Abstract
Lower leaves of greenhouse-grown common cocklebur and velvetleaf were shaded to 5% of full light over a 12-d period while upper leaves remained exposed to full light to determine weed foliar and branching responses to partial shading similar to that encountered in soybean crops. Shading increased lower leaf senescence and specific leaf area, and decreased branch length and number of second-order leaves in both species compared to unshaded controls. Common cocklebur branched more extensively along the lower portion of its stem than velvetleaf under both shaded and unshaded conditions. Upper leaves of partially shaded velvetleaf were held in a more perpendicular position to the light source beginning 3 days after treatment (DAT) compared to upper leaves of unshaded plants. Shading of lower leaves caused an increase in upper (unshaded) leaf area beginning 3 and 6 DAT in velvetleaf and common cocklebur, respectively. Petiole length of upper leaves also increased in response to shading in both species. Total plant dry weight at 12 DAT was unaffected by shading in velvetleaf but was reduced 10% by shading in common cocklebur. While common cocklebur maintained greater lower shoot growth in the presence of shade than velvetleaf, there was a greater change in upper leaf angle by velvetleaf in response to shading than by common cocklebur. These results support previous field observations of apparent greater shade tolerance of common cocklebur compared to velvetleaf and indicate that both species have the ability to compensate for shading of lower leaves by altering upper shoot growth.
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Claims 13
Claim · model-written summary
Shading increased lower leaf senescence and specific leaf area in both species.
- Taxon
- Common Cocklebur (Xanthium strumarium) and Velvetleaf (Abutilon theophrasti)
Abutilon theophrasti
Xanthium strumariumt0 - Treatment
- Shadinge0
- Outcome
- lower leaf senescence and specific leaf areae0
- Direction
- increasede0
- Comparator
- unshaded controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Shading increased lower leaf senescence and specific leaf area, and decreased branch length and number of second-order leaves in both species compared to unshaded controls”
t0“Common Cocklebur (Xanthium strumarium) and Velvetleaf (Abutilon theophrasti)”
Claim · model-written summary
Shading reduced branch length and second-order leaf number in both species.
- Taxon
- Common Cocklebur (Xanthium strumarium) and Velvetleaf (Abutilon theophrasti)Abutilon theophrastiXanthium strumariumt0
- Treatment
- Shadinge0
- Outcome
- branch length and number of second-order leavese0
- Direction
- decreasede0
- Comparator
- unshaded controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Shading increased lower leaf senescence and specific leaf area, and decreased branch length and number of second-order leaves in both species compared to unshaded controls”
t0“Common Cocklebur (Xanthium strumarium) and Velvetleaf (Abutilon theophrasti)”
Claim · model-written summary
Cocklebur branched more extensively low on the stem than velvetleaf in both light conditions.
Verbatim
e0“Common cocklebur branched more extensively along the lower portion of its stem than velvetleaf under both shaded and unshaded conditions”
Claim · model-written summary
Partially shaded velvetleaf oriented upper leaves more perpendicularly to light from day 3.
- Taxon
- velvetleafAbutilon theophrastie0
- Treatment
- partially shadede0
- Outcome
- more perpendicular position to the light sourcee0
- Direction
- more perpendiculare0
- Qualifier
- beginning 3 days after treatment (DAT)e0
- Comparator
- unshaded plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Upper leaves of partially shaded velvetleaf were held in a more perpendicular position to the light source beginning 3 days after treatment (DAT) compared to upper leaves of unshaded plants”
Claim · model-written summary
Shading increased upper leaf area in velvetleaf beginning at day 3.
- Taxon
- velvetleafAbutilon theophrastie0
- Treatment
- Shading of lower leavese0
- Outcome
- upper (unshaded) leaf areae0
- Direction
- increasee0
- Qualifier
- 3 and 6 DAT in velvetleaf and common cocklebur, respectivelye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Shading of lower leaves caused an increase in upper (unshaded) leaf area beginning 3 and 6 DAT in velvetleaf and common cocklebur, respectively”
Claim · model-written summary
Shading increased upper leaf area in cocklebur beginning at day 6.
- Taxon
- common cocklebure0
- Treatment
- Shading of lower leavese0
- Outcome
- upper (unshaded) leaf areae0
- Direction
- increasee0
- Qualifier
- 3 and 6 DAT in velvetleaf and common cocklebur, respectivelye0
Not reportedComparator
Verbatim
e0“Shading of lower leaves caused an increase in upper (unshaded) leaf area beginning 3 and 6 DAT in velvetleaf and common cocklebur, respectively”
Claim · model-written summary
Upper leaf petioles lengthened under shading in both species.
- Taxon
- Common Cocklebur (Xanthium strumarium) and Velvetleaf (Abutilon theophrasti)Abutilon theophrastiXanthium strumariumt0
- Treatment
- shadinge0
- Outcome
- Petiole length of upper leavese0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Petiole length of upper leaves also increased in response to shading in both species”
t0“Common Cocklebur (Xanthium strumarium) and Velvetleaf (Abutilon theophrasti)”
Claim · model-written summary
Shading left velvetleaf dry weight unaffected at day 12.
- Taxon
- velvetleafAbutilon theophrastie0
- Treatment
- shadinge0
- Outcome
- Total plant dry weighte0
- Direction
- unaffectede0
- Qualifier
- 12 DATe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total plant dry weight at 12 DAT was unaffected by shading in velvetleaf”
Claim · model-written summary
Shading reduced cocklebur dry weight by 10% at day 12.
- Taxon
- common cocklebure0
- Treatment
- shadinge0
- Outcome
- Total plant dry weighte0
- Direction
- reducede0
- Value
- 10%e0
- Qualifier
- 12 DATe0
Not reportedComparator
Verbatim
e0“Total plant dry weight at 12 DAT was unaffected by shading in velvetleaf but was reduced 10% by shading in common cocklebur”
Claim · model-written summary
Cocklebur maintained greater lower shoot growth under shade than velvetleaf.
Verbatim
e0“common cocklebur maintained greater lower shoot growth in the presence of shade than velvetleaf”
Claim · model-written summary
Velvetleaf changed upper leaf angle more under shading than cocklebur.
- Taxon
- velvetleafAbutilon theophrastie0
- Outcome
- change in upper leaf anglee0
- Direction
- greatere0
- Comparator
- common cocklebure0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was a greater change in upper leaf angle by velvetleaf in response to shading than by common cocklebur”
Claim · model-written summary
The results support greater shade tolerance of cocklebur than velvetleaf.
Verbatim
e0“greater shade tolerance of common cocklebur compared to velvetleaf”
Claim · model-written summary
Both species can compensate for lower-leaf shade by changing upper-shoot growth.
- Taxon
- Common Cocklebur (Xanthium strumarium) and Velvetleaf (Abutilon theophrasti)Abutilon theophrastiXanthium strumariumt0
- Outcome
- compensate for shading of lower leavese0
- Qualifier
- altering upper shoot growthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both species have the ability to compensate for shading of lower leaves by altering upper shoot growth”
t0“Common Cocklebur (Xanthium strumarium) and Velvetleaf (Abutilon theophrasti)”
The same questions in other papers
shade · growth · Xanthium strumarium (cocklebur)Positive and negative results
1 in the opposite direction
- negative
shade · growth · Abutilon theophrasti (velvetleaf)Results agree
2 papers in the same direction as this paper
- positive
- 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.