BIOL 145 -Week 7- Simpson college

Angiosperms =

flowering plants

Magnoliopsida =

Dicots

Liliopsida =

Monocots

Formation of male gametophytes takes place in

Anthers

Pollination =

Transfer of pollen grains from anther to stigma

Self-pollination =

Pollen grains germinate on stigma of same flower

Fertilization =

Union of sperm and egg

After pollination, further development of male gametophyte may not take place unless pollen grain is:

From a different plant of the same species. From a variety different from that of the receiving flower

Mature male gametophyte =

Germinated pollen grain with its vegetative nucleus and two sperms within tube cell

Endosperm tissue =

nutritive tissue for embryo

Double Fertilization

One sperm unites with egg, forming zygote, then embryo. Other sperm unites with central cell nuclei, producing triploid endosperm nucleus that develops into endosperm tissue.

Apomixis

Without fusion of gametes but with the normal structures otherwise being involved. Create new plant genetically identical to parent plant

Parthenocarpy

Fruits develop from ovaries with unfertilized eggs. Results in seedless fruits (grapes, bananas, oranges, etc.)

Inferior ovary (epigynous flower)

Receptacle or other flower parts fused to ovary and grown up around it. Calyx and corolla appear to be attached to top of ovary

Superior ovary (hypogynous flower)

Ovary produced on top of receptacle. Other flower parts attached around ovary base

Perigynous flowers (superior ovary)

Flower parts attached to corolla tube of fused petals, creating floral tube that is not attached to ovary

Complete flower

Has calyx, corolla, stamens and pistil

Incomplete flower

Corolla or other flower parts missing.

Perfect flower

Both stamens and pistil present

Imperfect flower

Either stamens or pistil missing.

Monoecious species (imperfect)

Male and female imperfect flowers on same plant

Dioecious species (imperfect)

Plant bears only male flowers and other plants bear only female flowers.

Bee-pollinated flowers:

See UV light (humans do not). Flower generally brightly colored, mostly blue or yellow. Often have lines or other distinctive markings, which may function as honey guides to lead bees to nectar.

Beetle-pollinated flowers:

Strong, yeasty, spicy or fruity odor. White or dull in color. Some do not secrete nectar, but furnish pollen or food on petals in special storage cells.

Fly-pollinated flowers:

Smell like rotten meat. Dull red or brown

Butterfly- and Moth-Pollinated Flowers:

Nectaries at bases of corolla tubes or spurs for long tongues. Often have sweet fragrances. White or yellow for night-flying things. Sometimes red, often blue, yellow or orange

Bird-Pollinated Flowers (Hummingbirds and Sunbirds):

Copious amounts of nectar. Often bright red or yellow. Little if any odor. Large and part of sturdy inflorescence. Long floral tubes

Bat-Pollinated Flowers:

Large enough for them to insert head or consist of ball-like inflorescence containing large numbers of small flowers. Primarily in tropics. Open at night. Dull in color

Members of Ophrys have

modified petal that resembles female bumble bee or wasp

Ophrys

Male bees or wasps try to copulate with flower

Gymnosperm refers to

The exposed nature of the seeds.

Gymnosperm Seeds

Produced on surface of sporophylls or similar structures, instead of enclosed within a fruit as in flowering plants. Often arranged in cones

Female gametophyte

Pollen cones produce pollen grains that are carried by the wind to female cones, where fertilization occurs.

Female gametophyte (Female gametophyte)

Produced inside an ovule that contains nucellus. Does not grow independently, but develops within sporophyte structures.

Phylum Pinophyta – the Conifers: Pines (Pinus)

largest genus. Dominant trees in coniferous forests of Northern Hemisphere

Pines (Pinus) Structure and form:

Leaves needlelike and arranged in clusters of two to five leaves. Cluster = fascicle. Fascicles are short shoots Have restricted growth

Maturation of Seed Cones: First year

Pollen grains catch on sticky pollen drops oozing out of micropyle. Pollen grain produces pollen tube that grows through nucellus. Megaspore develops

Second Year of Seed Cone Development

Female gametophyte and archegonium mature. Pollen tube arrives at archegonium. One sperm unites with egg, forming zygote. Other sperm degenerates. Embryo nourished by female gametophyte. Integument becomes seed coat.

Production of Megaspores

Ovule contains a megasporangium containing a nucellus and a single megasporocyte. Megasporangium surrounded by integument. Megasporocyte undergoes meiosis, producing four megaspores.

Are gymnosperms known for their hardwood true or false?

False

Phylum Equisetophyta

the Horsetails and Scouring Rushes

Phylum Polypodiophyta

The Ferns

Introduction to the Seedless Vascular Plants

Internal conducting tissue developed. True leaves appeared. Roots that function in absorption and anchorage developed. Gametophytes became progressively smaller.

Psilotophyta

Sporophytes have neither true leaves, nor roots. Stems and rhizomes fork evenly

Lycophyta

Plants covered with microphylls.

Microphylls

Leaves with single vein whose trace is not associated with a leaf gap

Equisetophyta

Sporophytes have ribbed stems containing silica. Have whorled, scalelike microphylls that lack chlorophyll

Polypodiophyta

Sporophytes have megaphylls that are often large and much divided.

Megaphylls

Leaves with more than one vein and a leaf trace associated with leaf gap

Phylum Psilotophyta: Structure and form

Dichotomously forking stems. Have neither leaves nor roots. Sporophytes

Phylum Psilotophyta– Reproduction

Self-fertilizers. Sporangia fused in threes and produced at tips of short branches. Gametophytes develop from spores beneath ground.

Phylum Lycophyta– the Ground Pines, Spike Mosses, and Quillworts

Have true roots and stems. Stems are simple or branched (branching rhizomes) Leaves usually less than 1 cm long. Roots develop along rhizomes.

Phylum Lycophyta (Lycopodium) Reproduction

Sporangia in axils of sporophylls. In sporangia, sporocytes undergo meiosis, producing spores.

Sporophyll

Sporangium bearing leaves

Do lycophytes produce seeds?

No sporophytes

Isoetes- Quillworts

Most found in areas partially submerged in water for part of year. Microphylls are arranged in a tight spiral on a stubby stem. Ligules occur towards leaf bases. Corms have vascular cambium

Microphylls

Small leaf-like structures in lycophytes that are usually spiral and arise from a single vascular strand

Isoetes Reproduction

Similar to spike mosses, except no strobili (spore like structures) Sporangia at bases of leaves

Phylum Equisetophyta – Equisetum

The Horsetails and Scouring Rushes

Phylum Equisetophyta: Structure and Form

Stems jointed and ribbed. Branches in whorls. Scalelike leaves in whorls at nodes. Stomata in grooves between ribs

Phylum Equisetophyta Anatomy

Hollow central cavity from break down of pith

Phylum Equisetophyta (Equisetum) Reproduction

Asexual by fragmentation of rhizomes. Strobili at tips of stems with sporangia connected to sporangiophores. Spores green with 4 ribbon-like elaters attached

Phylum Polypodiophyta

The Ferns

Fern leaves are megaphylls

Referred to as fronds

Phylum Polypodiophyta Reproduction

Sporophyte is conspicuous phase of life cycle, producing spores in clusters called sori on the underside of fronds.

Phylum Polypodiophyta – Meiosis and Development

Meiosis forms spores in sporangia.

Fronds first appear

coiled in crozier (fiddlehead), and then unroll and expand

Fronds often divided

into segments called pinnae (singular: pinna).