TY - JOUR

T1 - Net O2 exchange rates under dark and light conditions across different stem compartments

AU - Natale, Sara

AU - Peralta Ogorek, Lucas Léon

AU - Caracciolo, Ludovico

AU - Morosinotto, Tomas

AU - van Amerongen, Herbert

AU - Casolo, Valentino

AU - Pedersen, Ole

AU - Nardini, Andrea

N1 - Publisher Copyright: © 2024 The Authors. New Phytologist © 2024 New Phytologist Foundation.

PY - 2024

Y1 - 2024

N2 - Woody plants display some photosynthetic activity in stems, but the biological role of stem photosynthesis and the specific contributions of bark and wood to carbon uptake and oxygen evolution remain poorly understood. We aimed to elucidate the functional characteristics of chloroplasts in stems of different ages in Fraxinus ornus. Our investigation employed diverse experimental approaches, including microsensor technology to assess oxygen production rates in whole stem, bark, and wood separately. Additionally, we utilized fluorescence lifetime imaging microscopy (FLIM) to characterize the relative abundance of photosystems I and II (PSI : PSII chlorophyll ratio) in bark and wood. Our findings revealed light-induced increases in O2 production in whole stem, bark, and wood. We present the radial profile of O2 production in F. ornus stems, demonstrating the capability of stem chloroplasts to perform light-dependent electron transport. Younger stems exhibited higher light-induced O2 production and dark respiration rates than older ones. While bark emerged as the primary contributor to net O2 production under light conditions, our data underscored that wood chloroplasts are also photosynthetically active. The FLIM analysis unveiled a lower PSI abundance in wood than in bark, suggesting stem chloroplasts are not only active but also acclimate to the spectral composition of light reaching inner compartments.

AB - Woody plants display some photosynthetic activity in stems, but the biological role of stem photosynthesis and the specific contributions of bark and wood to carbon uptake and oxygen evolution remain poorly understood. We aimed to elucidate the functional characteristics of chloroplasts in stems of different ages in Fraxinus ornus. Our investigation employed diverse experimental approaches, including microsensor technology to assess oxygen production rates in whole stem, bark, and wood separately. Additionally, we utilized fluorescence lifetime imaging microscopy (FLIM) to characterize the relative abundance of photosystems I and II (PSI : PSII chlorophyll ratio) in bark and wood. Our findings revealed light-induced increases in O2 production in whole stem, bark, and wood. We present the radial profile of O2 production in F. ornus stems, demonstrating the capability of stem chloroplasts to perform light-dependent electron transport. Younger stems exhibited higher light-induced O2 production and dark respiration rates than older ones. While bark emerged as the primary contributor to net O2 production under light conditions, our data underscored that wood chloroplasts are also photosynthetically active. The FLIM analysis unveiled a lower PSI abundance in wood than in bark, suggesting stem chloroplasts are not only active but also acclimate to the spectral composition of light reaching inner compartments.

KW - FLIM

KW - microsensor

KW - oxygen exchange rate

KW - PSI : PSII Chl ratio

KW - radial O profile

KW - stem photosynthesis

U2 - 10.1111/nph.19782

DO - 10.1111/nph.19782

M3 - Journal article

C2 - 38703003

AN - SCOPUS:85192182324

VL - 243

SP - 72

EP - 81

JO - New Phytologist

JF - New Phytologist

SN - 0028-646X

IS - 1

ER -