Forms of Asexual Reproduction in Plants

Clonal Growth (revisited) Rhizome Stolon Suckers Plantlets Bulbils

Fragmentation: jumping cholla

Agamospermy Production of seeds with no fertilization

Key Stages in the Life-History of a Plant Growth Flowering Pollination Seed Maturation Dispersal Dormancy Germination seed phase

Sexual Reproduction in Plants

Typical Angiosperm Lifecycle Alternation of generations Sporophyte (2n) Gametophytes (1n)

Typical Angiosperm Lifecycle Alternation of generations Sporophyte (2n) Gametophytes (1n) Fertilization

♂ ♀ Hermaphrodites Gender Expression in Plants

Sequential Hermaphrodism Jack-in-the-pulpet (Arisemea triphyllum) Some plants change sex over time!

Distribution of Flower Types

Variability in Flowering Patterns Semelparity Iteroparity Flower once and die Flower many times

Semelparity: A closer look Annuals Biennials

Biennial plant Year 1 Year 2 © R. Jackson

Semelparity: A closer look Big bang perennials

Bet Hedging Big bang Vegetative reproduction

Semelparity vs. Iteroparity

Tradeoffs in Phenology of Flowering AnnualsPerennialsBig Bang Advantages Quick reproduction Protected as seed Disadvantages High environmental risk Poor competitors Special Circumstances Poor conditions for extended time periods Strong signal for breaking seed dormancy Advantages Increased size Reproduce when resources are plentiful Disadvantages Slower initial population growth Require relatively stable habitats Special Circumstances Advantages Increased fecundity* Predator satiation Disadvantages Delayed reproduction “All eggs in one basket” Special Circumstances Can succeed in situations with high stress, low resources Better competitor* * (vs. annuals) Unpredictable resource for seed predators

A Majority of Plants are Iteroparous Perennials

Key Stages in the Life-History of a Plant Growth Flowering Pollination Seed Maturation Dispersal Dormancy Germination seed phase

The Ecology of Pollination Passive Modes Wind Pollination Pollination via water

General Considerations Regarding Passive Modes of Pollination Requires high levels of pollen production Little energy expended on producing intricate flower structures Most effective for plants growing at high density Risky at low density due to low probability of success

Dispersal Profiles for Wind Born Pollen Plantago lanceolata

Active Modes of Pollen Delivery: Directed Pollination Insects Birds BatsBats

Costs Incurred in Employing Pollen Vectors Rewards Fragrance Nectar Pollen Advertising Flower color Flower shape Fragrance Bottom line: Pollinators benefit from the incentives provided; not from the services they give to plants Bottom line: Pollinators benefit from the incentives provided; not from the services they give to plants  There are some cheaters!

Movement of Pollen by an Animal Vector Only measures first visit