Abstract
Recently, we showed that secretion of citrate in an aluminium (Al) tolerant cultivar soybean ( Glycine max ) (cv. Suzunari) is a specific response to Al stress [Yang et al. (2000) Physiol Plant 110: 72–77]. Here we investigated the intrinsic mechanisms behind the secretion of citrate induced by Al. The amount of citrate secreted during the 24‐h Al treatment period increased with increasing concentration of Al (0–70 μ M ). We analysed citrate secretion basically under 3 conditions: (1) by varying light‐exposure, (2) with intact or excised shoots and (3) by using a divided chamber technique. Further, the content of organic acids in the tissue and the activity of enzymes involved in organic acid metabolism were analysed and evaluated. The results indicate that high rate of citrate secretion in soybean requires a 4‐h induction period. Al had a continuous effect on the citrate secretion when Al was removed from the treatment solution. Citrate secretion increased steadily under exposure to continuous light. However, when the shoots were excised the citrate secretion rate dropped to 3–6 times that of their control counterparts. Results of root manipulation experiments revealed that citrate secretion required the direct contact of Al. In other words, only the Al‐treated root portions secreted citrate. All these observations suggest that the shoots play a role in Al‐induced citrate secretion. Although shoots may not supply citrate for the secretion upon Al treatment, it seems that they may provide the carbon source and/or energy for citrate synthesis in the root. On the other hand, the root organic acid content (1‐cm apex) indicated that malate might contribute to citrate secretion by keeping the balance between citrate synthesis and release in the root apices. Quantification of enzymes involved in organic acid metabolism showed only a 16% increase in citrate synthase activity upon Al treatments (6 h) with no differences in other enzymes. Hence, we could not rule out completely the potential contribution of citrate from shoots and the results are discussed in the light of shoots contributing either energy or citrate itself for enhanced citrate secretion in the Al‐tolerant plant roots.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 8
Claim · model-written summary
Citrate secretion increased with aluminium concentration over 24 hours.
- Taxon
- soybean
Glycine maxt0 - Treatment
- Al (0–70 μ M )e0
- Outcome
- amount of citrate secretede0
- Direction
- increasede0
- Qualifier
- 24‐h Al treatment periode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The amount of citrate secreted during the 24‐h Al treatment period increased with increasing concentration of Al (0–70 μ M ).”
t0“soybean”
Claim · model-written summary
High citrate secretion required a four-hour induction period.
- Taxon
- soybeanGlycine maxe0
- Outcome
- high rate of citrate secretione0
- Qualifier
- 4‐h induction periode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The results indicate that high rate of citrate secretion in soybean requires a 4‐h induction period.”
Claim · model-written summary
Aluminium continued to affect citrate secretion after removal.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Ale0
- Outcome
- citrate secretione0
- Qualifier
- when Al was removed from the treatment solutione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Al had a continuous effect on the citrate secretion when Al was removed from the treatment solution.”
t0“soybean”
Claim · model-written summary
Continuous light steadily increased citrate secretion.
- Taxon
- soybeanGlycine maxt0
- Treatment
- continuous lighte0
- Outcome
- Citrate secretione0
- Direction
- increased steadilye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Citrate secretion increased steadily under exposure to continuous light.”
t0“soybean”
Claim · model-written summary
Shoot excision lowered citrate secretion rate to 3–6 times that of controls.
- Taxon
- soybeanGlycine maxt0
- Treatment
- shoots were excisede0
- Outcome
- citrate secretion ratee0
- Direction
- droppede0
- Value
- 3–6 timese0
- Comparator
- control counterpartse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“However, when the shoots were excised the citrate secretion rate dropped to 3–6 times that of their control counterparts.”
t0“soybean”
Claim · model-written summary
Only aluminium-treated root portions secreted citrate.
- Taxon
- soybeanGlycine maxt0
- Organ / stage
- root portionse0
- Treatment
- Al‐treatede0
- Outcome
- Al‐treated root portions secreted citratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In other words, only the Al‐treated root portions secreted citrate.”
t0“soybean”
Claim · model-written summary
Aluminium increased citrate synthase activity by 16%.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Al treatments (6 h)e0
- Gene
- citrate synthasee0
- Outcome
- citrate synthase activitye0
- Direction
- increasee0
- Value
- 16%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Quantification of enzymes involved in organic acid metabolism showed only a 16% increase in citrate synthase activity upon Al treatments (6 h) with no differences in other enzymes.”
t0“soybean”
Claim · model-written summary
Other organic acid metabolism enzymes showed no difference after aluminium treatment.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Al treatments (6 h)e0
- Outcome
- other enzymese0
- Direction
- no differencese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Quantification of enzymes involved in organic acid metabolism showed only a 16% increase in citrate synthase activity upon Al treatments (6 h) with no differences in other enzymes.”
t0“soybean”
The same questions in other papers
aluminium atom · physiology: enzyme activity · Glycine max (soybean)Results agree
1 paper in the same direction as this paper
- positive
light · molecular: metabolites · Glycine max (soybean)Positive and negative results
26 papers in the same direction as this paper · 20 in the opposite direction · 1 reporting no difference from an alternative
- negative
- no effect
- negative
44 papers more in this group
See all 48 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.