Abstract
The growth and circumnutation of the stem of three-week old Helianthus annuus in the 16:8 h light:dark photoperiod were monitored using an angular position-sensing transducer and a time lapse photography system. It was found that the rate of growth and circumnutation reached a high level in the dark stage; in the light stage, however, only the growth rate reached the same high level, whereas the circumnutations were weak. These results showed that in the light stage the stem circumnutation was downregulated more strongly than the growth. Short-term stem responses to darkening and illumination were a further display of the relation between growth and circumnutations. Switching off the light caused an increase in the growth and circumnutation rate. In some cases it was accompanied by changes in the rotation direction. On the other hand, switching the light on caused an immediate transient (several-minute long) decrease in the growth rate resulting in stem contraction, and this was accompanied by an almost complete pause of circumnutation. Additionally, under light, there occurred a subsequent decrease in the magnitude, disturbance of circumnutation trajectory and, in some cases, changes in the direction of rotation. The observed stem contraction and disturbance of circumnutation imply the occurrence of turgor changes in sunflower stem, which may be caused by a non-wounding, darkening or illumination stimulus. Our experiments indicate that the disturbances of the growth rate are accompanied by changes in circumnutation parameters but we have also seen that there is no simple quantitative relation between growth rate and circumnutation rate.
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Claims 13
Claim · model-written summary
Circumnutation of sunflower stems was weak in the light stage compared with the dark stage, where it reached a high level.
- Taxon
- Helianthus annuus
Helianthus annuuse0 - Treatment
- light stagee2
- Outcome
- circumnutationse2
- Direction
- weake2
- Comparator
- dark stagee1
- Setting
- 16:8 h light:dark photoperiode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three-week old Helianthus annuus in the 16:8 h light:dark photoperiod”
e1“It was found that the rate of growth and circumnutation reached a high level in the dark stage”
e2“in the light stage, however, only the growth rate reached the same high level, whereas the circumnutations were weak”
Claim · model-written summary
In the light stage, growth rate reached the same high level as in the dark stage.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- light stagee2
- Outcome
- growth ratee2
- Direction
- no_changeinferrede2
- Comparator
- dark stagee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three-week old Helianthus annuus in the 16:8 h light:dark photoperiod”
e1“It was found that the rate of growth and circumnutation reached a high level in the dark stage”
e2“in the light stage, however, only the growth rate reached the same high level, whereas the circumnutations were weak”
Claim · model-written summary
In the light stage, stem circumnutation was downregulated more strongly than growth.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- light stagee3
- Outcome
- stem circumnutatione3
- Direction
- downregulatede3
- Comparator
- growthe3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three-week old Helianthus annuus in the 16:8 h light:dark photoperiod”
e3“in the light stage the stem circumnutation was downregulated more strongly than the growth”
Claim · model-written summary
Switching off the light increased growth and circumnutation rate.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- Switching off the lighte4
- Outcome
- growth and circumnutation ratee4
- Direction
- increasee4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three-week old Helianthus annuus in the 16:8 h light:dark photoperiod”
e4“Switching off the light caused an increase in the growth and circumnutation rate”
Claim · model-written summary
Switching the light on caused an immediate transient decrease in growth rate.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- switching the light one5
- Outcome
- growth ratee5
- Direction
- decreasee5
- Qualifier
- immediate transient (several-minute long)e5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three-week old Helianthus annuus in the 16:8 h light:dark photoperiod”
e5“switching the light on caused an immediate transient (several-minute long) decrease in the growth rate resulting in stem contraction”
Claim · model-written summary
Switching the light on resulted in stem contraction.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- switching the light one5
- Outcome
- stem contractione5
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three-week old Helianthus annuus in the 16:8 h light:dark photoperiod”
e5“switching the light on caused an immediate transient (several-minute long) decrease in the growth rate resulting in stem contraction”
Claim · model-written summary
Switching the light on was accompanied by an almost complete pause of circumnutation.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- switching the light one5
- Outcome
- pause of circumnutatione6
- Qualifier
- almost completee6
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three-week old Helianthus annuus in the 16:8 h light:dark photoperiod”
e5“switching the light on caused an immediate transient (several-minute long) decrease in the growth rate resulting in stem contraction”
e6“this was accompanied by an almost complete pause of circumnutation”
Claim · model-written summary
Under light, the magnitude of circumnutation subsequently decreased.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- under lighte1
- Outcome
- magnitudee1
- Direction
- decreasee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three-week old Helianthus annuus in the 16:8 h light:dark photoperiod”
e1“Additionally, under light, there occurred a subsequent decrease in the magnitude, disturbance of circumnutation trajectory and, in some cases, changes in the direction of rotation”
Claim · model-written summary
Under light, circumnutation trajectory was disturbed.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- under lighte1
- Outcome
- disturbance of circumnutation trajectorye1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three-week old Helianthus annuus in the 16:8 h light:dark photoperiod”
e1“Additionally, under light, there occurred a subsequent decrease in the magnitude, disturbance of circumnutation trajectory and, in some cases, changes in the direction of rotation”
Claim · model-written summary
Under light, the direction of rotation changed in some cases.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Treatment
- under lighte1
- Outcome
- changes in the direction of rotatione1
- Qualifier
- in some casese1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three-week old Helianthus annuus in the 16:8 h light:dark photoperiod”
e1“Additionally, under light, there occurred a subsequent decrease in the magnitude, disturbance of circumnutation trajectory and, in some cases, changes in the direction of rotation”
Claim · model-written summary
Stem contraction and disturbance of circumnutation imply turgor changes in the sunflower stem.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Outcome
- stem contraction and disturbance of circumnutatione1
- Qualifier
- turgor changes in sunflower steme1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three-week old Helianthus annuus in the 16:8 h light:dark photoperiod”
e1“The observed stem contraction and disturbance of circumnutation imply the occurrence of turgor changes in sunflower stem”
Claim · model-written summary
Disturbances of growth rate are accompanied by changes in circumnutation parameters.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Outcome
- changes in circumnutation parameterse1
- Setting
- 16:8 h light:dark photoperiode0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three-week old Helianthus annuus in the 16:8 h light:dark photoperiod”
e1“Our experiments indicate that the disturbances of the growth rate are accompanied by changes in circumnutation parameters”
Claim · model-written summary
There is no simple quantitative relation between growth rate and circumnutation rate.
- Taxon
- Helianthus annuusHelianthus annuuse0
- Outcome
- simple quantitative relation between growth rate and circumnutation ratee1
- Setting
- 16:8 h light:dark photoperiode0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three-week old Helianthus annuus in the 16:8 h light:dark photoperiod”
e1“there is no simple quantitative relation between growth rate and circumnutation rate”
The same questions in other papers
light · growth · Helianthus annuus (common sunflower)Positive and negative results
9 papers in the same direction as this paper · 13 reporting no difference from an alternative
- positive
- positive
- positive
19 papers more in this group
See all 23 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.