KINGDOM PLANTAE Overview of Plant Diversity To Accompany the Kingdom Plantae Foldable Notes Section 1: Plant Evolution & Adaptations Plant Evolution Algae & Plants Plants do not exist Algae in oceans Algae at the edges of Seas adapt to life on land Simple plants appear When compared to algae, plants share 6 common characteristics. 1. Cell walls composed of cellulose. 2. Cell division that includes the formation of a cell plate. 3. Chlorophyll used for photosynthesis. 4. Similar genes used in ribosomal RNA. 5. Food stored as starch. 6. Same enzymes in cellular vessels. Plant Adaptations Over time, plants developed adaptations for living on land. Cuticle: Waxy surface on leaves to retain water. Stomata: Allows for the exchange of gases. Vascular Tissue: Allows for the transport of water and nutrients throughout plant. Reproduction: Seed covering allows for sperm to reach egg without presence of water. Seeds: Enable survival in harsh environments and sprout with conditions are favorable. Criteria for Organisms in Kingdom Plantae Recall from our previous lessons on taxonomy, members of this kingdom must meet certain criteria. Cell type: Eukaryotes. Cell structure: Cell wall made of cellulose. Cell number: Multicellular. Mode of nutrition: Autotrophic. Carry out photosynthesis using the green pigments chlorophyll a and b. Some are parasitic or saprobes. 1
Plant Life Cycle All plants have a life cycle with alternation of generations, in which the haploid gametophyte phase alternates with the diploid sporophyte phase. Plant Life Cycle Alternation of Generations Haploid (N) Gametophyte plant (N) Produces either sperm or eggs. (gametes = reproductive cells) Diploid (2N) The sperm and egg join to create the sporophyte plant (2N), which is diploid. Egg and sperm join to create spores by meiosis. Evolutionary Cladogram Plant Survival Sunlight needed to carry out photosynthesis. Minerals and water are needed to make new plant parts. Non-Vascular Plants (Bryophytes) Green Algae Ancestor Seedless Vascular Plants (Ferns) Vascular Tissue Cone-bearing Plants (Gymnosperms) Seeds Flowering Plants (Angiosperms) Flowers, seeds enclosed in fruit Gas exchange (through photosynthesis and cellular respiration) must occur without losing excessive amounts of water. Movement of water and nutrients is required for plant energy production and growth. Embryo Protection Overview of the Plant Kingdom The majority of plant life is. flowering plants Non-Vascular Plants: Bryophytes Mosses, Liverworts, Hornworts Life cycles depend on water for reproduction. Water moves through by osmosis & diffusion. Abundant in damp, shady areas because there is no vascular tissue. Sphagnum moss alive is used in gardening, and when compacted (peat) it s used for fuel. 2
Typical Moss Plant Capsule Stalk Sporophyte What happened between plant divisions 1 & 2? Leaflike Structure Gametophyte Stemlike Structure Rhizoid Vascular tissue: specialized tissue to transport water and nutrients throughout the plant. Seedless Vascular Plants Typical Fern Plant Divisions include: Phylum Lycophyta: Club mosses Phylum Pterophyta: Ferns & horsetails Strobilus is a compact structure of sporebearing structures which can be carried by the wind. Found in moist, shaded forest areas. Leaves are called fronds. Undergound stems called rhizomes. Fern spores on the underside of fronds are called sporangium and clusters for a sorus (sori=plural). Life Cycle of a Fern Gymnosperms: Cone Bearing Plants Means naked seed. Includes conifers (pines & spruces) and palms (cycads & ginkgoes). Second evolutionary development: Adapted seed to allow reproduction without water; able survive in dry and extreme temperatures. 3
Diversity of Seed Plants Reproduction Vascular plants that produce seeds. Seeds have one or more cotyledons, structures that either store food or absorb food for the tiny sporophyte. The early growth stage of a plant embryo is called germination. Dormancy is a period of time during which a plant embryo is alive but not growing. A cone is a that contains the male and female reproductive structures of gymnosperms. Features that allow seeds to reproduce without water: Reproduction in cones. Movement of gametes by pollination. Protection of embryo in a seed. Pollination Diagram of a Seed Transfer of pollen from the male reproductive structure to the female reproductive structure. Embryo Growing part of seed Endosperm Tissue that provides nutrition for the developing seed. Seed Coat Protective outer covering of the seed. Adaptations of Gymnosperms Needles Winged Seeds Angiosperms: Flowering Plants Dominate plant life. Flowers are the reproductive organs of plants. Has ovaries (fruit) to protect the seeds. Attracts animals which help with pollination. Can be classified into: 1. Lifespans: annuals, biennials, perennials. 2. Seeds: Monocotyledonous vs. dicotyledonous. 3. Stems: herbaceous vs. woody. 4
Lifespans Monocots vs. Eudicots Cotyledon = Seed Chamber Annuals Complete life cycle in one year. Biennials Life cycle takes 2 years Year one: germinate and grow roots, maybe leaves. Year two: grow new stems, leaves, and flowers. Perennials Live through many years May die back in winter, but re-grow in the spring (asparagus, peonies, many grasses). Most have woody stems (palms, trees, honeysuckle). Identifying Plant Cells Section 2: Plant Cells & Tissues Typical plant cell has cell wall and large vacuole. However, adaptations help plant carry out specific functions. Parenchyma Cells: Most common; responsible for storage, photosynthesis, gas exchange, protection. Collenchyma Cells: Elongated cells that provide structure and support. Sclerenchyma Cells: Lack cytoplasm and other living components, but provide support for the plant. Phloem: Transports carbohydrates and other items. Xylem: Transports water and other minerals. Plant Tissues: Vascular Tissue A tissue is a group of cells that work together to perform a specific function. Vascular tissue is responsible for the movement of water, food and dissolved substances in the plant. Xylem: moves water and nutrients throughout plant using a tracheid. A tracheid is specialized cell that can move fluids through the plant body, even against the force of gravity. Phloem: moves carbohydrates throughout the plant through sieve tubes. 5
Plant Tissues: Vascular Tissue Plant Tissues: Meristematic Tissue A tissue is a group of cells that work together to perform a specific function. Meristematic Tissue: regions of rapidly dividing cells. Apical meristems: Tips of roots and stems. Intercalary meristems: Produces new cells resulting in added stem or leaf length. Lateral meristems: Increase root or stem diameter. Plant Tissues A tissue is a group of cells that work together to perform a specific function. Dermal Tissue the Epidermis: The layer of cells that makes up the outer covering of a plant. Section 3: Plant Anatomy & Physiology Plant Anatomy & Physiology Transport Roots, stems, leaves. Energy Production Leaves. Reproduction Flowers. Roots: Plant Transport System Root Functions 1. Absorbs water & nutrients from the soil. 2. Transports water & nutrients to stem. 3. Anchors plant to maintain stability. 4. Stores food and water. 6
Roots: Plant Transport System Root Structures Endodermis Casparian Strip Roots: Plant Transport System Root Structures Taproot: primary root grows down from the stem with secondary roots forming. ex. carrot, radish, beets Fibrous: small lateral roots that spread out just below surface of the soil. Taproot System ex. weeds Water & nutrient pathways Cortex Pericycle Xylem Phloem Epidermis Root Hair Fibrous Root System Stems: Plant Transport System Stem Structures Woody Thick cell walls that support the plant. Trees, shrubs, and vines. Herbaceous Stems are smooth, supported by hydrostatic (turgor) pressure. Dandelions, zinnias, petunias. Stems: Plant Transport System Herbaceous Stems The xylem and phloem of stems are grouped together in vascular bundles. Eudicot stems have one ring or concentric rings of vascular bundles. The vascular bundles in a monocot stem are scattered. Eudicot Monocot Stems: Plant Transport System Function of Stems 1. Transports water & nutrients from roots to leaves. 2. Supports/produces leaves, branches, fruits/flowers. 3. Stores food. Tuber: swollen underground stem which stores food. Bulb: shortened, compressed stem surrounded by fleshy leaves. Corm: composed almost entirely of stem tissue. Rhizome: underground horizontal stem which may store food. Stems: Plant Transport System Transport in Plants Capillary action: the tendency of water to rise in a thin tube. The result of the water molecules ability to stick to one another (cohesion) and to the walls of the tube (adhesion). Contributes to the movement of water up the cells of the xylem tissue. 7
Leaves: Plant Transport & Energy System Photosynthesis Photosynthesis Process that plants use to produce their food. 6CO2 + 6H2O C6H12O6 + 6O2 Leaves: Plant Transport & Energy System Leaf Structure Cuticle Epidermis Palisade mesophyll Vascular bundle Xylem Phloem Lower epidermis Stomata Guard Cells Spongy mesophyll Leaves: Plant Transport & Energy System Leaf Structure Letter Structure Color Function A Cuticle Yellow Waxy outer surface; retains moisture. B Epidermis Orange Skin of leaf - responsible for gas exchange. C Vein (Xylem) Blue Pumps water up from soil through roots. D Vein (Phloem) Red Moves nutrients and carbohydrates throughout the plant. E Mesophyll Green Middle layer of leaf where photosynthesis occurs. F Stomata Pink G Guard Cells Brown Outside layer of leaf opening in epidermis where gas and water exchange. Control stomata; trigger when water is scarce causing stomata to become flaccid and pores close. Leaves: Plant Transport & Energy System Gas Exchange & Transpiration Transpiration Loss of water and exchange of carbon dioxide. Stomata function to open and close to allow diffusion of gases and water needed for photosynthesis. Stomata close automatically when supplies of water from roots start to dry up. Guard cells trigger when water is scarce causing stomata to become flaccid and pores close. Leaves: Plant Transport & Energy System Leaf Modifications Flower Structure 8
Flower Structure Male Plant Organs Petals Highly colored part of the flower, may contain perfume and/or nectar glands. Sepals Small green structures on the base of a flower that protect the flower bud. Image found at: http://biology.clc.uc.edu Stamen contains: Anther: produces pollen. Filament: upholds anther. Female Plant Organs Carpel/Pistil contains: Stigma: sticky for pollen to attach. Style: sperm travel to ovary. Ovary: fruit. Ovules: eggs. Pollination The goal of every living organism, including plants, is to create offspring for the next generation. Pollination is the act of transferring pollen grains from the male anther of a flower to the female stigma. Pollen can t move on its own, so animals or the wind (and water in rare cases) move the pollen for plants. Development Ovary Ovule Four haploid megaspores 1 haploid nucleus Other haploid nucleus Fruit Development As the endospore matures, cell walls form. The outside layers of the ovule harden to form a seed coat (or shell, husk). As the ovule develops into a seed, changes lead to the formation of a fruit. Fruits form primarily from the ovary wall. Undergoes mitosis three times, producing 8 haploid nuclei. dies dies dies 6 of the nuclei develop membranes; one becomes the egg cell. The 2 remaining nuclei migrate to the center of the cell and are called polar nuclei. 9
Seed Dispersal & Germination The early growth stage of a plant embryo is called germination. Seeds are dispersed by: Wind Water Animal Factors that affect seed germination: Temperature Moisture Plants: Responding to Environment Plant hormones: chemical substances that control a plant s patterns of cell division, growth & differentiation. Made in one part of a plant and transported to another where they have effect. Receptor proteins: specific sites where plant hormones work. Auxin: One of the first plant hormones to be identified. A substance produced in the tip of the seeding. Usually stimulates the lengthening, or elongation, of cells. Plants: Responding to Environment Nastic response: response that causes movement that is not dependent on the direction of the stimulus. Tropic response: response of a plant to an environmental stimulus. Gravitropism: response of a plant to the force of gravity. Phototropism: tendency of a plant to grow towards light. Thigmotropism: response of plants to touch. Plants: Responding to Environment Photoperiodism: the timing of seasonal activities such as flowering and growth. Herbicides: auxin-like compounds in high concentrations that are toxic to plants therefore inhibiting growth. Chemical defenses: many plants defend themselves against insect attack by manufacturing compounds that have powerful effects on animals, ex. poison oak. 10