ความ เกี่ยวข้องของ antioxidant enzymes และ lipid ... - CRDC

554 ปี ที่ 41 ฉบับที่ 3/1 (พิเศษ) กันยายน-ธันวาคม 2553 ว. วิทยาศาสตร์เกษตร
Introduction
Priming has been widely used to improve seed germination and vigour in many crop species. The advantages
of priming, improved seed vigour, are reported to involve with the repair and build up of nucleic acids, the
increased synthesis of proteins as well as the repair of membranes (McDonald, 1999). Priming also enhances the
activities of scavenging enzymes and reduces lipid peroxidation, indicating by MDA content, result to the increase
in seed germination and vigour in purple coneflower (Chiu et al., 2006) and bitter gourd seeds (Wang et al.,
2003). However, improper priming processes, due to the unfavorable imbibitions and re-drying steps, generate
reactive oxygen species (ROS) such as superoxide radical (O 2 - ), hydrogen peroxide (H 2 O 2 ) and hydroxyl radical
(Leprince et al., 1994). ROS can initiate injurious degradation causing lipid peroxidation, membrane deterioration,
protein and nucleic acids degradation leading to reduce seed vigour and cell death (McDonald, 1999).The poorer
longevity of primed sh-2 sweet corn seeds than unprimed seeds was found (Chang and Sung, 1998). The effect of
priming on seed vigour and biochemical mechanisms is depended on seed species and priming methods
(McDonald, 1999). The aim of this research was to study the involvement of antioxidant enzymes and lipid
peroxidation on seed vigour of maize seeds cv. Suwan 5 through the variations of hydropriming times.
Material and Methods
Maize seeds (Zea mays L.) ‘Suwan 5’, harvested in December, 2008, was purchased from Nation Corn and
Sorghum Research Center (NCSRC). The seeds were hydroprimed by placing them on metal wire sieve container
laying on distilled water surface for 6-18 h at 25C. Thereafter, the imbibed seeds were immediately dried at 40C
for 24 h to reduce the moisture content down to initial moisture content. The unprimed seeds were used as a
control sample. Moisture content (%), germination (%), vigour test (accelerated ageing test at 42C and 100%RH
for 96 h) of primed and unprimed seeds was investigated followed by ISTA rule (2007). The lipid peroxidation was
explained in term of malondialdehyde (MDA) content in the seeds (Tamagnone et al., 1998). Superoxide
dismutase (SOD) (Beauchamp and Fridovish, 1971) and ascobate peroxidase (APX) (Nakano and Asada, 1987)
were analyzed. The experiment was arranged as a completely randomized design (CRD) with four replications.
Data were subjected to analysis of variance (ANOVA) and significant differences among means were determined
by Duncan’s New Multiple Range Test at P