F Kingdom Plantae Part 1

Kingdom Plantae Adapting to Land • Plants began in water & evolved to land • Advantages to being on land: 1. more exposure to sunlight 2. increased CO2 supply 3. increased inorganic nutrient supply • Adaptations for plants to live on land: 1. Preventing water loss o Drying out due to evaporation due to the sunlight o Cuticle: waxy outer layer o Stomata: holes/pores on surfaces enabling O2 & CO2 gas exchange 2. Reproduce without water o Seeds & spores o Spore: haploid nuclei surrounded by hard shell o Seed: embryo surrounded by protective coat that may contain an endosperm which provides nutrients for embryo 3. Nutrient absorption o Aquatic plants get nutrients from water o Absorb nutrients from soil with root system o Certain plants develop vascular tissue allowing transport of water & nutrients o 2 types of vascular tissue 1. Xylem: absorbs H2O & inorganic nutrients from soil; moves in 1 direction 2. Phloem: distributes organic compounds in any direction throughout plant

Classification Kingdom Plantae

Non-Vascular

Vascular

Seedless Plants

Seeded Plants

Gymnosperms

Angiosperms

Seeds not enclosed by fruit

Seeds within fruit

Gymnosperms • Seeds not protected by fruit • Most are evergreens  produce seeds in cones; hard shell with scales where seeds lie open on the scales Angiosperms • Seeds enclosed in fruit • Flowering plants; Flowers are the reproductive structures • Advantages o Seeds germinate & produce mature plants that produce seeds all in one season; gymnosperms take years o Fruit protects seed o Use animal pollination which spreads seeds further than wind o Exist in more than one environment (aquatic/parasitic/epiphytic) • 2 classes: 1. Monocotyledons (monocots) o 1 cotyledon (embryo) o Leaves with parallel veination o Vascular tissue scattered o Flower petals occur in groups of 3 o Ex. Lilies, orchids, banana trees 2. Dicotyledons (dicots) o 2 cotyledons o Leaves have net veination o Vascular tissue is radial (circular) o Petals occur in groups of 4 or 5

o

Ex. Lettuce, oak trees, maple trees, cactuses

Fruits and Seeds Structure of Seeds • seed: fertilized ovule • Dicot o Seed Coat: protective covering o Hilum: marks the location of where seed was attached to ovary wall o Micropyle: opening through which pollen tube grows o Contains 2 fleshy cotyledons o Radicle: embryonic root o Hypocotyl: stem-like area between cotyledons & the radicle o Epicotyl: region above the cotyledons o Plumule: epicotyl & any embryonic leaves • Monocot o Coleoptile: embryonic shoot covered with cylindrical sheath o Coleorhiza: embryonic root covered with cylindrical sheath Types of Fruit • fruit: mature ovary 1. simple fruit: 1 pistil of a simple flower 2. aggregate fruit: several pistols of a single flower 3. multiple fruit: several flowers growing together Dispersal 1. Animal 2. Wind 3. Water 4. Forcible Discharge 5. Gravity Germination • Seed is ‘dormant’ phase (reduced metabolism) • Required conditions o Water o Oxygen o Light o Temperature • First to emerge from soil is root system (radicle)

Non-Vascular Plants Phylum Bryophyta • Mosses; live near water; terrestrial • Reproduces by sperm that swims through water to reach the egg • Can only reproduce in moist seasons but asexual (spores) doesn’t require water • Typically in gametophyte phase • Has rhizoids: root-like; anchors mosses to the ground & absorb water & nutrients • Gametophyte can be male, female, or both • Sporophyte grows from the top of the gametophyte • “pioneer plants”  first to arrive on barren land (devastated by fires, volcanic eruptions, or clear cut areas); they continue the job of lichens by accumulating organic & inorganic matter on rock, creating more soil • Prevent soil erosion by creating a moss layer on the top of the soil to retain moisture • Genus Sphaenium o Peat moss o Bogs & swamps o Produces acids that slow decomposition o Becomes peat  chemically broken down & compressed moss of partially decomposed plants  used for fuel  used to enhance water retention in soil Phylum Hepatophyta • liverworts; grow in moist areas • 2 versions 1. Leafy Liverwort: thin, transparent leaf-like structure with a stem 2. Thalloid Liverwort: flat body • Low to the ground • Gametophyte has a umbrella-like reproductive structure Phylum Anthocerotophyta • Hornworts; grow in moist, shady areas • Sporophyte resembles a horn, is green, and photosynthetic • Anchored by rhizoids • Similar to algae: 1 large chloroplast instead of multiple smaller chloroplasts • Similar to vascular plants: cuticle, stomata; tube-like structures resembling vascular tissue

• Considered a transition species

Vascular Seedless Plants Phylum Psilophyta • Whisk ferns • No true roots, stems, or leaves • Produce spores at the end of branches • Considered the closest resemblance to early land plants • Are epiphytes: grow on other plants • Not parasites Phylum Lycophyta • Club mosses • Resemble miniature spine trees (sometimes called “ground pines”) • Produce strobilus (cones) that contain a cluster of sporangia Phylum Sphenophyta (new name: Equisetophyta) • Horsetails of Genus Equistem • Have jointed photosynthetic stems containing silica (sand) • Scale-like leaves • Has rhizomes: jointed hollow stems • Cones form at the tip of the stem to form spores Phylum Pteridophyta • Ferns • Vary widely in size • Tropical & subtropical areas • Underground stem called rhizome • Fiddleheads: tightly curled leaves; edible; develop into mature leaves called fronds

Vascular Seeded Plants: Gymnosperms Phylum Cycadophyta • Resemble ferns; have leathery leaves & short trunks • Found in tropical areas • Can be male or female • Survive for a very long period of time but grow very slowly • Endangered • Produces large cones Phylum Ginkgophyta • Endangered • Around 12.5 million years ago • Found in China • Deciduous: lose leaves in winter • Produce fern-like leaves & plum-shaped fleshy seeds • Very tolerant to air pollution Phylum Coniferophyta • Pine, cedar, fir, cypress, redwood • Largest trees • Paper production & Christmas trees • Yellow resin called sap; turns into amber & fossilizes insects • Needles or scale-like leaves • reproduction o Produce both male & female cones o Male cones are small & grow in clusters o Female cones are bigger o Male cones produce pollen which land on the female cones o Male cones fall off tree o Pollen fertilizes the egg on the scale of the female cone o Scales close up & mature after 1 or 2 years o When mature scales open & seeds are released Phylum Gnetophyta • Produce cones • Vascular system more like angiosperms

Vascular Seeded Plants: Angiosperms Phylum Anthophyta (*flowering) • Fruit: ripe ovary that surrounds the seed • Ovary: female reproductive structure • Oak tree & birch tree are angiosperms • Grasses are angiosperms Alternation of Generations Alternation of generations 1. diploid sporophyte: 2 sets of chromosomes; produces spores 2. haploid gametophyte: 1 set of chromosome; produces sperm & egg Life Cycles Non-vascular Plants • gametophyte is dominant phase • Antheridium: male reproductive structure; makes sperm • Archegonium: female reproductive structure; makes egg • During moist periods the sperm swims from atheridium to archegonium • 2n zygote is formed • Zygote becomes an embryo through mitosis • Repeated mitotic divisions of embryo form a multicellular sporophyte • Sporophyte at first is a tall stalk that grows on top of the gametophyte • Sporophyte is dependant on the gametophyte for nourishment • Cells at the tip divide & form a sporangium called a capsule • Cells within capsule undergo meiosis to form n spores • When spores are mature the capsule splits open & releases them • Spores dispersed by wind • Those which land in favourable environments germinate & produce a protenoma • The protenoma is an early stage of gametophyte development • Homospory: all spores look alike & produce similar gametophytes Vascular Seedless Plants • Sporophyte is dominant phase • Gametophytes are called prothallus; leaf-like, short and broad • Antheridia & Archegonia on underside of prothallus • Sperm swims to egg in rainy seasons  zygote  embryo  sporophyte • Young sporophyte grows from the prothallus & is dependant on it for food • Mature sporophyte produces rhizomes (underground stems) to obtain nutrients • Prothallus dies • Fern forms fronds (leaves) which develop called sorus/sori (round orange spore clusters)

• Sorus undergo meiosis & develop spores • Fronds catch the wind & catapult the spores away • Some spores carried by wind

Vascular Seeded Plants • 2 types of spores 1. microspore: male gametophyte 2. megaspore: female gametophyte • heterospory: different spores produced • microspores develop into pollen & is carried by wind • not dependent on rainy seasons • Pine trees o Make megasporangium (female cone) and microsporangium (male cone) o Megasporangium produces megaspores o Megaspore surrounded by a protective layer called an integument o Microphyle: opening in the integument o Microsporangium produce microspores which develop into pollen o Wind dispersal spreads pollen to the megagametophyte/megaspore o Water captures the pollen on the microphyle & draws it into the megagametophyte o Pollen tube forms & 2 sperm from the pollen reaches the egg o One sperm fertilizes the egg while the other dies o Takes 1 year for the sperm to reach the egg o Cone will close & take several months for the zygote to develop into an embryo o Embryo becomes a seed with wings; dispersed by wind Life Cycle of Flowering Plants Phylum Anthophyta Parts of a Flower • flower is highly modified branch • Receptacle: the swollen tip of a branch that is the base of a flower • Sepal: a modified leaf that protects a young flower • Calyx: what all the sepals are collectively called • Petal: showy part of the flower; attract animals • Petals/sepals of wind-pollinated flowers are usually reduced or absent • Corolla: what all the petals are collectively called • Stamen: male reproductive structure 1. Anther: the microsporangium that produces microspores, then pollen grains

• • • • • • •

2. Filament: stalk-like; supports the anther Carpel: female reproductive structure Pistil: structure formed of fused carpels Ovary: the base of the pistil Style: arises from ovary; supports stigma Stigma: entrance for pollen; generally sticky & hairy to catch pollen Perfect flower: has both stamen and pistil Imperfect flower: lack either stamen or pistil 1. monoecious: when male flowers and female flowers are on the same plant 2. dioecious: when the male flowers and female flowers are on different plants

Pollen Grain Formation • each anther contains 4 pollen sacs • pollen sacs contain 2n microspore mother cells • each microspore mother cell undergoes meiosis to produce 4 n microspores • nucleus of each microspore divides by mitosis to produce 2 n cells • thick cell wall surrounds both cells • resulting n, 2-celled structure is the male gametophyte: the pollen grain • larger cell: tube cell (will form pollen tube) • smaller cell: generative cell (will form 2 sperm) Ovule Formation • Ovule: megasporangia formed in ovaries • Ovule contains a large 2n megaspore mother cell • megaspore mother cell undergoes meiosis to produce 4 n megaspores • 3 of the 4 megaspores degenerate & die

• Remaining megaspore enlarges & undergoes 3 mitotic divisions to produce 8 n nuclei o Arranged in 2 groups of 4; one group at each end of the cell o 1 nucleus from each group migrates to centre; called polar nuclei o Cell walls form around each of the remaining 6 nuclei o 3 cells farthest from the micropyle called antipodals o One of the three cells nearest the micropyle enlarges & becomes egg o Remaining 2 cells called synergids • By the time these are formed, the ovule has also formed 1-2 layers of protective coverings called integuments which don’t completely encase ovule • At one end of ovule is micropyle, a small opening through which pollen enters • Final structure, which contains 7 cells & 8 nuclei is the mature megagametophyte; called the embryo sac Pollination • Process by which pollen is transferred from an anther to a stigma • Self-pollination: transfer of pollen between flowers on same plant • Cross-pollination: transfer of pollen between 2 plants of same species • Wind Pollination depends on: o o o

release of large amounts of pollen a lot of wind to carry pollen close proximity to other plants

o o o

Colourful flowers Scent Nectar: sugar & amino acids

• Animal Pollination requires plants to attract animals:

Fertilization • Union of gametes • Requires the pollen grain to travel to the egg • Pollen grain germinates after landing on stigma (germination requires moisture) • Tube cell forms pollen tube that grows through stigma & style towards the ovule • n generative cell divides mitotically to form 2 sperm • pollen tube grows through micropyle & into embryo sac • sperm enters embryo sac through pollen tube • one sperm fuses with the egg to form 2n zygote • zygote develops into embryo • second sperm fuses with the 2 polar nuclei to produce 3n nucleus • 3n nucleus divides by mitosis; eventually becomes endosperm, provides nutrients • Double fertilization: 2 types of cell fusion taking place o one produces zygote o one produces endosperm Asexual Reproduction

1. Vegetative Propagation o Naturally occurring production of new plants from non reproductive plant parts 1. Stolon (runner): horizontal above ground stem that produces leaves & roots at its nodes; a new plant can grow from each node 2. Rhizome: horizontal below ground stem that produces leaves & roots at its nodes; a new plant can grow from each node 3. Bulb: very short, underground monocot stem with thick, fleshy leaves adapted for storage; bulbs divide naturally to produce new plants 4. Tuber: underground swollen fleshy stem specialized for storage; the buds on a tuber can grow into new plants 2. Artificial Propagation o Human application of vegetative reproduction 1. Cuttings: take cuttings from plant (pieces of roots or stems) and plant them to grow into new plants 2. Grafting: take a branch from 1 plant & join it to another branch of another plant