Why 10°C-primed sh-2 sweet corn seeds were of higher quality than 20°C-primed seeds: some physiological clues

Publisher： International Seed Testing Association

ISSN： 1819-5717

Source： Seed Science and Technology, Vol.33, Iss.1, 2005-04, pp. : 199-213

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Abstract

The effects of hydration temperature on anti-oxidative capacity in sh-2 corn (Zea mays L.) seeds during hydration and re-drying processes were evaluated. Seeds were incubated in moistened vermiculite at 10 or 20°C for 36 h and subsequently air-dried at 25°C for 48 h. Seeds were sampled during the hydration and redrying periods and tested for germination and physiological measurements. Hydration and re-drying increased germination percentage but reduced germination speed. Marked decreases in malondialdehyde (MDA) and total peroxide contents and significant increases in reducing sugar were also observed in the embryos and endosperms during hydration. The activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutahione peroxidase (GPX) and glutathione reductase (GR) were enhanced in hydrated embryos and endosperms. Re-drying resulted in increases in MDA, total peroxides and reducing sugars. Significant declines in the activities of SOD, CAT, APX, GPX and GR also occurred in dehydrated embryos and endosperms. Moreover, re-drying decreased ascorbate and reduced glutathione contents. Hydration temperature plays a crucial role in affecting the extent of lipid peroxidation in the treated embryos and endosperms. 10°C-hydrated seeds contained lower contents of peroxidative product and reducing sugar and maintained higher activities of ROS scavenging activity than 20°C-hydrated seeds. These results may explain in part why 10°C-hydrated seeds have better initial seed quality and potential storability than 20°C-hydrated seeds.