TY - JOUR

T1 - Photosynthetic capacity in seagrass seeds and early-stage seedlings of Zostera marina

AU - Brodersen, Kasper Elgetti

AU - Kühl, Michael

N1 - Publisher Copyright: © 2023 The Authors. New Phytologist © 2023 New Phytologist Foundation.

PY - 2023

Y1 - 2023

N2 - In many terrestrial seeds, photosynthetic activity supplies O2 to the developing plant embryo to sustain aerobic metabolism and enhance biosynthetic activity. However, whether seagrass seeds possess similar photosynthetic capacity to alleviate intra-seed hypoxic stress conditions is unknown. We used a novel combination of microscale variable chlorophyll fluorescence imaging, a custom-made O2 optode microrespirometry system and planar optode O2 imaging, to determine the O2 microenvironment and photosynthetic activity in developing seeds and seedlings of seagrass (Zostera marina). Developing, sheath-covered seeds exhibited high O2 concentrations in the photosynthetic active seed sheath and low O2 concentrations in the centre of the seed at the position of the embryo. In light, photosynthesis in the seed sheath increased O2 availability in central parts of the seed enabling enhanced respiratory energy generation for biosynthetic activity. Early-stage seedlings also displayed photosynthetic capacity in hypocotyl and cotyledonary tissues, which may be beneficial for seedling establishment. Sheath O2 production is important for alleviating intra-seed hypoxic stress, which might increase endosperm storage activity, improving the conditions for successful seed maturation and germination.

AB - In many terrestrial seeds, photosynthetic activity supplies O2 to the developing plant embryo to sustain aerobic metabolism and enhance biosynthetic activity. However, whether seagrass seeds possess similar photosynthetic capacity to alleviate intra-seed hypoxic stress conditions is unknown. We used a novel combination of microscale variable chlorophyll fluorescence imaging, a custom-made O2 optode microrespirometry system and planar optode O2 imaging, to determine the O2 microenvironment and photosynthetic activity in developing seeds and seedlings of seagrass (Zostera marina). Developing, sheath-covered seeds exhibited high O2 concentrations in the photosynthetic active seed sheath and low O2 concentrations in the centre of the seed at the position of the embryo. In light, photosynthesis in the seed sheath increased O2 availability in central parts of the seed enabling enhanced respiratory energy generation for biosynthetic activity. Early-stage seedlings also displayed photosynthetic capacity in hypocotyl and cotyledonary tissues, which may be beneficial for seedling establishment. Sheath O2 production is important for alleviating intra-seed hypoxic stress, which might increase endosperm storage activity, improving the conditions for successful seed maturation and germination.

KW - microenvironment

KW - photosynthesis

KW - respiration

KW - seagrass

KW - seed

U2 - 10.1111/nph.18986

DO - 10.1111/nph.18986

M3 - Journal article

C2 - 37222134

AN - SCOPUS:85160065805

VL - 239

JO - New Phytologist

JF - New Phytologist

SN - 0028-646X

IS - 4

ER -