Abstract
Experiments were conducted to determine the influence of glyphosate [N-(phosphonomethyl)glycine] on extractable nitrate reductase activity during light and dark growth of soybean (Glycine max) seedlings. Glyphosate (5×10−4 M), applied via root-feeding to three-day-old etiolated seedling, significantly reduced enzyme activity in roots (48 to 96 h) and leaves (96 h) of seedlings placed in the light, but had little effect on enzyme activity in cotyledons compared to enzyme levels in tissues of untreated seedlings. During dark-growth, nitrate reductase activity increased with time in cotyledons of untreated seedlings (activity about 85-fold less than in cotyledons of light-grown plants) but much lower enzyme levels were found in cotyledons of glyphosate-treated seedlings after 72 and 96 h. In leaves of dark-grown seedlings, glyphosate reduced nitrate reductase levels by 95%. Most inhibition of extractable enzyme activity occurred in newly developing organs (leaves and roots) which correlates well with reports that glyphosate is rapidly translocated to these sites. However, the fact that glyphosate inhibits growth prior to lowering enzyme activity levels indicates a secondary effect on nitrate reductase.
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Claims 9
Claim · model-written summary
Glyphosate significantly reduced nitrate reductase in roots of light-grown seedlings at 48 to 96 h.
- Taxon
- Soybean
Glycine maxt0 - Organ / stage
- rootse0
- Treatment
- Glyphosate (5×10−4 M)e0
- Outcome
- enzyme activity in rootse0
- Direction
- reducede0
- Qualifier
- 48 to 96 he0
- Comparator
- untreated seedlingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Glyphosate (5×10−4 M), applied via root-feeding to three-day-old etiolated seedling, significantly reduced enzyme activity in roots (48 to 96 h) and leaves (96 h) of seedlings placed in the light, but had little effect on enzyme activity in cotyledons compared to enzyme levels in tissues of untreated seedlings”
t0“Soybean (Glycine max)”
Claim · model-written summary
Glyphosate significantly reduced nitrate reductase in leaves of light-grown seedlings at 96 h.
- Taxon
- SoybeanGlycine maxt0
- Organ / stage
- leavese0
- Treatment
- Glyphosate (5×10−4 M)e0
- Outcome
- enzyme activity in roots (48 to 96 h) and leavese0
- Direction
- reducede0
- Qualifier
- 96 he0
- Comparator
- untreated seedlingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Glyphosate (5×10−4 M), applied via root-feeding to three-day-old etiolated seedling, significantly reduced enzyme activity in roots (48 to 96 h) and leaves (96 h) of seedlings placed in the light, but had little effect on enzyme activity in cotyledons compared to enzyme levels in tissues of untreated seedlings”
t0“Soybean (Glycine max)”
Claim · model-written summary
Glyphosate had little effect on cotyledon enzyme activity in light-grown seedlings.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Glyphosate (5×10−4 M)e0
- Outcome
- enzyme activity in cotyledonse0
- Direction
- little effecte0
- Comparator
- untreated seedlingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Glyphosate (5×10−4 M), applied via root-feeding to three-day-old etiolated seedling, significantly reduced enzyme activity in roots (48 to 96 h) and leaves (96 h) of seedlings placed in the light, but had little effect on enzyme activity in cotyledons compared to enzyme levels in tissues of untreated seedlings”
t0“Soybean (Glycine max)”
Claim · model-written summary
In untreated dark-grown cotyledons nitrate reductase increased over time.
- Taxon
- SoybeanGlycine maxt0
- Organ / stage
- cotyledonse0
- Outcome
- nitrate reductase activitye0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“During dark-growth, nitrate reductase activity increased with time in cotyledons of untreated seedlings”
t0“Soybean (Glycine max)”
Claim · model-written summary
Cotyledon activity in dark-grown plants was about 85-fold less than in light-grown plants.
- Taxon
- SoybeanGlycine maxt0
- Outcome
- activitye0
- Direction
- lesse0
- Value
- 85-folde0
- Comparator
- cotyledons of light-grown plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“activity about 85-fold less than in cotyledons of light-grown plants”
t0“Soybean (Glycine max)”
Claim · model-written summary
Glyphosate-treated dark-grown cotyledons had much lower enzyme levels after 72 and 96 h.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- glyphosate-treatede0
- Outcome
- enzyme levelse0
- Direction
- lowere0
- Qualifier
- after 72 and 96 he0
- Comparator
- untreated seedlingse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“much lower enzyme levels were found in cotyledons of glyphosate-treated seedlings after 72 and 96 h”
e1“cotyledons of untreated seedlings”
t0“Soybean (Glycine max)”
Claim · model-written summary
Glyphosate reduced leaf nitrate reductase by 95% in dark-grown seedlings.
- Taxon
- SoybeanGlycine maxt0
- Organ / stage
- leavese0
- Treatment
- glyphosatee0
- Outcome
- nitrate reductase levelse0
- Direction
- reducede0
- Value
- 95%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In leaves of dark-grown seedlings, glyphosate reduced nitrate reductase levels by 95%”
e1“cotyledons of untreated seedlings”
t0“Soybean (Glycine max)”
Claim · model-written summary
Inhibition was greatest in newly developing leaves and roots.
- Taxon
- SoybeanGlycine maxt0
- Organ / stage
- newly developing organs (leaves and roots)e0
- Outcome
- inhibition of extractable enzyme activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Most inhibition of extractable enzyme activity occurred in newly developing organs (leaves and roots)”
t0“Soybean (Glycine max)”
Claim · model-written summary
Authors interpret nitrate reductase inhibition as secondary because growth inhibition preceded enzyme reduction.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- glyphosatee0
- Outcome
- secondary effect on nitrate reductasee0
- Qualifier
- inhibits growth prior to lowering enzyme activity levelse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“glyphosate inhibits growth prior to lowering enzyme activity levels indicates a secondary effect on nitrate reductase”
t0“Soybean (Glycine max)”
The same questions in other papers
glyphosate · soil: biology · Glycine max (soybean)Positive and negative results
7 papers in the same direction as this paper · 4 in the opposite direction
- positive
- positive
- positive
8 papers more in this group
See all 12 papers →glyphosate · physiology: enzyme activity · Glycine max (soybean)Results agree
4 papers in the same direction as this paper
- negative
- negative
- negative
1 paper more in this group
See all 5 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.