* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download BIO509 Lecture # 12 File
Survey
Document related concepts
Plant tolerance to herbivory wikipedia , lookup
History of herbalism wikipedia , lookup
Cultivated plant taxonomy wikipedia , lookup
Plant use of endophytic fungi in defense wikipedia , lookup
Plant defense against herbivory wikipedia , lookup
Venus flytrap wikipedia , lookup
History of botany wikipedia , lookup
Flowering plant wikipedia , lookup
Historia Plantarum (Theophrastus) wikipedia , lookup
Plant physiology wikipedia , lookup
Ornamental bulbous plant wikipedia , lookup
Plant evolutionary developmental biology wikipedia , lookup
Plant morphology wikipedia , lookup
Sustainable landscaping wikipedia , lookup
Evolutionary history of plants wikipedia , lookup
Transcript
School of Sciences, Lautoka Campus BIO509 Botany Lecture 12: Ferns and Allies Seedless Vascular Plants Four phyla of seedless vascular plants • Phylum Psilophyta (whisk ferns). • Phylum Lycophyta (club mosses and quillworts). • Phylum Equisetophyta (horsetails and scouring rushes). • Phylum Polypodiophyta (ferns) Learning outcomes • Know the distinguishing features of seedless vascular plants. • Know the similarities and differences amongst bryophytes, seedless vascular plants and higher plants. • Know the differences between the four phyla of seedless vascular plants. • Know the reproductive structures and lifecycle of a fern. • Understand and appreciate the human and ecological significance of seedless vascular plants . Evolutionary trends As plants move from the aquatic to the terrestrial environment new features developed: • • • • Sterile jackets around the gametangia. Embryos within protective tissues. Cuticle. Internal vascular tissue system (xylem and phloem). These protect the tissues from drying out • • • • • True leaves Roots – for absorption and anchorage Smaller gametophytes Larger sporophytes Apical meristem (subapical in bryophytes) allows branching – More light interception/ reproductive structures • Lignin (support) • Tissue systems (dermal, vascular, ground) These lower plants do not have seeds Lets learn some terminologies first Vascular Tissue System • Xylem- plant tissue that conducts water and minerals. Has Tracheary elements • Tracheids • Vessel elements • Phloem- plant tissue that conducts food (mainly sucrose). Has Sieve elements Vascular Plant Terminology 1 • Leaves- photosynthetic, principal lateral appendages of the stem. Microphylls - small leaves that contain a single strand of vascular tissue. Megaphylls - large leaves that contain multiple strands of vascular tissue. Vascular Plant Terminology 2 • Homosporousproduction of one type of spore from one kind of sporangium. • Heterosporousproduction of two types of spores from two different kinds of sporangia. Vascular Plant Terminology 3 Sporophyll - a modified leaf that bears sporangia. Sporangium - a structure that produces spores. Microsporangium - microspores Megasporangium - megaspores Vascular Plant Terminology 4 • Microsporophyll - a modified leaf that bears microsporangia, a sporangium that produces microspores. • Megasporophyll - a modified leaf that bears megasporangia, a sporangium that produces megaspores. Vascular Plant Terminology 5 • Strobilus- a reproductive structure consisting of nonphotosynthetic sporophylls; a cone. – Microstrobilus- a microsporangiate cone. – Megastrobilus- a megasporangiate cone. Generalized life cycle of vascular plants Generalized life cycle of vascular plants Phylum Psilophyta – The whisk ferns Phylum Psilophyta – The whisk ferns • Resemble green whisk brooms. • Habitat- epiphytic or on rich soils • Sporophyte has dichotomously forking stems • No true leaves or roots • Rhizoids function as roots • Grow up to 30 cm Unique features: • Stems and sporophytes have neither true leaves or roots • Stems and rhizomes that fork evenly. • Enations – green superficial leaf like, vein less photosynthetic tissues are spirally arranged along the stems. • Photosynthesis takes place on the stem • Centrally cylinderal xylem is surrounded by phloem Psilotophyta are native to tropical and sub tropical regions. Native to Australia and the South Pacific Reproduction • Sporangia are at tips of branches. • Gametophytes are bisexual, resemble portions of the rhizome and have a mycorrhizal fungus. • Homosporous and spores produced in sporangia (fused into synangia in Psilotum) Sporangia Gametophyte Psilotum reproduction Homosporous life cycle Human and ecological relevance of whisk ferns. • Little economic importance. • Spores have oily feel and were used by Hawaiian men to reduce loincloth skin irritations. • Hawaiians also boiled it to make a laxative liquid. • It is said that the species Psilotum nudum is one of the very old plants. • Psilotum resembles the first land plants that appeared on the globe about 400 million years ago. • First land plants had naked stems and terminal sporangia. Extinct Seedless Vascular Plants • Representatives (425-370 MYA) – Rhyniophyta – Zosterophyllophyta – Trimerophytophyta Cooksonia, a vascular plant of the Silurian period. Note tall stature and large branched sporophyte with numerous sporangia. Psilotum is similar to Cooksonia. Rhizome (underground horizontal stem) Questions??