Abstract
Abstract We examined whether extensive dry season dieback and mortality in a South African fynbos community were due to drought or pathogen attack. Plant dieback and mortality have been reported elsewhere in similar plant communities suggesting potential for a widespread climatic or biotic threat to this community. We collected tissue samples from Brunia noduliflora , the dominant plant in the community, and cultured them for potential plant pathogens. We also measured dry season predawn and midday water potentials of healthy and stressed plants and constructed pressure‐volume curves to assess turgor loss point. Plant stress and mortality were monitored over a 2‐year study period. Both healthy plants and plants that displayed moderate signs of stress had dry season predawn water potentials well above their turgor loss point suggesting plants were not water stressed. However, plants displaying >60% crown dieback had much lower water potentials (as low as −12 MPa). A previously undescribed fungus ( Pythium sp.) was isolated from the root vascular tissue of all stressed plants and was not present in healthy plants. The proximate cause of plant stress was likely pathogen‐induced, while the ultimate cause of plant death appears to be extreme water stress. The present study suggests that Brunia (Bruniceae), Leucadendron (Proteaceae) and Erica (Ericaceae), all emblematic and dominant genera within the diverse fynbos community, may be susceptible to Pythium infection. This may pose a serious threat to communities already threatened by climate change.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. 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
Claim · model-written summary
Healthy and moderately stressed plants had predawn water potential above turgor loss.
- Taxon
- Brunia noduliflora
Brunia noduliflorat0 - Outcome
- dry season predawn water potentialse0
- Direction
- well abovee0
- Comparator
- turgor loss pointe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both healthy plants and plants that displayed moderate signs of stress had dry season predawn water potentials well above their turgor loss point”
t0“Brunia noduliflora ,”
Claim · model-written summary
Plants with over 60% crown dieback had water potentials as low as −12 MPa.
- Taxon
- Brunia nodulifloraBrunia noduliflorat0
- Organ / stage
- crowne0
- Outcome
- water potentialse0
- Direction
- much lowere0
- Value
- −12 MPae0
- Qualifier
- >60% crown diebacke0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plants displaying >60% crown dieback had much lower water potentials (as low as −12 MPa)”
t0“Brunia noduliflora ,”
Claim · model-written summary
Pythium was isolated from root vascular tissue of all stressed plants and absent from healthy plants.
- Taxon
- Brunia nodulifloraBrunia noduliflorat0
- Organ / stage
- root vascular tissuee0
- Outcome
- isolated from the root vascular tissue of all stressed plantse0
- Direction
- not presente0
- Comparator
- healthy plantse0
.jpg?width=60){kind=small}
PythiumOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“A previously undescribed fungus ( Pythium sp.) was isolated from the root vascular tissue of all stressed plants and was not present in healthy plants”
t0“Brunia noduliflora ,”
Claim · model-written summary
Pathogen effects were considered the proximate cause of stress.
- Taxon
- Brunia nodulifloraBrunia noduliflorat0
- Outcome
- plant stresse0
- Qualifier
- pathogen‐inducede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The proximate cause of plant stress was likely pathogen‐induced”
t0“Brunia noduliflora ,”
Claim · model-written summary
Extreme water stress was considered the ultimate cause of death.
- Taxon
- Brunia nodulifloraBrunia noduliflorat0
- Outcome
- plant deathe0
- Qualifier
- extreme water stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the ultimate cause of plant death appears to be extreme water stress”
t0“Brunia noduliflora ,”
Claim · model-written summary
Brunia may be susceptible to Pythium infection.
- Outcome
- susceptible to Pythium infectione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Brunia (Bruniceae), Leucadendron (Proteaceae) and Erica (Ericaceae), all emblematic and dominant genera within the diverse fynbos community, may be susceptible to Pythium infection”
Claim · model-written summary
Leucadendron may be susceptible to Pythium infection.
- Taxon
- Leucadendron
Leucadendrone0 - Outcome
- susceptible to Pythium infectione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Brunia (Bruniceae), Leucadendron (Proteaceae) and Erica (Ericaceae), all emblematic and dominant genera within the diverse fynbos community, may be susceptible to Pythium infection”
Claim · model-written summary
Erica may be susceptible to Pythium infection.
- Outcome
- susceptible to Pythium infectione0
EricaNot reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Brunia (Bruniceae), Leucadendron (Proteaceae) and Erica (Ericaceae), all emblematic and dominant genera within the diverse fynbos community, may be susceptible to Pythium infection”