Abstract
Abstract Portulaca oleracea , a C 4 species, is reported to be a serious weed in 45 crops in 81 countries. Experiments were conducted in the laboratory, the screenhouse and the field to determine the influence of environmental factors on seed germination and seedling emergence of P. oleracea . In the laboratory, germination in the dark was low and was not influenced by the tested temperatures (35/25°C, 30/20°C and 25/15°C alternating day/night temperatures). In the light/dark regime, however, germination was lower at 25/15°C and 35/25°C than at 30/20°C (70%, 75% and 81% germination, respectively). In conditions of 106 mM sodium chloride or −0.34 MPa osmotic potential, seeds germinated to only 50% of maximum germination of the control. Germination was not influenced by buffered pH solutions ranging from 5 to 9. In the screenhouse, germination was greatest for seeds placed on the soil surface, but emergence declined with increasing seed burial depth in soil; no seedlings emerged from the depth of 2 cm. Seedling emergence and seedling dry matter were markedly reduced by the addition of rice residue to the soil surface at rates equivalent to 4 to 6 t ha −1 . In the field, seedling emergence of P. oleracea was greater under zero till (ZT) (17–20%) than under minimum tillage (6–10%), a likely reflection of low seed burial and exposure of seeds to light with a ZT system. This study identifies some of the factors enabling P. oleracea to be a widespread weed in the humid tropics, and the information could contribute to improved control strategies.
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Claims 9
Claim · model-written summary
Dark germination was low and unaffected by tested temperatures.
- Taxon
- Portulaca oleracea
Portulaca oleraceat0 - Outcome
- germination in the darke0
- Direction
- lowe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“germination in the dark was low and was not influenced by the tested temperatures”
t0“Portulaca oleracea”
Claim · model-written summary
In light and dark cycles, germination was lower at 25/15 and 35/25 than 30/20 degrees.
- Taxon
- Portulaca oleraceaPortulaca oleraceat0
- Outcome
- germinatione0
- Direction
- lowere0
- Comparator
- 30/20°Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“germination was lower at 25/15°C and 35/25°C than at 30/20°C (70%, 75% and 81% germination, respectively)”
t0“Portulaca oleracea”
Claim · model-written summary
Sodium chloride at 106 mM reduced germination to half the control maximum.
- Taxon
- Portulaca oleraceaPortulaca oleraceat0
- Treatment
- 106 mM sodium chloridee0
- Outcome
- seeds germinatede0
- Value
- 50%e0
- Comparator
- controle0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In conditions of 106 mM sodium chloride or −0.34 MPa osmotic potential, seeds germinated to only 50% of maximum germination of the control”
t0“Portulaca oleracea”
Claim · model-written summary
Osmotic potential of minus 0.34 MPa reduced germination to half the control maximum.
- Taxon
- Portulaca oleraceaPortulaca oleraceat0
- Treatment
- −0.34 MPa osmotic potentiale0
- Outcome
- seeds germinatede0
- Value
- 50%e0
- Comparator
- controle0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“−0.34 MPa osmotic potential, seeds germinated to only 50% of maximum germination of the control”
t0“Portulaca oleracea”
Claim · model-written summary
Buffered pH from 5 to 9 did not affect germination.
- Taxon
- Portulaca oleraceaPortulaca oleraceat0
- Treatment
- buffered pH solutionse0
- Outcome
- Germinatione0
- Direction
- not influencede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Germination was not influenced by buffered pH solutions ranging from 5 to 9”
t0“Portulaca oleracea”
Claim · model-written summary
Germination was greatest on the soil surface.
- Taxon
- Portulaca oleraceaPortulaca oleraceat0
- Organ / stage
- seedse0
- Outcome
- germinatione0
- Direction
- greateste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“germination was greatest for seeds placed on the soil surface”
t0“Portulaca oleracea”
Claim · model-written summary
Emergence declined as burial depth increased, reaching zero at 2 cm.
- Taxon
- Portulaca oleraceaPortulaca oleraceat0
- Outcome
- emergencee0
- Direction
- declinede0
- Value
- 2 cme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“emergence declined with increasing seed burial depth in soil; no seedlings emerged from the depth of 2 cm”
t0“Portulaca oleracea”
Claim · model-written summary
Rice residue reduced seedling emergence and dry matter.
- Taxon
- Portulaca oleraceaPortulaca oleraceat0
- Treatment
- addition of rice residuee0
- Outcome
- Seedling emergence and seedling dry mattere0
- Direction
- reducede0
- Value
- 4 to 6 t ha −1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seedling emergence and seedling dry matter were markedly reduced by the addition of rice residue to the soil surface at rates equivalent to 4 to 6 t ha −1”
t0“Portulaca oleracea”
Claim · model-written summary
Zero tillage had greater seedling emergence than minimum tillage.
- Taxon
- P. oleraceaPortulaca oleraceae0
- Treatment
- zero till (ZT)e0
- Outcome
- seedling emergence of P. oleraceae0
- Direction
- greatere0
- Value
- 17–20%e0
- Qualifier
- 6–10%e0
- Comparator
- minimum tillagee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“seedling emergence of P. oleracea was greater under zero till (ZT) (17–20%) than under minimum tillage (6–10%)”
The same questions in other papers
sodium chloride · growth · Portulaca oleraceaResults agree
3 papers in the same direction as this paper
- no effect
- negative
- negative
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.