Response of Salvinia spp. to different nitrogen sources: the acid-base regulation approach.
This paper shows the importance of acid-base analyses and Δ13C measurements in the evaluation of the responses of Salvinia species' responses to different N sources. It also highlights the importance of these methodologies as potential tools in the study of differences between habitats and nutrient acquisition, particularly N. This study used three different species of Salvinia cultured in the absence of combined N or in the presence of either NOinf3sup-or NHinf4sup+as N sources. The interaction between NOinf3sup-or NHinf4sup+as N source and organic acid metabolism, and the information on diazotrophy from the organic acid measurements, were also examined. Nevertheless, the results presented may not be used per se to assign diazotrophy. Carboxylate (C-A) levels in the different Salvinia species are much lower than the norm for bryophytes and tracheophytes, consistent with previously published work on Azolla. This might be related to the aquatic life form of these plants, since they seem to have no potential to increase the availability of Fe or P by the acidification of their rooting medium (water) that a larger net synthesis of organic acids, with cation-H+exchange, could achieve.
Departmento de Biologia Vegetal, Faculdade de Ciências de Lisboa, Campo Grande, Bloco C2, Piso 4, 1700, Lisboa, Portugal.
M Amélia
MA
Martins-Loução
Department of Agricultural Sciences, 40 Thorvaldsensvej, DK-1871, Fredeiksberg C, Copenhagen, Denmark.
Bernd
B
Wollenweber
Department of Biological Sciences, University of Dundee, DD1 4HN, Dundee, UK.
John A
JA
Raven
Acid-base regulation; Carboxylates; Nutrient acquisition; pH modulation; Δ13C