Similar a Nutrient supply, below ground processes and elevated CO2 change the nutritional quality of cyanogenic clover Trifolium repens - Ros Gleadow (20)
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Nutrient supply, below ground processes and elevated CO2 change the nutritional quality of cyanogenic clover Trifolium repens - Ros Gleadow
1. CCRSPI Feb 2011
Plant theme
Nutrient supply, below ground
processes and elevated CO2 change
the nutritional quality of cyanogenic
clover Trifolium repens
Ros Gleadow
Siobhan Isherwood, Tim Cavagnaro, Saman
Seneweera, Rebecca Miller,
2. 2/20
Factors affecting food security
Production
•Yield
•Area
•Agronomy
Change in precipitation
Availability Nutrition
•Distribution •Safety
•Cost •Value
•Wealth
Change in temperature
IPCC WG1
3. 3/20
How will climate change affect nutritional value?
1. Yield
2. Nutritional value
3. Availability
4. 4/20
Why clover? 1. Interesting roots
VAM
Legume – N fixing Mycorrhizae – P uptake
Access to nutrients may facilitate positive response to CO2
6. 6/20
Why clover?
3. Model for other important cyanogenic crops
Forage sorghum Cassava/Manioc
Photo: Peter Stuart, Pac Seeds, Qld Photo: Julie Cliff, UEM, Moz
5-10% of all plants cyanogenic Gleadow, Conn et al, 2008 Phytochem, 69: 1870
60% crop plants (some parts) Jones 1998 Phytochem 47: 155; Miller et al. 2006 Ann Bot 97: 1017.
7. 7/20
IF Less protein required for photosynthesis at high CO2
THEN resources may be diverted to defence
120
Is “excess” N used to
Rubisco (% of control)
100
synthesise cyanide?
80
60
Rubisco
40
Other
Cyanide
20
0
350 700
CO2 ppm
Gleadow and Woodrow 1999, Plants in Action –
Leaf protein, Rice available www.plantsci.org.au/publications/
8. 8/20
More Nitrogen allocated to cyanide at high-CO2
Sugar gums
Natimuk Road, Horsham
20 ~400 ppm CO2
~ 800 ppm CO2
CN-N per N %
E
A
10
E
A
0
Low Nitrogen High Nitrogen
Gleadow et al. 1998, Plant Cell Environ, 12:21
9. 9/20
CO2 effects on cyanogenesis in clover
Siobhan Isherwood
• FACE
• Pot trials (ANU)
CassavaFACE
• Nutrient trials –N, P, microbes
11. 11/20
Cyanide in clover trending higher at 550 ppm
1000
Cyanide mg/g dry wt
800
600
400
200
380 ppm 550 ppm
• Is leaf protein lower?
• Nodulation rates: 6% higher significant??
• Mycorrhizae colonisation: 5% higher ns?
12. 12/20
ANU study: More cyanide relative protein at
elevated CO2…ONLY with +P
370 ppm
12 700 ppm
10
Cyanide : protein
8
6
4
2
0
-N-P -N+P +N+P
Gleadow et al. 2009 J Chem. Ecol 35, 476
Edwards & Evans 2005 Global Change Biol.11, 1968
13. 13/20
Nutrient cyanogenesis trials
1.2
1.0
CN-N/N% 0.8
0.6
0.4
0.2
0.0
HP:HN HP:LN LP:HN LP:LN
Nutrient Treatment
• N15/N14 isotopes
– P improved N fixation
High P: 0.125g/kg
– Fixed N used to make HCN Low P: 0.025g/kg
High N: 8mM
Low N: 2mM
Isherwood, 2010 HONS THESIS
14. 14/20
Conclusion: nutritional value IS affected by eCO2
• Leaf composition
– Less leaf protein
– Increased cyanide, relative to protein
– Increase tannins, phenolics
• Soil environment is crucial
• Microbes important in nutrient acquisition
…How will elevated CO2 affect these symbioses???
VIEWPOINT:
Cavagnaro, Gleadow, Miller (2011) Functional Plant Biology 38, 87–96
15. 15/20
Monash Cyanogenesis Group
Collaborators Cecilia Blomstedt
Tim Cavagnaro
University of Copenhagen
Rebecca Miller
Birger Møller
Kirsten Jørgensen, Morten Møldrup Alan Neale
John Hamill
RSB (ANU) Anna Burns
John Evans, Stephanie McCaffrey Natalie O’Donnell
Howard Bradbury, Bill Foley Cara Griffiths
Sam Fromhold
Pacific Seeds
Melissa Bain
Peter Stuart, Wayne Chesser
Siobhan Isherwood
Mozambique/South Africa Kiara O’Gorman
Julie Cliff UEM
Anabela Zacarias, IIAM FUNDING
Simon Adams (Monash) ARC Linkage
AusAID
University of Melbourne
Finkel Foundation
Saman Sereweena (AGFACE)
Ian Woodrow, Jennifer Fox Monash University
Casstech
DPI: AGFACE Pacific Seeds
Notas del editor
Yield Nutritional value Protein contentPlant defence: cyanogenic glycosideAvailability
Below ground, : soil microbial associations MODEL FOR OTHER CYANOGENIC PLANTSsubterranean clover is the most important annual pasture legume sown in southern Australia. It originated in the Mediterranean region, parts of western Europe, southern England and Ireland.Subterranean clover (sub clover) was accidentally brought to Australia in hay, straw and pasture seed, probably as early as the 1830s, and was spread along transport routes, in stock camps and on town commons throughout southern Australia.The potential of sub clover to provide nutritious feed for livestock and improve soil fertility
Ever since I did this work I’ve been wondering what the impact would be on crop plants.
To investigate relationships between cyanogenesis in T. repens and nutrient supplyIs allocation of N to chemical defence affected by relative availability N and P?How this that affected by microbial associationsIs there a trade off between defence & growth?How is cyanogen concentration likely to change under future climate changes & eCO2? AgFACE elevated CO2 study, Horsham
Does this translate into higher HCN levels?
27 vs. 36% (+/- 3) Mycorrhizae colonisation: 54 vs. 59 % (+/- 5) ns?
Haven’t yet measured total N and other nutrients – expect CN per protein will be higher as in this study given sufficient nutrientsConsistent with this pot study – higher CN: protein at eCO2. This study also shows that importance of nutrient supply. These plants has rhizobium but were not inoculated mycrorrhizae.Effect only detected when P was added/sufficient.So here N – no difference with soil N because able to fix N, take up N to compensate for low soil N.
IN order to understand importance of N and phosphorus and whether the source of N and P (i.e. whether from soil microbes) impacts on HCN content,Q…..N from rhizobium compensates for less soil N and plants can continue to synthesis cyanogenic glycosidesAs before under low N , rhizobium compensated i.e. low N plants actually had higher plant NBUT low P plants had lower PO4- mycorrhizae were unable to compensate.N treatment had no effect on HCN, but P treatment did.
Available nitrogen is reallocated to cyanide in plants grown at elevated CO2ANDNitrogen (and Cyanogenesis) is dependent on soil microbesTHEN