Effects of ageing on peroxidase activity and localization in radish (Raphanus sativus L.) seeds

Abstract

SUMMARYPeroxidase activity was assayed in crude extracts of integument, cotyledons and embryo axis of radish seeds, deteriorated under accelerated ageing conditions. Over five days of ageing, in which germination decreased from 100 to 52%, the enzyme activity in integument was higher than that in other seed parts, increasing in the first days of ageing and then decreasing sharply in extremely aged seeds. Polyacrylamide gel electrophoresis analysis showed four peroxidase isoenzymes with MM of 98, 52.5, 32.8 and 29.5 kDa in the embryo axis of unaged seeds, and only the 32.8 and 29.5 kDa MM isoforms in the integument and cotyledons. In these parts of the seed, only the 29.5 kDa MM isoenzyme increased in activity in early days of ageing and decreased thereafter. In the embryo axis, the 29.5 kDa MM isoenzyme activity increased slowly in the first day of ageing, while the 98 and 52.5 kDa MM isoenzyme activities disappeared. A cytochemical localization of peroxidase activity in the various tissues showed that main differences between unaged and extremely aged seeds occurred in the embryo axis.

Guaiacol peroxidase zymography for the undergraduate laboratory

“…This enables them, furthermore, to visualize a broader scope of the protein structure. Though it has been reported that each polypeptide chain is 31,965.5 Da, with a hemin plus Ca 21 of 656.578 Da, and a carbohydrate moiety of 1,418.4 Da, students have also found others M r values for POD [2,17,43]. According to this, students may discuss facts related to protein stability, recovery and maintenance of the tertiary structure after protein renaturalization by SDS removal in order to regain biological/catalytical activity.…”

“…PODs are ubiquitous in plants and have various physiological roles in plant tissues, including oxidation of a wide range of biomolecules by accumulation of active forms of oxygen, such as the superoxide radical (O 2 Á 2 ), the hydroxyl radical ( Á OH), and hydrogen peroxide (H 2 O 2 ) [2]. In plants, POD plays different roles, including construction, rigidification, and eventual lignifications of cell walls.…”

“…Although POD plays important roles in plant defense mechanisms, the precise function of all POD isozymes are still unknown. Moreover, plant PODs are tissue specific and developmentally regulated in the absence of stress stimuli, thus its study is more complex [1,2,7].…”

Isozyme Variations in some Wheat Genotypes at Siwa Oasis and Ashmon Habitats

“…The studied isozymes are those of peroxidase (Px), polyphenol oxidase (PPO) and malate dehydrogenase (Mdh). Separation of isoenzymes of Px, PPO and Mdh were performed by Native PAGE ( Isozyms staining and detection (Scialabba et al, 2002) After electrophoresis, the gels were stained according to their enzyme systems with the appropriate substrate and chemical solutions then incubated at room temperature in dark for complete staining. In most cases, incubation for about 1 to 2 hr was enough.…”

Changes of enzymes activities in botanical treated aged seed of soybean (Glycine max (L.) Merrill) cv. CO 3 seeds

“…Accelerated ageing has been widely used to study the pattern of seed deterioration in various crops instead of waiting to obtain naturally aged seeds (Jatoi et al, 2001;Scialabba et al, 2002). Hence, with this backdrop, the present investigation was formulated to study the effect of nano size botanical powders for improving the performance of the aged soybean seeds.…”