Plant Organs and Tissues
Mr. Ramos
Introduction to Plants
 There are over 260,000 different species of flowering plants
alone!
 Plants are
 multicellular, eukaryotic organisms.
 Photosynthetic
 Plants have a cell wall made of cellulose.
 Plants take up water via capillary action.
Plant Classification
Bryophytes are nonvascular.
Tracheophytes are vascular
Seeds, Vascular
Seedless, Vascular Nonvascular
Angiosperms
Ferns
Mosses
Gymnosperms
Horsetails
Liverworts
Whisk ferns
Hornworts
Club mosses
Plants are classified as bryophytes and
tracheophytes
Bryophytes and Tracheophytes
 Bryophytes are plants that lack specialized tissues for the transport
of water. They absorb substances directly from their surroundings.
 Mosses, liverworts, & hornworts
 Tracheophytes are vascular plants. They can be seeded or seedless.
 Seeded: Flowering & non-flowering plants
 Seedless: ferns
 Vascular tissue transports water and nutrients.
 Phloem transports food from the leaves down to other plant parts
 Xylem moves water and nutrients from the ground upward in the
plant.
Xylem and Phloem
Roots
 Function of plant roots include
 Anchoring and supporting the plant
 Absorbing water & nutrients from the soil
 Store food and water
 Root Classification
 Fibrous roots (monocots)
 Taproot (dicots)
Stems
 Stems transport materials between a plant’s root and its
leaves and flowers.
 Trees have hard, rigid stems called a trunk. These plants are
called woody plants.
 Plants with green, flexible stems are called herbaceous
plants. These include grasses and garden plants.
Leaves
 Leaves are the main organs that carry out photosynthesis.
 Photosynthesis is a process by which plants use sunlight to
make food from carbon dioxide and water.
 Leaves have small openings called stomata where CO2 and
O2 are exchanged.
 Guard cells open and close the stomata.
Gymnosperms
 Gymnosperms are the woody plants.
 They are vascular plants that contain seeds.
 One way to determine the age of a gymnosperm is by
counting the number of tree rings. The rings are dead xylem.
Angiosperms
 Angiosperms are the flowering plants.
 They are vascular and contain seeds.
 Angiosperms can be further divided into monocots and
dicots.
 Some flowering plants are woody: oak, cherry & walnut.
The fruits develop inside
the flowers
Seeds
 A seed is a reproductive structure that contains a plant
embryo.
 In flowering plants, the seed stores food in parts called
cotyledon, or seed leaves.
 Angiosperms may have one or two cotyledons.
 Monocots contain one seed leaf, or cotyledon.
 Dicots contain two seed leaves or cotyledons.
Flower Anatomy
 The male reproductive part
is called the stamen.
 The female reproductive
part is called the pistil or
carpel.
 For sexual reproduction,
pollen from the stamen must
be transferred to the stigma.
 The wind or animals can
carry pollen to the stigma.
This is called pollination.
Cones
 Cones are structures that are adapted for sexual reproduction
in conifers.
 Male cones produce pollen & female cones produce eggs.
 After fertilization, a seed develops.
 Unlike the seeds of flowering plants, conifer seeds are not
enclosed in protective fruit.
Spores
 Nonvascular plants, such as mosses, reproduce by making &
releasing spores.
 A spore is a tiny, waterproof reproductive cell that can grow
into a new organism if it falls on soil with the right
conditions.
 Seedless vascular plants, such as ferns, also reproduce with
spores.
Life Cycle & Reproduction
 Plants have an alternation of generation.
 They spend half of their lives as haploids and part of their lives
as diploid.
 A gametophyte is a haploid plant that produces haploid
gametes.
 A sporophyte is a diploid plant that gives rise to haploid
spores by meiosis.
 Spores grow to be gametophytes.
Plant Life Cycle
Spores
Sporophyte
N
Gametophyte
2N
N
Fertilization
Sperm
Zygote
2N
N
Egg
Mitosis
N