Organic acids in root exudates and soil solutions. Importance to calcicole and calcifuge behaviour of plants.

Lena Ström

Organic acids in root exudates and soil solutions. Importance to calcicole and calcifuge behaviour of plants.

Institutionen för naturgeografi och ekosystemvetenskap

Forskningsoutput: Avhandling › Doktorsavhandling (sammanläggning)

Sammanfattning

Popular Abstract in Swedish
Många växtarter kan inte kolonisera kalkjordar och det är stora skillnader i artsammansättningen mellan kalkjordar och närliggande surare jordar. Detta beteende kallas ofta för kalkskyende och tycks orsakas av en oförmåga hos dessa växtarter att lösa och ta upp fosfat och järn ur kalkjordar. Kalkjordar innehåller mycket låga halter av järn och fosfat löst i marklösningen och lättillgängligt för upptag av växtrötter. I min avhandling visar jag att kalkgynnade arter, som normalt växer på kalkjordar, utsöndrar vissa organiska syror i mycket större mängder än kalkskyende arter. De syror som främst utsöndras av kalkgynnade arter är dikarboxylsyran oxalat och trikarboxylsyran citrat. I försök där kalkjord extraherats med dessa två syror har de visat sig lösa järn och fosfat mycket bra. En av mekanismerna bakom kalkgynnat beteende hos växter kan alltså vara att dessa arter utsöndrar substanser från sina rötter som gör det möjligt för dem att lösa järn och fosfat ur kalkjorden och själva göra dessa bristämnen tillgängliga för upptag, en förmåga som saknas hos kalkskyende arter.

Originalspråk	engelska
Kvalifikation	Doktor
Tilldelande institution	Biologiska institutionen
Handledare	[unknown], [unknown], handledare, Extern person
Tilldelningsdatum	1998 nov. 13
Förlag	Department of Ecology, Lund University
ISBN (tryckt)	ISBN 91-7105-106-6
Status	Published - 1998

Bibliografisk information

Defence details

Date: 1998-11-13
Time: 10:00
Place: Blå Hallen, Ecology Building, Sölvegatan 37

External reviewer(s)

Name: Lee, John A
Title: Prof
Affiliation: Department of Animal and Plant Science, University of Sheffield, UK.

---

The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Plant Ecology and Systematics (Closed 2011) (011004000), Dept of Physical Geography and Ecosystem Science (011010000)

Ämnesklassifikation (UKÄ)

Ekologi

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title = "Organic acids in root exudates and soil solutions. Importance to calcicole and calcifuge behaviour of plants.",

abstract = "Many vascular plant species are unable to colonise calcareous sites, the floristic composition of adjacent limestone and acid silicate soils differing markedly. The inability of these 'calcifuge' species to establish themselves and grow on limestone soil appears to mainly be related to their low capacity for solubilising and absorbing phosphate and/or iron from such soils. Differences between calcifuge and calcicole species (the latter normally growing on calcareous soil) in their root exudation of low-molecular organic acids (LOAs) can lead to their ability to solubilise mineral nutrients from the soil differing. In the studies presented in this thesis I examined exudation by many calcicole and calcifuge species. Exudation was studied for plants grown hydroponically, for germinating seeds and seedlings and for plants grown in a pH intermediate soil. I found that calcicole species generally have a higher, often much higher, exudation rate of dicarboxylic oxalate and tricarboxylic citrate than calcifuge species do. These two LOAs were also shown to have a strong solubilising effect on soil phosphate and iron, both in calcareous and silicate soil. I also studied the calcifuge behaviour of Rumex acetosella in greater detail. R. acetosella was found to be a highly phosphate-limited species, its growth being closely correlated to the amount of easily exchangeable phosphate in the soil. This species, which contain large amounts of oxalate in its leaves, appears in any case to lack the ability to increase the exudation rate of LOAs in response to phosphate limitation. In my thesis I propose that high exudation rates of dicarboxylic and tricarboxylic organic acids is one of the mechanisms explaining calcifuge behaviour in plants. I also propose that high root exudation rates of LOAs from plants can be an adaptation to nutrient limiting conditions in soils.",

keywords = "nutrient-solubilisation, iron, phosphate, nutrient-limitations, citrate, oxalate, organic acids, root exudation, acidifuge, Calcicole, calcifuge, adaptations., Plant ecology, V{\"a}xtekologi",

author = "Lena Str{\"o}m",

note = "Defence details Date: 1998-11-13 Time: 10:00 Place: Bl{\aa} Hallen, Ecology Building, S{\"o}lvegatan 37 External reviewer(s) Name: Lee, John A Title: Prof Affiliation: Department of Animal and Plant Science, University of Sheffield, UK. --- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Plant Ecology and Systematics (Closed 2011) (011004000), Dept of Physical Geography and Ecosystem Science (011010000)",

year = "1998",

language = "English",

isbn = "ISBN 91-7105-106-6",

publisher = "Department of Ecology, Lund University",

type = "Doctoral Thesis (compilation)",

school = "Department of Biology",

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TY - THES

T1 - Organic acids in root exudates and soil solutions. Importance to calcicole and calcifuge behaviour of plants.

AU - Ström, Lena

N1 - Defence details Date: 1998-11-13 Time: 10:00 Place: Blå Hallen, Ecology Building, Sölvegatan 37 External reviewer(s) Name: Lee, John A Title: Prof Affiliation: Department of Animal and Plant Science, University of Sheffield, UK. --- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Plant Ecology and Systematics (Closed 2011) (011004000), Dept of Physical Geography and Ecosystem Science (011010000)

PY - 1998

Y1 - 1998

N2 - Many vascular plant species are unable to colonise calcareous sites, the floristic composition of adjacent limestone and acid silicate soils differing markedly. The inability of these 'calcifuge' species to establish themselves and grow on limestone soil appears to mainly be related to their low capacity for solubilising and absorbing phosphate and/or iron from such soils. Differences between calcifuge and calcicole species (the latter normally growing on calcareous soil) in their root exudation of low-molecular organic acids (LOAs) can lead to their ability to solubilise mineral nutrients from the soil differing. In the studies presented in this thesis I examined exudation by many calcicole and calcifuge species. Exudation was studied for plants grown hydroponically, for germinating seeds and seedlings and for plants grown in a pH intermediate soil. I found that calcicole species generally have a higher, often much higher, exudation rate of dicarboxylic oxalate and tricarboxylic citrate than calcifuge species do. These two LOAs were also shown to have a strong solubilising effect on soil phosphate and iron, both in calcareous and silicate soil. I also studied the calcifuge behaviour of Rumex acetosella in greater detail. R. acetosella was found to be a highly phosphate-limited species, its growth being closely correlated to the amount of easily exchangeable phosphate in the soil. This species, which contain large amounts of oxalate in its leaves, appears in any case to lack the ability to increase the exudation rate of LOAs in response to phosphate limitation. In my thesis I propose that high exudation rates of dicarboxylic and tricarboxylic organic acids is one of the mechanisms explaining calcifuge behaviour in plants. I also propose that high root exudation rates of LOAs from plants can be an adaptation to nutrient limiting conditions in soils.

AB - Many vascular plant species are unable to colonise calcareous sites, the floristic composition of adjacent limestone and acid silicate soils differing markedly. The inability of these 'calcifuge' species to establish themselves and grow on limestone soil appears to mainly be related to their low capacity for solubilising and absorbing phosphate and/or iron from such soils. Differences between calcifuge and calcicole species (the latter normally growing on calcareous soil) in their root exudation of low-molecular organic acids (LOAs) can lead to their ability to solubilise mineral nutrients from the soil differing. In the studies presented in this thesis I examined exudation by many calcicole and calcifuge species. Exudation was studied for plants grown hydroponically, for germinating seeds and seedlings and for plants grown in a pH intermediate soil. I found that calcicole species generally have a higher, often much higher, exudation rate of dicarboxylic oxalate and tricarboxylic citrate than calcifuge species do. These two LOAs were also shown to have a strong solubilising effect on soil phosphate and iron, both in calcareous and silicate soil. I also studied the calcifuge behaviour of Rumex acetosella in greater detail. R. acetosella was found to be a highly phosphate-limited species, its growth being closely correlated to the amount of easily exchangeable phosphate in the soil. This species, which contain large amounts of oxalate in its leaves, appears in any case to lack the ability to increase the exudation rate of LOAs in response to phosphate limitation. In my thesis I propose that high exudation rates of dicarboxylic and tricarboxylic organic acids is one of the mechanisms explaining calcifuge behaviour in plants. I also propose that high root exudation rates of LOAs from plants can be an adaptation to nutrient limiting conditions in soils.

KW - nutrient-solubilisation

KW - iron

KW - phosphate

KW - nutrient-limitations

KW - citrate

KW - oxalate

KW - organic acids

KW - root exudation

KW - acidifuge

KW - Calcicole

KW - calcifuge

KW - adaptations.

KW - Plant ecology

KW - Växtekologi

M3 - Doctoral Thesis (compilation)

SN - ISBN 91-7105-106-6

PB - Department of Ecology, Lund University

ER -

Organic acids in root exudates and soil solutions. Importance to calcicole and calcifuge behaviour of plants.

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