Phosphorus nutrition of phosphorussensitive Australian native plants:
threats to plant communities in a
global biodiversity hotspot
Hans Lambers
School of Plant Biology
University of Western Australia
Soils and plant species in Western
Australia
• Soils in south-western
Australia are the most
nutrient-impoverished in
the world
• Plant species
richness is
amongst the
highest in the world
‘Biodiversity Hotspots’
is more than ‘lots of
species’
It is also about
‘patterns and
processes’
And threats!
Lambers, H., Ahmedi, I., Berkowitz, O., Dunne,
C., Finnegan, P.M., Hardy, G.E.St.J., Jost, R.,
Laliberté, R., Pearse, S.J. & and Teste, F.P.
2013. Phosphorus nutrition of P-sensitive
Australian native plants: Threats to a global
biodiversity hotspot. Conserv. Physiol. 1: (1)
doi: 10.1093/conphys/cot010.
Plant species diversity increases with
decreasing soil fertility
Available P consistently
approx. 5% of total P
Lambers, H., Shane, M.W., Laliberté, E., Swarts, N.D., Teste, F. & Zemunik, G. 2014. Plant mineral
nutrition. In: Plant Life on the Sandplains in Southwest Australia, a Global Biodiversity Hotspot.
Lambers, H. (ed.). University of Western Australia Publishing, Crawley, pp. 101-127.
The cover of Proteaceae and non-Proteaceae
species and soil P status along the Jurien Bay
chronosequence
Values do not add up to
100%, because of the
presence of bare soil
Lambers, H., Shane, M.W., Laliberté, E., Swarts, N.D., Teste, F. & Zemunik, G. 2014. Plant mineral
nutrition. In: Plant Life on the Sandplains in Southwest Australia, a Global Biodiversity Hotspot.
Lambers, H. (ed.). University of Western Australia Publishing, Crawley, pp. 101-127.
In the rest of the world, plants on nutrient-poor
soils plants tend to live symbiotically with
mycorrhizal fungi
• The mycorrhizal fungi acquire
phosphorus for the plants, in exchange for
carbon
• Mycorrhizas also occur in south-western
Australia, but this symbiosis is relatively
less common
What special features allow the
non-mycorrhizal plants in Western
Australia to acquire nutrients from
very poor soils?
Many have cluster roots, as illustrated here
Developmental aspects of cluster roots
0
1-2
4-5
7-8
12-13
20-21
Shane, M.W., Cramer, M.D., Funayama-Noguchi, S., Cawthray, G.R., Millar, A.H., Day, D.A. &
Lambers, H. 2004. Plant Physiol. 135: 549-560.
Respiration and carboxylate exudation in
cluster roots of Hakea prostrata
10
8
-1
-1
C use (nmol g FW s )
Respiration
6
Carboxylate
exudation
4
2
0
0
10
20
Time (days)
30
Shane et al. 2004.
Plant Physiol. 135:
549-560.
Some
Cyperaceae have
‘dauciform’ roots
Photo:
Dr Michael W. Shane
Other specialised roots
include ‘capillaroid
roots’ in some
Restionaceae
Photos: Dr Michael Shane
Sand-binding roots of Lyginia barbata (Restionaceae)
Shane, M.W., McCully, M.E., Canny, M.J., Pate, J.S. & Lambers, H. 2011. Development and
persistence of sandsheaths of Lyginia barbata (Restionaceae): Relation to root structural
development and longevity. Ann. Bot. 108: 1307-1322.
Lambers, H., Hayes, P.E., Laliberté, E., Oliveira, R.S. & Turner, B.L. 2014. Leaf manganese
accumulation and phosphorus-acquisition efficiency. Trends Plant Sci., submitted.
160
Young leaf
140
Old leaf
Mn concentration in mature leaves (µg g-1)
[Mn] mature leaves ( µg Fe g -1 leaf fresh mass
Suppression of cluster roots at a
high leaf P status has major effects
on Mn uptake from native soil
R2 = 0.8632
120
100
Manganese
80
60
40
20
R2 = 0.0105
0
0
20
40
60
80
Percentage cluster roots
Shane, M.W. & Lambers, H. 2005. Physiol.
Plant. 124: 441-450.
Photo Michael W. Shane
In Western Australia, we work
on The Jurien Bay dune
sequence
Spearwood
(120–500 ka)
Quindalup
(0–7 ka)
Jurien
Bay
Bassendean
(>1,800 ka)
Perth
Indian
Ocean
0
Stage 1
Mobile dunes
0 ka
7
12
0
200
Stage 2
Quindalup
1 ka
?
?
500
Stage 3
Quindalup
7 ka
Estimated
age (ka)
180
0
Stage 4
Spearwood
120 ka
Stage 5
Bassendean
1800 ka
Laliberté, E. et al. J. Ecol. 100: 631-642.
Mn accumulation
- Mn accumulation is highest in NM species
- Interestingly, leaf [Mn] increased with soil age for all strategies
Hayes, P., Turner, B.L., Lambers, H. & Laliberté, E. 2014. Leaf nutrient concentration and
resorption along a 2-million year dune chronosequence in south-western Australia. J. Ecol. 102:
396-410.
Acquisition
strategy
Nutrient and mycorrhizal status as dependent
on soil age
Primary
mycorrhizal
colonisers
Arbuscular
mycorrhizal
Ectomycorrhizal
Ericoid
mycorrhizal
Quantity of major
nutrients
Ptotal
Ntotal
Mycorrhizal
with simple
clusters
Nonmycorrhizal
with simple
Nonclusters
mycorrhizal
with
compound
clusters
Poorly
developed,
very young
Lambers, H. et al. 2008. Trends Ecol. Evol. 23: 95-103.
Ancient, highly
weathered
Soil age
Acquisition
strategy
Primary
mycorrhizal
colonisers
Arbuscular
mycorrhizal
Ectomycorrhizal
Ericoid
mycorrhizal
Quantity of major
nutrients
Ptotal
Ntotal
Mycorrhizal
with simple
clusters
Nonmycorrhizal
with simple
Nonclusters
mycorrhizal
with
compound
clusters
Poorly
developed,
very young
Lambers, H. et al. 2008. Trends Ecol. Evol. 23: 95-103.
Ancient, highly
weathered
Soil age
In Western Australia, we work
on the Jurien Bay dune
sequence
Spearwood
(120–500 ka)
Quindalup
(0–7 ka)
Jurien
Bay
Bassendean
(>1,800 ka)
Perth
Indian
Ocean
0
Stage 1
Mobile dunes
0 ka
7
120
200
Stage 2
Quindalup
1 ka
?
?
500
Stage 3
Quindalup
7 ka
Estimated
age (ka)
1800
Stage 4
Spearwood
120 ka
Stage 5
Bassendean
1800 ka
Laliberté, E., Turner, B.L., Costes, T., Pearse, S.J., Wyrwoll, K.-H., Zemunik, G. & Lambers, H.
2012. J. Ecol. 100: 631-642.
Along that dune chronosequence, we find a
gradually declining phosphorus (P) availability,
and declining leaf P concentrations
Hayes, P., Turner, B.L., Lambers, H., Laliberté, E.. 2014. Foliar nutrient concentration and
resorption along a 2-million year dune chronosequence. J. Ecol. 100: 631-642.
Where might P-efficient Proteaceae
economise?
• Inorganic P: We
are on to
something!
• Lipid P: Definitely!
• Ester P: No
(glucose 6phosphate)
• Nucleic acids:
Definitely!
Lowering substrate concentrations would not
work at lower enzyme levels
Extreme sensitivity of many
Proteaceae to phosphate supply:
phosphorus toxicity
Leaf crystal
formation during
the development
of “phosphorustoxicity”
symptoms in
Hakea prostrata
Plants were grown at
phosphorus supply rates of
100 and 200 mmol P day-1
Shane, M.W., McCully, M.E. &
Lambers, H. 2004. J. Exp. Bot. 55:
1033-1044.
Threats to south-western Australia’s
biodiversity
• Increased soil phosphorus levels
–
–
–
–
–
–
Run-off from urban settlements
Spread from agricultural land
Dust from roads
Increased fire frequency
Fire retardants
Spraying with phosphite
• Phytophthora cinnamomi
Mean leaf phosphorus concentration of native
and introduced species in Bold Park, Perth
• GC: good condition
• PCe: poor condition
with Ehrharta calycina
• PCp: poor condition
with Pelargonium
capitatum
Fisher, J.L., Veneklaas, E.J., Lambers,
H. & Loneragan, W.A. 2006. Enhanced
soil and leaf nutrient status of a
Western Australian Banksia woodland
community invaded by Ehrharta
calycina and Pelargonium capitatum.
Plant Soil 284: 253-264.
Lambers, H., Ahmedi, I.,
Berkowitz, O., Dunne,
C., Finnegan, P.M.,
Hardy, G.E.St.J., Jost,
R., Laliberté, R., Pearse,
S.J. & and Teste, F.P.
2013. Conservation
Physiology 1: (1) doi:
10.1093/conphys/cot010.
Phosphite application rates
In Western Australia:
-spraying deposits up to 10-50 kg phosphite ha-1
(DPaW recommended application rates)
-the recommended broad-acre phosphate
fertilisation rate for the region is 10-40 kg ha-1 yr-1
(Bowden et al., 1993)
-phosphite is microbially oxidised to phosphate
(White and Metcalf, 2007)
Lambers, H., Ahmedi, I., Berkowitz, O., Dunne,
C., Finnegan, P.M., Hardy, G.E.St.J., Jost, R.,
Laliberté, R., Pearse, S.J. & and Teste, F.P.
2013. Conservation Physiology 1: (1) doi:
10.1093/conphys/cot010.
Effect of phosphite (Phi) spraying on leaf
phosphorus (P) concentrations
Long-term implications for ecosystem function?
A
D
B
C
Ahmedi I. 2012. Long-term phosphite application is detrimental to a low phosphorus Banksia
woodland community in the south-western Australia. Murdoch University.
Conclusions
• As long as we have no alternative for phosphite
to combat Phytophthora we must use it with the
greatest possible care
• We must also continue our research on how
phosphite actually works to immunise plants
• Based on our understanding how phosphite
works, we should test harmless alternative
chemicals
• We need new tools for Fighting Dieback!
• If we continue business as usual, we will lose
Proteaceae species due to phosphate fertilisation
• For everything you ever
wanted to know about this
biodiversity hotspot
• Available online:
http://uwap.uwa.edu.au/collecti
ons/hans-lambers
• For as little as $69,99; >350
pages of text and
illustrations in colour
• To enhance awareness of
this treasure
Acknowledgements
• Oliver Berkowitz, Mark Brundrett, Greg Cawthray, Peta
Clode, David Day, Matt Denton, Patrick Finnegan,
Giles Hardy, Steve Hopper, Ricarda Jost, John Kuo,
Etienne Laliberté, Harvey Millar, Sachiko Noguchi,
Jiayin Pang, Stuart Pearse, Megan Ryan, Michael
Shane, François Teste & Erik Veneklaas
• Idriss Ahmedi, Patrick Hayes, Lalith Suriyagoda &
Graham Zemunik
• Michael Cramer, Patrick Giavalisco, Hirofumi Ishihara,
Margaret McCully, Rafael Oliveira, John Raven, WolfRüdiger Scheible, Armin Schlereth, Mark Stitt, Ronan
Sulpice & Ben Turner
• Australian Research Council
[email protected]