Exam 4: Chapter 23

Plants grow via two processes

Increasing the number cells via mitosis and Increasing the size of existing cells via osmosis

Animal growth is typically

determinate

Plant growth is typically

indeterminate

Meristem

give rise to new organs

Plasticity

of growth gives “flexibility” since plants are sessile

Apical

meristem add to length of root and shoot

Lateral

meristem add to girth of root and shoot

Vascular cambium (meristem)

must remain in order for further growth to occur

Cork cambium (meristem)

is similar but produces outer bark layers

Meiosis produces (Plant Life Cycles)

spores

Gametes in plants

are produced via mitosis

Alternation of generations

Cycle between haploid and diploid phases

Sporophytes (2n)

produce spores (n) in sporangia

Gametophytes (n)

produce gametes (n) in gametangia

Mitosis in Plants

Occurs in meristem of sporophyte generation and Occurs in gametophyte generation

During Telophase, cell plate forms

Barrel-shaped spindle fibers (phragmoplasts) trap dictyosome vesicles to form the new cell wall between daughter cells

• ER trapped between vesicles form plasmodesmata

Cell plate becomes

middle lamella

Three Main Groups of Plants

Bryophyta, Pterophyta, and Spermatophyta

Spermatophyta

Gymnosperms and Angiosperms and Seed plants

Pterophyta

Ferns and relatives and Seedless, vascular plants

Bryophyta

Mosses and relatives and Non-vascular plants

Spor-

Related to spores

Gamet-

Related to gametes

Mega-

Related to “female”

Micro-

Related to “male”

-phyte

Plant

-phyll

Leaf

-angium

Structure that produces

-cyte

Cell that becomes

Sporophyte dominates

all organisms commonly known as “plants”

Sporophylls form

clusters (flowers)

Big spores

megaspores

Small spores

microspores

Gametophyte generation microscopically small

Consist of 8 cells (megagametophyte) or 3 cells (microgametophyte) and Complete their lives within flower structures

Megaspores formed on leaves (Spermatophyta)

carpels (megasporophylls)

Megasporangium is a

ovule

Megaspore develops within ovule

e into female gametophyte

Forms egg cell which is fertilized

while still within ovule

Fertilized egg cell within ovule develops into

seed containing embryo

Two types of carpels:

gymnosperms and angiosperms

Ovules in the open

gymnosperms (naked seed)

Ovules covered

angiosperms (enclosed seed)

Microspores (pollen grains) produced

in stamens (microsporophylls)

Pollination is

Transfer of pollen to female reproductive parts (carpels)

Pollen grains (microgametophyte) produce

sperm

Pollen grains

germinate on carpels

pollen tubes grow

through the carpel tissue towards ovules, release sperm leading to fertilization

Evolutionary advancement in flowering plants over other

seed plants

Microspore originates as 2 cells

Tube nucleus and generative nucleus

Germination of microspore leads to mitosis of

generative nucleus into 2 sperm nuclei

One sperm nucleus fuses with one egg nucleus to form

zygote (2n)

Other sperm nucleus fuses with two polar nuclei in the embryo sac to form

endosperm tissue (3n)

Zygote develops into

embryo

Protected by seed coat

Formerly the outside of the ovule

Eudicots have

two cotyledons (seed leaves)

Monocots have

one cotyledon (coleoptile)

Primary growth

is the elongation of roots and stems as a result of cell division in the apical meristems

Secondary growth

is the increase in thickness of roots and stems due to the activity of lateral meristems, such as the vascular cambium and cork cambium