Abstract
Two upland rice varieties, Azucena and Bala, were screened for root response to drought in two field sites with slightly different penetration resistance characteristics at the West Africa Rice Development Association (WARDA, Côte d'Ivoire) during the dry season of 1999/2000. The soil was a freely drained sandy clay loam Paleudult containing frequent gravelly iron concretions. The number of nodal root axes per unit area passing through horizontal transects (root density) was counted at 35, 56, 77 and 98 DAS at 10 cm depth intervals. Azucena consistently maintained a greater root density and rooting depth than Bala. Azucena was also able to access water at greater depth although it did not extract significantly more soil water from the profile. There were no consistent site differences but root density and depth were significantly greater on irrigated plots. There was no variety by treatment interaction suggesting that the response of Azucena and Bala were similar. Penetration resistance (PR) between 0-30 cm depth increased greatly during the drought, in line with a reduction in soil water content. This was likely to prevent or greatly impair further nodal root growth within this layer. At 40 cm depth, PR was high (3-4 MPa) and did not increase under drought, at this depth root growth rate was likely to be greatly reduced despite the availability of water. Our results suggest that varietal differences in root morphology characterised in the laboratory can be detected in impeding field soils as difference in the density of roots at depth. Relatively poor root growth in these fields in the absence of drought was probably due to the high mechanical impedance and/or the physiological stress of the plants in dry season screens. Further reductions in root growth under drought treatments could be due either to the higher mechanical impedance in the upper portions of the soil or the further increase in plant water stress as the soil dries. We suggest that root response to mechanical impedance was a more fundamental constraint than root response to water stress during the drought. Thus, varietal differences to impedance could be importance for drought avoidance in soils of this type.
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Claims 14
Claim · model-written summary
Azucena maintained greater root density and rooting depth than Bala.
- Taxon
- rice varieties
Oryza sativat0 - Material
- Azucenae0
- Outcome
- root density and rooting depthe0
- Direction
- greatere0
- Comparator
- Balae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Azucena consistently maintained a greater root density and rooting depth than Bala.”
t0“rice varieties”
Claim · model-written summary
Azucena accessed water at greater depth than Bala.
- Taxon
- rice varietiesOryza sativat0
- Material
- Azucenae0
- Outcome
- access watere0
- Direction
- greater depthe0
- Comparator
- Balae1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Azucena was also able to access water at greater depth although it did not extract significantly more soil water from the profile.”
e1“Azucena consistently maintained a greater root density and rooting depth than Bala.”
t0“rice varieties”
Claim · model-written summary
Azucena did not extract significantly more soil water from the profile.
- Taxon
- rice varietiesOryza sativat0
- Material
- Azucenae1
- Outcome
- soil water from the profilee0
- Direction
- did not extract significantly moree0
- Comparator
- Balae1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it did not extract significantly more soil water from the profile”
e1“Azucena consistently maintained a greater root density and rooting depth than Bala.”
t0“rice varieties”
Claim · model-written summary
Root density and depth were significantly greater on irrigated plots.
- Taxon
- rice varietiesOryza sativat0
- Treatment
- irrigated plotse0
- Outcome
- root density and depthe0
- Direction
- greatere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There were no consistent site differences but root density and depth were significantly greater on irrigated plots.”
t0“rice varieties”
Claim · model-written summary
There were no consistent site differences in root density and depth.
- Taxon
- rice varietiesOryza sativat0
- Outcome
- site differencese0
- Direction
- no consistente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There were no consistent site differences but root density and depth were significantly greater on irrigated plots.”
t0“rice varieties”
Claim · model-written summary
Azucena and Bala responded similarly to irrigation treatment.
- Taxon
- rice varietiesOryza sativat0
- Material
- Azucena and Balae0
- Treatment
- treatmente0
- Outcome
- response of Azucena and Balae0
- Direction
- similare0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was no variety by treatment interaction suggesting that the response of Azucena and Bala were similar.”
t0“rice varieties”
Claim · model-written summary
Penetration resistance at 0-30 cm increased greatly during drought, alongside declining soil water content.
- Taxon
- rice varietiesOryza sativat0
- Treatment
- droughte0
- Outcome
- Penetration resistance (PR) between 0-30 cm depthe0
- Direction
- increased greatlye0
- Qualifier
- reduction in soil water contente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Penetration resistance (PR) between 0-30 cm depth increased greatly during the drought, in line with a reduction in soil water content.”
t0“rice varieties”
Claim · model-written summary
Penetration resistance at 40 cm was 3-4 MPa and did not increase under drought.
Not reportedTaxon
Verbatim
e0“At 40 cm depth, PR was high (3-4 MPa) and did not increase under drought”
Claim · model-written summary
High penetration resistance at 40 cm likely greatly reduced rice root growth despite available water.
- Taxon
- rice varietiesOryza sativat0
- Outcome
- root growth ratee0
- Direction
- greatly reducede0
- Qualifier
- PR was high (3-4 MPa)e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“at this depth root growth rate was likely to be greatly reduced despite the availability of water.”
e1“At 40 cm depth, PR was high (3-4 MPa) and did not increase under drought”
t0“rice varieties”
Claim · model-written summary
Laboratory root morphology differences between varieties were detectable as root-density differences at depth in impeding field soils.
- Taxon
- rice varietiesOryza sativat0
- Outcome
- difference in the density of roots at depthe0
- Setting
- impeding field soilse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Our results suggest that varietal differences in root morphology characterised in the laboratory can be detected in impeding field soils as difference in the density of roots at depth.”
t0“rice varieties”
Claim · model-written summary
Poor root growth without drought was probably due to mechanical impedance and/or physiological stress.
- Taxon
- rice varietiesOryza sativat0
- Outcome
- Relatively poor root growthe0
- Qualifier
- high mechanical impedance and/or the physiological stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Relatively poor root growth in these fields in the absence of drought was probably due to the high mechanical impedance and/or the physiological stress of the plants in dry season screens.”
t0“rice varieties”
Claim · model-written summary
Additional root-growth reductions under drought could reflect upper-soil impedance or increasing plant water stress.
- Taxon
- rice varietiesOryza sativat0
- Treatment
- drought treatmentse0
- Outcome
- Further reductions in root growthe0
- Qualifier
- higher mechanical impedance in the upper portions of the soil or the further increase in plant water stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Further reductions in root growth under drought treatments could be due either to the higher mechanical impedance in the upper portions of the soil or the further increase in plant water stress as the soil dries.”
t0“rice varieties”
Claim · model-written summary
Root response to mechanical impedance was suggested to constrain rice more fundamentally than water stress during drought.
- Taxon
- rice varietiesOryza sativat0
- Outcome
- root response to mechanical impedancee0
- Qualifier
- during the droughte0
- Comparator
- root response to water stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We suggest that root response to mechanical impedance was a more fundamental constraint than root response to water stress during the drought.”
t0“rice varieties”
Claim · model-written summary
Varietal differences in impedance response could matter for drought avoidance in this soil type.
- Taxon
- rice varietiesOryza sativat0
- Outcome
- drought avoidancee0
- Qualifier
- varietal differences to impedancee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Thus, varietal differences to impedance could be importance for drought avoidance in soils of this type.”
t0“rice varieties”
The same questions in other papers
irrigation · growth · Oryza sativa (rice)Positive and negative results
221 papers in the same direction as this paper · 62 in the opposite direction · 7 reporting no difference from an alternative
- negative
- negative
- negative
287 papers more in this group
See all 291 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.