Abstract
Mitotic activity was studied in the root apices of aeroponically grown sunflower seedlings (Helianthus annum L. var. Russian Giant) which were draughted or treated with abscisic acid (ABA) over a 7 d period. Labelling index (LI) and mitotic index (MI) were scored from autoradiographs of median longitudinal sections of [3H] methyl-thymidine treated root apices. Both drought stress and ABA-treatment (at a concentration of 10−2 mol m−3 inhibited DNA synthesis and mitosis within the first 6 h of treatment. The depression of mitotic activity was first evident in the proximal regions of the meristem (1000–1500 μm from the cap junction). This was followed by a general depression of mitotic activity throughout the meristem which was, in turn, followed by a partial recovery of mitotic activity in the distal regions of the meristem. The beginning of this partial recovery was concurrent with the activation of the quiescent centre (QC). Treatment with lower concentrations of ABA (10−3 mol m−3 and 10−4 mol m−3) also inhibited mitotic activity. Exogenous supplements of sucrose to the plant did not alleviate the inhibition of mitotic activity by drought or ABA. These findings support the hypothesis that ABA mediates drought-induced changes in the primary development of sunflower 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 10
Claim · model-written summary
Drought inhibited DNA synthesis and mitosis in sunflower root apices within six hours.
- Taxon
- sunflower
Helianthus annuuse0 - Organ / stage
- root apicese2
- Treatment
- drought stresse1
- Outcome
- DNA synthesis and mitosise1
- Direction
- inhibitede1
- Qualifier
- within the first 6 h of treatmente1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower seedlings (Helianthus annum L. var. Russian Giant)”
e1“Both drought stress and ABA-treatment (at a concentration of 10−2 mol m−3 inhibited DNA synthesis and mitosis within the first 6 h of treatment.”
e2“Mitotic activity was studied in the root apices”
Claim · model-written summary
ABA at 10−2 mol m−3 inhibited DNA synthesis and mitosis in sunflower root apices within six hours.
- Taxon
- sunflowerHelianthus annuuse0
- Organ / stage
- root apicese2
- Treatment
- ABA-treatment (at a concentration of 10−2 mol m−3e1
- Outcome
- DNA synthesis and mitosise1
- Direction
- inhibitede1
- Qualifier
- within the first 6 h of treatmente1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower seedlings (Helianthus annum L. var. Russian Giant)”
e1“Both drought stress and ABA-treatment (at a concentration of 10−2 mol m−3 inhibited DNA synthesis and mitosis within the first 6 h of treatment.”
e2“Mitotic activity was studied in the root apices”
Claim · model-written summary
Mitotic activity first declined in proximal meristem regions.
- Taxon
- sunflowerHelianthus annuuse0
- Organ / stage
- proximal regions of the meristeme1
- Outcome
- mitotic activitye1
- Direction
- depressione1
- Value
- 1000–1500 μme1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower seedlings (Helianthus annum L. var. Russian Giant)”
e1“The depression of mitotic activity was first evident in the proximal regions of the meristem (1000–1500 μm from the cap junction).”
Claim · model-written summary
Mitotic activity then declined throughout the meristem.
- Taxon
- sunflowerHelianthus annuuse0
- Organ / stage
- meristeme1
- Outcome
- mitotic activitye1
- Direction
- depressione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower seedlings (Helianthus annum L. var. Russian Giant)”
e1“This was followed by a general depression of mitotic activity throughout the meristem”
Claim · model-written summary
Mitotic activity partially recovered in distal meristem regions.
- Taxon
- sunflowerHelianthus annuuse0
- Organ / stage
- distal regions of the meristeme1
- Outcome
- mitotic activitye1
- Direction
- partial recoverye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower seedlings (Helianthus annum L. var. Russian Giant)”
e1“followed by a partial recovery of mitotic activity in the distal regions of the meristem.”
Claim · model-written summary
The onset of partial mitotic recovery coincided with quiescent centre activation.
- Taxon
- sunflowerHelianthus annuuse0
- Organ / stage
- quiescent centree1
- Outcome
- partial recoverye1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower seedlings (Helianthus annum L. var. Russian Giant)”
e1“The beginning of this partial recovery was concurrent with the activation of the quiescent centre (QC).”
Claim · model-written summary
Lower ABA concentrations also inhibited mitotic activity.
- Taxon
- sunflowerHelianthus annuuse0
- Treatment
- lower concentrations of ABA (10−3 mol m−3 and 10−4 mol m−3)e1
- Outcome
- mitotic activitye1
- Direction
- inhibitede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower seedlings (Helianthus annum L. var. Russian Giant)”
e1“Treatment with lower concentrations of ABA (10−3 mol m−3 and 10−4 mol m−3) also inhibited mitotic activity.”
Claim · model-written summary
Sucrose supplements did not alleviate drought inhibition of mitotic activity.
- Taxon
- sunflowerHelianthus annuuse0
- Treatment
- Exogenous supplements of sucrosee1
- Outcome
- inhibition of mitotic activitye1
- Direction
- did not alleviatee1
- Comparator
- droughte1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower seedlings (Helianthus annum L. var. Russian Giant)”
e1“Exogenous supplements of sucrose to the plant did not alleviate the inhibition of mitotic activity by drought or ABA.”
Claim · model-written summary
Sucrose supplements did not alleviate ABA inhibition of mitotic activity.
- Taxon
- sunflowerHelianthus annuuse0
- Treatment
- Exogenous supplements of sucrosee1
- Outcome
- inhibition of mitotic activitye1
- Direction
- did not alleviatee1
- Comparator
- ABAe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower seedlings (Helianthus annum L. var. Russian Giant)”
e1“Exogenous supplements of sucrose to the plant did not alleviate the inhibition of mitotic activity by drought or ABA.”
Claim · model-written summary
The results support ABA mediation of drought-related sunflower root development changes.
- Taxon
- sunflowerHelianthus annuuse0
- Treatment
- ABAe1
- Outcome
- primary development of sunflower rootse1
- Qualifier
- drought-induced changese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower seedlings (Helianthus annum L. var. Russian Giant)”
e1“These findings support the hypothesis that ABA mediates drought-induced changes in the primary development of sunflower roots.”
The same questions in other papers
sucrose · disease · Helianthus annuus (common sunflower)Positive and negative results
1 reporting no difference from an alternative
- positive
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.