botany exam 1 readings

meristems

specialized groups of dividing cells from which tissues are derived

vascular tissue system includes

xylem and phloem

types of simple tissues

parenchyma, collenchyma, sclerenchyma

parenchyma cells

• typically thin primary wall, spherical or elongated shape

• lignin makes wall impermeable to water

• perform basic metabolic fxns of cells (respiration, photosynthesis, storage, secretion)

cortex

region b/w plant’s epidermal & vascular tissues

pith

at center of stems, contains storage

mesophyll

bulk of leaves, site of most photosynthesis & water storage

chollenchyma

aggregated strengthening tissue, supports young stems & leaf petioles

elongated, chloroplast containing cells

schlerenchyma

provides mechanical support and strength

rigid tissues: fibers and sclereids

thick cell walls, dead at maturity

the only living cells in xylem are the

parenchyma

evolutionary advantage of seeds

mixing of genetic material through meiotic recombination & gene transfer

measure of successful germination

emergence of radicle

at germination, cell division occurs in

epicotyl

epicotyl

embryonic shoot region above attachment point of cotyledons

hypocotyl

embryonic region below the cotyledon attachment point, extending down to where the root begins

epigeal seedling emergence

cell division in the hypocotyl is initially moe active. cotyledonary node is above the ground

hypogeal germination

apical meristem at tip of epicotyl is more active, pushing above the surface while the cotyledons & hypocotyl remain underground.

leaves attach at

nodes

transpiration

water evaporates back into air off leaves

blade/lamina

flattened part with high chloroplast concentration

petiole

stalk that attaches blade to stem

sessile

leaves without petiole

stipules

small leaves at petiole

monocots typically exhibit ___ venation

parallel

palmate venation

several veins radiate from petiole attachment

simple leaves

uninterrupted leaf margin

compound leaves

blades are segmented into separate leaflets

rachis

central axis beyond first leaflet

palmately compound

all leaflets attached to petiolule

trifoliate leaf

3 leaflet compound with rachis

shoot

mde up of a central axis (stem) and the components that grow off of it

node

place of origin on the stem for branches, leaves, and inflorescences

internodes

stretches of stem between nodes

apex

tip of the stem

apical bud/meristem

bud at tip of stem

leaf axil

crotch formed between leaf petiole and stem

axillary meristems

buds found within leaf axil

stolons

branches that stem from nodes that are very close to the soil surface

adventitious roots

roots that emerge from the stem above ground rather than the roots

rhizomes

node that is below the surface of the soil

purposes of roots

anchorage, support, absorption, symbiotic interaction with other organisms

rhizobia bacteria

nitrogen fixation: converting nitrogen from atmosphere into nitrogen compounds that the plant can use

mycorrhizal fungi

fungi that grow in association with roots. acquire phosphorus from the soil and make it available

radicle

section of the embryo that is root tissue c

apical meristem (roots)

region of rapid cell division and growth at the apex of radicle

primary root

root that forms from the embryonic radicle

tap root

strong primary root that grows downward, provides good leverage. persistent throughout the life of plant. lateral or secondary roots grow off it

fibrous root systems

radicle stops growing and adventitious roots begin to form from underground tissue, just above primary root.

basal roots

roots that emerge from the region just above where the main stem stops (base of stem)

hypocotyl roots

roots above basal roots

hypocotyl

portion of stem just above the root-shoot transition zone

root hairs

short-lived extensions of the epidermis of young roots. gather moisture and nutrients