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Title: Relationship of free radical scavenging enzymes to fruit growth, development, ripening, and senescence in 'Red Delicious' apples
Author(s): Abbasi, Nadeem Akhtar
Doctoral Committee Chair(s): Kushad, Mosbah M.
Department / Program: Agriculture, Agronomy
Chemistry, Biochemistry
Biology, Plant Physiology
Discipline: Agriculture, Agronomy
Chemistry, Biochemistry
Biology, Plant Physiology
Degree Granting Institution: University of Illinois at Urbana-Champaign
Degree: Ph.D.
Genre: Dissertation
Subject(s): Agriculture, Agronomy
Chemistry, Biochemistry
Biology, Plant Physiology
Abstract: Changes in free radical scavenging (antioxidant) enzymes:superoxide dismutase (SOD; EC 1.1.15.1.1), catalase (EC 1.11.1.6), peroxidase (POD; EC 1.11.1.7)activities and polyphenol oxidizing enzyme:polyphenol oxidase (PPO; EC 1.14.18.1) activity were investigated during different stages of fruit bud growth and development in 'Red Spur Delicious' apples (Molus domestica Borkh.). Changes in the activities of these enzymes were also monitored at harvest and during cold storage in relation to ripening, senescence, and scald development. At bud swelling stage SOD, POD, and catalase activities were at highest level. Higher activities of these enzymes might be related to the detoxification of free radicals and hence resumption of growth. With the onset of bud break and fruit development, a 5- to 8-fold decline in the activities of SOD and POD occurred. However, catalase maintained relatively higher activity during early stages of fruit growth then declined at full fruit maturity. POD activity showed another increase at full fruit development, which might be linked to ethylene synthesis. PPO activity remained relatively low during flower and early stages of fruit development, increased after active cell division phase, then slightly declined at full maturity. Activities of these enzymes did not show consistently significant changes at various stages of harvest maturity. During ripening and senescence of fruits at $-$1C, SOD activity increased significantly. This increase was relatively higher in full mature and over mature fruits, which developed significantly less scald, than early mature fruits. POD activity increased during fruit ripening then declined after 3 months in cold storage. This decrease in POD occurred after scald induction and continued to decline with further increase in senescence. PPO activity also increased during storage in scald susceptible fruits. Experiments were also conducted to determine the effect of scald inhibitors diphenylamine (DPA) and CaCl$\sb2$ on activities of these enzymes during fruit ripening and scald development. There were significant relationships among DPA treatment, enzymes activities, fruit maturity, and scald development. DPA treatment and maturity were involved in enhancement of SOD and catalase activities and in inhibition of POD and PPO activities during storage. CaCl$\sb2$ treatment did not affect enzymes activities except catalase, which increased during storage in fruits treated with 2% CaCl$\sb2.$
Issue Date: 1996
Type: Text
Language: English
URI: http://hdl.handle.net/2142/23834
ISBN: 9780591087604
Rights Information: Copyright 1996 Abbasi, Nadeem Akhtar
Date Available in IDEALS: 2011-05-07
Identifier in Online Catalog: AAI9702434
OCLC Identifier: (UMI)AAI9702434


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