Chapter 9: Flowers and Reproduction

Asexual Reproduction

fragmentation = several self sufficient parts

common in cacti

numerous methods

Sexual Reproduction #

Flower Structure

Gametophytes

The Plant Life Cycle

Sepals

Petals

Stamens

Carpels

Megagametophytes

Microgametophytes

Fertilization

Fruit Development

Flower Structure and Cross-Pollination #

Cross-Pollination

Stamen and Style Maturation Times

Stigma and Pollen Incompatibility

Monoecious and Dioecious Species

Animal-Pollinated Flowers #

Wind-Pollinated Flowers

Ovary Position

Inflorescenes and Pollination #

Fruit Types and Seed Dispersal

True Fruits and Accessory Fruits

Classification of Fruit Types

gametophyte stage

gametophytes

sporophyte stage

Mammal life cycle

gametes

zygote

simple

eggs

sperm

diploid

fertilized egg

sporophyte generation

one phase of life

sporophytes = diploid

spores

haploid

plant gametes

syngamy or fertilization

mitosis

undergo syngamy ---> zygote ---> diploid sporophyte

gametophyte

new haploid plant

from spores

microgametophytes

megagametophytes

sperm

male

microspores

egg

female

megaspores

pedicel = flower stalk

receptacle = end of flower axis

floral appendages

stamens

carpels

petals

sepals

complete flowers = ALL

incomplete flowers = lack one or two

thick

tough

lowermost and outermost floral appendage

waxy

all sepals = calyx

on receptacle

all petals = corolla

sepals + petals = perianth

attract correct pollinators

not typically in wind pollinated plants

all stamens = androecium

two parts

anther = pollen

filament = stalk

microsporocytes

undergo meiosis

produce four microspores

microspore mother cells

tapetum = nurse cells

gynoecium

highest level on receptacle

parts

style = elevates stigma

ovary = megaspore produced

stigma = catches pollen

placentae

inside ovary

bear ovules

have nucellus

short stalk

Embryo and Seed Development #

develop from microspores

mitotic division

generative cell

vegetative cell

two sperm cells

pollen grain lands on stigma and germinates #

penetrates stigma

pollen tube is produced

protected and nourished by style

develop from megaspores

embryo sac = multinucleate megagametophyte

seven cells

one large central cell

two polar nuclei

three small antipodal cells

egg aparatus

one egg

two synergids

second sperm nucleus into central cell

syngamy

karyogamy = fusion of nuclei

plasmogamy

fusion of gametes

fusion of protoplasts

endosperm nucleus

three full sets of genes

triploid

double fertilization

one sperm fuses with egg

one sperm fuses with polar nuclei

endosperm = all tissue

cellular

coenocytic

zygote

suspensor = short stalked structure

embryo proper

end of embryo = 2 cotyledons

torpedo stage

radicle = embryonic root

epicotyl = embryonic stem

hypocotyl = root/shoot junction

seeds

exalbuminous = sparse endosperm

albuminous = abundant endosperm

seed coat or testa = integuments surround nucellus

fruit = mature ovary

layers = pericarp

exocarp = outer, skin or peel

mesocarp = middle, flesh

endocarp = innermost, stone or pit

self = pollination by own plant

cross = pollination of carpel by other individual

genetics

mutations = new genes

cross pollination = lots of new genes

self pollination decreased and cross pollination increased

anthers and stigma mature differently

not effective for ensuring cross pollination

pollination effected by young flowers

compatibility barriers inhibit self pollination

pollen growth prevented

diploid = greater chance of pollen rejection

essential organs

stamens

carpels

imperfect flowers = miss essential organs

perfect flowers

have essential organs

may lack petals or sepals

nonessential organs

petals

sepals

staminate/ carpellate flowers

monoecy

dioecy

same plant

monoecious

dioecious

different plants

evolution of flowering plants

wind pollination has low probability rate

coevolution = flower adapted for visitation

flower shape

symmetrical/regular/actinomorphic

bilaterally symmetrical/zygomorphic

added by growth pattern

not widely scattered individuals

no need to attract pollinators

superior = hypogynous

inferior = epigynous

half - inferior = perigynous

inflorescence

many flowers grouped together

signal pollinators

arrangements

determinate inflorescences

indeterminate inflorescences

lowest flowers open first

new flowers initiated at apex

terminal flower opens first

limited growth potential

types

accessory fruit

true fruit

simple fruit

aggregate fruit

multiple fruit

fruit opening

Dehiscent fruits

indehiscent fruots

life cycle

ovary position

flower parts

seed parts

animal pollinated