Does photosynthesis drive growth? Hendrik Poorter Plant Sciences, FZJ

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1 Does photosynthesis drive growth? Hendrik Poorter Plant Sciences, FZJ

2 Research center Jülich (Germany): Focusing on high-throughput phenotyping at a range of integration levels

3 Light CO 2 fixation Sugars Growth No growth without photosynthesis! drawing: Michael Hagelberg

4 What is true at the subcellular scale is not necessarily true at the ecological scale: Absorptance after De Castro (2) Wavelength (nm) Absorptance Wavelength (nm) Absorptance (rel. units) Chl B Chl A Wavelength (nm)

5 Spanning 5 integration levels: To what extent does an photosynthesis leads to a growth?

6 Both terms are ambiguous: photosynthesis: /area, /mass? one leaf, whole plant? growth light, saturating light, CO 2, both? middle of the day, after a rain event? how long into treatment, ontogeny? growth: vegetative biomass, yield? above-ground, below-ground, both? LER, AGR, RGR?

7 Capturing photosynthesis: 25 2 An (umol m -2 s -1 ) A C V CMAX. C C K ( 1O / K C O ) R d C i (µmol mol -1 ) A J. C J R d 4C 8 Von Caemmerer & Farquhar(1981) Planta

8 Capturing the C-budget: + PS A. SLA. LMF RGR = - LR. LMF - SR. SMF - RR. RMF / C p Poorter & Van der Werf (1998) Book chapter

9 A more simple equation: PSA. FCI RGR. SLA. LMF [ C] RGR ULR. SLA. LMF Poorter (22) Encyclopedia of Life Sciences

10 1. The case of differences between species or genotypes: Triticum & others Grain weight (mg ear -1 ) PS a (mol m -2 s -1 ) Evans & Dunstone (197) Aust. J. Plant Physiol.

11 1b. Differences between species: 15 PS A (mol m -2 s -1 ) RGR (mg g -1 day -1 ) Poorter et al. (199) Plant Physiol.

12 1c. Growth Response Coefficients summarise the relative change in growth parameters relative to RGR, and normally add up to 1.; SLA most important factor: PSA. FCI RGR. SLA. LMF [ C] GRC X dx X drgr RGR GRC 24 species PS A.5 FCI.29 [C] (-).1 SLA.53 LMF.28 GRC meta analysis Poorter & Van der Werf (1998) Book

13 2. The case of light intensity: 4 Chenopodium album provisional data RGR (mg g -1 day -1 ) DPI (mol m -2 day -1 ) Pons & Poorter, unpubl.

14 2b. The effect of light on RGR-components: (provisional data) Photosynthesis (µmol m -2 s -1 ) FCI (mol mol -1 ) SLA (m 2 kg -1 ) LMF (g g -1 ) DPI (mol m -2 day -1 ) Pons & Poorter, unpubl.

15 2c. Growth Response Coefficients for lightinduced variation, PSa most important positive factor, SLA most negative factor: PSA. FCI RGR. SLA. LMF [ C] GRC X dx X drgr RGR GRC 5 species PS A 2.3 GRC meta anal. FCI [C].9 SLA LMF Poorter & Van der Werf (1998) Book chapter

16 Effect of light on chemical composition: Low Light High Light Protein TNC Lignin Salix aquatica Light CO 2 fixation Sugar TNC production Growth Waring et al. (1985) Oecologia

17 a. The case of nutrients: RGR (mg g -1 day -1 ) Nutrient supply SLA (m 2 kg -1 ) Photosynthesis (µmol m -2 s -1 ) LMF (g g -1 ) FCI (mol mol -1 ) Holcus lanatus Poorter et al. (1995) Plant & Soil Nutrient supply

18 3b. GRC s for nutrients, most important decrease is in PSa: PSA. FCI RGR. SLA. LMF [ C] GRC X dx X drgr RGR GRC PS A.45 FCI.41 [C] -.2 SLA.8 LMF.3 Provisional data

19 3c. But: in every experiment considered Total Nonstructural Carbohydrates rather than proteins accumulate in the leaves at low N. So, is there a limitation by photosynthesis?: 4 low N high N TNC (mg g -1 ) Each line is the regression line through data from 1 species in 1 experiment; red = woody species Protein (mg g -1 ) Poorter & Villar (1997) Book chapter

20 3d. Negative effect of low nutrients on photosynthesis, but more on growth TNC accumulation: N-supply Light CO 2 fixation Sugar production Growth TNC

21 3e. How do we perceive a plant?

22 3f. Reduced demand from the sinks, or limited export out of the leaf has a negative feedback on photosynthesis: Phloem 25 Glycine max PS A (mol m -2 s -1 ) Xylem Control Depodded Girdled Setter et al. (198) Plant Physiol.

23 4. A short-term response curve of photosynthesis with respect to CO 2 : Brassica oleraceae 4 A N (µmol m -2 s -1 ) C i (µmol mol -1 ) Sage et al. (1989) Plant Physiol.

24 4b. A-c i curves of plants grown for longer time at low- and high CO 2 Brassica oleraceae 4 A N (µmol m -2 s -1 ) Grown at low CO 2 Grown at high CO C i (µmol mol -1 ) Sage et al. (1989) Plant Physiol.

25 4c. Another example of strong feedback: The higher the growth [CO 2 ], the lower Amax!?! 3 15 A MAX (µmol m -2 s -1 ) Rubisco activity (mol m -2 s -1 ) [CO 2 ] (µmol mol -1 ) Van Oosten et al. (1995) New Phytol.

26 4d. Decreased transcription of rbcs genes, most likely because of high [soluble sugars]: hexose 25 Hexokinase [Soluble Sugars] (g m -2 ) mrna rbcs hexose-6-p downstream regulation of signal transduction [CO2] (ppm) gene expression Van Oosten et al. (1995) New Phytol.

27 4e. Effect of elevated CO 2 on growth components, a meta-analysis: photosynthesis increase, SLA decrease, RGR generally 2 stimulated the first week after Poorter & Navas (23) GRC PS A 2.28 Value at high CO 2 / value at low CO % +22% +2% +1% -13% % FCI.23 [C].11 SLA LMF..5 RGR PS A FCI [C] SLA LMF after Poorter & Navas (23) New Phytol.

28 4f. High CO 2 affects chemical composition: lower [protein] and [minerals], much higher TNC Poorter et al. (1997) PCE Sol. Phen. Org. Ac. Lipids Lignin TSC Protein % Change Minerals TNC

29 4g. Effect of elevated CO 2 : photosynthesis increases more than growth TNC accumulation [CO 2 ] Light CO 2 fixation Sugar production Growth TNC

30 So, are all sugars equally valuable for a plant?

31 Plants have quite similar GRC s for light and CO 2, but photosynthetic capacity response to high light is different from high CO2: Light: CO 2 : GRC GRC A Act (µmol m -2 s -1 ) PS A 2.3 FCI.36 [C].9 SLA -.85 LMF. A max (µmol m -2 s -1 ) PS 3 A 2.28 FCI.23 [C].11 2 SLA LMF DPI (mol m -2 day -1 ) [CO 2 ] (µmol mol -1 )

32 5b. Increasing light for 1 day for a tomato leaf increases respiration the night after: 2 2. PS A (mol m -2 s -1 ) I = 1 I = Respiration (mol m -2 s -1 ) Time (h) Ludwig et al. (1975) Book chapter.

33 5c. LR A is positively correlated with PS A, but. 6 Lycopersicon esculentum 2 Daily Respiration (mmol m -2 day -1 ) 4 2 HL LL varying Irradiance 2 4 varying Irradiance & CO Daily PS A (mmol m -2 day -1 ) Ludwig et al. (1975) Book chapter.

34 5d. Meta-Phenomics: Meta-Phenomics: summarising, by means of a meta-analysis of a wide array of literature data, the phenome of a plant, Aim: constructing dose-response curves for 12 environmental variables, 4 traits, 2 species groups So far: >8 records (each record consists of all observations of 1 species in 1 experiment grown under 1 condition), for > 8 species in a total of >8 experiments. More info: and J. Exp. Bot. 61:

35 5e. Meta-Phenomics: The environmental factors, traits, and characteristics of the species involved: Stress box 1. Light quantity 2. Light quality 3. UV-B 4. CO 2 5. O 3 6. Nutrient supply 7. Drought stress 8. Waterlogging 9. Submergence 1.Temperature 11. Salinity 12. Soil compaction Trait box - RGR, ULR, SLA, LMF, SMF, RMF - TPM, Yield, HI -A Act, A Max, Respiration, J/V MAX - Transpiration, g s, c i /c a, ð 13 C - height, leaf size - leaf thickness, density, DMC - [C], [N], [P] - Starch, Fructan, Sol. Sugars - Minerals, Ash, Nitrate, Org. Acids - Lignin, (Hemi-)Cellulose - Protein, Org. N, Chlorophyll - Sol. Phenolics, Tannin, Anthocya. - Rubisco, other enzymes - mrna Species box - woody / herbaceous - deciduous / evergreen - shrub / tree - annual / perennial -N 2 fixing yes / no -C 3 / C 4 / CAM - Phylogeny - Sun / Shade - Dry / Wet -Cold/ Warm - Non-saline / Saline

36 SLA (scaled) f. An example: SLA responses to light, gases, and nutrients, including normal ranges a b n = c DPI (mol m -2 day -1 ) R / FR UV-B (kj m -2 day -1 ) d e f SLA (scaled) CO 2 (µmol mol -1 ) O 3 (nmol mol -1 ) Nutrient availability (rel. scale) Poorter et al. (21) J. Exp. Bot.

37 5g. Plasticity in SLA and LMF, based on fitted curves: Range PI SLA Irradiance 1 5 mol m -2 day CO µmol mol Compaction g cm Salinity 1 % seawater 1.16 Waterlogging R : FR mol mol UV-B 1 2 kj m -2 day O nmol mol Water.5 1 rel. units 1.27 Nutrients.5 1 rel. units 1.29 Submergence Temperature 5 35 o C 2.7

38 5h. Is growth equally sensitive to ìncreased photosythesis due to light and CO 2? DPI (mol m -2 day -1 ) Mass relative to DPI = 1 or [CO2] = DPI CO 2 DPI: % CO 2 : % CO 2 (µmol mol -1 ) Poorter, provisional data

39 5i. Why might the effect of elevated CO 2 be different from high light? [CO 2 ] Light CO 2 fixation Sugar production Growth TNC Phytochromes Phototropins Cryptochromes

40 Smallest growth reduction when TNC is accumulating? 2.5 O 3 2. BER Irradiance 1.5 Water UV-B Nutrients 1. Temp growth reduction at ambient CO 2 Poorter & Perez-Soba (22) EGEC.

41 Conclusions: 1. No growth without C-fixation 2. But PS A is not the only driver (SLA!) 3. Most likely growth needs C and some (light) signal 4. Strongest interaction of high CO 2 with low T and low nutrients.

42 More info: Meta-Phenomics: Poorter H, Niinemets U, Walter A, Fiorani F, Schurr U (21) A method to construct dose-response curves for a wide range of environmental factors and plant traits by means of a meta-analysis of phenotypic data. J. Exp. Bot. 61: Methods GRC: - Renton M, Poorter H (211). Using log-log scaling slope analysis for determining the contributions to variability in biological variables such as leaf mass per area (LMA): why it works, when it works and how it can be extended. New Phytol. 19: 5-8. Growth analysis: - Poorter H & Van der Werf A (1998). Is inherent variation in RGR determined by LAR at low irradiance and by NAR at high irradiance? A review of herbaceous species. In: Inherent Variation in Plant Growth. Physiological Mechanisms and Ecological Consequences. Lambers H, Poorter H & Van Vuuren MMI (eds). Backhuys Publishers, Leiden, The Netherlands, pp