Joint International Conference on Long-term Experiments ...

possibility that, due to the chelating properties of these compounds, some inhibitors
present in the embryogenic cultures are inactivated.
The process of generating free radicals can be minimized by adding SA, which can
chelating transitional metals, thus reducing the production of hydroxyl radicals (HO - ) or
it can act directly as an antioxidant against these types of free radicals of oxygen
(Antofie et al., 2003).
Prachi et al. (2002) have found that addition of 104 M SA, to callus cultures of
Zingiber officinale produced the increased of peroxidase and β-1,3-glucanase activity,
as well as the appearence of two new proteins in the calli.
Some enzymes, such as guaiacol-peroxidase and glutation-reductase, are activated
by the treatments with SA solutions and others, such as catalase are inhibited as a result
of SA treatments and changes in the patterns of its isoensimes can be noticed (Horvath
et al., 2002).
The aim of this work was to study the influence of the exogenous SA on maize
caryopsiss germination (Zea Mays) and on the peroxidase activity in maize plantlets
(roots and coleoptiles) derivates from its..
2./ MATHERIALS AND METHODS
Sample preparation: SA treatments were applied to lots of 150 maize caryopsis
sample, germinated into plastic recipients. The maize caryopsis used in this study have
90% germination faculty.
The germination was maded in plastic recipients, on a filter paper, moistened with
20 ml:
- tap water , for the control sample,
- salicylic acid solution 0.1mg/l
- salicylic acid solution 1mg/l,
- salicylic acid solution 5mg/l.
The germination was maded at room temperature. Every day, the quantity of
solution from the recipients was brought to the level of 20 ml. The germination
temperature was around 22 ± 2˚C.
Germination energy, represents the speed with which the germination process begins.
It is estimated by the number of germinated grains in 72 hours. The number of normally
germinated grains over the three repetitions is divided by 100 for each plastic recipient
to determine the germination energy (Andrei et al. 1981).
Preparation of enzyme extract: 1g for each samples separatelly (roots and coleoptiles)
were collected from each variant, at 72, 96 and 120 hours of caryopsis put on
germination, and were blended with 4ml phosphate buffer solution, pH 7.0, diluted 1:9
with distilled water, cooled at 4˚C.
The samples were centrifuged at 10000 rpm, for 15 minutes at 4˚C, and supernatant
were separated. The extract is kept in the refrigerator, for 2 hours for stabilizing and
expressing enzyme activity.
Enzyme assay: peroxidase activity (PA) was determinated at 483nm wavelenght using
phosphate buffer of 7.0 pH, hydrogen peroxide as substrate and p-phenilendiamine as
chromogen (Hans-Luck, 1970 modified by Sipoş et al. 2003). The extension for each
sample was noted after 30 seconds of reaction period. For each extract were made four
determinations.
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