Abstract:

This study investigated the drought resistant of different lines of Brassica napus, which provided germplasm resources for the breeding of drought resistant rapeseed varieties. Eight different genetic background lines of Brassica napus were used as experimental materials to simulate drought stress treatment with different concentrations of polyethylene glycol 6000 (PEG-6000). The SOD activity, CAT activity and MDA content were measured by colorimetric method, potassium permanganate titration method, and thiobarbituric acid method, respectively. The germination ratio and plant height of eight rapeseed lines both decreased with the increase of drought stress degree. However, the germination rate of ‘G32-1’ was between 96% and 98%, and it was almost unaffected. The plant height inhibition degree of‘G763-2’was the lightest (29.1%). The SOD activity of ‘G7-1’ showed the most significant decrease, with a decrease of 23.59 U/kg. Overall, the trend of SOD activity in ‘G32-1’ was higher than that in ‘G7-1’. The CAT activity of ‘Qingza No.1’ was relatively higher (1.16-1.48 mg/g), but the CAT activity of ‘G32-1’ was relatively lower (0.88-1.30 mg/g). The MDA content of ‘G7-1’ and ‘G32-1’ was at a relatively low level, which MDA content was 0.55-0.83 μmol/g and 0.47-1.14 μmol/g, respectively. In total, ‘G32-1’ had the strongest drought resistance and could be used as an excellent germplasm resource for cultivating drought resistant varieties of rapeseed.

Key words: Brassica napus, drought stress, germination ratio, plant height, SOD, CAT, MDA, drought resistance