Abstract
Abstract Sweet potato production, particularly in coastal areas is often prone to salinity. Salt‐tolerant clones will be needed to maintain production, but to date, little is known about salt tolerance traits in sweet potato. Salt stress may result in excessive uptake of unwanted ions into plant tissues leading to the formation of reactive oxygen species (ROS), which in turn may destroy membranes and reduce photosynthesis and growth. Antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), glutathione reductase (GR) and ascorbate peroxidase (APX) scavenge ROS and early changes in the activities of such enzymes could be used to identify salinity tolerant genotypes. Therefore, cuttings of two contrasting cultivars of sweet potato, BARI SP 8 (tolerant) and BARI SP 4 (sensitive) were greenhouse‐cultivated in nutrient solution for 21 days and then exposed to 100 mmol NaCl for 7 days. Three, five and seven days after salt application the youngest leaves were sampled individually and enzyme activities, potassium (K) and sodium (Na) concentrations, and SPAD (as a proxy for chlorophyll content) were determined. In both varieties leaf growth was not affected by salinity and young leaves grown under salinity had higher SPAD values than older leaves. Na concentration increased over time, particularly in earlier and in older leaves, whereas K was reduced in younger leaves. In general, enzyme activities were strongly affected by leaf age and leaf position. SOD and APX showed varietal but no salinity effects, CAT increased under salinity in both varieties, whereas POX was strongly reduced and GR was strongly increased under salinity in BARI SP 8 with no effect in BARI SP 4. Enzyme activities were not correlated to leaf Na, neither in relation to leaf age, nor leaf number or duration of salt stress in both varieties. However, varietal differences were observed regarding leaf K. Activities of SOD were highly positive and of CAT highly negatively correlated with leaf K under salinity in BARI SP 8 but not in BARI SP 4, whereas activities of GR and POX were strongly positively correlated with leaf K in BARI SP 4 under salinity but not in BARI SP 8. We conclude that potassium may have a strong regulating role on leaf stress levels and therefore on the activities of antioxidant enzymes. Varieties may differ in their tolerance strategy and we have shown that salinity does not generally increase levels of ROS‐scavenging enzymes in sweet potato leaves under salt stress. Confounding factors such as leaf age and leaf position as well as maintaining high leaf level K concentrations need to be considered when evaluating metabolic traits for salinity tolerance traits.
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Claims 18
Claim · model-written summary
Leaf growth of both sweet potato varieties was not affected by 100 mmol NaCl.
- Taxon
- sweet potato
_Flower.jpg?width=60)
Ipomoea batatast0 - Treatment
- 100 mmol NaCle1
- Outcome
- leaf growthe2
- Direction
- not affectede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Flower.jpg?width=500)
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e1“exposed to 100 mmol NaCl for 7 days”
e2“In both varieties leaf growth was not affected by salinity and young leaves grown under salinity had higher SPAD values than older leaves”
Claim · model-written summary
Young leaves grown under salinity had higher SPAD values than older leaves.
- Taxon
- sweet potatoIpomoea batatast0
- Organ / stage
- young leavese2
- Outcome
- SPAD valuese2
- Direction
- highere2
- Comparator
- older leavese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e2“In both varieties leaf growth was not affected by salinity and young leaves grown under salinity had higher SPAD values than older leaves”
Claim · model-written summary
Leaf Na concentration increased over time, particularly in earlier and older leaves.
- Taxon
- sweet potatoIpomoea batatast0
- Organ / stage
- earlier and in older leavese3
- Outcome
- Na concentratione3
- Direction
- increasede3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e3“Na concentration increased over time, particularly in earlier and in older leaves, whereas K was reduced in younger leaves”
Claim · model-written summary
Leaf K was reduced in younger leaves under salinity.
- Taxon
- sweet potatoIpomoea batatast0
- Organ / stage
- younger leavese3
- Outcome
- Ke3
- Direction
- reducede3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e3“Na concentration increased over time, particularly in earlier and in older leaves, whereas K was reduced in younger leaves”
Claim · model-written summary
Enzyme activities were strongly affected by leaf age and leaf position.
- Taxon
- sweet potatoIpomoea batatast0
- Outcome
- enzyme activitiese4
- Qualifier
- strongly affected by leaf age and leaf positione4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e4“In general, enzyme activities were strongly affected by leaf age and leaf position”
Claim · model-written summary
SOD and APX activities differed between the two varieties but were not affected by salinity.
- Taxon
- sweet potatoIpomoea batatast0
- Treatment
- salinitye5
- Outcome
- SOD and APXe5
- Direction
- no salinity effectse5
- Qualifier
- varietale5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e5“SOD and APX showed varietal but no salinity effects”
Claim · model-written summary
CAT activity increased under salinity in both sweet potato varieties.
- Taxon
- sweet potatoIpomoea batatast0
- Treatment
- salinitye6
- Outcome
- CATe6
- Direction
- increasede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e6“CAT increased under salinity in both varieties”
Claim · model-written summary
POX activity was strongly reduced under salinity in BARI SP 8.
- Taxon
- sweet potatoIpomoea batatast0
- Material
- BARI SP 8e7
- Treatment
- salinitye7
- Outcome
- POXe7
- Direction
- reducede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e7“POX was strongly reduced and GR was strongly increased under salinity in BARI SP 8 with no effect in BARI SP 4”
Claim · model-written summary
GR activity was strongly increased under salinity in BARI SP 8.
- Taxon
- sweet potatoIpomoea batatast0
- Material
- BARI SP 8e7
- Treatment
- salinitye7
- Outcome
- GRe7
- Direction
- increasede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e7“POX was strongly reduced and GR was strongly increased under salinity in BARI SP 8 with no effect in BARI SP 4”
Claim · model-written summary
POX activity showed no effect under salinity in BARI SP 4.
- Taxon
- sweet potatoIpomoea batatast0
- Material
- BARI SP 4e7
- Treatment
- salinitye7
- Outcome
- POXe7
- Direction
- no effecte7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e7“POX was strongly reduced and GR was strongly increased under salinity in BARI SP 8 with no effect in BARI SP 4”
Claim · model-written summary
GR activity showed no effect under salinity in BARI SP 4.
- Taxon
- sweet potatoIpomoea batatast0
- Material
- BARI SP 4e7
- Treatment
- salinitye7
- Outcome
- GRe7
- Direction
- no effecte7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e7“POX was strongly reduced and GR was strongly increased under salinity in BARI SP 8 with no effect in BARI SP 4”
Claim · model-written summary
Enzyme activities were not correlated with leaf Na in either variety.
- Taxon
- sweet potatoIpomoea batatast0
- Compound
- leaf Nae0
- Outcome
- enzyme activitiese0
- Direction
- no_changeinferrede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e0“Enzyme activities were not correlated to leaf Na, neither in relation to leaf age, nor leaf number or duration of salt stress in both varieties”
Claim · model-written summary
Varietal differences were observed for leaf K.
- Taxon
- sweet potatoIpomoea batatast0
- Outcome
- varietal differencese1
- Qualifier
- regarding leaf Ke1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e1“varietal differences were observed regarding leaf K”
Claim · model-written summary
Under salinity in BARI SP 8, SOD activity was highly positively correlated with leaf K.
- Taxon
- sweet potatoIpomoea batatast0
- Material
- BARI SP 8e2
- Treatment
- under salinitye2
- Compound
- leaf Ke2
- Outcome
- Activities of SODe2
- Direction
- highly positivee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e2“Activities of SOD were highly positive and of CAT highly negatively correlated with leaf K under salinity in BARI SP 8 but not in BARI SP 4”
Claim · model-written summary
Under salinity in BARI SP 8, CAT activity was highly negatively correlated with leaf K.
- Taxon
- sweet potatoIpomoea batatast0
- Material
- BARI SP 8e2
- Treatment
- under salinitye2
- Compound
- leaf Ke2
- Outcome
- CATe2
- Direction
- highly negatively correlatede2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e2“Activities of SOD were highly positive and of CAT highly negatively correlated with leaf K under salinity in BARI SP 8 but not in BARI SP 4”
Claim · model-written summary
Under salinity in BARI SP 4, GR and POX activities were strongly positively correlated with leaf K.
- Taxon
- sweet potatoIpomoea batatast0
- Material
- BARI SP 4e3
- Treatment
- under salinitye3
- Compound
- leaf Ke3
- Outcome
- GR and POXe3
- Direction
- strongly positively correlatede3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e3“activities of GR and POX were strongly positively correlated with leaf K in BARI SP 4 under salinity but not in BARI SP 8”
Claim · model-written summary
Potassium may have a strong regulating role on leaf stress levels and on antioxidant enzyme activities.
- Taxon
- sweet potatoIpomoea batatast0
- Compound
- potassiume4
- Outcome
- the activities of antioxidant enzymese4
- Qualifier
- potassium may have a strong regulating role on leaf stress levelse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e4“We conclude that potassium may have a strong regulating role on leaf stress levels and therefore on the activities of antioxidant enzymes”
Claim · model-written summary
Salinity does not generally increase levels of ROS-scavenging enzymes in sweet potato leaves under salt stress.
- Taxon
- sweet potatoIpomoea batatast0
- Treatment
- salinitye5
- Outcome
- levels of ROS‐scavenging enzymese5
- Direction
- does not generally increasee5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones”
e5“we have shown that salinity does not generally increase levels of ROS‐scavenging enzymes in sweet potato leaves under salt stress”
The same questions in other papers
sodium chloride · growth · Ipomoea batatas (sweet potato)Results differ
4 papers in the same direction as this paper · 1 in the opposite direction
- positive
- no effect
- negative
2 papers more in this group
See all 6 papers →salinity · physiology: oxidative · Ipomoea batatas (sweet potato)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- positive
- 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.