Abstract
Summary Plants protect themselves against potentially harmful UV-B radiation mainly by epidermal accumulation of UV-B shielding phenolic compounds and repair of cellular damage. The capacity and necessity for these protection mechanisms alter with the stage of plant and leaf development, which might be crucial for horticultural hardening techniques aiming at a UV-B pre-acclimation of greenhouse grown seedlings before transplantation to the field. In order to examine the development-dependence of UV-B responses and to estimate the efficiency of different hardening strategies, lettuce ( Lactuca sativa L., var. crispa L. 'Bughatti') was raised in greenhouses covered with a UV-B transmitting and a UV-B excluding covering material and transferred from one treatment to the other at the age of 20 days. Plant fresh mass and flavonoid content were frequently determined. Distribution of flavonoids within the plants was assessed by extraction of different leafage classes. Continuous exposure to near ambient UV-B induced a strong enhancement in cyanidin and quercetin content and a severe growth reduction, whereas late UV-B treatment merely led to a slight enhancement of quercetin in the absence of any growth response. At the leaf level, continuous UV-B exposure caused a comparable quercetin induction at all three stages of leaf development, whereas late treatment caused a much stronger response in young compared to intermediate and old leaves. These findings indicate that UV-B effects on growth and flavonoid content and pattern of lettuce plants are highly dependent on the leaf and plant developmental stage. We conclude that UV-B exposure throughout seedling development is a more efficient hardening strategy than late short-term exposure.
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Claims 6
Claim · model-written summary
Continuous near-ambient UV-B strongly enhanced cyanidin and quercetin content in lettuce.
- Taxon
- lettuce
Lactuca sativae0 - Treatment
- Continuous exposure to near ambient UV-Be1
- Outcome
- cyanidin and quercetin contente1
- Direction
- enhancemente1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lettuce ( Lactuca sativa L., var. crispa L. 'Bughatti')”
e1“Continuous exposure to near ambient UV-B induced a strong enhancement in cyanidin and quercetin content and a severe growth reduction”
Claim · model-written summary
Continuous near-ambient UV-B severely reduced lettuce growth.
- Taxon
- lettuceLactuca sativae0
- Treatment
- Continuous exposure to near ambient UV-Be1
- Outcome
- growthe1
- Direction
- reductione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lettuce ( Lactuca sativa L., var. crispa L. 'Bughatti')”
e1“Continuous exposure to near ambient UV-B induced a strong enhancement in cyanidin and quercetin content and a severe growth reduction”
Claim · model-written summary
Late UV-B treatment merely gave a slight enhancement of quercetin without any growth response in lettuce.
- Taxon
- lettuceLactuca sativae0
- Treatment
- late UV-B treatmente2
- Outcome
- quercetine2
- Direction
- enhancemente2
- Qualifier
- in the absence of any growth responsee2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lettuce ( Lactuca sativa L., var. crispa L. 'Bughatti')”
e2“late UV-B treatment merely led to a slight enhancement of quercetin in the absence of any growth response”
Claim · model-written summary
Continuous UV-B exposure caused a comparable quercetin induction at all three stages of leaf development.
- Taxon
- lettuceLactuca sativae0
- Organ / stage
- all three stages of leaf developmente3
- Treatment
- continuous UV-B exposuree3
- Outcome
- quercetin inductione3
- Direction
- inductione3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lettuce ( Lactuca sativa L., var. crispa L. 'Bughatti')”
e3“At the leaf level, continuous UV-B exposure caused a comparable quercetin induction at all three stages of leaf development”
Claim · model-written summary
Late UV-B treatment caused a much stronger quercetin response in young leaves than in intermediate and old leaves.
- Taxon
- lettuceLactuca sativae0
- Organ / stage
- younge4
- Treatment
- late treatmente4
- Outcome
- responsee4
- Direction
- strongere4
- Comparator
- intermediate and old leavese4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lettuce ( Lactuca sativa L., var. crispa L. 'Bughatti')”
e4“late treatment caused a much stronger response in young compared to intermediate and old leaves”
Claim · model-written summary
UV-B exposure throughout seedling development is a more efficient hardening strategy for lettuce than late short-term exposure.
- Taxon
- lettuceLactuca sativae0
- Treatment
- UV-B exposure throughout seedling developmente5
- Outcome
- a more efficient hardening strategye5
- Comparator
- late short-term exposuree5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lettuce ( Lactuca sativa L., var. crispa L. 'Bughatti')”
e5“We conclude that UV-B exposure throughout seedling development is a more efficient hardening strategy than late short-term exposure”
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See all 13 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.