Abstract
The influence of nitrate availability on growth of seminal roots, and root cytokinin levels, was studied in barley (Hordeum vulgare L. cv Golf). Nitrate was continuously supplied to initially N-starved seedlings at relative addition rates (RA) of 0.03 to 0.21 per day (standard cultures) or at RA 0.09 per day in split root cultures with the nitrate additions distributed in ratios of 100:0 or 80:20 to the two subroots. Data were collected both during a phase of acclimation (first 10 days of N additions) and in the acclimated stage (>10 days after onset of N additions). Limitation of whole-plant growth was observed at RA <0.15 per day. The lateral root frequency increased with RA in plants of equal chronological age. However, the lateral root frequency was related to root size rather than to RA; roots of uneven age but having comparable total root lengths also had comparable lateral root frequencies. Growth of individual subroots in split root systems during acclimation was proportional to the fraction of the total N addition that was fed to the root. All subroots had comparable relative growth rates in acclimated plants, and their lateral root frequency correlated with total root length in the same manner as in standard cultures. Onset of N additions in a 80:20 split root culture resulted in doublings of zeatin riboside (ZR) levels in shoots and in the "80" root, whereas the response of the "20" root was small. No effect of perturbed nitrate availability on xylem translocation of ZR was observed. The ZR levels remained higher in the "80" root during acclimation but returned to the level of the "20" root after acclimation. Root cytokinin levels and xylem translocation in acclimated standard cultures were unaffected by RA in the lower range but increased at high RA. Arguments for involvement of cytokinins in the nitrate-regulated growth response are discussed.
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 13
Claim · model-written summary
Whole-plant barley growth was limited below a nitrate relative addition rate of 0.15 per day.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaree1 - Treatment
- RA <0.15 per daye0
- Outcome
- Limitation of whole-plant growthe0
- Direction
- Limitatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Limitation of whole-plant growth was observed at RA <0.15 per day.”
e1“barley (Hordeum vulgare L. cv Golf)”
Claim · model-written summary
Lateral root frequency rose with nitrate addition rate among equal-aged barley plants.
- Taxon
- barleyHordeum vulgaree1
- Treatment
- RAe0
- Outcome
- lateral root frequencye0
- Direction
- increasede0
- Qualifier
- equal chronological agee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The lateral root frequency increased with RA in plants of equal chronological age.”
e1“barley (Hordeum vulgare L. cv Golf)”
Claim · model-written summary
Lateral root frequency was related to root size rather than nitrate addition rate.
- Taxon
- barleyHordeum vulgaree1
- Organ / stage
- roote0
- Outcome
- lateral root frequencye0
- Qualifier
- related to root size rather than to RAe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the lateral root frequency was related to root size rather than to RA; roots of uneven age but having comparable total root lengths also had comparable lateral root frequencies.”
e1“barley (Hordeum vulgare L. cv Golf)”
Claim · model-written summary
During acclimation, growth of individual barley subroots tracked their share of total nitrogen addition.
- Taxon
- barleyHordeum vulgaree1
- Treatment
- fraction of the total N additione0
- Outcome
- Growth of individual subrootse0
- Direction
- proportionale0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Growth of individual subroots in split root systems during acclimation was proportional to the fraction of the total N addition that was fed to the root.”
e1“barley (Hordeum vulgare L. cv Golf)”
Claim · model-written summary
Acclimated barley subroots had comparable relative growth rates.
- Taxon
- barleyHordeum vulgaree1
- Organ / stage
- subrootse0
- Outcome
- comparable relative growth ratese0
- Qualifier
- acclimated plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All subroots had comparable relative growth rates in acclimated plants, and their lateral root frequency correlated with total root length in the same manner as in standard cultures.”
e1“barley (Hordeum vulgare L. cv Golf)”
Claim · model-written summary
In acclimated plants, lateral root frequency correlated with total root length as in standard cultures.
- Taxon
- barleyHordeum vulgaree1
- Organ / stage
- roote0
- Outcome
- lateral root frequencye0
- Qualifier
- correlated with total root lengthe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“their lateral root frequency correlated with total root length in the same manner as in standard cultures.”
e1“barley (Hordeum vulgare L. cv Golf)”
Claim · model-written summary
Starting nitrate addition in an 80:20 split-root culture doubled shoot zeatin riboside levels.
- Taxon
- barleyHordeum vulgaree1
- Organ / stage
- shootse0
- Treatment
- N additions in a 80:20 split root culturee0
- Outcome
- zeatin riboside (ZR) levelse0
- Direction
- doublingse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Onset of N additions in a 80:20 split root culture resulted in doublings of zeatin riboside (ZR) levels in shoots and in the "80" root, whereas the response of the "20" root was small.”
e1“barley (Hordeum vulgare L. cv Golf)”
Claim · model-written summary
Starting nitrate addition in an 80:20 split-root culture doubled zeatin riboside levels in the 80 root.
- Taxon
- barleyHordeum vulgaree1
- Organ / stage
- "80" roote0
- Treatment
- N additions in a 80:20 split root culturee0
- Outcome
- zeatin riboside (ZR) levelse0
- Direction
- doublingse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Onset of N additions in a 80:20 split root culture resulted in doublings of zeatin riboside (ZR) levels in shoots and in the "80" root, whereas the response of the "20" root was small.”
e1“barley (Hordeum vulgare L. cv Golf)”
Claim · model-written summary
The zeatin riboside response of the 20 root was small.
- Taxon
- barleyHordeum vulgaree1
- Treatment
- N additions in a 80:20 split root culturee0
- Outcome
- response of the "20" roote0
- Direction
- smalle0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Onset of N additions in a 80:20 split root culture resulted in doublings of zeatin riboside (ZR) levels in shoots and in the "80" root, whereas the response of the "20" root was small.”
e1“barley (Hordeum vulgare L. cv Golf)”
Claim · model-written summary
Perturbed nitrate availability had no observed effect on xylem translocation of zeatin riboside.
- Taxon
- barleyHordeum vulgaree1
- Treatment
- perturbed nitrate availabilitye0
- Outcome
- xylem translocation of ZRe0
- Direction
- No effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No effect of perturbed nitrate availability on xylem translocation of ZR was observed.”
e1“barley (Hordeum vulgare L. cv Golf)”
Claim · model-written summary
Zeatin riboside stayed higher in the 80 root during acclimation but returned to the 20-root level afterward.
- Taxon
- barleyHordeum vulgaree1
- Organ / stage
- "80" roote0
- Outcome
- ZR levelse0
- Direction
- highere0
- Qualifier
- during acclimatione0
- Comparator
- "20" roote0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The ZR levels remained higher in the "80" root during acclimation but returned to the level of the "20" root after acclimation.”
e1“barley (Hordeum vulgare L. cv Golf)”
Claim · model-written summary
In acclimated standard cultures, lower nitrate rates did not affect root cytokinin levels or xylem translocation.
- Taxon
- barleyHordeum vulgaree1
- Treatment
- RA in the lower rangee0
- Outcome
- Root cytokinin levels and xylem translocatione0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root cytokinin levels and xylem translocation in acclimated standard cultures were unaffected by RA in the lower range but increased at high RA.”
e1“barley (Hordeum vulgare L. cv Golf)”
Claim · model-written summary
In acclimated standard cultures, high nitrate rates increased root cytokinin levels and xylem translocation.
- Taxon
- barleyHordeum vulgaree1
- Treatment
- high RAe0
- Outcome
- Root cytokinin levels and xylem translocatione0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root cytokinin levels and xylem translocation in acclimated standard cultures were unaffected by RA in the lower range but increased at high RA.”
e1“barley (Hordeum vulgare L. cv Golf)”
The same questions in other papers
nitrogen · nutrient: content · Hordeum vulgare (barley)Results differ
20 papers in the same direction as this paper · 44 in the opposite direction
- no effect
- no effect
- positive
61 papers more in this group
See all 65 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.