Paper · 2026 · Biology

Do Plants Need to Be Sprayed? New Insights into VOC-Mediated Biostimulation by Wood Vinegar

Riccardo Fedeli; Stefano Loppi

8
claims
30
verbatim quotes
0
citations
2
research areas
✓
Open access · cc-by

Abstract

Wood vinegar (WV), a by-product of biomass pyrolysis rich in organic acids and phenolic compounds, has gained increasing attention as a sustainable input for crop production, mainly through foliar application. However, its high content of volatile organic compounds (VOCs) suggests that WV may (also) interact with plants through the gaseous phase, a pathway that has so far been overlooked. This study tested the hypothesis that WV can modulate plant physiological performance, metabolic status, and nutrient accumulation not only via direct foliar contact but also through exposure to WV-derived VOCs. Lettuce (Lactuca sativa L.) was used as a model crop and grown under controlled environmental conditions. Plants were subjected to weekly treatments consisting of either foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCs released from the same solution in a sealed chamber, without direct contact between the liquid and plant tissues, and were compared with untreated controls. Notably, plants exposed exclusively to WV-derived VOCs showed responses similar to those observed following foliar application. Both treatments significantly increased fresh weight, the content of chlorophyll, total polyphenols and the accumulation of key macro- and micronutrients, including Ca, K, P, S, and Zn. For both treatments, the efficiency of photosystem II remained stable, indicating the absence of photochemical stress, while stomatal conductance, transpiration rate, intercellular CO2 concentration, and net photosynthetic rate were markedly reduced, suggesting a regulated stomatal response. Physiological, biochemical, and mineral parameters were assessed using non-destructive optical techniques, gas exchange measurements, spectrophotometric assays, and X-ray fluorescence analysis. These findings indicate that exposure to the volatile fraction released from WV under the exposure conditions adopted in this study can elicit biostimulant-like responses comparable to those observed after foliar application.

Abstract from the paper’s OpenAlex record; open copy licensed cc-by. 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 8

Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

VOC exposure produced responses similar to foliar application.

Taxon
LettuceLactuca sativae1
Treatment
WV-derived VOCse0
Outcome
responsese0
Direction
similare0
Comparator
foliar applicatione0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Lactuca sativa
Lactuca sativa · Taxonen:User:Geographer · CC BY 1.0 · Wikimedia Commons ↗

Verbatim

e0

“plants exposed exclusively to WV-derived VOCs showed responses similar to those observed following foliar application”

✓ located verbatim in the source · abstract, characters 1006–1123 · show in text ↑
e1

“Lettuce (Lactuca sativa L.) was used as a model crop”

✓ located verbatim in the source · abstract, characters 604–656 · show in text ↑
Intervention effectobservedoriginal resultpositivesignificant (as stated)measured

Claim · model-written summary

Both wood-vinegar treatments significantly increased lettuce fresh weight.

Taxon
LettuceLactuca sativae3
Treatment
foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCse1
Outcome
fresh weighte0
Direction
increasede0
Comparator
untreated controlse2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Lactuca sativa
Lactuca sativa · Taxonen:User:Geographer · CC BY 1.0 · Wikimedia Commons ↗

Verbatim

e0

“Both treatments significantly increased fresh weight, the content of chlorophyll, total polyphenols and the accumulation of key macro- and micronutrients, including Ca, K, P, S, and Zn.”

✓ located verbatim in the source · abstract, characters 1125–1310 · show in text ↑
e1

“foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCs released from the same solution”

✓ located verbatim in the source · abstract, characters 774–871 · show in text ↑
e2

“compared with untreated controls”

✓ located verbatim in the source · abstract, characters 963–995 · show in text ↑
e3

“Lettuce (Lactuca sativa L.)”

✓ located verbatim in the source · abstract, characters 604–631 · show in text ↑
Intervention effectobservedoriginal resultpositivesignificant (as stated)measured

Claim · model-written summary

Both treatments increased chlorophyll and polyphenol content.

Taxon
LettuceLactuca sativae3
Treatment
foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCse1
Outcome
the content of chlorophyll, total polyphenolse0
Direction
increasede0
Comparator
untreated controlse2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Lactuca sativa
Lactuca sativa · Taxonen:User:Geographer · CC BY 1.0 · Wikimedia Commons ↗

Verbatim

e0

“Both treatments significantly increased fresh weight, the content of chlorophyll, total polyphenols and the accumulation of key macro- and micronutrients”

✓ located verbatim in the source · abstract, characters 1125–1278 · show in text ↑
e1

“foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCs released from the same solution”

✓ located verbatim in the source · abstract, characters 774–871 · show in text ↑
e2

“compared with untreated controls”

✓ located verbatim in the source · abstract, characters 963–995 · show in text ↑
e3

“Lettuce (Lactuca sativa L.)”

✓ located verbatim in the source · abstract, characters 604–631 · show in text ↑
Intervention effectobservedoriginal resultpositivesignificant (as stated)measured

Claim · model-written summary

Both treatments increased accumulation of Ca, K and P.

Taxon
LettuceLactuca sativae3
Treatment
foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCse1
Outcome
accumulation of key macro- and micronutrients, including Ca, K, Pe0
Direction
increasede0
Comparator
untreated controlse2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Lactuca sativa
Lactuca sativa · Taxonen:User:Geographer · CC BY 1.0 · Wikimedia Commons ↗

Verbatim

e0

“Both treatments significantly increased fresh weight, the content of chlorophyll, total polyphenols and the accumulation of key macro- and micronutrients, including Ca, K, P, S, and Zn.”

✓ located verbatim in the source · abstract, characters 1125–1310 · show in text ↑
e1

“foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCs released from the same solution”

✓ located verbatim in the source · abstract, characters 774–871 · show in text ↑
e2

“compared with untreated controls”

✓ located verbatim in the source · abstract, characters 963–995 · show in text ↑
e3

“Lettuce (Lactuca sativa L.)”

✓ located verbatim in the source · abstract, characters 604–631 · show in text ↑
Intervention effectobservedoriginal resultpositivesignificant (as stated)measured

Claim · model-written summary

Both treatments increased accumulation of S and Zn.

Taxon
LettuceLactuca sativae3
Treatment
foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCse1
Outcome
accumulation of key macro- and micronutrients, including Ca, K, P, S, and Zne0
Direction
increasede0
Comparator
untreated controlse2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Lactuca sativa
Lactuca sativa · Taxonen:User:Geographer · CC BY 1.0 · Wikimedia Commons ↗

Verbatim

e0

“Both treatments significantly increased fresh weight, the content of chlorophyll, total polyphenols and the accumulation of key macro- and micronutrients, including Ca, K, P, S, and Zn.”

✓ located verbatim in the source · abstract, characters 1125–1310 · show in text ↑
e1

“foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCs released from the same solution”

✓ located verbatim in the source · abstract, characters 774–871 · show in text ↑
e2

“compared with untreated controls”

✓ located verbatim in the source · abstract, characters 963–995 · show in text ↑
e3

“Lettuce (Lactuca sativa L.)”

✓ located verbatim in the source · abstract, characters 604–631 · show in text ↑
Intervention effectobservedoriginal resultno effectmeasured

Claim · model-written summary

Photosystem II efficiency remained stable under both treatments.

Taxon
LettuceLactuca sativae3
Treatment
foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCse1
Outcome
efficiency of photosystem IIe0
Direction
remained stablee0
Comparator
untreated controlse2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Lactuca sativa
Lactuca sativa · Taxonen:User:Geographer · CC BY 1.0 · Wikimedia Commons ↗

Verbatim

e0

“For both treatments, the efficiency of photosystem II remained stable”

✓ located verbatim in the source · abstract, characters 1311–1380 · show in text ↑
e1

“foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCs released from the same solution”

✓ located verbatim in the source · abstract, characters 774–871 · show in text ↑
e2

“compared with untreated controls”

✓ located verbatim in the source · abstract, characters 963–995 · show in text ↑
e3

“Lettuce (Lactuca sativa L.)”

✓ located verbatim in the source · abstract, characters 604–631 · show in text ↑
Intervention effectobservedoriginal resultmeasured

Claim · model-written summary

Stomatal conductance, transpiration and intercellular CO2 were reduced under both treatments.

Taxon
LettuceLactuca sativae3
Treatment
foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCse1
Outcome
stomatal conductance, transpiration rate, intercellular CO2 concentratione0
Direction
reducede0
Comparator
untreated controlse2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Lactuca sativa
Lactuca sativa · Taxonen:User:Geographer · CC BY 1.0 · Wikimedia Commons ↗

Verbatim

e0

“stomatal conductance, transpiration rate, intercellular CO2 concentration, and net photosynthetic rate were markedly reduced”

✓ located verbatim in the source · abstract, characters 1436–1560 · show in text ↑
e1

“foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCs released from the same solution”

✓ located verbatim in the source · abstract, characters 774–871 · show in text ↑
e2

“compared with untreated controls”

✓ located verbatim in the source · abstract, characters 963–995 · show in text ↑
e3

“Lettuce (Lactuca sativa L.)”

✓ located verbatim in the source · abstract, characters 604–631 · show in text ↑
Intervention effectobservedoriginal resultmeasured

Claim · model-written summary

Net photosynthetic rate was markedly reduced under both treatments.

Taxon
LettuceLactuca sativae3
Treatment
foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCse1
Outcome
net photosynthetic ratee0
Direction
reducede0
Comparator
untreated controlse2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Lactuca sativa
Lactuca sativa · Taxonen:User:Geographer · CC BY 1.0 · Wikimedia Commons ↗

Verbatim

e0

“stomatal conductance, transpiration rate, intercellular CO2 concentration, and net photosynthetic rate were markedly reduced”

✓ located verbatim in the source · abstract, characters 1436–1560 · show in text ↑
e1

“foliar spraying with a 0.2% (v/v) WV solution or exposure to VOCs released from the same solution”

✓ located verbatim in the source · abstract, characters 774–871 · show in text ↑
e2

“compared with untreated controls”

✓ located verbatim in the source · abstract, characters 963–995 · show in text ↑
e3

“Lettuce (Lactuca sativa L.)”

✓ located verbatim in the source · abstract, characters 604–631 · show in text ↑

volatile organic compound · growth · Lactuca sativa (garden lettuce)Positive and negative results

3 papers: 2 positive, 1 negative or no effect

1 paper in the same direction as this paper · 1 in the opposite direction

  1. negative
  2. positive
See all 3 papers →

application · molecular: metabolites · Lactuca sativa (garden lettuce)Positive and negative results

17 papers: 13 positive, 4 negative or no effect

12 papers in the same direction as this paper · 4 in the opposite direction

  1. negative
  2. no effect
  3. negative

13 papers more in this group

See all 17 papers →

application · growth · Lactuca sativa (garden lettuce)Positive and negative results

72 papers: 64 positive, 8 negative or no effect

63 papers in the same direction as this paper · 7 in the opposite direction · 1 reporting no difference from an alternative

  1. negative
  2. negative
  3. no effect

68 papers more in this group

See all 72 papers →

application · physiology: pigments · Lactuca sativa (garden lettuce)Results agree

19 papers: 19 positive, 0 negative or no effect

18 papers in the same direction as this paper

  1. positive
  2. positive
  3. positive

15 papers more in this group

See all 19 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.