Plant Ecology Chapter 7 Growth Reproduction Plant Growth
- Slides: 70
Plant Ecology - Chapter 7 Growth & Reproduction
Plant Growth - Modular
Plant Growth - Modular Apical meristems Intercalary meristems Axillary meristems Vascular cambium
Plant Architecture Raunkaier classification system of perennial growth forms >25 cm <25 cm At ground level Below ground level
Plant Architecture Plasticity can change plant shape in response to environmental conditions Sun vs. shade Self-pruning
Clonal Plants Spatial distribution of ramets affected by: Competition among genets Spatial variation in resource distribution
Clonal Plants Two growth forms Phalanx - tightly grouped advancing front Guerilla - isolated ramets penetrating competitors’ turf All in the perspective
Clonal Plants - Why variation? Mechanics of clonal spread “Foraging” for resources Following the resource distribution Integration within clone to minimize environmental variation
Vegetative Reproduction Apomixis general term for asexual reproduction Can take on many different forms
Vegetative Reproduction Stolons - runners - branches that spread at surface of the soil, generate new ramets
Vegetative Reproduction Rhizomes underground horizontal stems growing near soil surface Many grasses (like bamboo)
Vegetative Reproduction Bulbs underground rosette stems that store nutrients Tulips, onions, daffodils
Vegetative Reproduction Suckers - bud formation on some of nearsurface roots Quaking aspen clones can cover many hectares
Vegetative Reproduction Clonal fragmentation pieces break off, are capable of rooting to form new plants Mother of thousands
Vegetative Reproduction Bulbils - bulblike organs produced in leaf axils
Seeds Produced Asexually Agamospermy partial meiosis without reduction division - new embryos are clones
Seeds Produced Asexually Grasses, raspberries, nettles
Sexual Life Cycles Alternation of generations Gametophyte Sporophyte Lower plants gametophyte dominant Higher plants sporophyte dominant
Pollination Ecology Pollination of typical, showy flowers done by birds or insects But many flowers not showy, and likely are pollinated by wind
Pollination Ecology Pollen transfer in most grasses and temperate-zone trees is by wind Human allergies to pollen (hay fever) due to huge amounts of pollen in air
Pollination Ecology Wind-pollinated flowers are not showy Waste of energy to produce big, colorful petals, scents, nectar Grasses often lack petals, sepals (interfere with pollen transfer by wind)
Pollination Ecology Wind-pollinated plants produce massive quantities of pollen Little influence over where pollen goes
Pollination Ecology Wind-pollinated plants have higher pollen: ovule ratios than their animalpollinated relatives
Pollination Ecology Wind pollination most common in plants of open habitats Usually flower before leaves emerge in spring Also windiest time of year Pollen can travel 100 s of miles
Pollination Ecology Wind pollination might be evolutionarily primitive But wind pollination is common in both “old” and “new” taxa Both can be present in same group
Visual Displays Flower shape and color are advertisements of the rewards an animal can expect to receive from the flower But both sides cheat
Visual Displays Insects usually see colors at shorter wavelengths than humans (e. g. , ultraviolet) Birds more sensitive to colors in middle and red parts of spectrum Birds may not see or be attracted to flowers bees can see
Visual Displays Many bee-pollinated flowers are yellow Bird-pollinated flowers often orange or red Moths: white to pale yellow Bats: white to brown
Visual Displays Some flowers reflect light in several different wavelengths - can be seen by different pollinators Contrasting colors may help guide pollinator - nectar guide
Visual Displays Some plants have modified other plant parts to attract pollinators Poinsettias - red bracts, leaves more attractive than small, yellow flowers
Visual Displays Some plants arrange flowers into various aggregations inflorescences Increase the size of the attractive display without altering the flowers themselves
Floral Odors Scents act as attractants over longer distances than visual attractants First locate generally by scent, then locate specifically by sight
Floral Odors can vary independently of colors Odors of different species can be highly variable, to attract different pollinators
Floral Odors Bees attracted to sweet odors (like we are) Bats like musty odors Flies like rotting flesh and dung odors
Restricting Visitors Adaptations to attract right visitor, repel unwanted visitors Change flower shape from unspecialized bowl to something else Only long tongues/mouthparts can access rewards
The Reward Usually nectar (sugars) or pollen (protein) Can also be oils, scent Timing of reward also changeable (day vs. night) Nectar robbers
Pollination Syndromes Certain combinations of flower color, shape, odor, reward type, timing of rewards often associated with certain types of pollinators Tightly coevolved mutualisms
Pollination Syndromes Bee-pollinated flowers - yellowish, sweetsmelling, broad to allow bee contact with anthers, stigma, produce nectar during daytime
Pollination Syndromes Bird-pollinated flowers - red or orange, little scent, produce lots of nectar during the day, shape with long tubes or spurs
Pollination Syndromes Strength, generality of pollination syndromes may be overstated Syndromes are tendencies rather than laws Animals “outside” syndrome can accomplish significant pollination
Pollination Syndromes emphasize specialist pollinators, but neglect the generalist pollinators, which may be more important
Complex Interactions! St. Johnswort on shores of Florida ponds Plants growing by fishfree ponds more pollenlimited than those around fish ponds
Aquatic Pollinators? Most aquatic plants bear flowers above water surface Plants pollinated by insects or wind
Aquatic Pollinators? Large numbers of aquatic plants have underwater flowers One strategy: make pollen dispersal units bigger, disperse/receive at surface (Vallisneria) Others: sticky pollen in rafts, elongated pollen
Plant Mating Systems Factors that govern who can mate with whom Many complications because of widely varying gender expression
Plant Mating Systems Obligatory selffertilization - inbreeding - individuals can only pollinate themselves Outcrossing mechanisms preventing self-fertilization Something in between
Gender Issues Some individual plants are cosexual - function as both males and females simultaneously Hermaphroditism - most common type of gender expression in plants Individuals have perfect flowers containing both functional stamens and functional stigmas
Monoecy Individual plants have some flowers with functional stamens only (staminate flowers) and some with functional stigmas only (pistillate flowers)
Monoecy All individuals have both types of flowers
Monoecy
Dioecy At least some plants in a population have only pistillate or only staminate flowers Function as female only or male only
Mixed gender expression 3 systems of gender expression can exist in combination with one another E. g. , gynomonoecy, androdioecy
Mixed gender expression Sequential hermaphroditism often begin life as male, then gradually switch to female
Self-fertilization Cosexual plants may or may not be capable of selffertilization 25% of windpollinated cosexual plants are mainly inbreeding remainder strongly outcrossing
Self-fertilization Animal-pollinated cosexual plants evenly divided among strongly inbreeding, strongly outcrossing, and mixtures of inbreeding and outcrossing
Confusion Different forms of gender expression can occur at same time within a population Difficult to determine how they actually function
Competition for Pollinators & Pollen Plants produce excess ovules that never produce viable seeds Competition for pollinators, pollen? Too few pollinators, or very inefficient at transferring pollen
Sexual Selection Differential success at mating among plants Male-to-male competition Female choice
Sexual Selection Male-to-male competition results in extremes of floral displays Large inflorescences where most flowers function only to attract pollinators Functionally male reproduce only by having pollen taken elsewhere
Sexual Selection Female choice occurs at site of pollination Competition among pollen grains Female flower “chooses” pollen via biochemical interactions Affect pollen germination, rate of pollen tube growth May selectively abort certain seeds
Pollen Dispersal Inbreeding common in plants Most matings occur among neighbors, which tend to be relatives
Pollen Dispersal Animal-pollinated plants Plants are clumped, pollinators don’t move much
Pollen Dispersal Wind-pollinated plants Most pollen grains fall nearest their source Plants releasingle pollen grains most likely to mate with most distant individuals Clumped pollen - mating with nearest neighbors
Assortative Mating Plants with similar phenotypes mate with one another more often than they would by chance Time of flowering, flower color, influence the pollinator
Negative Assortative Mating Plants with dissimilar phenotypes mate with one another more often than they would by chance Heterostyly styles/stigmas of different lengths cause obligate outcrossing
Fruits and Seeds Fruit - mature ovary with seeds - great variety Two functions protect developing seeds, affect dispersal of seeds
Fruits and Seeds Compromise between protecting seeds from being eaten, and attracting animal consumers to aid in seed dispersal
Fruits and Seeds Wind dispersal - float, flutter based on mass, surface area, shape
Fruits and Seeds Animal dispersal attract/reward disperser, but protect seeds Thick, hard seed coats Spit out, regurgitated, pass with feces
Seed Banks Dispersal in time Seedbank - collection of seeds in the soil Short-lived plants tend to have long-lived seeds, and vice versa
- Venn diagram of sexual and asexual reproduction
- Asexualk
- Venn diagram of sexual and asexual reproduction in animals
- Population ecology example
- Exponential growth equation ecology
- Logistic model of population growth
- Section 1 population dynamics answer key
- Growth and reproduction
- Growth and reproduction
- Cell growth division and reproduction
- Plant reproduction
- Anther function in a flower
- Unit 17 plant reproduction
- Nonvascular plants reproduction
- Plants reproduce asexually
- Plant and animal reproduction venn diagram
- Which seedless plants have been used to treat bee stings
- Plant reproduction virtual lab
- Chapter 35 plant structure growth and development
- Chapter 35 plant structure growth and development
- Chapter 52 an introduction to ecology and the biosphere
- Chapter 3 section 1: community ecology answer key
- Chapter 56 conservation biology and restoration ecology
- Chapter 55 ecosystems and restoration ecology
- Chapter 54 community ecology
- Chapter 53 population ecology
- Chapter 52 an introduction to ecology and the biosphere
- Organism
- Equilibrial life history
- Principles of ecology section 2 flow of energy
- Principles of ecology chapter 2 section 2 answer key
- Chapter 2 principles of ecology answers
- Chapter 4 population ecology answer key
- Chapter 54 community ecology
- Chapter 53 population ecology
- Chapter 55 ecosystems and restoration ecology
- Chapter 5 evolution and community ecology
- Chapter 5 evolution and community ecology answer key
- Chapter 4 population ecology section 1 population dynamics
- Principles of ecology chapter 2 section 1 answer key
- Chapter 4 section 1 population dynamics
- Chapter 53 population ecology
- Chapter 54 community ecology
- Sexual reproduction
- Chapter 10 sexual reproduction and genetics
- Reproduction in humans
- Chapter 9 section 1 cellular growth
- Lesson 20.2 the male reproductive system
- Chapter 19 asexual reproduction answer key
- Chapter 10 sexual reproduction and genetics
- Chapter 9 section 1 cellular growth
- Chapter 34 reproduction and development answer key
- Chapter 6 chromosomes and cell reproduction
- Chapter 9 cellular reproduction
- Nondisjunction in meiosis
- Relative growth rates
- Root hair structure
- Growthchain
- Primary growth and secondary growth in plants
- Geometric growth population
- Neoclassical growth theory vs. endogenous growth theory
- Organic vs inorganic growth
- Plant growth and development ppt presentation
- Rice plant morphology
- Dough stage of rice
- Plant growth with different liquids
- Role of water in plant growth
- Geotropism
- Environmental requirements for good plant growth
- What is growth in biology
- Microtubules in plant cells