Abstract
Abstract The effects of defoliation treatments on plant growth in sunflower ( Helianthus annuus ) were studied in the field. Four defoliation treatments, 0 (control), 37.4, 56.1 and 93.4% of the total leaf dry weight, were applied to plants that had small third leaves. Decreased leaf weight/whole plant weight (F/W) ratios in defoliated plants rapidly recovered to almost the same ratio as that observed in the control within 12 to 16 days after defoliation according to the degree of defoliation. The mechanism involved in the recovery of the F/W ratio in defoliated plants mainly consisted of three parameters: enhancement of (1) carbon distribution ratios in the leaves, (2) photosynthetic activity in the remaining leaves, and (3) retranslocation of carbon from the stem and/or roots to leaves. Inhibitive effects of defoliation on relative growth rate and net assimilation rate were seen at an early stage, but subsequently both rates became larger in defoliated plants than in controls. Defoliated plants tended to show rapid development and expansion of new leaves, and to show increased specific leaf area and protein synthesis in individual leaves. The sugar content of leaves in defoliated plants was higher than that in controls, while the content in both stem and roots was lower. These responses seem to be advantageous for development of the photosynthetic system. Heights of defoliated plants were clearly depressed according to the degree of defoliation, and this was attributed largely to differences in the elongation rates of the internodes resulting from defoliation.
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Claims 12
Claim · model-written summary
The reduced leaf-to-plant weight ratio of defoliated sunflower recovered near control levels within 12 to 16 days.
- Taxon
- sunflower
Helianthus annuust0 - Treatment
- defoliated plantse0
- Outcome
- leaf weight/whole plant weight (F/W) ratiose0
- Direction
- recoverede0
- Value
- 12 to 16 dayse0
- Comparator
- the controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“sunflower ( Helianthus annuus )”
e0“Decreased leaf weight/whole plant weight (F/W) ratios in defoliated plants rapidly recovered to almost the same ratio as that observed in the control within 12 to 16 days after defoliation”
Claim · model-written summary
Defoliation enhanced carbon distribution to leaves during ratio recovery.
- Taxon
- sunflowerHelianthus annuust0
- Outcome
- carbon distribution ratios in the leavese0
- Qualifier
- enhancemente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“sunflower ( Helianthus annuus )”
e0“enhancement of (1) carbon distribution ratios in the leaves”
Claim · model-written summary
Defoliation enhanced photosynthetic activity in remaining leaves during ratio recovery.
- Taxon
- sunflowerHelianthus annuust0
- Outcome
- photosynthetic activity in the remaining leavese0
- Qualifier
- photosynthetic activity in the remaining leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“sunflower ( Helianthus annuus )”
e0“(2) photosynthetic activity in the remaining leaves”
Claim · model-written summary
Carbon retranslocation from stems or roots to leaves contributed to recovery.
- Taxon
- sunflowerHelianthus annuust0
- Outcome
- retranslocation of carbon from the stem and/or roots to leavese0
- Qualifier
- retranslocation of carbon from the stem and/or roots to leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“sunflower ( Helianthus annuus )”
e0“(3) retranslocation of carbon from the stem and/or roots to leaves”
Claim · model-written summary
Relative growth rate was inhibited early after defoliation but later exceeded controls.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- defoliatione0
- Outcome
- relative growth ratee0
- Direction
- largere0
- Qualifier
- at an early stagee0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“sunflower ( Helianthus annuus )”
e0“Inhibitive effects of defoliation on relative growth rate and net assimilation rate were seen at an early stage, but subsequently both rates became larger in defoliated plants than in controls”
Claim · model-written summary
Net assimilation rate was inhibited early after defoliation but later exceeded controls.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- defoliatione0
- Outcome
- net assimilation ratee0
- Direction
- largere0
- Qualifier
- at an early stagee0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“sunflower ( Helianthus annuus )”
e0“Inhibitive effects of defoliation on relative growth rate and net assimilation rate were seen at an early stage, but subsequently both rates became larger in defoliated plants than in controls”
Claim · model-written summary
Defoliated plants tended toward rapid development and expansion of new leaves.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- new leavese0
- Outcome
- rapid development and expansion of new leavese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“sunflower ( Helianthus annuus )”
e0“Defoliated plants tended to show rapid development and expansion of new leaves”
Claim · model-written summary
Defoliated plants tended toward increased specific leaf area and protein synthesis.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- individual leavese0
- Outcome
- specific leaf area and protein synthesise0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“sunflower ( Helianthus annuus )”
e0“increased specific leaf area and protein synthesis in individual leaves”
Claim · model-written summary
Defoliated sunflower leaves had higher sugar content than controls.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- defoliated plantse0
- Outcome
- sugar content of leavese0
- Direction
- highere0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“sunflower ( Helianthus annuus )”
e0“The sugar content of leaves in defoliated plants was higher than that in controls”
Claim · model-written summary
Defoliated sunflower stems and roots had lower sugar content than controls.
- Taxon
- sunflowerHelianthus annuust0
- Outcome
- content in both stem and rootse0
- Direction
- lowere0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“sunflower ( Helianthus annuus )”
e0“while the content in both stem and roots was lower”
Claim · model-written summary
Sunflower plant height was depressed increasingly with degree of defoliation.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- defoliatione0
- Outcome
- Heights of defoliated plantse0
- Direction
- depressede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“sunflower ( Helianthus annuus )”
e0“Heights of defoliated plants were clearly depressed according to the degree of defoliation”
Claim · model-written summary
Differences in internode elongation rates were attributed as the cause of reduced height after defoliation.
- Taxon
- sunflowerHelianthus annuust0
- Outcome
- elongation rates of the internodese0
- Qualifier
- differences in the elongation rates of the internodese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“sunflower ( Helianthus annuus )”
e0“this was attributed largely to differences in the elongation rates of the internodes resulting from defoliation”
The same questions in other papers
pruning · growth · Helianthus annuus (common sunflower)Positive and negative results
4 papers in the same direction as this paper · 3 in the opposite direction
- no effect
- negative
- negative
4 papers more in this group
See all 8 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.