ferns, fern allies, and fungi. alternation of generations

Ferns, fern allies, and fungi

Alternation of generations

Fungi

• Basic Structure of Fungi• 1. Hyphae, tubular threads• 2. Mycelium, a mass of hyphae• Mycology• 1. Study of fungi• 2. Mycologists• • scientists who study fungi

Vocabulary• Hyphae – long filaments in the body of a fungus.• Mycelium – the fungus body; a collection of interconnecting

hyphae. • Heterothallic – when a fungus has two mating types (+ and -).• Sporangia – fruiting bodies involved in asexual production of

spores.• Conidiophores – fruiting bodies involved in asexual production of

conidia spores.• Basidiocarps – fruiting bodies involved in production of sexual

spores only in Basidiomycetes.• Gametangia – reproductive tissue formed between two hyphae

of complementary mating type during sexual reproduction.

Phylum Zygomycota • 1. Habitat• a. Organic matter; untreated breads• b. Soil (nematode-trapping fungi), dung-fungi• 2. Shape• • hyphae coenocytic• 3. Reproduction—Rhizopus (bread mold)• a. Asexual• 1) Sporangiophores grow upright and produce sporangia at their tips• 2) Numerous spores produced in each sporangium• b. Sexual• 1) Conjugation of different mating strains• 2) Formation of progametangia• 3) Gametangia merge, becoming large multinucleate cell• 4) Wall develops around cell, forming the zygospore

• 1. One group of zygomycetes forms mycorrhizae, which are mutualistic associations with plant roots.

• 2. They reproduce asexually, through asexual spores contained in sporangia.

• 3. When reproducing sexually, hyphae of two different mating strains meet, create gametangia, fuse, and subsequently create a diploid zygosporangium and zygospore.

• 3. The zygospore goes through meiosis and produces haploid sporangia.

Sac fungus Lab p 143

• Use the previous slide to label the lab figure

Basidiomycetes (Club Fungi)

• 1. Habitat• a. Saprophytes• 1) Mushrooms (toadstools)• 2) Puffballs, earth stars, jelly fungi,

stinkhorns• b. Parasites• 1) Shelf or bracket fungi• 2) Rusts, smuts• 2. Shape• a. Mycelium septate with pores• b. Uninucleate or binucleate stages of mycelium

Mycelium septate with pores

• a. Asexual• • infrequent, rare• b. Sexual• 1) Hyphae of mycelium are monokaryotic• 2) Hyphal cells of compatible mating types may unite, initiating a

new dikaryotic mycelium• 3) Formation of clamp connection, with one nucleus migrating into

clamp• 4) Mitosis and formation of crosswalls• 5) Dikaryotic mycelium may become very dense, forming the button,

which may penetrate the surface and expand into the basidiocarp (mushroom)• 6) Gill of mushroom has numerous basidia• 7) As each basidium matures, the two nuclei unite, and then undergo

meiosis; the four nuclei become the nuclei of the four basidiospores

Start Lichens

• 26 September 2012

Lichens

• 1. Symbiosis between a fungus and an algaa. Can be viewed as a controlled

parasitism of the alga by the fungusb. About 25,000 species of lichens

2. Grow very slowly3. May live 4,500 years or more and are very tolerant of extreme environmental conditions, except for pollution and nuclear radiation

Lichens cont.• 4. Forms a spongy body (thallus)• a. Consists of three or four layers of cells or hyphae• 1) Upper cortex• 2) Algal layer• 3) Medulla• 4) Lower cortex• 5) Rhizines• b. Growth forms• 1) Crustose lichens• • often brightly colored, crusty patches• 2) Foliose lichens• • leaf-like thalli• 3) Fruticose lichens• • thalli branched and cylindrical in shape• Red tips are fruiting bodies

Lichens cont.

• c. Algal partners• • three genera of green algae and one of blue-

green bacterium involved in 90% of lichen species• d. Fungal partners• • almost all lichens have members of the sac

fungi as their fungal component• e. Classification• • lichen species identified according

to the fungus present

Crustose lichen

Foliose lichens

Fruticose lichens

Lichen types

Lichens cont.

• Reproduction• 1. Lichens dispersed

primarily by asexual means• • some produce powdery

clusters of hyphae and algae called soredia• 2. Sexual reproduction similar to the sac

fungi, except ascocarps produce spores continually for many years

Asexual reproduction

Ferns and fern allies

Ferns and fern allies• A. General Characteristics• 1. Xylem and phloem present• • internal conducting tissues for water and food, respectively• 2. Spores, but no seeds• 3. Ferns and relatives ("fern allies")• B. Classification• 1. Phylum Psilotophyta (Whisk Ferns)• • no leaves or roots• 2. Phylum Lycophyta (Club Mosses and Quillworts)• • small leaves called microphylls• 3. Phylum Equisetophyta (Horsetails & Scouring Rushes)• • ribbed stems and whorled leaves• 4. Phylum Polypodiophyta (Ferns)• • large, complex leaves called megaphylls

Mosses

• Phylum Bryophyta– Some plants are called mosses, but are not• Irish moss - dicot• Raindear moss- lichen • Spanish moss – bromeliad

– 3 classes• Peat moss• True moss• Rock moss

– Leave,s stems, rhizoids (no roots)

Mosses cont.

• Sexual Reproduction1. Female gametangium called the archegonium (flask shaped)2. Male gametangium called the antheridium (club shaped)3. Gametangia produced at tips of leafy gametophytes4. Sperm are flagellated and reach archegonium by swimming in a film of water5. Sporophyte develops in base of archegonium and grows into a foot, seta,

and a capsule6. Calyptra sits on top of capsule7. Meiosis takes place in the capsule producing spores8. Peristome teeth at rim of capsule aid in dispersal of spores9. Spores germinate on moist soil and develop into an algal-like protonema 10. Protonema develops tiny "leafy" buds which will produce the upright

gametophytes

Phylum Equisetophyta • A. Structure and Form• 1. Equisetum = means "horsetail"• a. Branching forms called horsetails• b. Unbranched forms called scouring rushes• 2. Silica content of stems—"Colonial Brillo"• 3. Herbaceous plants less than 4 feet tall• 4. Whorls of branches and leaves (microphylls)• 5. Stems distinctly ribbed• 6. Canal system in stem• a. Carinal canal, involved in water conduction• b. Vallecular canal is air filled• 7. Ancient tree-like forms now extinct

Chapter 21

• You will be responsible for Equisetophyta and Polypodiophyta in this chapter only

Equisetum

Equisetum

• B. Reproduction• 1. Cones or strobili formed• 2. Sporangiophores bear the elongated

sporangia• 3. Spores produced by meiosis in the sporangia• 4. Elaters are appendages of the spores, aid in

spore dispersal• 5. Spores germinate and produce green

pincushion-like gametophytes• 6. Male and female gametophytes formed; female

gametophytes become bisexual after 4-6 weeks

Sexual cycles

See figure 21.13 in text

Phylum Polypodiophyta

• A. Structure and Form• 1. Tiny floating (aquatic) ferns to

giant tropical tree ferns• 2. Leaves called fronds• • young coiled fronds called

fiddleheads• 3. Underground stems called

rhizomes• 4. Abundant in tropical climates

Aquatic fern

• B. Reproduction• 1. Fronds may bear sporangia on

underside• 2. Sporangia form clusters called sori

(sorus: singular)• 3. Sporangia may be protected by tissue

called indusium• 4. Meiosis occurs in sporangia• 5. Spores (meiospores) violently ejected from

sporangium by action of the annulus

Indusium

Annulus (ring like structure)

Reproduction cont

• 6. Spores grow into heart-shaped prothallus which is the gametophyte phase, this is what we are growing on the agar plates

• 7. Archegonia and antheridia produced on prothallus

• 8. Part or all of the gametophyte prothallus dies, so sporophyll is independent

• 9. Fertilization results in a zygote (2n) which grows into an embryo

• 10. Embryo develops into new fern plant (sporophyte)

Prothallus

Fern life cycle - see figure in lab book

• Use the lab book and the text book book along with this power point to understand these plants

Conifers see figure in lab book