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Home , Algae, Microsporangia, Viridiplantae

Plants

The Producers Ecological classification • Produce the (photosynthesis) • Condition the environment • for energy fuel, organic chemical • Create shelter monomers, structural polymers. and • for aerobic respiration.

Ecological communities are often named for the dominant producers Photosynthetic bacteria

Cyanobacteria — “-green ” use

Halophilic archaea — “purple bacteria” • Not all producers are use bacteriorhodopsin

Photosynthetic Plants Cells [ecological classification] — earth’s dominant producers! •

•

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Plant Cells / Tissues / Organs Alternation of Generations in

Alternation of Generations in the (Chlorophyte) Ulva Changing definitions of the Plantae

MITOSIS MALE & FEMALE 1. Classical: everything photosynthetic FLAGELLATED ZOOSPORES (1N) / not an 2. Whitaker’s 5-kingdom model: all eukaryotic multicellular photosynthetic 3. Phylogenetic: “land plants” — exclude the algae = Embryophyta: dependent , growth & differentiation, cuticle MITOSIS MALE & FEMALE FLAGELLATED (1N) 4. Cladistic: (“green plants”) — (2N) embryophyta + (“green algae”)

Changing definitions of the Kingdom Plantae Plants

? • Algae — green alga, brown alga, red alga ? • — , liverworts, • — and horsetails • — and

• Angiosperms — flowering plants Embryophyta Viridiplantae Plantae (eukaryotic photoautotrophs)

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(Macro-)Algae — Aquatic Plants • Three Divisions (Phyla)

Chlorophyta Life “Green Algae” Rhodophyta Cycle “” Phaeophyta “” { including the “kelp” family }

• Not directly related to each other, “Dependent embryo” nor to terrestrial vascular plants. — analogous to • Accessory allow greater light sensitivity at depth.

Contrast between terrestrial form and aquatic algal form. Bryophytes: Mosses • Land plants – Photosynthesis and gas exchange in . – Nutrient and uptake from by . – Vascular system transports between leaves & roots. – Woody tissues provide erect support. – Waxy cuticle resists drying. • Algae – Bathed in medium providing water, nutrients, and dissolved gases — roots, stomata, cuticle, and vascular • Haploid are the dominant, conspicuous phase systems not needed – Photosynthesis occurs all over plant • “swim” to female ; require moist habitat body — no specialization – Water environment provides • may be dispersed by wind buoyancy / woody not needed

Vascular Plants (Tracheophytes) Pterophytes: Ferns - up! - down!

• Diploid is the dominant, conspicuous phase • Sperm “swim” to female gametophyte; require moist habitat • Spores are dispersed by wind

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Fern Life Cycle frond x-sect w/ sorus http://www.flickr.com/photos/72616463@N00/4202468205/

Seed-bearing plants () Gametophytes & Two : • The visible plant body is the diploid sporophyte • Gymnosperms “naked ” • The gametophytes are transient – Division: Conifers “cone microscopic structures bearers” – Female gametophyte within the – Male gametophyte within the grain • Pollen grains resist desiccation • Angiosperms “vessel seeds” — allow transport of sperm – Division: Anthophytes independent of water “flowering • After fertilization, ovule plants” develops into bearing the embryo

Gymnosperms “naked seeds” Angiosperms — the flowering plants Conifers “cone bearers”

>250,000 known living species = 90% of all plant species

World’s largest biome: boreal coniferous [taiga] World’s largest organisms: sequoia & coast redwood

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Vascular Plants Xylem - up! Phloem - down!

Vascular-plant structure

Tracheophytes • 3 major tissue types 1. Vascular 2. Dermal 3. Ground

Yet more surprising analogy between land plants and • Non-vascular plants increase surface area • Dependent for absorption & attachment with rhizoids • Meristematic growth • Differentiated tissues • – Phloem-like sieve vessels • Trumpet-filaments joined by sieve plates in medulla

Green algae

Moss Fern prothallium cross section of a giant kelp stipe

Non-vascular Rhizoids ! Vascular Roots • Taproot: from enlargement and Fern sporophyte branching of the seminal (seed) root. – Extends deeply – storage • Fibrous root: thin roots originating from base of stem around seminal Fern prothallium root. – Dense network near soil surface • Adventitious root: fibrous-like roots rhizoids originating from additional stem nodes. – Extend fibrous root area – Asexual propagation – Prop roots root – Climbing anchors

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(dicot) Stele Gas exchange in vascular plants (vascular cylinder)

• CO2 taken in and O2 given out by leaves for/from photosynthesis.

• Dissolved O2 taken in with H2O from soil by roots for tissue (monocot) respiration.

• During daylight: O2 out > O2 in • In dark of night: O2 out < O2 in Root Anatomy

Leaves & Stems Leaves & Stems

Alternate, simple leaves Opposite, compound leaves

Leaf Anatomy Stomata — “little mouths” — adjustable openings for gas exchange on the undersides of leaves

O2 bubbles forming from stomata

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Developmental Phase Changes of Meristem Two main classes of angiosperms: and • Monocots — grasses & grains (~70,000 spp.) Determinate Development of Leaves • Dicots —non-grasses (~180,000 spp.)

Horizontal Stems

• Stolon: above the surface

• : below the surface

Adventitious Roots

Vascular Bundles Vascular bundles of xylem & phloem Xylem - up! Phloem - down! in stem and leaf of monocot stem

root

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Secondary xylem & Secondary xylem & phloem in plants phloem in woody plants Support (Dicot Angiosperms) Fibers (Dicot Angiosperms) [Gymnosperms are similar] [Gymnosperms are similar]

Ray Secondary phloem

Support Fibers Secondary xylem

Ray

Dialated phloem ray

Annual growth rings in woody plants

Seed-

Spermatophytes

Gymnosperm (“naked seed”) vs. Gymnosperms “naked seeds” Angiosperm (“vessel seed”) Conifers “cone bearers”

Conifers: cones as sex organs

• Seed develops from megasporangium: integument + nucellus with megasporocyte • In angiosperms, megasporangium develops within (the “vessel”)

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Gymnosperm Gymnosperm Life Cycle Conifers: cones as sex organs • Conifers: • “ leaves” with cones as sex organs • sporangia • Pollen cones [male] • Microsporophylls • • (n) • Ovulate cones [female] • Megasporophylls • Megasporangia • (n)

Gymnosperm Seed Development Angiosperms — the flowering plants Anthophytes: as the sex organs

• Non-reproductive

Style – form calyx – form corolla

• Male : – Filament & Anther – Anther produces pollen

• Female organ: Carpel – , Style & Ovary

– Stigma collects pollen – Ovary produces

Reproductive Phase Changes of Meristem Angiosperm Gametophyte Development and Floristic Development • Meristem identity genes: leaf primordia → floral primordia • Organ identity genes: which floral primordia becomes which floral component – The ABC hypothesis

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Angiosperm Gametophyte Development Angiosperm Life Cycle

Double Fertilization in Angiosperms Dicot- Angiosperm Seed Development

Germinating pollen grains

Angiosperm “vessel seeds” A is a structure to protect and walls of ovary thicken to form fruit to carry the seeds disperse the embryos within the seeds

More on later!

• Simple fruits develop from a single ovary of a single • Compound fruits develop from the fusion of many ovaries or many flowers

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Seed Development Seed Development

Sporophyte embryo: • Leaves [cotyledons] • [hypocotyl] • Root [radicle]

Hypocotyl

Avery GSJ (1933) Structure and germination of tobacco seed and the developmental anatomy of the seedling plant. American Journal of Botany 20: 309-327

Seed Development Monocots vs. Dicots Anthophyte Diversity (2)

(1) Flowers & Fruits

Flower

Floral Anatomy regular / radial symmetry irregular / bilateral symmetry

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Flowers Flower Morphology and Ovary Position

• Complete flower – calyx+corolla++carpels

• Hermaphroditic: – Both male + female organs in same flower Hypogynous flower Perigynous flower Epigynous flower with superior ovary with superior ovary with inferior ovary • Monoecious: Lily [note non-green sepals!] – Separate male flowers & female • Hypogynous (flower “below ovary”): ovary positioned on the peak of the flowers on the same plant receptacle (torus). Other flower parts arise below the base of the carpels. E.g., Pea. • Perigynous (flower “around ovary”): ovary positioned in cup-like torus. Other • Dioecious: flower parts arise from edge of the cup. E.g., Rose. – Separate male flowers & female • Epigynous (flower “above ovary”): ovary completely embedded and fused within the receptacle. Other flower parts arise from the top of the ovary. E.g., Apple. flowers on separate plants Staminate Carpellate flower flower Begonias

Bracts

Inflorescence Multiple flowers (florets)) growing • Specialized leaves associated with as a distinct cluster flowers or cones • Most commonly with an

Protective convergence with flower parts • -like bracts of poinsettias & bouganvillas Enclosing inflorescence inflorescence of banana flowers (florets)

bracts

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Myriads of floral designs Floral characters relevant to

Bats Bees Beetles Birds Butterflies Flies Wind reflect methods to achieve pollination FLOWER dull white, bright dull white, red, red, dull brown, dull green, green, white, green orange, orange, purple brown color purple , white purple blue strong, fresh, mild, fruity, spicy none spicy, none putrid none odor fruity pleasant

regular, tubular large, large, narrow shallow regular or bowl- with bowl- funnel- tube with funnel or petals shaped. shallow shaped shaped; wide trap-like reduced or Closed landing perch landing absent; shape during day platform support, pad stigmata but no protruding landing platform

bloom night day day day day any time any time time

abundant; usually sometimes abundant; abundant; usually none hidden present; present; deeply deeply none not hidden not hidden hidden hidden

Angiosperm “vessel seeds” As ovules within the ovary develop into seeds, walls of ovary thicken to form fruit to carry the seeds the walls of the ovary (carpels) grow & develop into the walls of the fruit (pericarp)

• Simple fruits develop from a single ovary of a single flower • Compound fruits develop from the fusion of many ovaries or many flowers

Myriads of fruit designs reflect methods to disperse seeds Fruit: agents of • Autochory: self dispersed (explosive or recoil) • Anemochory (wind-) & Hydrochory (water-dispersed)

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Fruit: agents of seed dispersal Fruit Types • Zoochory (animal-dispersed) – Synzoochory – stockpiling & sloppy feeding • Comparing Apples to Oranges – Epizoochory – attach/adhere to fur/feathers – Endozoochory – digestion-resistant seeds pass through gut

• An orange is a fruit. • An apple contains a fruit!

Fruit Types Fruit Types • Simple Fruit: derived from a single ovary • Simple Fruit: derived from a single ovary – Dehiscent Fruit: dry fruit remains attached to plant. – Indehiscent Fruit: fruit dispersed with seeds. Splits open to release mature seeds • Dry Fruit: pericarp hardens • Pod; ; follicle – Grain (Caryopsis): pericarp thin, fused to seed coat – Achene: pericarp thin, not fused to seed – Nut: pericarp forms thick shell, not fused to seed

Legume pod

Lily capsule

Fleshy Fruits Fruit Types • Pericarp (from carpels of ovarian wall) thickens • Simple Fruit: derived from a single ovary • Derives into three layers – Indehiscent Fruit: fruit dispersed with seeds. – Endocarp – • Fleshy Fruit: mesocarp thick/pulpy/juicy (= sarcocarp) innermost layer – : endocarp thin » Bacca (true berry): exocarp → thin skin – Mesocarp – » Tomato, grape, coffee bean, cucumber middle layer » Hesperidium: exocarp → thick rind – Exocarp – » Citrus outermost layer

• Mesocarp becomes thick, fleshy, & juicy.

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Fruit Types Fruit Types • Simple Fruit: derived from a single ovary • Simple Fruit: derived from a single ovary – Indehiscent Fruit: fruit dispersed with seeds. – Indehiscent Fruit: fruit dispersed with seeds. • Fleshy Fruit: mesocarp thick/pulpy/juicy (= sarcocarp) • Accessory Fruit (Anthocarp): pericarp thin; other flower parts contribute to much of fruit structure – Drupe: endocarp thickens/hardens → pit around – Pome: papery pericarp from inferior ovary forms single seed core around seeds; » Peach, cherry, plum, mango, olive, coconut Receptacle/perianth form the fleshy layer & skin » Apple, pear

Fruit Types Fruit Types • Compound Fruit: derived from multiple ovaries or • Compound Fruit: derived from multiple ovaries or multiple flowers multiple flowers – Aggregate drupes: from flowers with multiple ovaries; – Aggregate achenes with accessory fruit: from flowers each drupelet with tiny pit with multiple ovaries; multiple achenes on fleshy • Blackberry, raspberry receptacle (torus) • Strawberry

Fruit Types Plant

• Compound Fruit: derived from multiple ovaries or Behavior multiple flowers (inflorescence) • Photoperiod responses • Defense responses – Multiple fruit: fusion of fruits from multiple flowers • Tropisms (analogous to • Pineapple, fig, mulberry taxis in )

1. Phototropism 2. Geotropism 3. Thigmotropism

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Photoreception in Plant Cells phytochromes & cryptochromes Photoperiodism & Biological Clocks

1 Reception 2 Transduction 3 Response • seasonal

CYTOPLASM Transcription factor 1 NUCLEUS Plasma cGMP P membrane kinase 1 Second Transcription Phytochrome messenger factor 2

P wall Protein kinase 2 Transcription Light

Translation

Ca2+ channel Activate cellular responses

Ca2+

Figure 39.4

Photoperiodism & Biological Clocks Photoperiodism & Biological Clocks • circadian • circadian

Linnaeus’ proposed Noon Midnight Horologium Florae (“flower clock”) garden

Photoperiodism Auditory Behavior? • circadian Responding to sound vibrations

• Hearing danger: predator vibrations trigger plant chemical defenses • Plants respond to leaf vibrations caused by insect chewing. Oecologia (2014) 10.1007/s00442-014-2995-6

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