32 Kingdom Plantae
-Viridiplantae = green plants including the green algae
-Multicellular
-Eukaryotic
-Cellulose-rich cell walls
-Carbohydrate food reserve is starch
-Phyla based on lifecycles
-Most plants are terrestrial
Evolutionary Origin of Land Plants
-Evolved from freshwater, green algae (Streptophyta)
Characteristics We See In Land Plants
-Protective cuticle
-protects from water loss
-formed of cutin
-Absent in many bryophytes
-Stoma (pores)
-found in leaves and portion of stems
-function: to permit gas exchange
-Mycorrhizae
Plant Life Cycles
-Alternation of generations
-All plants exhibit alternation of generations
Generalized Life Cycle
-Start with syngamy, which is fertilization or sexual reproduction
-Zygote (2N)
-Sporangia
-Spore Mother cell
-Meiosis where tetrad of spores produce the gametangia which produce gametophyte (1N) which goes through mitosis which produce the antheridia (1N sperm) and archegonia (1N egg)
-Back to syngamy
Evolution In Reproduction
-Reduction in the gametophyte
-Loss of multicellular gametangia (sex organs)
-Increasing specialization for life on land
-Nonvascular plants, to ferns - seedless, to gymnosperms - naked seed, to anthophyta - flowering plants with enclosed seeds
Differences between Vascular and Nonvascular
-Nonvascular lacking vascular tissue
-Nonvascular having smaller sporophyte that are dependent on the gametophyte for food
-Vascular plants, what you see is the sporophyte stage- trees, leaves of the fern, etc. It is dominant.
-Nonvascular plants, when you see the plant, what you see is the gametophyte stage - green part of moss. It is the most apparent, or conspicuous.
-Vascular plants have true roots, stems, and leaves
Nonvascular Plants
-Common among nonvascular plants
-All called bryophytes
-Common names are mosses, liverworts, and hornworts
-Most primitive of the terrestrial plants
-Found in moist places
-Require water external of plant to reproduce sexually
-Rhizoid - slender, usually colorless projections of one or a few cells
-Function is to anchor bryophytes to substrate
Nonvascular Phyla
Phylum Bryophyta
-Mosses
-Largest phylum of nonvascular plants
-Gametophytes are almost always leafy with small, simple leaves that are tufted or creeping
-Most abundant plants in Arctic and Antarctic
-Sensitive to air pollution (same as lichen)
-The sporophyte are yellowish or brownish at maturity
-Having a sporangium or capsule which is first covered with the operculum (lid that covers the spores), then the hooded calyptra at the tip; this is stalked (called seta)
-Protonema - First thread-like, germinating spores
-Examples:
-Peat Moss, used for fuel and soil conditioner
-Sphagnum - moss used in potted plants for water retention
-Mnium - prepared slides in lab
-Unusual mosses
-Copper mosses - only grow in the vicinity of copper and serves as an indicator plant for copper deposits
-Luminous moss - glows with a golden green light -- found in caves along or under the roots of trees
-Irish moss - really an edible algae, grows along northern sea coasts
-Reindeer moss - is really a lichen
-Club moss - really a vascular plant
-Spanish moss - really a flowering plant from pineapple family
Phylum Hepaticophyta
-Liverworts (liver herbs)
-The body (thallus) of the plant with it’s lobes is shaped like a liver
-Only 1/5th of this phylum is shaped as such
-The rest look like mosses
-Gametophyte of liverwort is very diverse
-Sporophyte is usually contained in the gametophyte until it releases spores
-Lab Example: Marchantia - also reproduces asexually by gemmae cups
Phylum Anthocertophyta
-Hornworts
-Smallest group of nonvascular plants (100 species)
-Gametophytes are similar to Marchantia - star-shaped, mostly creeping
-Sporophytes are elongated capsules that stand up from the surface of creeping gametophyte
-Looks like a horn
-Have stomata, are photosynthetic
-Believed this might be the link between nonvascular and vascular plants
-All nonvascular plants’ gametophytes are photosynthetic
-Hornworts are the only nonvascular plant whose sporophytes are photosynthetic
-The are embedded in the gametophyte tissue
Lab Example: Anthoceros
Vascular Phyla
-All vascular plants are homosporous or heterosporous.
Early Vascular Plants
-Homosporous - Produce only one kind of spore
Later Vascular Plants
-Heterosporous - Plants with two morphologically different spores
General Characteristics -
-Sporophyte is large and dominant and nutritionally independent
-Has conducting tissues (vascular system)
-Has specialized leaves, stems, and roots
-Cuticle and Stomata always present
Types of Growth in Vascular Plants
-Primary Growth - results from cell division at the tips of the stems and roots increase in length
-Secondary Growth - results from cell division that takes place in regions around the plant’s periphery -- increase in diameter
Two Types of Conducting Elements-
-Sieve-tube elements - soft-walled cells
-Conduct carbohydrates from areas where they are manufactured in the plant
-These make up the Phloem
-Vessel Members and Tracheids - Hard-walled cells
-Transport water and minerals up from the root
-These make up the Xylem
Vascular Plants are Divided into Seeded and Seedless.
Seedless Vascular Plants-
-All of these plants are from ancient forms
Phylum Pterophyta
-Ferns, Whisk Ferns, Horsetails
-Ferns:
-Most abundant of the seedless plants - over 12,000 species
-Size ranges from ¼” to over 78’ tall
-Most are homosporous
-Some aquatic ferns are heterosporous
-Motile sperm
-Root: is a Rhizome -- a root like subterranean stem, commonly horizontal in position, that produces roots(rhizoid) below and sends up shoots to the upper surface
-Leaves: Fronds
-Sori - Sporangia on back of fronds
-Stalked
-Look like little dots
-Some have a protective covering - indusium (shield-shaped)
-Lab Examples: A common fern with Sori
-Salvina (aquatic fern)
-Value of Ferns -
-Used as ornamental plants
-Used in florist bouquets
-Building Material - tropical ferns - wood resists decay and termites
-Medicinal Value - used as an astringent during childbirth to stop bleeding
-Maidenhair fern is a source of an expectorant
-Whisk Ferns:
-Found in tropics and subtropics
-U.S.: Arizona, Texas, Louisiana, Florida
-Homosporous
-Have Motile sperm
-No leaves
-No differentiation between root and stem
-Branched rhizome has rhizoids and a mycorrhizal fungus to help gather nutrients
-Sporangia locate at the ends of short branches
-Lab Example: Psilotum
Horsetails -
-Common name: Scouring rush
-Ribbed epidermal cells have silica deposits
-Homosporous and herbaceous(no woody material)
-Stems are ribbed, jointed, and photosynthetic
-Has underground rhizomes with roots and nodes
-Sporophytes are called strobili - cone-shaped
-Found on beach or edge of swamp
-Lab Example: Equisetum
Phylum Lycophyta
-Club mosses or quillworts
-Used to be the “tree” plants during the carboniferous era
-Now up to 1 foot high
-Common in moist woodlands of temperate zones - known as ground pines
-Tightly packed, scale-like leaves cover stem and branches
-Leaves are microphylls; have only one strand of vascular tissue
-Homosporous or heterosporous
-Examples in Lab: Lycopodium(homosporous)--some species on endangered list; Selaginella(heterosporous)--resurrection plant
Other representatives of selaginella are small-leafed ground covers.
Seeded Vascular Plants
Functions of the Seed
-For dispersal
-Protects developing sporophyte (embryo)
-Provides food storage
Gymnosperms and Angiosperms -
-Most later vascular plants are heterosporous
Gymnosperms-naked seeds
-Have ovules (fruit) that are not completely enclosed
-The seed contains the embryo, stored food, and a partial seed coat
-Four Phyla
Phylum Cycadophyta
-Cycads (Sago Palm)
-Heterosporous
-Sperm are flagellated and motile
-Palm-like pants
-Tropical and subtropical evergreens
-First appeared in Permian period 270-280 million years ago
-Most primitive of the living seed-bearing plants
-In many ways, resemble the ferns
-Mistaken for palms
-Only 10 Genera, 100 species
-Some are found in very restricted areas
-Many Cycads bear poisonous nut-like seeds
-Lab Example: The florist’s Sago Palm, not a true palm Zamia
-Grown as ornamentals in warm regions and in greenhouses
