Abstract
Exudation of organic anions is believed to be a common tolerance mechanism for both aluminium toxicity and phosphorus deficiency. Nevertheless, which of these stresses that actually elicit the exudation of organic anions from rape (Brassica napus L) remains unknown, and the combined effects of Al toxicity and P deficiency on rape have not been reported before. Therefore, in the current study, Brassica napus var. Natane nourin plants grown with or without 0.25 mM P were exposed to 0 or 50 micro M AlCl(3) and several parameters related to the exudation of organic anions from the roots were investigated. Eight days of P deficiency resulted in a significant growth reduction, but P deficiency alone did not induce exudation of organic anions. In contrast, Al strongly induced organic acid exudation, while simultaneously inhibiting root growth. Increased in-vitro activity of citrate synthase (CS, EC 4.1.3.7), malate dehydrogenase (MDH, EC 1.1.1.37) and phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31), together with reduced root respiration, indicated that the Al-induced accumulation and subsequent exudation of citrate and malate were associated with both increased biosynthesis and reduced metabolism of citric and malic acid. Phosphorus-sufficient plants showed more pronounced aluminium-induced accumulation and exudation of organic anions than P-deficient plants. A divided root chamber experiment showed the necessity of direct contact between Al and roots to elicit exudation of organic anions. Prolonged exposure (10 days) to Al resulted in a decrease in the net exudation of citrate and malate, and the rate of decrease was much more rapid in P-deficient plants than in P-sufficient plants. It is concluded that P nutrition affects the level of Al-induced synthesis and exudation of organic anions. However, the mechanism needs further investigation.
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Claims 11
Claim · model-written summary
Eight days of P deficiency significantly reduced rape growth.
- Taxon
- Brassica napus
_Brassica_napus_-_Habit.jpg?width=60)
Brassica napust0 - Treatment
- P deficiencye0
- Outcome
- growthe0
- Direction
- reductione0
- Qualifier
- Eight dayse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)
Verbatim
t0“Brassica napus”
e0“Eight days of P deficiency resulted in a significant growth reduction”
Claim · model-written summary
P deficiency alone did not induce exudation of organic anions.
- Taxon
- Brassica napusBrassica napust0
- Treatment
- P deficiency alonee0
- Outcome
- exudation of organic anionse0
- Direction
- did not inducee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Brassica napus”
e0“P deficiency alone did not induce exudation of organic anions”
Claim · model-written summary
Al strongly induced organic acid exudation from rape roots.
- Taxon
- Brassica napusBrassica napust0
- Treatment
- Ale0
- Outcome
- organic acid exudatione0
- Direction
- strongly inducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Brassica napus”
e0“Al strongly induced organic acid exudation, while simultaneously inhibiting root growth”
e1“exposed to 0 or 50 micro M AlCl(3)”
Claim · model-written summary
Al inhibited root growth of rape.
- Taxon
- Brassica napusBrassica napust0
- Treatment
- Ale0
- Outcome
- root growthe0
- Direction
- inhibitinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Brassica napus”
e0“Al strongly induced organic acid exudation, while simultaneously inhibiting root growth”
Claim · model-written summary
Al increased in-vitro activities of citrate synthase, malate dehydrogenase and PEPC in rape.
- Taxon
- Brassica napusBrassica napust0
- Treatment
- Ale1
- Gene
- citrate synthase (CS, EC 4.1.3.7), malate dehydrogenase (MDH, EC 1.1.1.37) and phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31)e0
- Outcome
- in-vitro activitye0
- Direction
- Increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Brassica napus”
e0“Increased in-vitro activity of citrate synthase (CS, EC 4.1.3.7), malate dehydrogenase (MDH, EC 1.1.1.37) and phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31)”
e1“Al strongly induced organic acid exudation”
Claim · model-written summary
Al reduced rape root respiration.
- Taxon
- Brassica napusBrassica napust0
- Treatment
- Ale1
- Outcome
- root respiratione0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Brassica napus”
e0“reduced root respiration”
e1“Al strongly induced organic acid exudation”
Claim · model-written summary
The authors interpret the Al-induced accumulation and exudation of citrate and malate as due to both increased biosynthesis and reduced metabolism of citric and malic acid.
- Taxon
- Brassica napusBrassica napust0
- Outcome
- Al-induced accumulation and subsequent exudation of citrate and malatee0
- Qualifier
- both increased biosynthesis and reduced metabolism of citric and malic acide0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Brassica napus”
e0“indicated that the Al-induced accumulation and subsequent exudation of citrate and malate were associated with both increased biosynthesis and reduced metabolism of citric and malic acid”
Claim · model-written summary
P-sufficient plants showed more pronounced Al-induced accumulation and exudation of organic anions than P-deficient plants.
- Taxon
- Brassica napusBrassica napust0
- Treatment
- Phosphorus-sufficient plantse0
- Outcome
- aluminium-induced accumulation and exudation of organic anionse0
- Direction
- more pronouncede0
- Comparator
- P-deficient plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Brassica napus”
e0“Phosphorus-sufficient plants showed more pronounced aluminium-induced accumulation and exudation of organic anions than P-deficient plants”
Claim · model-written summary
A divided root chamber showed that direct contact between Al and roots was necessary to elicit organic anion exudation.
- Taxon
- Brassica napusBrassica napust0
- Treatment
- direct contact between Al and rootse0
- Outcome
- exudation of organic anionse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Brassica napus”
e0“A divided root chamber experiment showed the necessity of direct contact between Al and roots to elicit exudation of organic anions”
Claim · model-written summary
Prolonged 10-day exposure to Al decreased net exudation of citrate and malate.
- Taxon
- Brassica napusBrassica napust0
- Treatment
- Prolonged exposure (10 days) to Ale0
- Outcome
- net exudation of citrate and malatee0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Brassica napus”
e0“Prolonged exposure (10 days) to Al resulted in a decrease in the net exudation of citrate and malate”
Claim · model-written summary
The decrease in net exudation was much more rapid in P-deficient than in P-sufficient plants.
- Taxon
- Brassica napusBrassica napust0
- Treatment
- P-deficient plantse0
- Outcome
- rate of decreasee0
- Direction
- much more rapide0
- Comparator
- P-sufficient plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Brassica napus”
e0“the rate of decrease was much more rapid in P-deficient plants than in P-sufficient plants”
The same questions in other papers
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This paper is about lacking the nutrient, so it counts the other way round here.
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See all 5 papers →phosphorus · growth · Brassica napus (oilseed rape)Positive and negative results
24 papers in the same direction as this paper · 3 in the opposite direction
This paper is about lacking the nutrient, so it counts the other way round here.
- negative
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See all 28 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.