Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review
Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review
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TY - JOUR
T1 - Shade and salinity responses of two dominant coastal wetland grasses
T2 - implications for light competition at the transition zone
AU - Jespersen, Emil
AU - Kirk, Gro H
AU - Brix, Hans
AU - Eller, Franziska
AU - Sorrell, Brian K
N1 - © The Author(s) 2021. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
PY - 2021/9
Y1 - 2021/9
N2 - BACKGROUND: Coastal wetlands are threatened by the increased salinity that may result from sea level rise. Salinity stress alters species zonation patterns through changes in competitive outcome between species differing in salinity tolerance. This study therefore aimed to understand how salinity and light affects two dominant and competing coastal wetland grasses that differ in salt tolerance, height and photosynthetic metabolism.METHODS: The C4 species Spartina anglica and the C3 species Phragmites australis were grown at 5 salinity levels (0, 7, 14, 21 and 28 ppt) and two light fluxes (100% and 50% of natural daylight) in an outdoor experimental setup for 102 days with full access to nutrients.KEY RESULTS: Salinity reduced the biomass, height and shoot density of P. australis from 81.7 gDW, 0.73 m and 37 shoots per pot at salinity 0 ppt to 16.8 gDW, 0.3 m and 14 shoots per pot at salinity 28 ppt. Biomass, height and shoot density of S. anglica did not respond or were only slightly reduced at the highest salinity of 28 ppt. High salinity also resulted in higher tissue concentration of N and P in P. australis. Both species had low ability to acclimate to the lower light flux. Shade acclimation in S. anglica occurred via modest changes in specific leaf area (SLA), pigment content and biomass allocation.CONCLUSIONS: High salinity reduced traits important for light competition and increased the nutrient concentration in P. australis leaf and root biomass, while this was overall unaffected in S. anglica. This is likely to reduce the competitive ability of P. australis over S. anglica for light because at high salinities the former cannot effectively shade the lower-growing S. anglica. Neither species effectively acclimates to shade, which could explain why S. anglica does not occur in the understory of P. australis at low salinities.
AB - BACKGROUND: Coastal wetlands are threatened by the increased salinity that may result from sea level rise. Salinity stress alters species zonation patterns through changes in competitive outcome between species differing in salinity tolerance. This study therefore aimed to understand how salinity and light affects two dominant and competing coastal wetland grasses that differ in salt tolerance, height and photosynthetic metabolism.METHODS: The C4 species Spartina anglica and the C3 species Phragmites australis were grown at 5 salinity levels (0, 7, 14, 21 and 28 ppt) and two light fluxes (100% and 50% of natural daylight) in an outdoor experimental setup for 102 days with full access to nutrients.KEY RESULTS: Salinity reduced the biomass, height and shoot density of P. australis from 81.7 gDW, 0.73 m and 37 shoots per pot at salinity 0 ppt to 16.8 gDW, 0.3 m and 14 shoots per pot at salinity 28 ppt. Biomass, height and shoot density of S. anglica did not respond or were only slightly reduced at the highest salinity of 28 ppt. High salinity also resulted in higher tissue concentration of N and P in P. australis. Both species had low ability to acclimate to the lower light flux. Shade acclimation in S. anglica occurred via modest changes in specific leaf area (SLA), pigment content and biomass allocation.CONCLUSIONS: High salinity reduced traits important for light competition and increased the nutrient concentration in P. australis leaf and root biomass, while this was overall unaffected in S. anglica. This is likely to reduce the competitive ability of P. australis over S. anglica for light because at high salinities the former cannot effectively shade the lower-growing S. anglica. Neither species effectively acclimates to shade, which could explain why S. anglica does not occur in the understory of P. australis at low salinities.
KW - C photosynthesis
KW - Phragmites australis
KW - Salt tolerance
KW - Spartina anglica
KW - ion regulation
KW - light competition
KW - salt exclusion
KW - shade acclimation
KW - sodium
U2 - 10.1093/aob/mcab089
DO - 10.1093/aob/mcab089
M3 - Journal article
C2 - 34259823
VL - 128
SP - 469
EP - 480
JO - Annals of Botany
JF - Annals of Botany
SN - 0305-7364
IS - 4
ER -