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Seasonal and inter-annual photosynthetic response of representative C-4 species to soil water content and leaf nitrogen concentration across a tropical seasonal floodplain

Mantlana, K B; Arneth, Almut LU ; Veenendaal, E M; Wohland, P; Wolski, P; Kolle, O and Lloyd, J (2008) In Journal of Tropical Ecology 24. p.201-213
Abstract
We examined the seasonal and inter-annual variation of leaf-level photosynthetic characteristics of three C-4 perennial species, Cyperus articulatus, Panicum repens and Imperata cylindrica, and their response to environmental variables, to determine comparative physiological responses of plants representing particular microhabitats within a seasonal tropical floodplain in the Okavango River Delta, Botswana. Five measurement campaigns were carried out over a period of 2 y which covered two early rainy seasons, two late rainy seasons and one dry season. For all three species, light-saturated net photosynthetic rates (A(sat)) and stomatal conductance (9,at) decreased with decreasing soil water content with a seasonal range for A(sat) of... (More)
We examined the seasonal and inter-annual variation of leaf-level photosynthetic characteristics of three C-4 perennial species, Cyperus articulatus, Panicum repens and Imperata cylindrica, and their response to environmental variables, to determine comparative physiological responses of plants representing particular microhabitats within a seasonal tropical floodplain in the Okavango River Delta, Botswana. Five measurement campaigns were carried out over a period of 2 y which covered two early rainy seasons, two late rainy seasons and one dry season. For all three species, light-saturated net photosynthetic rates (A(sat)) and stomatal conductance (9,at) decreased with decreasing soil water content with a seasonal range for A(sat) of approximately 5-45 mu mol m(-2) s(-1), and for g(sat) of 0.03-0.35 mol m-2 s(-1). The species representing the wettest microhabitat (Cyperus) had the highest g(sat) at low leaf-to-air vapour pressure deficits (D-l), the highest ratio of intercellular to ambient CO2 concentration (C-i/C-a), as well as the highest degree of variation in C-l/C-a from season to season. We interpret this as being indicative of its adaptation to a moist growth environment allowing for non-conservative water use strategies as soil moisture is usually abundant. For all three species there was significant variation in photosynthetic fluxes from one year to another that was related to variation in leaf nitrogen and phosphorus. This study shows that when assessing the role of savanna stands in large-scale carbon balance models, the remarkable inter-annual variation in leaf photosynthesis reported in this study should be taken into account. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
conductance, stomatal, savanna, leaf-to-air vapour pressure deficit, leaf phosphorus, leaf nitrogen, grassland, C-i/C-a ratio, Africa, C-4 photosynthesis
in
Journal of Tropical Ecology
volume
24
pages
201 - 213
publisher
Cambridge University Press
external identifiers
  • wos:000254964500009
  • scopus:43649088633
ISSN
0266-4674
DOI
10.1017/S0266467408004859
language
English
LU publication?
yes
id
66da5e7b-8000-41a5-9164-c9fd5cdf5424 (old id 1206246)
date added to LUP
2008-09-19 12:09:14
date last changed
2017-01-01 05:00:30
@article{66da5e7b-8000-41a5-9164-c9fd5cdf5424,
  abstract     = {We examined the seasonal and inter-annual variation of leaf-level photosynthetic characteristics of three C-4 perennial species, Cyperus articulatus, Panicum repens and Imperata cylindrica, and their response to environmental variables, to determine comparative physiological responses of plants representing particular microhabitats within a seasonal tropical floodplain in the Okavango River Delta, Botswana. Five measurement campaigns were carried out over a period of 2 y which covered two early rainy seasons, two late rainy seasons and one dry season. For all three species, light-saturated net photosynthetic rates (A(sat)) and stomatal conductance (9,at) decreased with decreasing soil water content with a seasonal range for A(sat) of approximately 5-45 mu mol m(-2) s(-1), and for g(sat) of 0.03-0.35 mol m-2 s(-1). The species representing the wettest microhabitat (Cyperus) had the highest g(sat) at low leaf-to-air vapour pressure deficits (D-l), the highest ratio of intercellular to ambient CO2 concentration (C-i/C-a), as well as the highest degree of variation in C-l/C-a from season to season. We interpret this as being indicative of its adaptation to a moist growth environment allowing for non-conservative water use strategies as soil moisture is usually abundant. For all three species there was significant variation in photosynthetic fluxes from one year to another that was related to variation in leaf nitrogen and phosphorus. This study shows that when assessing the role of savanna stands in large-scale carbon balance models, the remarkable inter-annual variation in leaf photosynthesis reported in this study should be taken into account.},
  author       = {Mantlana, K B and Arneth, Almut and Veenendaal, E M and Wohland, P and Wolski, P and Kolle, O and Lloyd, J},
  issn         = {0266-4674},
  keyword      = {conductance,stomatal,savanna,leaf-to-air vapour pressure deficit,leaf phosphorus,leaf nitrogen,grassland,C-i/C-a ratio,Africa,C-4 photosynthesis},
  language     = {eng},
  pages        = {201--213},
  publisher    = {Cambridge University Press},
  series       = {Journal of Tropical Ecology},
  title        = {Seasonal and inter-annual photosynthetic response of representative C-4 species to soil water content and leaf nitrogen concentration across a tropical seasonal floodplain},
  url          = {http://dx.doi.org/10.1017/S0266467408004859},
  volume       = {24},
  year         = {2008},
}