Abstract
Viticulture in Michigan is often limited by cool and humid climate conditions that impact vine growth and the achievement of adequate fruit quality at harvest. Sugars, pH, acids, and yeast available nitrogen (YAN) are indices of quality and, as such, of suitability for wine production. The aim of this study was to evaluate the efficacy of foliar nitrogen (N) fertilization applied as a 1% w/v urea solution at veraison as a method to increase canopy N availability during the fruit ripening stage. To test the effect on different source sink conditions, we imposed three levels of defoliation (0%, 33%, and 66% of leaves removed per vine) and measured net photosynthetic rate (P n ), leaf efficiency parameters, yield components, and fruit quality parameters. Apical leaf P n was increased by the 33% defoliation (+12% from the undefoliated control) and by the urea application (+6%) 2 weeks after veraison. In basal leaves we observed a reduction in chlorophyll content (SPAD) and maximum photochemical efficiency of PSII (F v /F m ) as a result of the defoliation treatment and secondarily by the N application, which resulted in a reduction in P n . Therefore, mean shoot P n was unaffected by the treatments. Although neither main nor lateral shoot growth was increased by any defoliation treatment, both percent soluble solids (%SS) and berry weight were significantly reduced by the 66% defoliation treatment. Application of urea increased yeast available amino acids by 20% but did not impact %SS or other chemical parameters indicating a different accumulation pathway for sugars and amino acids in the berry.
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Claims 12
Claim · model-written summary
Defoliation at 33% increased apical leaf net photosynthesis by 12% over the undefoliated control.
- Taxon
- Vitis vinifera
Vitis viniferat1 - Material
- Chardonnayt1
- Organ / stage
- Apical leafe1
- Treatment
- 33% defoliatione1
- Outcome
- Apical leaf P ne1
- Direction
- increasede1
- Value
- +12%e1
- Qualifier
- 2 weeks after veraisone1
- Comparator
- undefoliated controle1
- Setting
- Michigane0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Viticulture in Michigan is often limited by cool and humid climate conditions”
e1“Apical leaf P n was increased by the 33% defoliation (+12% from the undefoliated control) and by the urea application (+6%) 2 weeks after veraison”
t1“‘Chardonnay’ (Vitis vinifera L.) Grapevines”
Claim · model-written summary
Defoliation reduced basal leaf chlorophyll content (SPAD).
- Taxon
- Vitis viniferaVitis viniferat1
- Material
- Chardonnayt1
- Organ / stage
- basal leavese2
- Treatment
- defoliation treatmente2
- Outcome
- chlorophyll content (SPAD)e2
- Direction
- reductione2
- Setting
- Michigane0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Viticulture in Michigan is often limited by cool and humid climate conditions”
e2“In basal leaves we observed a reduction in chlorophyll content (SPAD) and maximum photochemical efficiency of PSII (F v /F m ) as a result of the defoliation treatment and secondarily by the N application, which resulted in a reduction in P n”
t1“‘Chardonnay’ (Vitis vinifera L.) Grapevines”
Claim · model-written summary
Defoliation reduced maximum photochemical efficiency of PSII (Fv/Fm) in basal leaves.
- Taxon
- Vitis viniferaVitis viniferat1
- Material
- Chardonnayt1
- Organ / stage
- basal leavese2
- Treatment
- defoliation treatmente2
- Outcome
- maximum photochemical efficiency of PSII (F v /F m )e2
- Direction
- reductione2
- Setting
- Michigane0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Viticulture in Michigan is often limited by cool and humid climate conditions”
e2“In basal leaves we observed a reduction in chlorophyll content (SPAD) and maximum photochemical efficiency of PSII (F v /F m ) as a result of the defoliation treatment and secondarily by the N application, which resulted in a reduction in P n”
t1“‘Chardonnay’ (Vitis vinifera L.) Grapevines”
Claim · model-written summary
Nitrogen application secondarily reduced basal leaf chlorophyll content (SPAD) and photochemical efficiency.
- Taxon
- Vitis viniferaVitis viniferat1
- Material
- Chardonnayt1
- Organ / stage
- basal leavese2
- Treatment
- N applicatione2
- Outcome
- chlorophyll content (SPAD) and maximum photochemical efficiency of PSII (F v /F m )e2
- Direction
- reductione2
- Qualifier
- secondarilye2
- Setting
- Michigane0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Viticulture in Michigan is often limited by cool and humid climate conditions”
e2“In basal leaves we observed a reduction in chlorophyll content (SPAD) and maximum photochemical efficiency of PSII (F v /F m ) as a result of the defoliation treatment and secondarily by the N application, which resulted in a reduction in P n”
t1“‘Chardonnay’ (Vitis vinifera L.) Grapevines”
Claim · model-written summary
Nitrogen application reduced basal leaf net photosynthesis.
- Taxon
- Vitis viniferaVitis viniferat1
- Material
- Chardonnayt1
- Organ / stage
- basal leavese2
- Treatment
- N applicatione2
- Outcome
- P ne2
- Direction
- reductione2
- Setting
- Michigane0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Viticulture in Michigan is often limited by cool and humid climate conditions”
e2“In basal leaves we observed a reduction in chlorophyll content (SPAD) and maximum photochemical efficiency of PSII (F v /F m ) as a result of the defoliation treatment and secondarily by the N application, which resulted in a reduction in P n”
t1“‘Chardonnay’ (Vitis vinifera L.) Grapevines”
Claim · model-written summary
Mean shoot net photosynthesis was unaffected by the treatments.
- Taxon
- Vitis viniferaVitis viniferat1
- Material
- Chardonnayt1
- Treatment
- treatmentse3
- Outcome
- mean shoot P ne3
- Direction
- no_changeinferrede3
- Setting
- Michigane0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Viticulture in Michigan is often limited by cool and humid climate conditions”
e3“Therefore, mean shoot P n was unaffected by the treatments”
t1“‘Chardonnay’ (Vitis vinifera L.) Grapevines”
Claim · model-written summary
Foliar urea application at veraison increased apical leaf net photosynthesis by 6%.
- Taxon
- Vitis viniferaVitis viniferat1
- Material
- Chardonnayt1
- Organ / stage
- Apical leafe1
- Treatment
- urea applicatione1
- Outcome
- Apical leaf P ne1
- Direction
- increasede1
- Value
- +6%e1
- Qualifier
- 2 weeks after veraisone1
- Setting
- Michigane0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Viticulture in Michigan is often limited by cool and humid climate conditions”
e1“Apical leaf P n was increased by the 33% defoliation (+12% from the undefoliated control) and by the urea application (+6%) 2 weeks after veraison”
t1“‘Chardonnay’ (Vitis vinifera L.) Grapevines”
Claim · model-written summary
Defoliation did not increase main or lateral shoot growth.
- Taxon
- Vitis viniferaVitis viniferat1
- Material
- Chardonnayt1
- Treatment
- defoliation treatmente4
- Outcome
- main nor lateral shoot growthe4
- Direction
- no_changeinferrede4
- Setting
- Michigane0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Viticulture in Michigan is often limited by cool and humid climate conditions”
e4“Although neither main nor lateral shoot growth was increased by any defoliation treatment”
t1“‘Chardonnay’ (Vitis vinifera L.) Grapevines”
Claim · model-written summary
The 66% defoliation treatment reduced percent soluble solids and berry weight.
- Taxon
- Vitis viniferaVitis viniferat1
- Material
- Chardonnayt1
- Treatment
- 66% defoliation treatmente5
- Outcome
- percent soluble solids (%SS) and berry weighte5
- Direction
- reducede5
- Setting
- Michigane0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Viticulture in Michigan is often limited by cool and humid climate conditions”
e5“both percent soluble solids (%SS) and berry weight were significantly reduced by the 66% defoliation treatment”
t1“‘Chardonnay’ (Vitis vinifera L.) Grapevines”
Claim · model-written summary
Urea application increased yeast available amino acids in berries by 20%.
- Taxon
- Vitis viniferaVitis viniferat1
- Material
- Chardonnayt1
- Treatment
- Application of ureae6
- Outcome
- yeast available amino acidse6
- Direction
- increasede6
- Value
- 20%e6
- Setting
- Michigane0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Viticulture in Michigan is often limited by cool and humid climate conditions”
e6“Application of urea increased yeast available amino acids by 20% but did not impact %SS or other chemical parameters”
t1“‘Chardonnay’ (Vitis vinifera L.) Grapevines”
Claim · model-written summary
Urea application did not change percent soluble solids or other chemical parameters of berries.
- Taxon
- Vitis viniferaVitis viniferat1
- Material
- Chardonnayt1
- Treatment
- Application of ureae6
- Outcome
- %SS or other chemical parameterse6
- Direction
- no_changeinferrede6
- Setting
- Michigane0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Viticulture in Michigan is often limited by cool and humid climate conditions”
e6“Application of urea increased yeast available amino acids by 20% but did not impact %SS or other chemical parameters”
t1“‘Chardonnay’ (Vitis vinifera L.) Grapevines”
Claim · model-written summary
Urea and defoliation results indicate a different accumulation pathway for sugars and amino acids in grape berries.
- Taxon
- Vitis viniferaVitis viniferat1
- Organ / stage
- berrye7
- Outcome
- a different accumulation pathway for sugars and amino acidse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“indicating a different accumulation pathway for sugars and amino acids in the berry”
t1“‘Chardonnay’ (Vitis vinifera L.) Grapevines”
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