Molecular Plant Breeding 2016, Vol.7, No.17, 1-7
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2 Conclusion
Based on obtained results, it could be concluded that activities of peroxidase had different change trends with
tolerant and sensible accession. The enhanced of scavenging ability for H
2
O
2
in tolerant was better than in
sensible accession. Two accessions Cil 126 and Cil 123 has potentially better antioxidant potential in roots tissues
than in aerial tissues. Cold adversely affects the plant metabolism in
Medicago
populations seedlings by affecting
antioxidant enzyme activities in leaves and roots tissues. Thus, this work can be benefited as potential targets for
enhancement of stress tolerance in
Medicago
species under different durations, through genetic of mRNAs
transcripts engineering and breeding programmes to develop cold tolerance local annuals
Medicago
cultivars.
3 Materials and Methods
The study was carried on two annual
Medicago ciliaris
Krockers (Cil 126, tolerant and Cil 123, sensible) (Table
1). Ten seeds for each accession were germinated after scarification and disinfected by dipping in 70% (v/v)
ethanol, at temperature room in Petri dishes containing universal compost imbibed with distiller water. At three
days growth stage, seedlings were divided into two lots. Cold treated lot at 4°C for three durations 2, 4 and 6 days
(T2, T4 and T6) and control lot kept at 23°C (T02, T04 and T06). The experimental layout was a completely
randomized block design with 3 replications.
Table 1 Accessions analyzed for peroxidase antioxidant under cold stress with their origin and ecological description
Species
Accessions
Origin
Latitude
Longitude
M. ciliaris
Krocker.
Cil 123 (S)
Algeria
36°46’02’’N
8° 18’ 9.57’’ E
Cil 126 (T)
Algeria
36° 28’ 0’’ N
7° 26’ 0’’ E
Notes: S: sensible, T: tolerant
Aerial (shoot and leaves) and root tissues from control and treated plants (Figure 4) were homogenized in
homogenization buffer (10 mM Tris-KCl, pH 6.8, 10% (w/v) saccharose and 1 mM PMSF).Tissues were frozen in
liquid nitrogen and ground in mortar on ice using homogenization buffer.
Figure 4 Aerial (shoot and leaves) and root tissues from control and treated plantlets
Peroxidase activity (EC 1.11.1.7) (POD) was assayed in reaction solution (3 ml) containing 0.2 M sodium acetate
buffer pH 4.6, 1% o-dianizidine, 10% H
2
O
2
(Mac Adam et al., 1992) modified. The reaction was started by adding
10 µl crude extract, and the enzyme activity is monitored for every 15 seconds for 3 minutes using a
