Celi, Luisella Roberta

Martin, Maria

Martinengo, Sara

SAID PULLICINO, Daniel

Santoro, Veronica

Schiavon, Michela

English

Institutional Research Information System University of Turin

Conclusions Phosphorus availability could influence the dynamics of Fe plaques on the root surface. The higher oxidation caused by P deficiency increased Fe plaque formation. Proton exudation induced by P deficiency caused the dissolution of Fe plaque, releasing P available for plant uptake. The debated role of Fe plaque in plant P nutrition is shown to be strongly influenced by P availability itself.Root dynamics of phosphorus and iron interaction in rice under variable phosphorus availability Materials and Methods 60 days hydroponic experiment with two levels of P in solution Daily measurement of nutrient solution pH Fe plaques induction at 30 and 45 days of plant growing Quantification of Fe plaque (oxalate extraction) Quantification of P in plant tissues after 60 days of growingIntroductionResearch questions1) Is the higher rhizosphere oxygenation under P  deficiency related to a higher Fe plaque formation?2) Is the higher H+ release responsible of the P-source function of Fe plaque under P limited conditions? Results & DisussionEffect of P availaibilty on Fe plaque formationDuring Fe-plaque induction, –P plants showed a faster oxidation of Fe(II)than +P plants, confirming that P availability influences Fe plaque formationon rice roots. The higher O2 release reported under P starvation couldexplain the higher oxidation rates of Fe(II). Despite no significant differenceswere observed in root biomass, –P plants showed a root surface area thatwas double than in +P plants, possibly increasing the root area for Fe plaqueformation.Effect of P availaibilty on the function of Fe plaque in plant P uptakeVariations in the amount of root-associated Fe plaque with time confirmed their dynamic nature. Despite –P plants had more Fe plaque than +P plants,particularly during the fast vegetative growth phase, no significant differences were observed 15 days after induction, probably due to the higher rate ofH+ released by P deficient rice plants. Acidification of the rhizosphere by P deficient plants could in fact favour the dissolution of Fe plaque releasingbound P for plant uptake. The values of plant P uptake confirmed that P availaibility cannot only influence Fe plaque formation but also their role as asource of P for plant nutrition. Under P-deprived conditions Fe plaque could represent a source of P for plant uptake, while at high P availability Feplaque could act as a sink of P.01020304050600 6 12 18 24 30 36 42 48Fe(II) (mg L-1)Time (h)+P-PControl (no plant)02040608010030 44 48 62Fe (mg g-1root)Time (days)+P+Fe-P+Fe+P-Fe-P-FeFe plaquedissolutiona aa aaa abFe plaquedissolution01234567+Fe -Fe +Fe -Fe+P -PP uptake (mg)aabbUnder low P availability, Fe plaques promote P uptakeUnder high P availability, Fe plaques hamper P uptake00.250.50.7511.251.50 31 60 91 121 152 182 213H+released (mM)Time (h)+P+Fe+P-Fe-P+Fe-P-FeBefore Fe plaqueinduction H+ release is enhanced in P-deprived plantsAfter Fe plaque inductionthe higher amount of H+is consumed by Fe plaquedissolutionFe plaquesinduction0 19224 48 72 120 144 168FundingThis research was supported by the Cassadi Risparmio di Torino Project FOS4FIX (Enhanced biological N fixation through improved P acquisition by leguminous plants).Conciliating, Sustainability Resilience, and Food Quality. New challenges for a 2030 agricultureXL SICA Congress, Pisa, Italy · 5-7 September 2022S. Martinengo , M. Schiavon, V. Santoro, M. Martin, L. Celi, D. Said-PullicinoDepartment of Agricoltural, Forest and Food Sciences Università degli studi di Torino, Italy

Root dynamics of phosphorus and iron interaction in rice under variable 
phosphorus availabilit

https://iris.unito.it/bitstream/2318/1880343/1/Martinengo_plant_poster2.pdf

Root dynamics of phosphorus and iron interaction in rice under variable phosphorus availabilit

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