Aluminium sulphate

Additional toxicological data

Administrative data

Endpoint:

additional toxicological information

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Reliable without restrictions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Materials and methods

Type of study / information:

plant's reaction to toxic levels of Al.

Test guideline

Qualifier:

according to guideline

Guideline:

other: see principles of method

Principles of method if other than guideline:

MATERIALS AND METHODS
Arabidopsis thaliana cv Columbia seeds were surface sterilized by a 20-min incubation in 1.5% (w/v) sodium hypochlorite containing 2% (v/v) Tween 20 per milliliter as a wetting agent. After three washes with water, seeds (5000 per bottle) were added to 1-L Schott bottles containing 400 mL of low-ionic-strength Ruakura medium (pH 4.3; Snowden et al., 1995). The bottles were aerated in a growth chamber under conditions of 16 h of light (190 mmol m22 s21) at 22°C and 8 h of dark at 18°C. Medium was replaced every 1 to 2 d. After 7 d of submerged growth, the seedlings were treated by adding Al2(SO4)3 to a final concentration of 25 µm (50 µm Al3+). Seedlings were harvested at various times with a combination taken from at least two bottles for each sample.
For experiments that required that only the roots be exposed to Al31, seeds were germinated on black muslin (Putterill et al., 1991) supported by stainless steel mesh (2 mm). The mesh was supported above (and in contact with) 1.5 L of aerated Arabidopsis medium (5 mm KNO3, 2.5 mm KH2PO4, 2 mm MgSO4, 2 mm Ca[NO3]2, 12.5 µm FeEDTA, 7 µm H3BO3, 14 µm MnCl2, 0.5 µm CuSO4, 1 µm ZnSO4, 10 µm NaCl, and 0.1 µm CoCl2, pH 5.8; Haughn and Somerville, 1986) and the seeds were allowed to germinate in a growth chamber under conditions of 16 h of light (90–150 mmol m22 s21), 8 h of dark at 20°C. After 5 d the seeds had germinated and the medium was changed to low-ionicstrength Ruakura medium (pH 4.3; Snowden et al., 1995). Nine days later the medium was treated with Al2(SO4)3, exposing the seedling roots to 50 mm Al31 for a range of times (0, 0.5, 2, and 8 h), and the roots were harvested.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Aluminium sulphate

EC Number:

233-135-0

EC Name:

Aluminium sulphate

Cas Number:

10043-01-3

Molecular formula:

Al2(SO4)3

IUPAC Name:

Aluminium sulphate

Test material form:

solid: compact

Details on test material:

- Name of test material (as cited in study report):aluminium sulfate

Results and discussion

Any other information on results incl. tables

RESULTS

The authors have isolated five new genes that are transientlyexpressed in response to Al treatment of A. thaliana seedlings.An additional six genes were shown to be inducedfor an extended period during Al stress. The identity of these genes led us to suggest that oxidative stress is acentral feature of the plant’s response to inhibitory levels ofAl.The authors predict that other oxidative stress genes (e.g. ascorbateoxidase, glutathione peroxidase) will also prove to beinduced by Al. It is possible that transgenic plants thatoverexpress oxidative stress enzymes and that are tolerantto a range of oxidative stresses and may also show increased tolerance to Al.

 

Applicant's summary and conclusion

Conclusions:

The results suggested that Al treatment of Arabidopsis induces oxidative stress. In confirmation of this hypothesis, three of four genes induced by Al stress in A. thaliana were also shown to be induced by ozone. Our results demonstrate that oxidative stress is an important component of the plant's reaction to toxic levels of Al.

Executive summary:

Changes in gene expression induced by toxic levels of Al were characterized to investigate the nature of Al stress. A cDNA library was constructed from Arabidopsis thaliana seedlings treated with Al for 2 h. We identified five cDNA clones that showed a transient induction of their mRNA levels, four cDNA clones that showed a longer induction period, and two down-regulated genes. Expression of the four long-term-induced genes remained at elevated levels for at least 48 h. The genes encoded peroxidase, glutathione-S-transferase, blue copper-binding protein, and a protein homologous to the reticuline:oxygen oxidoreductase enzyme. Three of these genes are known to be induced by oxidative stresses and the fourth is induced by pathogen treatment. Another oxidative stress gene, superoxide dismutase, and a gene for Bowman-Birk protease inhibitor were also induced by Al in A. thaliana. These results suggested that Al treatment of Arabidopsis induces oxidative stress. In confirmation of this hypothesis, three of four genes induced by Al stress in A. thaliana were also shown to be induced by ozone. Our results demonstrate that oxidative stress is an important component of the plant's reaction to toxic levels of Al