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Phenotypic plasticity in Phragmites australis as a functional response to water depth

Vretare, V; Weisner, Stefan LU ; Strand, J A and Granéli, Wilhelm LU (2001) In Aquatic Botany 69(2-4). p.127-145
Abstract
We have performed investigations to see if the emergent macrophyte Phragmites australis (Cav.) Trin. ex Steud. exhibits phenotypic plasticity as a response to water depth and if such responses in biomass allocation pattern and morphology are functional responses, improving the performance of the plant. In greenhouse experiments plants were grown in deep or shallow water to evaluate plastic responses. Allometric methods were used to handle effects caused by size differences between treatments. To evaluate if phenotypic responses to water depth are functional, the relative growth rate (RGR) of plants acclimatised to shallow or deep water, respectively, were compared in deep water, and the growth of plants in fluctuating and constant water... (More)
We have performed investigations to see if the emergent macrophyte Phragmites australis (Cav.) Trin. ex Steud. exhibits phenotypic plasticity as a response to water depth and if such responses in biomass allocation pattern and morphology are functional responses, improving the performance of the plant. In greenhouse experiments plants were grown in deep or shallow water to evaluate plastic responses. Allometric methods were used to handle effects caused by size differences between treatments. To evaluate if phenotypic responses to water depth are functional, the relative growth rate (RGR) of plants acclimatised to shallow or deep water, respectively, were compared in deep water, and the growth of plants in fluctuating and constant water level were compared.



When grown in deep (70 or 75 cm), compared to shallow (20 or 5 cm) water, plants allocated proportionally less to below-ground weight, made proportionally fewer but taller stems, and had rhizomes that were situated more superficially in the substrate. Plants acclimatised to shallow water had lower RGR than plants acclimatised to deep water, when they were grown in deep water, and plants in constant water depth (40 cm) grew faster than plants in fluctuating water depth (15/65 cm). In an additional field study, the rhizomes were situated superficially in the sediment in deep, compared to shallow water.



We have shown that P. australis acclimatises to deep water with phenotypic plasticity through allocating more resources to stem weight, and also by producing fewer but taller stems, which will act to maintain a positive carbon balance and an effective gas exchange between aerial and below-ground parts. Furthermore, the decreased proportional allocation to below-ground parts probably results in decreased nutrient absorption, decreased anchorage in the sediment and decreased carbohydrate reserves. Thus, in deep water, plants have an increased risk of becoming uprooted and experience decreased growth and dispersal rates. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Aquatic Botany
volume
69
issue
2-4
pages
127 - 145
publisher
Elsevier
external identifiers
  • scopus:0035048425
ISSN
0304-3770
DOI
10.1016/S0304-3770(01)00134-6
language
English
LU publication?
yes
id
cd5fb3ef-33b1-4b8b-a014-3fdd8dd2ca3a (old id 149826)
date added to LUP
2007-06-29 08:26:51
date last changed
2018-07-29 03:55:37
@article{cd5fb3ef-33b1-4b8b-a014-3fdd8dd2ca3a,
  abstract     = {We have performed investigations to see if the emergent macrophyte Phragmites australis (Cav.) Trin. ex Steud. exhibits phenotypic plasticity as a response to water depth and if such responses in biomass allocation pattern and morphology are functional responses, improving the performance of the plant. In greenhouse experiments plants were grown in deep or shallow water to evaluate plastic responses. Allometric methods were used to handle effects caused by size differences between treatments. To evaluate if phenotypic responses to water depth are functional, the relative growth rate (RGR) of plants acclimatised to shallow or deep water, respectively, were compared in deep water, and the growth of plants in fluctuating and constant water level were compared.<br/><br>
<br/><br>
When grown in deep (70 or 75 cm), compared to shallow (20 or 5 cm) water, plants allocated proportionally less to below-ground weight, made proportionally fewer but taller stems, and had rhizomes that were situated more superficially in the substrate. Plants acclimatised to shallow water had lower RGR than plants acclimatised to deep water, when they were grown in deep water, and plants in constant water depth (40 cm) grew faster than plants in fluctuating water depth (15/65 cm). In an additional field study, the rhizomes were situated superficially in the sediment in deep, compared to shallow water.<br/><br>
<br/><br>
We have shown that P. australis acclimatises to deep water with phenotypic plasticity through allocating more resources to stem weight, and also by producing fewer but taller stems, which will act to maintain a positive carbon balance and an effective gas exchange between aerial and below-ground parts. Furthermore, the decreased proportional allocation to below-ground parts probably results in decreased nutrient absorption, decreased anchorage in the sediment and decreased carbohydrate reserves. Thus, in deep water, plants have an increased risk of becoming uprooted and experience decreased growth and dispersal rates.},
  author       = {Vretare, V and Weisner, Stefan and Strand, J A and Granéli, Wilhelm},
  issn         = {0304-3770},
  language     = {eng},
  number       = {2-4},
  pages        = {127--145},
  publisher    = {Elsevier},
  series       = {Aquatic Botany},
  title        = {Phenotypic plasticity in Phragmites australis as a functional response to water depth},
  url          = {http://dx.doi.org/10.1016/S0304-3770(01)00134-6},
  volume       = {69},
  year         = {2001},
}