Angiosperms

Synapomorphy

derived trait shared by two or more groups i.e traits similar to each other because descended from same common ancestor

Complete Flower

4 Whorls

• stamen

• sepal

• petals

• carpels

petals

• sterile

  • may be coloured and showey to attract pollinators

Sepals

• sterile

• protect inner whorls of flower during development

Calyx

whorl of sepals

corolla

whorl of petals

Perianth

Sepals + Petals = Calyx + Corolla

Pedicel

flower stalk

Receptacle

portion of stalk where floral parts are attached

Stamens

= androecium

• pollen bearing

• Anther + filament

Anthers

contain microsporangia where pollen form

Filaments

can be elongated to expose anthers

Carpels

= pistil = gynoecium

• highly modified megasporophyll that enclose ovule

  • differentiated into stigma, style, ovary

Stigma

where pollen adheres

Style

elevates stigma where pollen can be intercepted

Ovary

houses ovules (integumented megasporangia)

Angiosperm Ovule

contains the megagametophyte = embryo sac

• when mature = 7cells but 8 nuclei

Pistil

comprises one or more carpels

• carpels can be fused → fused carpels can be partitioned

Placenta

part of ovary wall where ovules attach

Chambers

locules

Placentation

arrangent of placentae with ovules

Parietal Placentation

attached to ovary wall or outgrowth

ex. cucumber, melon

Axile Placentation

attached at central column in gynoecium with multiple locules

ex. bell pepper, tomatoes, lemon

Free Central Placentation

attached at central column in gynoecium with one locule

ex. carnation

Marginal Placentation

attached to one elongated placenta on one side of ovary

ex. peas

Superior Ovary

Sepals, stamens, and petals attached to receptacle BELOW ovary

• Hypogynous flower

• Perigynous flower

Inferior Ovary

sepals, petals, stamens attached to receptacle ABOVE ovary

• Epigynous flower

Hypogynous Flower

sepals, petals and stamens not fused

ex. canola

Perigynous Flower

sepals, petals, stamens fused to form hypanthium

ex. cherry

Epigynous Flower

Ovary embedded in fused bases or perianth and stamens or in receptacle tissue

ex. apple

radial Symmetry

two or more planes of symmetry

Bilateral Symmetry

one plane of symmetry - divided into halves on single plane

Perfect Flowers

stamens + carpels

Imperfect Flowers

either stamens or carpels missing

Inflorescense

clusters of flower arrangements

Vegetative Meristem

vegetative shoot apical meristem

• becomes floral meristem

Floral Meristem

flowering shoot apical meristem

• transition to it controlled by photoperiod and temperature

ABC Model

three classes of floral organ identity genes (transcription factors) control organ identity (whorls)

Class A genes

sepals

Class A+B Genes

petals

Class B+C Genes

stamens

Class C Genes

carpels

No Class A (mutatnt)

class c genes will expand to that region = stamens and carpels only

No Class C (mutatant)

sepals and petals only

No Class B (mutant)

sepals and carpels

No Class A and C

flowers are really small and abnormal (don’t look like flowers)

• primordia (just initiated organs)

ABCE Model

class E genes encode transcription factors necessary for activities of calls A, B, C

Class D Genes

for ovule formation

Flower

Modified shoot with sterile and reproductive organs

Tube Cell

elongates to form pollen tube

• grows down style to ovary

Generative Cell

undergoes mitosis in pollen tube to give two sperm

Double Feralization

1. one sperm unites with egg cell in embryo sac = zygote

2. other sperm unites two polar nuclei in embryo sac = endosperm

Pollination

transfer of pollen from anther to stigma

1. pollen lands on stigma and germinates

2. produces pollen tube that penetrates stigma to ovule

3. generative cell divides to produce two sperm cells

Pollination Syndrome

floral traits that have evolved in response to natural selection imposed by biotic or abiotic pollen vectors

Cross-Pollination

transfer of pollen to stigma of different individual of same species

Self-pollination

transfer of pollen to stigma of same individual

• same flower or other flower on plant

Evolved Mechanism

• decrease self-pollination

• increase cross pollination

= increase genetic variation

Compatibility Barriers

protein-based signaling between germinating pollen and stigma allows for recognition of self or non-self

• surface proteins match protein kinase receptor = pollen tube blocked by carpel

Dioecy

flowers are imperfect and pollen producing flowers on different plants than ovule-bearing flowers

• rare

Decrease Self-Pollination Mechanisms

• temporal separation of maturation for staminate and pistilate structures

• spatial separation of staminate and pistilate structures (heterostyly of anther and stigma)

Wind Pollination

• reduced perianth (don’t need to attract pollinators)

• stigma small = lots of pollen needed

• large feathery stigma to increase surface area

• effective in dense populations

Animal Pollination

• coevolution

• usually both get benefit

  • animals: food, plants: pollination

  • animals evovle specilaized body parts and behaviours that aid plant pollination

Coevolution

interaction between two different clades as selective forces on each other = adaptations that increase interdependency

Maintaining Fidelity

• plants attract animal pollinators by flower scent and colour

• flower shape and inflorescence type influence efficiency of visits

• produce rewards suited to pollinator

  • pollinators can learn the features of specific flowers

Bee & Wasp Pollinators

orchids look like female bees or wasps and may possess their pheromones

• male attempt to mate with them and pollinate plant

Fruit

mature ovary and associated parts

Andoroecium

stamen = anther + filament

Gynoecium

carpel/pistil = stigma + style + ovary

Pericarp

fruit wall that develops from the ovary wall

Accessory Fruit

additional flower parts included

Hypanthium

fusion of perianth bases

ex. apples

Simple Fruit

derived from one pistil (one carpel, one set fused carpels)

ex. lemon

Aggregate

derived from flowers with multiple separate pistils

ex.. strawberries, raspberries

Multiple Fruit

derived from pistils of more than one flower

ex. pinapple

Berry

• Fleshy fruit

• one ovary, pericarp all soft

• many seeds

tomamtoe

Hesperidium Citrus

exocarp is leathery

Drupe

• Fleshy fruit

• endocarp is hard

• exocarp and mesocarp are soft

• one-seeded

ex. peaches and plumes

Pome

• Fleshy fruit

• outer portion develops from floral parts surrounding ovary

• endocarp leathery

• mesocarp and exocarp soft

ex. apples and pears

Pepo

• Fleshy fruit

• exocarp is hard

• mesocarp and endocarp and soft

  • maybe not ditinct

Ex. pumpkin

Dehiscent

break open to release seeds

Indehiscent

do not break open to release seeds

Seed Dispersal Vectors

• Ants

• Digestion

• Attachment

• Self-Propelling

• Wind

Ants

Elaiosomes attract ants

ANA Grade & Magnoliids

• series of linages

• combination of primitive characteristics and derived characteristics

• radial symmetry

• tepals

• apocarpic = separate carpels

• stamens poorly differentiated into filaments and anters

Canellales

cinnamon

Piperales

black pepper

Lauralse

bay laurel, avocado, sassafran

Magnoliales

mutmeg

Bay Laurel

• major aromatic compound in bay leaves: terpenoid

Terpenes

-CH2-O-P-P

Nutmeg & mace

• spices in cooking

• contains camphene (terpenoid compound)

• contains myristicin (phenolic compound)

Sassafras

• eastern north america

  • source of safrole (phenolic compound)

• treat inflammation

Shared derived features

two linages have character in common

Shared Derived Feature of Monocots

1. one cotyledon

2. parallel leaf venation

3. scattered vascular bundles

4. vascular cambium absent

5. flower parts in threes

6. pollen has one pore/aperture

Liliaceae

• lilies

• herbaceous

• simple leaves with parallel venation

• 6 tepals - class b genes extend into whorl 1

• perfect flowers

• hypogynous flower

• have bulbs

ex. camus, yellow glacier lily, wood liliy

Poaceae

Grasses

• perennials with horizontal stems

• sheathing leaves

• highly reduced flowers

• fruit = grain = caryopsis

Grainoids

grasses and other non-woody angiosperms that have grass-like appearance

Forbs

non-woody angiosperms (eudicots) that are not grasses or grass-like

Spikelets

highly reduced grass flower inflorescences

• modified leaves (palea and lemma bracts)

• lodicule open