BS 162 Material for Final Exam Chapter 26 Plants Stomata openings in plant leaves that allows for water to diffuse out and air to diffuse in Tracheids specialized cells that facilitate the transport of water and minerals Xylem conducts water and dissolved nutrients Phloem conducts food sucrose and hormones Sporophyte diploid generation Gametophyte haploid generation Diploid sporocytes under meiosis in structures called sporangia Liverworts flattened gametophytes Sporophytes resemble mosses 3 clades of vascular plants tracheophytes Lycophytes club mosses Pterophytes ferns horsetails whisk ferns Seed plants conifers cycads Gnetophytes gingkoes angiosperms Stems evolved prior to roots Roots provide structural support and transport capacity Seeds usually contain food for the developing plant Sori clusters on ferns that contain sporangia Found on the underside of the fronds Pro gymnosperms spore bearing plants An extra layer or two of sporophyte tissue called the integument which creates the ovule protects the embryo Pollen tube sperm moves towards the egg through this in some seed plants Conifers pines spruces firs cedars hemlocks yews larches cypresses etc Pines have tough needle like leaves that are in clusters of 2 5 They retard water loss Resin is secreted by the leaves and deters insect and fungal attacks Cycads slow growing gymnosperms of tropical and sub tropical regions produce cones and have a life cycle that is similar to pines Vessels particularly efficient conducting cell type that is a common feature in angiosperms Dioecious male and female reproductive structures are found on separate plants Each flower originates as a primordium that develops into a bud at the end of a stalk called a pedicel Double Fertilization one sperm unites with the egg and forms a zygote which develops into an embryo sporophyte plant the other sperm and the two polar nuclei unite forming a triploid primary endosperm nucleus Dominant stage in life cycle of plants haploid in bryophytes and diploid in vascular plants Chapter 30 Plant Reproduction 4 genetically regulated pathways to flowering 1 Light dependent pathway 2 Temperature dependent pathway 3 Gibberellin dependent pathway 4 Autonomous pathway Plants can rely on only one pathway but all four can be present A complete flower has 4 whorls calyx sepals corolla petals androecium male structures gynoecium female structures Self pollination is ecologically advantageous under certain circumstances because no pollinator is needed and the plant spends less energy trying to attract pollinators Self pollination produced progenies that are more uniform Monoecious male and female structures are found on the same plant Dichogamous plant that has both male and female structures but they are functional reach maturity at different times Increases out crossing Genetic self incompatibility increases outcrossing Double Fertilization produced 1 the fertilization of the egg and 2 the formation of endosperm tissue that nourishes the embryo This occurs in angiosperms Fruits are mature ovaries During seed formation the flower ovary begins to develop into fruit Pericarp three layers of ovary wall Vegetative reproduction asexual reproduction new plant individuals are simply cloned from parts of adults Runners Stolons long slender stems that grow along the surface of the soil The tip of the runner turns up and thickens this produces first adventitious roots and a new shoot Rhizomes underground horizontal stems Invade the area near the parent plant and each node can give rise to a new flowering shoot Suckers sprouts that can give rise to new plants Adventitious plantlets in a few plant species even the leaves are reproductive Whole plants can be cloned by regenerating plant cells or tissues on nutrient medium with growth hormones When single plant cells are cultured wall regeneration takes place Cell division follows to form a callus undifferentiated mass of cells Once a callus is formed whole plants can be produced in culture Phase change produces flowers Self pollination is desirable in stable environments Apomixis the production of genetically identical seeds through mitosis In angiosperms eggs are a product of meiosis of the megaspore mother cell Class Notes 4 6 Bryophytes liverworts and mosses Vascular Plants Seedless ferns allies and Seed plants gymnosperms ginkgoes cycads Conifers and angiosperms anthophyta Charophyceans possible ancestor to land plants Many live in shallow waters that regularly dry up has a coating that protects the zygote from drying retain zygote in body for protection Apical meristems actively dividing cells primarily confined to specialized tissues Allows plants to Spores primary dispersal unit of early plants have a protective coating to help survive without water Sporangium has sterile jacket of cells around it Animals produce gametes by meiosis plants produce gametes by mitosis and produce spores by meiosis Embryo retained within archegonia Early land plants fertilization still requires water For bryophytes gametophyte is dominant stage and sporophyte is dependent on gametophyte Cuticle above ground parts covered with waxy layer prevents plant from desiccation Stomata openings for Co2 intake Controlled by guard cells close when plant looses too much water 6 Class Notes 4 8 Seed plants sporophyte is dominant gametophyte is physically dependent on sporophyte Double Fertilization 1 sperm 1 egg zygote 2n 1 sperm 2 polar endosperm 3n provides food for growing embryo Chapter 25 Fungi Body of fungus is composed mainly of slender pipe like hyphae continuous of branching tubes filled with cytoplasm and multiple nuclei they are typically made up of long chains of cells joined end to end and divided by cross walls called septa A mass of connected hyphae is called a mycelium Cell walls are formed of polysaccharides mostly chitin Fungi cells can house more multiple nuclei Monokaryotic hypha with one nuclei Dikaryotic Cell with 2 nuclei they exist independently Many fungi are capable of reproducing sexual and asexual spores Microsporidia obligate intracellular animal parasites have no mitochondria Chitridiomycetes Chytrids aquatic flagellated fungi that are closely related to ancestral fungi Blastocladiomycota have unflagellated zoospores Sirenin Allomyces pheromone Glomeromyceyes facilitated the invasion of land by plants they cannot survive in the absence of a host plant mutualistic relationship Conidia a means of asexual reproduction asexual spores