Effects of root morphology, respiration and carboxylate exudation on carbon economy in two non‐mycorrhizal lupines under phosphorus deficiency

• Published in: Plant, cell and environment Vol. 44; no. 2; pp. 598 - 612
• Main Authors: Funayama‐Noguchi, Sachiko, Shibata, Masaru, Noguchi, Ko, Terashima, Ichiro
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.02.2021; Wiley Subscription Services, Inc
• Subjects: Alternative oxidase; alternative oxidase (AOX); Biomass; Carbon; carbon budget; Carboxylates; cluster roots; Clusters; Exudation; Hydroponics; L. angustifolius; Lupinus albus; Morphology; P deficiency; Phosphorus; Proteins; Respiratory rate; root respiration; Roots; Species; uncoupling protein (UCP); root respiration; L. angustifolius; carbon budget; Lupinus albus; alternative oxidase (AOX); uncoupling protein (UCP); P deficiency; cluster roots
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/pce.13925

Under phosphorus (P) deficiency, Lupinus albus develops cluster roots that allow efficient P acquisition, while L. angustifolius without cluster roots also grows well. Both species are non‐mycorrhizal. We quantitatively examined the carbon budgets to investigate the different strategies of these species. Biomass allocation, respiratory rates, protein amounts and carboxylate exudation rates were examined in hydroponically‐grown plants treated with low (1 μM; P1) or high (100 μM; P100) P. At P1, L. albus formed cluster roots, and L. angustifolius increased biomass allocation to the roots. The respiratory rates of the roots were faster in L. albus than in L. angustifolius. The protein amounts of the non‐phosphorylating alternative oxidase and uncoupling protein were greater in the cluster roots of L. albus at P1 than in the roots at P100, but similar between the P treatments in L. angustifolius roots. At P1, L. albus exuded carboxylates at a faster rate than L. angustifolius. The carbon budgets at P1 were surprisingly similar between the two species, which is attributed to the contrasting root growth and development strategies. L. albus developed cluster roots with rapid respiratory and carboxylate exudation rates, while L. angustifolius developed a larger root system with slow respiratory and exudation rates. Under phosphorus deficiency, Lupinus albus developed cluster roots with fast respiratory and carboxylate exudation rates, while L. angustifolius developed a large root system with slow respiratory and exudation rates. These contrasting traits resulted in similar whole‐plant carbon budgets.