科研之友
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摘要
This experiment was designed to measure the changes in ultrastructure, antioxidant enzymatic activities and lipid peroxidation in ultra-dried (4% moisture content) and artificially aged (48 days at 45 degrees C) oat (Avena sativa L.) seeds. The seeds were also primed with polyethylene glycol (PEG) solutions (0,-0.3,-0.6,-0.9 and-1.2 MPa) for 12 hours at 20 degrees C. The results showed that seed vigour, antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX) and glutathione reductase (GR), and the ultrastructure of the embryo cells were improved at lower water potential, whilst the malondialdehyde (MDA) contents decreased significantly (P < 0.05). This indicated that the effect of PEG-priming on seed vigour was positively related to antioxidant enzymes and ultrastructure of embryo cells, but was negatively related to MDA content. In terms of ultrastructure, the mitochondria were the most sensitive organelles to PEG-priming. PEG priming at 0 ,-0.3 and -0.6 MPa aggravated the damage of seed ageing, but priming at -0.9 and -1.2 MPa was beneficial. It is therefore recommended that the water potential used for priming with PEG should be less than -0.9 MPa for ultra-dried aged seeds.
