuclei
- have special companion cells with nuclei next to conducting cells
air space
intercellular gaps filled with gas (CO2, O2) within the spongy mesophyll
cuticle
waxy, water-repelling layer on top and bottom surfaces of a leaf
- keeps leaf from drying out
- protects against bacteria, insects, fungi
- secreted by the epidermis
guard cell
one of a pair of sausage-shaped cells surrounding a stoma
- change shape, causing stoma to open and close
lower epidermis
waxy skin on the underside of a leaf, one cell thick, keeps leaf from drying out - outermost cells
upper epidermis
protective, outer layer of cells on upper surface of leaf, one cell thick, secreted by waxy cuticle, contains some guard cells
mesophyll
chlorophyll-containing leaf tissue located between the upper and lower epidermis; convert sunlight into usable chemical energy for plant
- two types: palisade, spongy
palisade mesophyll
layer of elongated cells located under the upper epidermis
- contain most of leaf’s chlorophyll, converting sunlight into energy for plant
spongy mesophyll
layer below the palisade mesophyll, has irregularly shaped cells with many air spaces between the cells
- cells contain some chlorophyll, cells communicate with guard cells, causing them to open and close, depending on concentration of gases
stoma
pore inleaf where water vapour and other gases leave and enter the plat; formed by two guard cells that regulate opening/closing of pore, mainly found on bottom of leaf
vein
provide support for leaf and transport both water and minerals (xylem) and food energy (phloem) through leaf and to rest of the plant
mesophytes
plants that thrive in average conditions
ex: maple trees, lilac bushes, tulips
xerophytes
plants that thrive in desert like conditions, with less water, more sun and hotter temperatures
ex: cactus, aloe vera
hydrophytes
plants that grow (float) on the surface of ponds and lakes
ex: water lily
roots
- responsible for absorbing and conducting water and mineral nutrients
- anchor the plant in place, providing structural support and resistance
stems
allows plant to push itself up against gravity, contain vascular tissue to conduct water and dissolved minerals up or down in the plant, provides support allowing plant to grow upwards, contains epidermal tissue to protect against pathogens
nodes
point where leaves attach to stem
internodes
stretches of stem seperating nodes
leaves
primary function is photosynthesis (production of organic compounds)
two types of plant tissue
meristematic and permanent
meristematic tissue
composed of immature cells actively dividing, found where plant is growing: root/stem tips, flower buds, embryos (seeds)
permanent plant tissue
three categories: surface, ground and vascular
surface tissues (permanent)
protective outer covering of plant body, cells are flat and interlock like puzzle pieces, outer walls thicker than inner walls and impregnanted with cutin (waxy substance)
ground tissues (permanent)
parenchyma, collenchyma, sclerenchyma (make up the bulk of plant organs)
parenchyma
predominant ground tissue cell, thin/flexible cells walls, unspecialized, contain plastids
- function: photosynthesis, nutrient storage, give support and shape to plant when filled with water, repair damaged tissues
collenchyma
thick cell walls, strong (additional cellulose and pectin), grouped into bundles of cells, function: support of plants
sclerenchyma
thick cell walls (hardened by lignin), at maturity cells are dead, important for support of plant, used for linen threads (weaving, sewing, paper); wood coconut shells and apple cores made of this
vascular tissues
xykem, phloem, air space, cuticle, guard cell, stoma, lower epidermis, upper epidermis, mesophyll (palisade and spongy), vein
