Why our native orchids are so difficult to grow...Orchids take mycorrhizae to an extreme Orchids...
46
Why our native orchids are so difficult to grow Melissa McCormick Smithsonian Environmental Research Center Edgewater, Maryland
Transcript of Why our native orchids are so difficult to grow...Orchids take mycorrhizae to an extreme Orchids...
Why our native orchids are so
difficult to grow
Melissa McCormick
Smithsonian Environmental Research Center
Edgewater, Maryland
• ~ 30,000 species (10% of all
flowering plants)
• Occur on all continents
except Antarctica
• Almost 50 species in PA
• Widely threatened and
endangered
• Complex life histories
• ‘Canary in the coal mine’ of
the plant world
Orchids
Source: USDA online database
Approximately 250 species of native orchids
57% listed as threatened or endangered at the state or federal level
Orchids in North America
was fascinated by orchids’
elaborate pollination and by
why plants that produce so
many seeds are so often rare.
calculated that if all seeds
grew into plants then the great
grandchildren of a single
orchid would “cover the earth
in one continuous green
carpet”.
Charles Darwin
Accordingly, our native orchids are notoriously
difficult to grow in the garden or greenhouse
©Prem Subrahmanyam
www.planteck.com
http://www.orchid-care-tips.com
http://www.vivaiozanelli.com
A few of our native orchids
are available to
gardeners...
but most are very difficult
to keep alive for long.
https://www.flickr.com/photos/ncorchid/
Some of our most attractive native orchids aren’t
available (unless they’re wild-collected),
often because
even
professional
growers have
trouble growing
them
How are orchids different from other plants?
What does orchid research tell us?
What will it take to apply this research to native orchids in North America and find out what it takes to grow them?
Where does the North AmericanOrchid Conservation Center fit in?
What is it about orchids?
Orchid reproduction depends on
other species
1cm
1mm
Fungi
Pollinators
Fungi
What do fungi do for plants?
A mycorrhiza is a symbiotic association between a plant
root and a fungus
Read 1997
Most plants in most ecosystems
All plant families
Essential for access to nutrients and
water
Protect against pathogens
OrchidsMost plants
0.05mm
Ectomycorrhizae
Arbuscular mycorrhizae
Wikipedia
genetik.bio.lmu.de Kuga et al. 2015Beyrle et al. 1995
Read 1997
www.hardyorchidsociety.org.uk
Tulasnella violacea
Tulasnella violea
Orchid mycorrhizal fungi:
Images from J. Breitenbach “Fungi
of Switzerland” 1986
Ecologically diverse
Ectomycorrhizae,
Mycoparasites,
Pathogens,
Decomposers
Poorly-studied
Widespread and common
Morphologically indistinguishable
Orchids take mycorrhizae to an
extreme
Orchids cheat their mycorrhizal fungi.
Orchids eat their fungi.
Orchids are entirely dependent on fungi for all their
nutrition at least early in life.
This early life stage may last only a few months or
many years.
2.5 mm
Ungerminated
Seeds
protocorms
1 mm1 mm
1cm
Seeds have no nutrients.
Germination requires specific fungi.
Fungi provide all nutrients, including carbon.
Fungi produce more vigorous seedlings
Orchid seeds and fungi:
Pelotons (fungal coils) in an orchid
root (Beyrle et al. 1995).
Adult orchids and fungi:
Adult Goodyera showing below-ground parts.
Fungi form pelotons in root cells.
Most orchids continue to get nutrients from fungi as adults.
Fungi help orchids tolerate stress.
(Zelmer 1994)
Canopy Thinning Experiment – Increase light
Transmitted Light (Mols / m2 / d)
4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0
Change in #
of P
lants
2012-2
014
-15
-10
-5
0
5
10
15
20
Populations with no thinning
Populations with thinning
In populations where we thinned the canopy, orchids got bigger
Adult dependence on fungi
Exposed plants of two orchid species to drought or
shade for 12 weeks.
Drought: Direct
effects on both
plant and fungus
Shade: Direct
effects on plant but
not fungus
We know fungi are important for orchids.
The fungus appears to get little out of this
relationship.
Most terrestrial orchids need specific fungi.
So, we set out to find out what we could do to
improve the fungal conditions for orchids.
How do we use this to conserve and
grow orchids?
Learning from nature
What fungi do different orchids need?
Where are those fungi?
When do the fungi support orchids?
What can we do to make the fungi grow and support orchid restoration and help grow orchids in our gardens?
Goodyera pubescens
rattlesnake plantainLiparis liliifolia
mauve twayblade
Tipularia discolor
cranefly orchid
A test with three orchids:
MD101GA243Tulasnella bifronsH
MD109MD141MD144pMD145pMD148pMD150pMD154pMD179NC245MI230NC239NC241NC244NC247NC248NC249
MD169MD186MD213-2MD219GA253Tulasnella calosporaC
Tulasnella deliquescensC
MD120MD196MD197MD191MD192MD140MD166pMI193IA233VA234IA238VA258
MD128MD170MD181MD175
MD188MD213-1
MD184MD183MD218
GA254Ceratobasidium obscurumG
Ceratobasidium cornigerumC
Ceratorhiza goodyerae-repentisC
Sistotrema brinkmaniCMD121pMD138pMD207Tomentella puniceaG
NC259Suillus cavipesG
Chroogomphus vinicolorG
Scutellospora castaneaG
Brauniella albidipesG
Gomphidius glutinosusG
Serpula himantioidesG
10 changes
*
*
*
*
*
*
*
*
**
*
*
**
**
**
*
McCormick et al. 2004
Different orchids need different fungi
Where are these fungi and when do
they support orchids?
There are LOTS of fungi in the soil!
Up to 150 species in 0.5g of soil.
Extract DNA from soil
2 samples 15cm apart may share only 25% of their species.
We use specific probes to look only at the DNA from the fungi we are interested in.
Fungal
DNA
Soil core
When do fungi support orchids?
Seed packets tell us when conditions are right for orchids
Host fungus distribution in 3 arrays of seed packets in Goodyera patches
West/East (cm)
When do fungi support orchids?
When they are abundant!
-100 -50 0 50 100
-100
-50
0
50
100
-100 -50 0 50 100
Nort
h/S
outh
(cm
)
-100 -50 0 50 100
Patches with multiple orchids One isolated orchid
McCormick et al. submitted
wood
leavescontrol
6 forest sites: 3 old (150+ years), 3 young (50-70 years)
36 subplots in each: 1/3 got chipped wood, 1/3 crushed
leaves, 1/3 control
What makes these fungi abundant?
Goodyera pubescensLiparis liliifoliaTipularia discolor
Seed packets of 3 species.
With and without appropriate fungi
for germination added.
What can we do to make fungi more abundant?
Tipularia discolor
n=16
P=0.003
0%10%20%30%40%50%60%70%80%90%
100%
Decomposing
Wood
Soil With
No Wood
% o
f sam
ple
s w
ith
pro
toco
rm f
un
gi
Tipularia only germinated in
old decomposing wood.
Liparis liliifolia
Every Liparis protocorm was from
a plot where fungi were added.
Goodyera pubescens
Rattlesnake plantain
Wood Leaves Control
Pro
tocorm
s
0
20
40
60
80
100
Amendment treatment
Did amendments affect host fungi and protocorm development?
P<0.001
Leaves
Tula
snella
ab
un
da
nce
(flu
ore
scent
inte
nsity+
SE
)
0
1000
2000
3000
4000
5000
6000
7000
ControlWood
P=0.002
McCormick et al. 2012
Adding wood and leaves increased host fungus abundance and germination for Goodyera.
For Liparis, fungi were rare but could grow in lots of places.
Tipularia needed decomposing wood.
All three were limited by the abundance of the fungi they needed, but the fungi were all limited by different things.
Orchids and host fungi:
How do we use this to grow our native orchids?
Orchids persist where fungi are abundant and diverse enough to tolerate stress.
So, we need to find out what it takes to make the host fungi happy.
How do we make gardens good for orchid fungi?
It depends on the orchid and their fungi.
Many orchid fungi need decomposing wood, some need old forests, some need young forests, some need particular types of trees.
What does this mean for growing native orchids from seed and in the garden?
Make the garden resemble the natural environment
Make mature orchids less dependent on their fungi
Choose orchids that are less picky about fungi once mature
Don’t fertilize. Use untreated hardwood or leaves as mulch.
Find out what conditions the fungi need
Cypripedium parviflorumSpiranthes cernua
Hexalectris
grandiflora
Goodyera
pubescens
Platanthera
praeclara
Photos courtesy of Hal Horwitz
Cypripedium parviflorumSpiranthes cernua
Hexalectris
grandiflora
Goodyera
pubescens
Platanthera
praeclara
Photos courtesy of Hal Horwitz
Our mission:
Conserve our native orchid heritage
EDUCATION
• Promote collaborative research to raise botanical literacy
• Create internships, fellowships, web sites, exhibits
• Develop dynamic and interactive web presence
• Develop educational tools
CONSERVATION
• Protect habitat
• Establish regional and national seed and fungal banks representing the range of species genetic diversity
PROPAGATION
• Develop protocols for propagating native orchids
• Restore native populations
• Establish sustainable populations in private and public gardens with an initial focus on botanic gardens
our approach is collaborative
SmithsonianU.S. Botanic Garden
APHIS-USDA Kew Gardens Longwood Gardens
Michigan State University Orchid Conservation Coalition Old Dominion University
Pollinator Partnership Seeds for Success University of Florida
UC, Berkley UC, Santa Cruz US Forest Service
Virginia Native Plant Society Wabash College Wintergreen Nature Foundation
Minnesota Landscape Arboretum NatureServe
NAOCC’s first exhibit at the annualSmithsonian-US Botanic Garden show
Go Orchids websitegoorchids.northamericanorchidcenter.org
Regional groups are forming to collect seeds and fungi as well as begin
propagation efforts
Cypripedium parviflorumSpiranthes cernua
Hexalectris
grandiflora
Goodyera
pubescens
Platanthera
praeclara
Photos courtesy of Hal Horwitz
Join and share in our vision and mission to:
Conserve our native orchid heritage
Cypripedium parviflorumSpiranthes cernua
Hexalectris
grandiflora
Goodyera
pubescens
Platanthera
praeclara
Photos courtesy of Hal Horwitz
