Hoa T Nguyen1, Daniel E Stanton2, Nele Schmitz2, Graham D Farquhar2, Marilyn C Ball2. 1. Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia and Institute of Botany, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria hoa-thi.nguyen@anu.edu.au. 2. Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia and Institute of Botany, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria.
Abstract
BACKGROUND AND AIMS: Halophytic eudicots are characterized by enhanced growth under saline conditions. This study combines physiological and anatomical analyses to identify processes underlying growth responses of the mangrove Avicennia marina to salinities ranging from fresh- to seawater conditions. METHODS: Following pre-exhaustion of cotyledonary reserves under optimal conditions (i.e. 50% seawater), seedlings of A. marina were grown hydroponically in dilutions of seawater amended with nutrients. Whole-plant growth characteristics were analysed in relation to dry mass accumulation and its allocation to different plant parts. Gas exchange characteristics and stable carbon isotopic composition of leaves were measured to evaluate water use in relation to carbon gain. Stem and leaf hydraulic anatomy were measured in relation to plant water use and growth. KEY RESULTS: Avicennia marina seedlings failed to grow in 0-5% seawater, whereas maximal growth occurred in 50-75% seawater. Relative growth rates were affected by changes in leaf area ratio (LAR) and net assimilation rate (NAR) along the salinity gradient, with NAR generally being more important. Gas exchange characteristics followed the same trends as plant growth, with assimilation rates and stomatal conductance being greatest in leaves grown in 50-75% seawater. However, water use efficiency was maintained nearly constant across all salinities, consistent with carbon isotopic signatures. Anatomical studies revealed variation in rates of development and composition of hydraulic tissues that were consistent with salinity-dependent patterns in water use and growth, including a structural explanation for low stomatal conductance and growth under low salinity. CONCLUSIONS: The results identified stem and leaf transport systems as central to understanding the integrated growth responses to variation in salinity from fresh- to seawater conditions. Avicennia marina was revealed as an obligate halophyte, requiring saline conditions for development of the transport systems needed to sustain water use and carbon gain.
BACKGROUND AND AIMS: Halophytic eudicots are characterized by enhanced growth under saline conditions. This study combines physiological and anatomical analyses to identify processes underlying growth responses of the mangrove Avicennia marina to salinities ranging from fresh- to seawater conditions. METHODS: Following pre-exhaustion of cotyledonary reserves under optimal conditions (i.e. 50% seawater), seedlings of A. marina were grown hydroponically in dilutions of seawater amended with nutrients. Whole-plant growth characteristics were analysed in relation to dry mass accumulation and its allocation to different plant parts. Gas exchange characteristics and stable carbon isotopic composition of leaves were measured to evaluate water use in relation to carbon gain. Stem and leaf hydraulic anatomy were measured in relation to plant water use and growth. KEY RESULTS:Avicennia marina seedlings failed to grow in 0-5% seawater, whereas maximal growth occurred in 50-75% seawater. Relative growth rates were affected by changes in leaf area ratio (LAR) and net assimilation rate (NAR) along the salinity gradient, with NAR generally being more important. Gas exchange characteristics followed the same trends as plant growth, with assimilation rates and stomatal conductance being greatest in leaves grown in 50-75% seawater. However, water use efficiency was maintained nearly constant across all salinities, consistent with carbon isotopic signatures. Anatomical studies revealed variation in rates of development and composition of hydraulic tissues that were consistent with salinity-dependent patterns in water use and growth, including a structural explanation for low stomatal conductance and growth under low salinity. CONCLUSIONS: The results identified stem and leaf transport systems as central to understanding the integrated growth responses to variation in salinity from fresh- to seawater conditions. Avicennia marina was revealed as an obligate halophyte, requiring saline conditions for development of the transport systems needed to sustain water use and carbon gain.
Authors: Nele Schmitz; Elisabeth M R Robert; Anouk Verheyden; James Gitundu Kairo; Hans Beeckman; Nico Koedam Journal: Ann Bot Date: 2007-11-15 Impact factor: 4.357
Authors: Katherine C Martin; Dan Bruhn; Catherine E Lovelock; Ilka C Feller; John R Evans; Marilyn C Ball Journal: Plant Cell Environ Date: 2009-11-11 Impact factor: 7.228
Authors: Ken W Krauss; Catherine E Lovelock; Luzhen Chen; Uta Berger; Marilyn C Ball; Ruth Reef; Ronny Peters; Hannah Bowen; Alejandra G Vovides; Eric J Ward; Marie-Christin Wimmler; Joel Carr; Pete Bunting; Jamie A Duberstein Journal: Sci Rep Date: 2022-10-21 Impact factor: 4.996
Authors: Guillermo Friis; Joel Vizueta; Edward G Smith; David R Nelson; Basel Khraiwesh; Enas Qudeimat; Kourosh Salehi-Ashtiani; Alejandra Ortega; Alyssa Marshell; Carlos M Duarte; John A Burt Journal: G3 (Bethesda) Date: 2021-01-18 Impact factor: 3.154
Authors: Nate G McDowell; Marilyn Ball; Ben Bond-Lamberty; Matthew L Kirwan; Ken W Krauss; J Patrick Megonigal; Maurizio Mencuccini; Nicholas D Ward; Michael N Weintraub; Vanessa Bailey Journal: Glob Chang Biol Date: 2022-07-29 Impact factor: 13.211
Authors: Paulo César Costa Virgulino-Júnior; Diego Novaes Carneiro; Wilson Rocha Nascimento; Michele Ferreira Cougo; Marcus Emanuel Barroncas Fernandes Journal: PLoS One Date: 2020-03-10 Impact factor: 3.240