Abstract
Soil contamination by heavy metals such as cadmium (Cd), molybdenum (Mo), lead, zinc and others as a result of industrial and agricultural practices, is a widespread problem in many countries across the world. Despite the fact that Mo is an essential nutrient required by plants in small concentrations, the exposure of crops, including metabolic and enzymatic activities during seed germination, to high concentrations of these metals can have adverse effects on their growth and performance. The current study assesses not only the deleterious effects of Cd and Mo contamination on barley grain germination but also the ability of gibberellic acid (GA3) to alleviate these negative effects. Stress generated by Cd and Mo contamination engendered the accumulation of total soluble proteins and a reduction of free amino acids in the endosperm followed by a decline of soluble proteins in seedling roots. This shows that protein reserves were not successfully mobilized in the endosperm of Cd or Mo-treated seeds, thus inhibiting protein synthesis in the roots. A reduction of soluble sugar content in the endosperm followed by a decrease in the activities of hydrolytic enzymes (α- and β-amylase, acid and alkaline phosphatase) also unveiled inhibited starch degradation caused by these heavy metals. However, the addition of 0.5 μM GA3 to the germination medium significantly alleviated the inhibitory effect of Cd and Mo on the activity of the four hydrolytic enzymes and concomitantly increased the sugar and amino acid content of the endosperm. Thus, GA3 treatment partially restored the mobilization of protein and starch reserves from the endosperm to seedling roots during germination. Alleviation of the phytotoxic effects of heavy metal pollution by GA3 in barley shows that the major effect of Cd and Mo toxicity is in suppressing the production of GA3 or inhibiting its activity in the aleurone tissue of the seed. In the future, barley improvement programs can use this information to devise strategies to enhance plant growth and production output in soils infected by heavy metals.
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Claims 11
Claim · model-written summary
Cd and Mo stress accumulated total soluble proteins in the endosperm.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaret0 - Treatment
- Cd and Mo contaminatione0
- Outcome
- total soluble proteinse0
- Direction
- accumulatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
t0“barley grains”
e0“Stress generated by Cd and Mo contamination engendered the accumulation of total soluble proteins”
Claim · model-written summary
Cd and Mo stress reduced free amino acids in the endosperm.
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- endosperme0
- Treatment
- Cd and Mo contaminatione0
- Outcome
- free amino acidse0
- Direction
- reductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley grains”
e0“Stress generated by Cd and Mo contamination engendered the accumulation of total soluble proteins and a reduction of free amino acids in the endosperm”
Claim · model-written summary
Cd and Mo stress reduced soluble proteins in seedling roots.
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- seedling rootse0
- Outcome
- soluble proteinse0
- Direction
- declinee0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley grains”
e0“a decline of soluble proteins in seedling roots”
Claim · model-written summary
Heavy metal treatment reduced endosperm soluble sugars.
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- endosperme0
- Outcome
- soluble sugar contente0
- Direction
- reductione0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley grains”
e0“A reduction of soluble sugar content in the endosperm”
Claim · model-written summary
Heavy metals decreased activity of four hydrolytic enzymes.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- these heavy metalse0
- Gene
- α- and β-amylase, acid and alkaline phosphatasee0
- Outcome
- activities of hydrolytic enzymese0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley grains”
e0“a decrease in the activities of hydrolytic enzymes (α- and β-amylase, acid and alkaline phosphatase) also unveiled inhibited starch degradation caused by these heavy metals”
Claim · model-written summary
Heavy metals inhibited starch degradation.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- these heavy metalse0
- Outcome
- starch degradatione0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley grains”
e0“inhibited starch degradation caused by these heavy metals”
Claim · model-written summary
GA3 significantly alleviated heavy metal inhibition of four hydrolytic enzymes.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- the addition of 0.5 μM GA3e0
- Outcome
- activity of the four hydrolytic enzymese0
- Direction
- alleviatede0
- Comparator
- Cd and Moe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley grains”
e0“the addition of 0.5 μM GA3 to the germination medium significantly alleviated the inhibitory effect of Cd and Mo on the activity of the four hydrolytic enzymes”
Claim · model-written summary
GA3 increased endosperm sugar content under heavy metal stress.
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- endosperme0
- Outcome
- sugare0
- Direction
- increasede0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley grains”
e0“concomitantly increased the sugar and amino acid content of the endosperm”
Claim · model-written summary
GA3 increased endosperm amino acid content under heavy metal stress.
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- endosperme0
- Outcome
- amino acid contente0
- Direction
- increasede0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley grains”
e0“concomitantly increased the sugar and amino acid content of the endosperm”
Claim · model-written summary
GA3 partially restored mobilization of protein and starch reserves.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- GA3 treatmente0
- Outcome
- mobilization of protein and starch reservese0
- Direction
- restorede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley grains”
e0“GA3 treatment partially restored the mobilization of protein and starch reserves from the endosperm to seedling roots during germination”
Claim · model-written summary
The authors infer that Cd and Mo toxicity suppresses GA3 production or inhibits its activity in aleurone tissue.
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- aleurone tissuee0
- Treatment
- Cd and Mo toxicitye0
- Outcome
- production of GA3 or inhibiting its activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley grains”
e0“the major effect of Cd and Mo toxicity is in suppressing the production of GA3 or inhibiting its activity in the aleurone tissue of the seed”
The same questions in other papers
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heavy metal · physiology: enzyme activity · Hordeum vulgare (barley)Results agree
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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.