Mariana Cruz Campos. School of Plant Biology Faculty of Natural and Agricultural Sciences

Transcription

1 Mariana Cruz Campos School of Plant Biology Faculty of Natural and Agricultural Sciences Mariana holds a Bachelor degree with Honours in Biological Sciences from the University of São Paulo, Brazil, where she comes from. She then completed a Master s degree on the relationship between forest structure, species composition and the soil properties in the Atlantic Rainforest, and was awarded a scholarship to undertake a PhD on Plant Physiological Ecology at UWA. Mariana now works on Phosphorus nutrition of Australian native species. She expects to submit her thesis in September this year.

2 The UWA Institute of Agriculture Living in poor soils: How plants cope with little phosphorus Mariana Cruz Campos Hans Lambers, Stuart Pearse and Rafael Oliveira

3 Acknowledgements Supervision of: Hans Lambers Stuart Pearse Rafael Oliveira Assistance of: Erik Veneklaas Mark Brundrett Rob Creasy Bill Piasini Infra-structure and grants: UWA and School of Plant Biology ANZ Holsworth Wildlife Foundation Mary Janet of Yanchep Memorial Brazilian Council for Research

4 Living in poor soils

5 Why study phosphorus?

6 Why study phosphorus?

7 Why study phosphorus? Total P Quantity of nutrients Total N Soil age Adapted from Lambers et al Trends in Ecology and Evolution 23 (2):

8 The case of Australia Total plant-available phosphorus (organic plus labile)

9 Cost of fertilisers

10 Environmental cost Dissolved concentrations of phosphorus in soil water

11 What are the alternatives? Low phosphorus availability in soil Change P level Fertilise Change plants Choose species adapted to low P Plant breeding Genetic modification Knowledge on native species is required

12 Native species Phosphorus-wise strategies: Increased uptake Cluster roots, exudates, mycorrhizas, etc. Remobilisation Efficiency and proficiency Nutrient use efficiency Longevity of leaves

13 Aims of my research 1. Correlate P-uptake to P remobilisation in leaves of four Perth native species 2. Compare different strategies within one species of legume 3. Investigate the proportion of root specialisations in three phosphorus impoverished locations worldwide

14 Uptake and remobilisation Regulation of uptake

15 Uptake and remobilisation Regulation of uptake Regulation Continued uptake: Possible toxicity or death

16 Experimental species

17 Experimental layout 4 species 5 phosphorus treatments 6 replicates per treatment

18 Experimental layout Grown in root cooling tanks Daily solution changes 10 weeks

19 Harvest Sampling of nutrient solution over time Determination of [P] Calculation of uptake Measurements of fresh and dry weight Measurements of leaf P concentration

20 Remobilisation Efficiency: percentage remobilised Proficiency: how little is left

21 Plant growth Root fresh weight (g) Acacia xanthina Acacia truncata Banksia attenuata Banksia menziesii Phosphorus treatment (µm)

22 Plant growth Shoot fresh weight (g) Acacia xanthina Acacia truncata Banksia attenuata Banksia menziesii Phosphorus treatment (µm)

23 Phosphorus uptake 0.25 Net P uptake (nmol P/g root/s) Acacia truncata Acacia xanthina Banksia attenuata Banksia menziesii Treatment (µm P)

24 Leaf analyses Leaf [P] (mg P/g dry leaf) Acacia xanthina Acacia truncata Banksia menziesii Banksia attenuata Treatment (µm P)

25 Remobilisation 0.8 Leaf [P] (mg P.g -1 leaf DW) Banksia attenuata (69%) Banksia menziesii (73%) Acacia xanthina (36%) Acacia truncata (41%)

26 Remobilisation Leaf [P] (mg P/g dry leaf) Mature Senesced Banksia attenuata Banksia menziesii Acacia xanthina Acacia truncata

27 Conclusions There is an inverse relationship between uptake regulation and remobilisation of phosphorus Results are more similar in same genus Natives can be a model for future agricultural research

28 Implications Images from: personal archive, and

29 Key messages Natives are very good in getting and keeping phosphorus Not all natives behave in the same manner: diversity By studying natives, we can: Target specific traits in crop species Use natives in rotations or mixed in crops Consider genetically modification