Abstract
BACKGROUND AND AIMS: Flooding results in hypoxia of the root system to which N2 fixation of nodulated roots can be especially sensitive. Morphological adaptions, such as aerenchyma formation, can facilitate the diffusion of oxygen to the hypoxic tissues. Using soybean, the aim of the study was to characterize the morphological response of the nodulated root system to flooding and obtain evidence for the recovery of N metabolism. METHODS: Sections from submerged tissues were observed by light microscopy, while sap bleeding from the xylem was analysed for nitrogenous components. KEY RESULTS: Flooding resulted in the rapid formation of adventitious roots and aerenchyma between the stem (immediately above the water line), roots and nodules. In the submerged stem, taproot, lateral roots and adventitious roots, lysigenous aerenchyma arose initially in the cortex and was gradually substituted by secondary aerenchyma arising from cells derived from the pericycle. Nodules developed aerenchyma from cells originating in the phellogen but nodules situated at depths greater than 7-8 cm showed little or no aerenchyma formation. As a result of aerenchyma formation, porosity of the taproot increased substantially between the 4th and 7th days of flooding, coinciding with the recovery of certain nitrogenous products of N metabolism of roots and nodules transported in the xylem. Thus, on the first day of flooding there was a sharp decline in xylem ureides and glutamine (products of N2 fixation), together with a sharp rise in alanine (product of anaerobic metabolism). Between days 7 and 10, recovery of ureides and glutamine to near initial levels was recorded while recovery of alanine was partial. CONCLUSIONS: N metabolism of the nodulated soybean root system can recover at least partially during a prolonged period of flooding, a process associated with aerenchyma formation.
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Claims 10
Claim · model-written summary
Flooding rapidly formed adventitious roots and aerenchyma.
- Taxon
- soybean
Glycine maxt0 - Treatment
- Floodinge0
- Outcome
- formation of adventitious roots and aerenchymae0
- Direction
- formatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Flooding resulted in the rapid formation of adventitious roots and aerenchyma between the stem (immediately above the water line), roots and nodules.”
t0“soybean”
Claim · model-written summary
Lysigenous aerenchyma arose in cortex and was replaced by secondary aerenchyma from pericycle-derived cells.
- Taxon
- soybeanGlycine maxt0
- Outcome
- lysigenous aerenchyma arose initially in the cortex and was gradually substituted by secondary aerenchymae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lysigenous aerenchyma arose initially in the cortex and was gradually substituted by secondary aerenchyma arising from cells derived from the pericycle.”
t0“soybean”
Claim · model-written summary
Nodule aerenchyma developed from phellogen cells.
- Taxon
- soybeanGlycine maxt0
- Organ / stage
- Nodulese0
- Outcome
- aerenchyma from cells originating in the phellogene0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nodules developed aerenchyma from cells originating in the phellogen”
t0“soybean”
Claim · model-written summary
Nodules deeper than 7–8 cm formed little or no aerenchyma.
- Taxon
- soybeanGlycine maxt0
- Organ / stage
- nodulese0
- Outcome
- aerenchyma formatione0
- Direction
- little or noe0
- Qualifier
- greater than 7-8 cme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nodules situated at depths greater than 7-8 cm showed little or no aerenchyma formation.”
t0“soybean”
Claim · model-written summary
Taproot porosity increased between flooding days four and seven.
- Taxon
- soybeanGlycine maxt0
- Organ / stage
- taproote0
- Outcome
- porositye0
- Direction
- increasede0
- Qualifier
- between the 4th and 7th days of floodinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“porosity of the taproot increased substantially between the 4th and 7th days of flooding”
t0“soybean”
Claim · model-written summary
Xylem ureides and glutamine declined sharply on flooding day one.
- Taxon
- soybeanGlycine maxt0
- Treatment
- floodinge0
- Outcome
- xylem ureides and glutaminee0
- Direction
- declinee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on the first day of flooding there was a sharp decline in xylem ureides and glutamine”
t0“soybean”
Claim · model-written summary
Xylem alanine rose sharply on flooding day one.
- Taxon
- soybeanGlycine maxt0
- Treatment
- floodingt1
- Outcome
- alaninee0
- Direction
- risee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“together with a sharp rise in alanine (product of anaerobic metabolism).”
t0“soybean”
t1“on the first day of flooding”
Claim · model-written summary
Ureides and glutamine recovered nearly to initial levels by days seven to ten.
- Taxon
- soybeanGlycine maxt0
- Outcome
- ureides and glutaminee0
- Direction
- recoverye0
- Qualifier
- Between days 7 and 10e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Between days 7 and 10, recovery of ureides and glutamine to near initial levels was recorded”
t0“soybean”
Claim · model-written summary
Alanine recovered only partially by days seven to ten.
- Taxon
- soybeanGlycine maxt0
- Outcome
- alaninee0
- Direction
- recoverye0
- Qualifier
- partiale0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Between days 7 and 10, recovery of ureides and glutamine to near initial levels was recorded while recovery of alanine was partial.”
t0“soybean”
Claim · model-written summary
The authors associate partial nitrogen metabolism recovery with aerenchyma formation.
- Taxon
- soybeanGlycine maxe0
- Organ / stage
- root systeme0
- Outcome
- N metabolisme0
- Direction
- recovere0
- Qualifier
- aerenchyma formatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N metabolism of the nodulated soybean root system can recover at least partially during a prolonged period of flooding, a process associated with aerenchyma formation.”
The same questions in other papers
flooding · molecular: metabolites · Glycine max (soybean)Positive and negative results
11 papers in the same direction as this paper · 4 in the opposite direction
- negative
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See all 16 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.