Abstract
The tropical and subtropical naturalized physic nut (Jatropha curcas L.), has been explored for biodiesel production in recent times. The oil is extracted from the seeds and, for the production to be feasible, utilization of the residual seed cake is crucial. Although the cake could be employed as a protein source in animal feed, it is rich in phorbol ester, which is toxic for animals. Therefore, breeding programs have been working to reduce or eliminate the phorbol ester content in physic nut. In this context, the present work aimed to evaluate the physic nut oil of toxic and non-toxic varieties (containing known or undetectable amounts of phorbol ester, respectively) with regards to phytotoxicity in a model experiment with Lactuca sativa L. For this, the percentage of germinated seeds was evaluated after 8, 16, 24, 36 and 48 hours of exposure to the treatments with toxic and non-toxic oil at concentrations of 22.5 %, 45 % and 67.5 % of emulsion (physic nut oil energetically mixed with distilled water). Root growth was determined after 48 hours of exposure and the germination speed index was obtained. The different stages of mitotic division as well as possible chromosomal and nuclear alterations were also recorded. The mitotic index was calculated as the number of dividing cells, as a fraction of the total number of cells, and the frequency of chromosome and nuclear alterations, expressed as the percentage of number of alterations divided by the total number of cells. Both varieties exhibited phytotoxicity, inducing significant reductions in percentage of germinated seeds (reduction of 98 %), germination speed index (reduction of 24.44) and root growth (reduction of 8.54 mm). In microscopic analysis, a mitodepressive effect was observed for both oils at the three concentrations used when compared to the negative control; however, it was possible to distinguish between the toxic and the non-toxic varieties based on the more expressive reduction of division promoted by the first, 2.19 %. Significant increments in the frequency of mitotic cells showing chromosome alterations as well, as the presence of condensed nuclei, were observed in the treated cells. However, these parameters were not significantly different from the control in the cells treated with both physic nut oils. In conclusion, the evaluation of root growth and cell division in the plant model L. sativa, can be proposed as an alternative to animal tests to distinguish the varieties with high and low phorbol ester concentration, thus contributing to the detection of toxicity in varieties used in breeding programs. Rev. Biol. Trop. 66(2): 495-502. Epub 2018 June 01.
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Claims 7
Claim · model-written summary
Both physic nut oils significantly reduced lettuce seed germination by 98%.
- Taxon
- Lactuca sativa L.
Lactuca sativae1 - Treatment
- Both varietiese0
- Outcome
- percentage of germinated seedse0
- Direction
- reductionse0
- Value
- 98 %e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both varieties exhibited phytotoxicity, inducing significant reductions in percentage of germinated seeds (reduction of 98 %), germination speed index (reduction of 24.44) and root growth (reduction of 8.54 mm)”
t0“Jatropha curcas”
e1“model experiment with Lactuca sativa L.”
Claim · model-written summary
Both oils reduced lettuce germination speed index by 24.44.
- Taxon
- Lactuca sativa L.Lactuca sativae1
- Treatment
- Both varietiese0
- Outcome
- germination speed indexe0
- Direction
- reductionse0
- Value
- 24.44e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both varieties exhibited phytotoxicity, inducing significant reductions in percentage of germinated seeds (reduction of 98 %), germination speed index (reduction of 24.44) and root growth (reduction of 8.54 mm)”
e1“model experiment with Lactuca sativa L.”
Claim · model-written summary
Both oils reduced lettuce root growth by 8.54 mm.
- Taxon
- Lactuca sativa L.Lactuca sativae1
- Treatment
- Both varietiese0
- Outcome
- root growthe0
- Direction
- reductionse0
- Value
- 8.54 mme0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both varieties exhibited phytotoxicity, inducing significant reductions in percentage of germinated seeds (reduction of 98 %), germination speed index (reduction of 24.44) and root growth (reduction of 8.54 mm)”
e1“model experiment with Lactuca sativa L.”
Claim · model-written summary
Both oils suppressed mitosis at all three concentrations relative to the negative control.
- Taxon
- Lactuca sativa L.Lactuca sativae1
- Treatment
- both oilse0
- Outcome
- mitodepressive effecte0
- Comparator
- negative controle0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a mitodepressive effect was observed for both oils at the three concentrations used when compared to the negative control”
e1“model experiment with Lactuca sativa L.”
Claim · model-written summary
Toxic oil reduced cell division more than non-toxic oil by 2.19%.
- Taxon
- Lactuca sativa L.Lactuca sativae2
- Treatment
- toxice1
- Outcome
- divisione0
- Direction
- reductione0
- Value
- 2.19 %e0
- Comparator
- non-toxice1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the more expressive reduction of division promoted by the first, 2.19 %”
e1“toxic and the non-toxic varieties”
e2“model experiment with Lactuca sativa L.”
Claim · model-written summary
Treated cells showed increased chromosome alterations and condensed nuclei.
- Taxon
- Lactuca sativa L.Lactuca sativae1
- Outcome
- frequency of mitotic cells showing chromosome alterationse0
- Direction
- incrementse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Significant increments in the frequency of mitotic cells showing chromosome alterations as well, as the presence of condensed nuclei, were observed in the treated cells”
e1“model experiment with Lactuca sativa L.”
Claim · model-written summary
Root growth and cell division in lettuce were proposed to distinguish oils with different phorbol ester concentrations.
- Taxon
- L. sativaLactuca sativae0
- Outcome
- evaluation of root growth and cell divisione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the evaluation of root growth and cell division in the plant model L. sativa, can be proposed as an alternative to animal tests to distinguish the varieties with high and low phorbol ester concentration”