Abstract
Abstract Senna occidentalis is an invasive plant producing a series of allelochemicals that might inhibit the development of other plants. The objective of this study was to assess the phytotoxic effect of S . occidentalis extracts on the germination, development and antioxidant defence of the native species Tabebuia chrysotricha , T. pentaphylla , T. roseoalba and Handroanthus impetiginosus (Ipê species). We evaluated the effects of chemicals extracted from S . occidentalis on the germination rate, germination speed index (GSI) and biometric parameters of the test species under controlled conditions. The effect of the extracts on the pigment content, amount of H 2 O 2 and malondialdehyde (MDA), and the activity of the antioxidant enzymes in roots and leaves were also tested. Alkaloids, coumarins, phenols, saponins, free steroids and condensed tannins were present in all extracts of S . occidentalis , while catechins were present only in leaf and stem extracts. Stem and root extracts caused a growth reduction in all Ipê species and total inhibition of seed germination in T . chrysotricha and T . roseoalba . All target species showed an increase in H 2 O 2 and MDA in radicles and leaves. Oxidative stress contributed strongly to the morphological changes, such as seed blackening, thinning and darkening of radicle tips and reduction of biomass allocation in all Ipê species. Although there was activation of antioxidant defence mechanisms, such as an increase in activity of ascorbate peroxidase (APX) and peroxidase (POD) enzymes, the joint action of the allelochemicals caused phytotoxicity, leading to cell dysfunction in all Ipê species.
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Claims 9
Claim · model-written summary
All Senna extracts contained alkaloids, coumarins, phenols, saponins, steroids and tannins.
- Taxon
- S . occidentalis
_Senna_occidentalis_-_Habit_-_Les_Martels%2C_Giroussens_Tarn.jpg?width=60)
Senna occidentalise0 - Outcome
- Alkaloids, coumarins, phenols, saponins, free steroids and condensed tanninse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Senna_occidentalis_-_Habit_-_Les_Martels%2C_Giroussens_Tarn.jpg?width=500)
Verbatim
e0“Alkaloids, coumarins, phenols, saponins, free steroids and condensed tannins were present in all extracts of S . occidentalis”
Claim · model-written summary
Catechins occurred only in Senna leaf and stem extracts.
- Taxon
- S . occidentalisSenna occidentalise1
- Organ / stage
- leaf and steme0
- Outcome
- catechins were present only in leaf and stem extractse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“catechins were present only in leaf and stem extracts”
e1“extracts of S . occidentalis , while catechins”
Claim · model-written summary
Senna stem and root extracts reduced growth of all Ipê species.
- Taxon
- Ipê speciese0
- Treatment
- Stem and root extractse0
- Interactor
- Senna occidentalis (L.) LinkSenna occidentalist0other
- Outcome
- growthe0
- Direction
- reductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stem and root extracts caused a growth reduction in all Ipê species”
t0“Senna occidentalis (L.) Link”
Claim · model-written summary
The extracts totally inhibited seed germination in T. chrysotricha.
- Taxon
- T . chrysotricha
_REFON.jpg?width=60)
Tabebuia chrysotrichae0 - Treatment
- Stem and root extractse1
- Outcome
- seed germinatione0
- Direction
- total inhibitione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_REFON.jpg?width=500)
Verbatim
e0“total inhibition of seed germination in T . chrysotricha and T . roseoalba”
e1“Stem and root extracts caused a growth reduction in all Ipê species”
Claim · model-written summary
The extracts totally inhibited seed germination in T. roseoalba.
- Taxon
- T . roseoalba
Tabebuia roseoalbae0 - Treatment
- Stem and root extractse1
- Outcome
- seed germinatione0
- Direction
- total inhibitione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total inhibition of seed germination in T . chrysotricha and T . roseoalba”
e1“Stem and root extracts caused a growth reduction in all Ipê species”
Claim · model-written summary
All target species showed increased H 2 O 2 and MDA in radicles and leaves.
Not reportedTreatmentComparator
Verbatim
e0“All target species showed an increase in H 2 O 2 and MDA in radicles and leaves”
e1“biomass allocation in all Ipê species”
Claim · model-written summary
Oxidative stress contributed to seed blackening, radicle changes and lower biomass allocation.
Verbatim
e0“Oxidative stress contributed strongly to the morphological changes, such as seed blackening, thinning and darkening of radicle tips and reduction of biomass allocation in all Ipê species”
Claim · model-written summary
Ascorbate peroxidase and peroxidase activity increased as antioxidant defence was activated.
Verbatim
e0“activation of antioxidant defence mechanisms, such as an increase in activity of ascorbate peroxidase (APX) and peroxidase (POD) enzymes”
e1“cell dysfunction in all Ipê species”
Claim · model-written summary
Joint allelochemical action caused phytotoxicity and cell dysfunction in all Ipê species.
Verbatim
e0“the joint action of the allelochemicals caused phytotoxicity, leading to cell dysfunction in all Ipê species”