Transcript Plant organs and tissues

Plant organs and tissues
Kingdom Plantae: more than
400,000 different kinds of plants
Cotyledons- seed leaves in their
embryos
-monocots- single seed leaf, one
group of plants
- dicots- two seed leaves, another
group of plants that are divided
further
An easier way to classify is by the:
1. number of seed leaves,
2. the strength and composition of
their stems, and
3. the number of growing seasons they
live.
•A
Alternation of generation
between haploid and
diploid phases.
Diploid (2N) phase is
known as the sporophyte
(spore-producing plant).
Haploid (N) phase is
known as the gametophyte
(gamete-producing plant)
sporophyte produces haploid
spores through meiosis.
• These spores grow into multicellular structures called
gametophytes
• Each gametophyte produces
reproductive cells called gametessperm and egg cells
• During fertilization, a sperm and
egg fuse with each other,
producing a diploid zygote.
• The Zygote develop into a new
sporophyte, and the cycle begins
again.
Bryophytes
• Mosses, liverworts, and
hornworts
• Lack specialized tissues for
the transport of water
• “nonvascular plants”
mosses
hornworts
liverworts
*Vascular Tissue:
tissue that transports water and
nutrients in some plants
Seedless
Vascular
Ferns
horsetails
Club mosses
Tracheophytes
• Vascular plants
• Seedless plants such as ferns
and both flowering and
nonflowering seed plants
• Contain specialized tissues
that transport water and
nutrients =tracheids
▫ Allows growth
to large sizes
 forms the transport system among the
roots, stems, and leaves of vascular plants.
 Two main types of vascular tissue:
1. Xylem- moves water and nutrients
from the ground upward in the plant.
2. Phloem- carries food made in a
plant’s leaves down to other plant
parts.
 Roots, stems, and leaves are plant organs
 Bryophytes do not have roots, stems,
or leaves. They absorb substances
directly from their surroundings.
o anchor and support the plant, absorb water and dissolved nutrients from
the soil, and store food and water.
TAPROOTS
• Single large root that grows
deep into the soil.
• As the root grows deeper, other
smaller roots branch from the
main root
• dandelion, carrots, and beets
• DICOTS
FIBROUS ROOTS
• Does NOT have a single main
root
• many small, shallow roots
branch out from the base of the
plant
• grass
• MONOCOTS
o transport materials between a plant’s roots and its leaves and flowers
o support the leaves and flowers
o some plants the stems store food and water (potato).
WOODY PLANTS
• plants
that develop into trees
and shrubs
• hard, rigid stems
• woody stem of a tree is its
trunk
• live for many years
HERBACEOUS PLANTS
• grasses
and many garden
plants
•green, flexible stems
• smaller
• have shorter life spans
o main organs that carry out photosynthesis in most vascular plants
o Stomata (stoma: singular)- small openings on their undersides
• carbon dioxide and oxygen are exchanged between the plant
and the air through the stomata
• water may also enter and exit a leaf through the stomata
o Guard Cells- tiny structures, control the size of the stomata
• help control the movement of materials into and out of the
plant.
Similar structures that all leaves share:
 Blade- is the broad, flat part of the leaf. Absorbs sunlight
needed for photosynthesis.
 Veins- running throughout the blade, tubelike structures
that transport water in the leaf
 Petiole- tubelike structure that attaches a leaf to its stem
Organs of Seed Plants
Roots
Stems
• Anchor and support the plant,
• absorb water and dissolved
nutrients from the soil,
• and store food and water
• Tap roots and fibrous roots
• Transport materials between a
plant’s roots and its leaves and
flowers.
• Support the leaves and flowers
• In some plants, it stores food
and water
• Woody plants and herbaceous
plants
Leaves
• Main organ that carry out photosynthesis
• Petiole, blade, veins are similar structures in all
leaves
• Monocots and dicots
 Plant embryo and a food supply, encased in a protective covering.
• Unlike mosses and ferns, gametes of seed plants do not need standing
water for fertilization.
• Adaptations that allow for reproduction without standing water:
1. Reproductive process that takes place in cones or flowers.
2. Transfer sperm by pollination
3. Protection of embryos in seeds
 Conifers- plants that form seeds in cones
 pines, cedar, firs, and juniper trees
 thin, needle-shaped leaves that help prevent
water loss
• this adaptation allows conifers to live in
places that are dry or cold for part of the
year
 Venus flytrap is a plant with a leaf
adaptation that when a insect
touches a receptor, the leaf shuts
and the insect becomes trapped.
 Reproduction in conifers takes place in cones, which are
produced by a mature sporophyte plant.
• produce two types of cones: pollen (male) and seed
(females) cones
• Seed cones are much larger and contain ovules near
the base of each scale.
Flowers are leaves that have been modified for sexual reproduction.
 a seed plant that produces seeds enclosed in fruits
 the fruit develops inside the flowers
 Flower- reproductive structure of an angiosperm
 attract birds and insects that help the plant reproduce
 petals surround its reproductive parts
 Stamen- male reproductive part
 Pistil- female reproductive part
• pistil contains the ovary, which produces the female sex cells and then
protects the seed as they develop
Pathway to making a baby flower:
 Pollen (male sex cell) must be transferred from
the stamen of a flower to the stigma on the pistil
 Transferred by the wind, or by animals
 Animals that transfer pollen are called
pollinators
 The transfer of pollen from the stamen to a pistil
is called pollination.
1. If pollen lands on the tip of the pistil of a similar
flower, the pollen can fertilize that flower
2. Sperm in the pollen travels through a tube to
reach the eggs in the ovary
3. Fertilization occurs when the sperm and egg
cells unite
4. After fertilization, one or more seeds develop in
the ovary
5. Finally, the ovary develops into a protective fruit
 Attract animals such as bees, moths,
or hummingbirds
• Drawn by color, scent, or even shape of
the flower—carry pollen with them as
they leave
• They go from flower to flower, carrying
pollen as they go, which is much more
efficient than the wind pollination of
most gymnosperms.
 After pollination, ovaries develop into a
fruit
• fruit- structure containing one or more
matured ovaries
• the wall of the fruit help disperse the
seeds inside it
• animals eat the fruit, and as the seeds
travel through the digestive system, it
develops and by the time it exits the
animal may be miles away.