higher plants + plant anatomy

vascular seed plants characteristics

• better adapted to terrestrial life than ferns

• not dependent on water for sperm transport

• maintains alternation of generations in life cycle

• well-developed vascular tissue

• dominant sporophyte

when does double fertilization occur in the angiosperm life cycle

right after pollination when a tube delivers 2 sperm cells into the ovule’s embyro sac

tap root

a single, large main root that grows straight down into the soil with smaller roots branching off it

meristematic tissue

plant tissue made of actively dividing cells responsible for new growth

apical meristem

growth tissue located at the tips of roots and shoots responsible for lengthening the plant

vascular cambium

a layer of growth tissue in stems and roots that produces new xylem and phloem, increasing the plant's thickness

companion cells

cells alongside sieve-tube members that help regulate their metabolic functions

vessel members

shorter, wider xylem cells connected end-to-end to transport large amount of water efficiently

tracheids

long, narrow xylem cells that conduct water + provide structural support

epidermis

outer protective layer of cells covering the plant body

polar nuclei

2 nuclei in the female embryo sac that fuse w/sperm cell to form the endosperm

pollen grains

structures that carry the sperm of seed plants

sieve-tube members

main conducting cells of the phloem through which sugars flow

root system

usually below ground, provides anchorage + absorbs water and minerals

shoot system

consists of stems, leaves, and reproductive organs; produces organic nutrients by photosynthesis

significance of xylem + phloem

provdes strucutral support for roots, stems, leaves, + transport of materials

leaves

• main photosynthetic organs

• supported by veins composed of vascular tissue

• contain guard cells

reproduction of seed plants

1. parent plant produces 2 types of spores insides its’ cones or flowers

2. spores are never released, + become microscopic pollen and ovules

3. pollen grains (carrying sperm) are carried by wind, water, or animals

4. pollen lands on the female structure of another plant

5. pollen grain grows a long tube downward into the female ovule

6. sperm travels down this tube to fertilize the egg, forming an embryo

7. ovule hardens into a protective seed containing the embryo + a food supply

8. seed is dispersed (by wind, fruit, or animals) + grows into a new mature plant

heterosporous

produce two types of meiospores, microspores and megaspores

microspores

produced in microsporangia + mature to become pollen grains that later develop into male gametophytes

megaspores

produces in megasporangia; develops into a female gametophyte containing one or more egg cells

each megasporangium is enveloped by ___

integuments

integuments

protective sporophytic tissues

ovule

• made up of integuments, megasporangium, + megaspore altogether

• a potential seed

pollination

pollen grains are transferred from male gametophyte to female gametophyte by wind or insects to undergo fertilization

pollen tube

male gametophyte structure that carries sperm nuclei to the egg in the female gametophyte for fertilization

zygote becomes a seed composed of ___

• the embryo sporophyte

• stored nutrients

• seed coat derived from integuments (resistant to unfavorable conditions)

→ seed germinates producing new sporophyte generations

what are the 3 types of plant tissues

dermal, ground, vascular

dermal tissue

• covers surface of entire plant

• contain guard cells

guard cells

specialized epidermal cells on stomata + root hairs that protect against desiccation

ground tissue

• all plant tissue that isn’t dermal or vascular

• used for storage, support, + photosynthesis

• contains parenchyma, collenchyma, sclerenchyma

parenchyma

support + storage

collenchyma

• elongated cells w/thick cell walls that provide support for plant organs

• alive at maturity

sclerenchyma

• used for support

• dead when mature

vascular tissue

contains xylem and phloem

xylem

• transport water + minerals

• contains tracheid cells + vessel members

phloem

• transport products of photosynthesis throughout the plant

• contains sieve-tube members + companion cells

gymnosperms

seed plants that have seeds exposed on the surface of modified leaves

divisions in gymnosperms

conipherophyta, cyadophyta, ginkophyta

characteristics that help gymnosperms on land

• small gametophyte (female + male)

• wind-pollinated (gametes resistant to desicciation)

• pollen tube

• vascular tissue

division coniferophyta

• cone-bearing plants

• largest + most known group of gymnosperms

• needlike or scalelike leaves

• conifers can attain considerable size + may live in dry habitats

• reproductive organs within pollen cones + seed cones

pollen cones

small, with paper-thin scales

pollen cones are also known as

staminate cones

seed cones

large, with woody scales

seed cones are also known as

ovulate cones

life cycle of a pine

1. wind carries pollen from male cone → female cone

2. pollen grains land on sticky scale of female cone

3. pollen grain grows a tube directly into female ovule

4. sperm travels down tube to fertilize egg, forming a diploid (2n) zygote

5. fertilized egg develops into an embryo inside a winged seed

6. seeds are naked on the upper surface of the female cone scales

7. cone opens to released winged seeds into the wind, which sprout into new pine seedlings

division cycadophyta

• palm-like, stout, thick trunk

• mostly in tropical regions (like florida)

• have separate male + female plants (dioecious)

• can be highly toxic to humans and animals

division gingkophyta

• woody stems, fan-shaped leaves

• incredibly resilient species w/high tolerance to air pollution, pests, + diseases

• popular herbal supplement used for blood circulation, cognitive impairment, antioxidant intake

importance of Gingko biloba

only one surviving species of division gingkophyta

division gnetophyta

• contains 3 living genera: Ephedra, Gnetum, Welwitschia

• contain angiosperm-like characteristics

examples of angiosperm-like characteristics in division gnetophyta

• cones enclosed by a structure that resembles fleshy fruits or primitive flowers

• pollination via wind + insects

• possess vessel elements in their xylem

angiosperms are also known as

flowering plants

angiosperm characteristics

• most “advanced” + diverse plants

• have well-developed vascular tissues + flowers that enhance reproductive success

• represent about 90% of all living land plant species

• contain major adaptations over gymnosperms

flowers

reproductive organs that protect gametes + attract animals that aid in pollination

fruits

a mature ovary that facilitate the dispersal of seeds

examples of major adaptations in angiosperms over gymnosperms

• flowers containing both micro + megasporangia usually in groups

• most are pollinated by animal pollinators instead of wind

→ ex: color, shape, smell, + nectar of flowers/fruits attract pollinators

• the ovary within flowers form fruits that enclose the plants seeds, enhacning the dispersal of seeds by animals after ingestion

external plant anatomy contains

stems, roots, nodes, leaves, petiole

stems

support nutrient transport + support leaves

roots

anchor the plant + absorb water + minerals

nodes

where leaves branch out from

petiole

leaf stalk that connects the midrib

flower anatomy contains

receptacle, petals, sepals, stamens, pistil

receptacle

• supports flowers on the stem

• reproductive structures are enclosed in two whorls of modified leaves

petals

• make the inner whorls

• usually colored to attract pollinators

sepals

• make outer whorl

• smaller than petals + green in color

stamen

male portions of a flower

stamen includes

anther, filament

anther

• top part of stamen

• contain microsporangia that produce pollen

filament

• bottom part of stamen

• support the anther

pistil

female portion of a flower

pistil includes

ovary, stigma, style

ovary

• basal portion

• contains megasporangia (ovule)

• nectar is secreted near the base of the ovary

stigma

• tip of the pisil

• receives pollen

• secretes enzymes promoting pollen germination

style

slender stalk that joins stigma + ovary

life cycle of angiosperm

1. anthers make pollen (male)

2. ovaries make eggs (female)

3. pollen lands on sticky stigma

4. insects or wind do the carrying

5. sperm 1 + egg = embryo (new baby plant)

6. sperm 2 + polar cells = endosperm (food for baby plant)

7. ovules become seeds

8. ovaries swell into fruit

pollination + fertilization in angiosperms

1. pollen production in anther

2. pollinators attracted by nectar, fragrance, + colorful petals

3. pollen transfer to stigma

4. fertilization process begins: pollen germinates + forms a pollen tube down into the flower’s ovary

5. ovule develops into a seed + ovary matures into a fruit, enclosing the seeds for dispersal

double fertilization

formation of an embryo + endosperm that provides nutrition for the embryo

ploidy of embryo

2n (diploid)

ploidy of endosperm

3n (triploid)

fruits + seeds

• seeds develop in ovary

• ovary grows + ripens to form a fruit providing protection for seeds

different types of fruits

dry dehiscent, dry indehiscent, fleshy

dry dehiscent

split open when dry to cast out the seeds

examples of dry dehiscent

pea, bean pods

dry indehiscent

don’t open + ovary wall tightly envelops the seed

examples of dry indehiscent

acorns, fruits of corn

fleshy

remain moist for a long period of time + usually edible and colored

example of fleshy fruits

strawberries, tomatoes

seed anatomy contains

seed coat, embryo sporophyte, cotyledons

seed coat

• derived from ovule wall

• protects seeds

cotyledons

• embryonic leaves

• contain many of the stored nutrients

• either dicots or monocots

seed anatomy characteristics

• seeds are able to withstand unfavorable conditions + tend to germinate only when favorable conditions exist

• stored nutrients in the endosperm

important feature of a monocot

1 cotyledon

important feature of a dicot

2 cotyledons

other features of monocots

• fibrous roots

• petals in multiples of 3

• leaves are narrow, parallel veins

• scattered vascular bundles

• 1 pore or furrow

other features of dicots

• tap roots

• 4 or 5 petals

• leaves are oval or palmate, net-like veins

• ringed

• 3 pores or furrows

leaf anatomy

• monocot leaves lack midrib

• dicot leaves have a central midrib