“Basal angiosperms”, and plant breeding systems

“Basal angiosperms”, and plant breeding systems

Soltis et al., 2011

Monocots'

ANITA'grade'

Magnoliids'

Ranunculaceae'

Angiosperm phylogeny

�Basal angiosperms�

tricolpate pollen

1 cotyledon ANITA grade • Amborella • Nymphaeaceae • Illicium • Trimenia • Austrobaileya


A – N – A

http://botany.csdl.tamu.edu/FLORA/tfplab/lilyp.gif

Nymphaeaceae

8 genera, 70 species (Nymphaea)

Victoria sp., Amazon water lily Nymphaea spp.

8 genera, 70 species (Nymphaea) Habit: Stems: Leaves:

Nymphaeaceae

Aquatic

Air canals

Long petioles, submerged or floating to emergent

Nymphaeaceae

Symmetry: Perianth parts: Stamens: Pistils: Ovary position: Fruit type:

radial

4-12 tepals, free; petal-like staminodes

3-many, laminar

1-many (1-many carpels/pistil)

superior or inferior

aggregate of nuts, or follicle, berry, fleshy capsule


tricolpate pollen

1 cotyledon


Magnolia x soulangeana

Magnoliaceae

2 genera, 220 species (Liriodendron, Magnolia)

Liriodendron tulipifera

2 genera, 220 species (Liriodendron, Magnolia) Habit: Leaves:

Magnoliaceae

Trees or shrubs Evergreen or deciduous

Alternate, simple, entire (lobed in Liriodendron) Ethereal oils

Magnoliaceae


radial

6-many tepals, free

many, laminar

many simple pistils = many free carpels

superior

aggregate of follicles (Magnolia), or samara (Liriodendron)

•  Insect-pollinated •  Radially symmetric •  Perfect •  Floral parts:

•  Several to many •  Spirally arranged •  Distinct (unfused)

•  Stamens laminar •  Pistils simple •  Ovaries superior

“Basal” angiosperms

Flowers of early angiosperms


tricolpate pollen

1 cotyledon


�Basal eudicots�

Asterids Rosids

Eudicots (Tricolpates)


Ranunculaceae

47 genera, 2,000 species

47 genera, 2,000 species Habit: Leaves:

Ranunculaceae

Usually herbaceous

Usually alternate (often all basal), simple to dissected to compound Usually lacking stipules

Ranunculaceae


radial or bilateral

5 sepals, 5 petals (or 4-many tepals), free

many

usually 5-many, simple

superior

usually aggregate, sometimes a berry

Plants vs. Animals

Plant breeding systems

bisexual

sex = dynamic

non-mobile

body plan = modular

unisexual

sex = fixed

mobile

body plan = fixed

Asexual reproduction

Vegetative reproduction: does not involve flowers Agamospermy (apomixis)

Flowers produced

Embryo produced clonally

No fertilization

•  Locally adapted offspring •  Less reproductive effort •  Reproductive assurance

Asexual reproduction

•  Little genetic variability •  Narrow range of environmental

tolerance •  Limited dispersal (except

agamospermy)

Advantages

Disadvantages

Sexual reproduction

Self pollination

Self pollination

Cross pollination

Self pollination: pollen transfer within an individual plant Self fertilization: fertilization of egg by sperm of same individual plant

Sexual reproduction: selfing

Self pollination: pollen transfer within an individual plant Self fertilization: fertilization of egg by sperm of same individual plant

Sexual reproduction: selfing

•  Double genetic contribution to offspring

•  Locally adapted offspring •  Less reproductive effort •  Reproductive assurance

•  Inbreeding depression •  Little genetic variability •  Narrow range of environmental

tolerance

Advantages

Disadvantages

•  Capable of self-fertilization •  Ovule may be fertilized by pollen from

the same plant, or from different plants

•  Only capable of cross-fertilization •  Ovule cannot be fertilized with pollen

from the same plant

Self-compatible (SC)

Self-incompatible (SI)

Sexual reproduction: outcrossing

•  How might you discover whether an unknown plant reproduces by self-fertilization, cross-fertilization, or agamospermy?

•  You may perform any of the following experiments to determine whether seed is set: –  Pollinator exclusion –  Remove stamens before pollen is released –  Artificial self-pollination –  Artificial cross-pollination

•  What do you predict will happen in each case?

Class discussion – breeding systems

Asexual reproduction Sexual reproduction

Agamospermy SC SI

Pollinator exclusion

Emasculation

Artificial self-pollination

Artificial cross-pollination

Will seed be set?

Pollen released before stigma is receptive

Stigma receptive before pollen is released

Temporal separation of male and female

Functions promoting outcrossing in plants

Protandry Protogyny

Within flowers Between flowers

Functions promoting outcrossing in plants

Spatial separation of male and female

Heterostyly Monoecy/dioecy

Sexual reproduction: outcrossing

•  High genetic diversity •  Avoid expression of deleterious

recessive alleles •  Broad range of environmental

tolerance

•  Reproduction less likely •  Dependent on pollinator •  Dependent on population

density

Advantages

Disadvantages

“Basal angiosperms”, and plant breeding systems

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