Botanical Sex In The Garden
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Transcript of Botanical Sex In The Garden
Sex in the Garden…From the plant’s perspective
Linda R McMahan, Extension HorticultureOregon State University, Yamhill County Extension Service
Question: Define Sex
Courtesy of Google
• sexual activity, e.g., "they had XXX in the back seat“
• either of the two categories (male or female) into which most organisms are divided
• tell the sex (of young chickens)• the properties that distinguish organisms on the
basis of their reproductive roles
More
• an Australian television series that ran from 1992 to 1993 on the Nine Network
• an album by popular Greek artist Elli Kokkinou• a 1926 play, written by, and starring, Mae West• est le titre d'un livre écrit par Madonna sorti en
1992 accompagnant son neuvième album Erotica. ...
Our Version
• Plant reproduction by whatever means, with the “intention” to produce more plants!
Various Reproductive Strategies• Cross-pollination• Self-pollination• Vegetative
Reproduction
Some “Choices” for Plants• Generalist vs. Specialist• Many Small Seeds vs. Few Large Seeds• Vegetative vs. Sexual• Self-pollinated vs. Cross-fertilization• Various modes of pollination and relationship
to abundance of pollinators, presence of wind or water, flowering time, and so on.
Some Vegetative Strategies
Piggyback plant – Tolmiea menziesii - produces plant “offsets” on the leaves
Crocus – division of the bulbs in the ground
Dune strawberry, Fragaria chiloensis, reproducing by runners
Some others methods include underground stems such as rhizomes and tuberous stems, new plant production from underground roots or tuberous roots, bulbils, and various strategies of rooting by forms of layering, such as when plant stems bend over and a new plant grows when it touches the ground.
So now ask yourself “Why do plants have flowers?” And then, “Why do plants have pretty flowers?”
Purpose of Flowers?
“The accomplishment of fertilization is the primary function of the flower”
1907 A Textbook of Botany
Purpose of Flowers?
• Produce pollen and ovules that combine to create embryos that are dispersed in seeds
Flowers are “Pretty” To Attract Attention
• Potential pollinators• Potential dispersal in other ways, such as by
people in gardens and landscapes
Flowers are a Form of Advertising
• To create a “sale” to pollinators or dispersers, an offer must take place. This is usually in the form of pollen or nectar.
• Then the plant needs to advertise the availability of the offer – hence the flower, which sometimes produces an odor attractive to the potential pollinator.
• The flower must then accept “payment” from the pollinator as a method to transfer of pollen to a stigma. Bargain complete.
Characteristics of Wind Pollinated Flowers – The Pollinator is Not a Creature in this Case
• Produce large amounts of pollen, often in catkins.
• Pollen is small to travel on the wind.• Timing takes advantage of seasonal wind
patterns.• Flowers may or may not be attractive, but are
usually small with little color or odor.• Grasses and conifers are typically wind
pollinated.
Wind Pollination
Western Hazelnut – Corylus nutalli
Willow – Salix species Stinging nettle, Urtica dioica
Plantain, Plantago Ginkgo biloba
Silk tassel bush, Garrya elliptica
Most conifers, this juniper for examples, are wind pollinated
Characteristics of Bee Pollinated Flowers
• Typically but not always blue or yellow.
• Produce ample pollen and nectar.
• Ultraviolet coloration and nectar guides.
• Sweet smell and strong “center.”• Have places for bees to land
safely to collect the pollen and nectar.
Photo of Lithodora and bee by Carolyn Devine.
Some Bee flowers
sunflower
Flannel bush, Fremontodendron californicum
Blueblossom, Ceanothus thyrsiflorus, bees, also beetles
Stream violet, Viola glabella, note nectar guides
Bumblebee on snowberry, Symphoricarpos alba. Many members of the heath family, Ericaceae, are pollinated by bumblebees
More Examples of Ericaceae Flowers
Strawberry tree, Arbutus unedo
Ghost plant, Monotropa uniflora
Salal, Gaultheria shallon
More Bee Flowers
Camas, Camassia
Douglas aster
Cat’s ear, Calochotus sp.
More bee flowers
Fairy slipper orchid, Calypso bulbosa
Fritillaria
Bleeding heart
Characteristics of Butterfly Pollinated Flowers
• Brightly colored – can be red
• Little if any odor• Flower arrangements
create landing platforms and places to walk around
• Plants with these flowers are often also hosts for the larval stage of particular butterflies
More Butterfly Flowers
Yarrow, Achillea millefolium
Wild carrot
Garden phloxYellow twig dogwood
More Butterly Flowers
Coltsfoot
Sedum spathulifolium
Ocean spray, Holodiscus discolor—also attracts other insects
More Butterfly Flowers
Sedum ‘Autumn Joy’
Echinacea ‘White Swan’ – odor of coneflowers may have developed especially to attract butterflies
Characteristics of Fly Pollinated Flowers
• Sometimes purple, brown, brownish red, OR in other plants, white
• Unattractive odor, at least to humans, such as rotting meat or dung OR slightly sweet odor – Depends on intended fly
Asarum caudatum, wild ginger
More Fly Flowers
Skunk cabbage, Lysichiton americanum
Slinkpod, Scoliopis bigelovii
Rubus parviflorus, thimbleberry, a “generalist” – bees, flies, beetles
Characteristics of Bird Pollinated Flowers
• Typically red, pink, or orange
• No odor• Facilitate hovering
or gathering nectar and pollen from the air
Bottlebrush, pollinated by honeyeater birds in its native Australia
More bird flowers- hummingbirds
Red flowering currant, Ribes sanguineum
California fuschia, Epilobium canum (Zauchneria californica)
More Bird flowers
Western columbine, Aquilegia formosa, also attracts other insects including spinx moth
Cape fuschia, PhygeliusWestern bleeding heart, Dicentra formosa
Other pollinators
• Moths – typically white or flowers with “big” sweet scent that are open at night.
• Beetles – attracted to many flowers where pollen is readily available.
• Spiders occasionally. Darlingtonia californica may be pollinated by a tiny spider.
• A vast variety of flying insects like wasps and many forms of flies.
• In other parts of the world, pollinators may be bats or other mammals.
Opuntia sp., prickly pear cactus
Guess the Pollinator
Guess the Pollinator
Clarkia sp.
Guess the Pollinator
Cistus sp.
Camellia sasanqua
Guess the Pollinator
Darmera peltata, umbrella plant
Guess the Pollinator
Iris tenax, Oregon iris
Guess the Pollinator
Guess the Pollinator
Trillium ovatum
Guess the Pollinator
Redwood sorrel, Oxalis oregana
Guess the Pollinator
Oleander
Ribes roselii
Guess the Pollinator
Some Plants Change the rules•Apomixis - replacement of the normal sexual
reproduction by asexual production of seeds but without fertilization. •Agamospermy - production by plants of seeds in
which the embryo is derived (without fertilization) from diploid cells of the parent.•Parthenogenesis - a form of reproduction in which
the egg develops into a new individual without fertilization.•Cleistogamy - production of flowers which do not
open, and are self-fertilized in the bud
Apomixis
• Seeds are produced, but they are genetically identical to the parent.
• Advantage may be to pass on genetic material that is highly useful. Example: Dandelions are apomictic.
• Embryo arises from an unfertilized egg.
• Techniques are being developed to use this feature in plant breeding programs to ensure identical nature of crops.
Agamospermy
• Includes any mechanism that produces a genetically identical seed, including Apomixes.
• This and similar strategies may be advantageous in disturbed habitats.
• Very common in Aster family, and sometimes found in roses and other plants.
• You cannot tell by looking at the flower.
Parthenogenesis
• Mother cell does not divide, but itself contributes the genetic identify to the seed.
• Apomixes, when it does not involve pollen, is considered to be a plant form of parthenogenesis.
Cleistogamy
• Individual flowers are obligate self-pollinators.• They are often colorless, and do not open.• Happens in many violets, peanuts and ground
nuts, for example.
Sometimes, like in Viola glabella, some of the flowers are insect pollinated and others, often the later ones, are self-pollinated and look very different from the insect-pollinated flowers
Seed Dispersal—How Seeds Get Around Once they are Formed
Western hazelnut, Cornus nuttalliWestern lupine, Lupinus polyphyllusBigleaf maple, Acer
macrophyllum
Techniques of dispersal vary considerably and include wind and water, consumed and transported by birds or animals, or dropping close to the parent plant. Dispersal animals include mammals, humans, ants, insects, birds, and probably many more.
Slinkpod, Scoliopis bigelovii – pollinated by flies but dispersal helped by slugs which often eat the edges of the pods and expose the seeds.
Asian pear dispersal?
Prickly pear cactus fruits attach to passer-by for a free ride to a new location, or because of their attractive taste and appearance, may be eaten and transported in that way
English ivy, dispersed by birds, but the birds often get sick in the process
Thank You for Coming Today!
Time to Travel Home—Thank You