• Login
    View Item 
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    An evaluation of antioxidant and hydration treatments for the improvement of the storability of Soybean (Glycine max (L.) Merr.) seeds : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Seed Technology at Massey University

    Icon
    View/Open Full Text
    02_whole.pdf (9.445Mb)
    01_front.pdf (1.493Mb)
    Export to EndNote
    Abstract
    Antioxidant and hydration treatments were evaluated for their potential to improve the storability of soybean cvs. Amsoy and Davis under different ageing conditions (accelerated ageing at 40°C, 36-100% RH; controlled deterioration at 40°C, 20% seed moisture; or slow ageing at 35°C, 9 or 12% seed moisture). Despite previous reports in the literature, no protective effects of treatment were found using 1% α-tocopherol, 0.1% butylated hyroxytoluene (BHT) in acetone solution for 16 h, (β-mercaptoethanol 0.52-52 ppm in aqueous solution or 0.1-1% iodine in calcium carbonate. High concentrations of BHT (2.2%) or iodine (1%) caused toxic effects to germination performance (as determined by normal germination, viability, fresh and dry weights of normal seedling axes). Acetone, used as a carrier for antioxidant treatments, was toxic to soybean seeds. Initial seed moisture contents, levels of mechanical damage, treatment duration and seed lot variation were key factors affecting susceptibility to acetone toxicity. Tetrazolium staining showed that acetone did not cause damage to a specific tissue but rather increased the area of dead tissue which had been mechanically damaged. Hydration-dehydration pre-storage treatments of soybean also showed damaging effects. Soaking treatments caused injury to low vigour lots immediately and reduced ageing resistance in high vigour material. Moisture equilibration (ME) for 24-48 h had no effects on seed performance, but an extended moisture equilibration period up to 72 h increased rates of germination loss during subsequent ageing. However, post-storage hydration treatments showed some capacity to repair damaged seeds. Increased conductivity of seed leachate was always significantly correlated with loss of germination performance, suggesting that membrane damage was related to seed deterioration. Changes in lipid and membranes were assessed in seeds aged at 40°C, ~100% RH or 35°C, 9% constant seed moisture. No changes in total lipid content due to ageing or treatments suggested that changes in storage lipid were not related to germination performance. Significant losses of phospholipid (PL) from cotyledons occurred 4 days after accelerated ageing. These losses were correlated with loss of seed performance, but no changes in PL contents from axes were detected throughout the ageing period. By itself, this result suggests that cotyledon damage may be an important contributing factor to seed deterioration, but the transmission electron microscopy (TEM) study indicated that damage occurring in axes due to accelerated ageing was more severe than in cotyledons. Acetone or water soaking pretreatments increased rates of loss of germination performance which were associated with PL losses or ultrastructural abnormalities in both axes and cotyledons. In addition, ME treatment (72 h) applied to slowly aged seeds accelerated PL loss in axes but, this was unrelated to seed performance. These data therefore indicate that PL losses per se are not a fundamental cause of seed deterioration and may not be the first event in membrane damage. Also germinating seeds seem to be able to repair some damage of this type. No changes in proportions of polyunsaturated fatty acids were observed in either total lipid from seed tissues or microsome fractions, indicating that lipid peroxidation was not involved in seed deterioration due to ageing or treatments. This, of course, explains the ineffectiveness of the antioxidant treatments in this study and suggests that hydrolytic damage may be involved in PL loss and seed deterioration. Possible reasons for the differences between these results and the small amount of other work published on seed treatments in soybean are discussed, but it was clear that chemical or hydration treatments of soybean are unlikely to be a commercially viable option for maintenance of soybean quality where poor storage conditions are inevitable. Nevertheless. this study indicates some interesting areas for future research into the critical events involved in soybean deterioration.
    Date
    1992
    Author
    Sakunnarak, Nit
    Rights
    The Author
    Publisher
    Massey University
    URI
    http://hdl.handle.net/10179/3094
    Collections
    • Theses and Dissertations
    Metadata
    Show full item record

    Copyright © Massey University
    | Contact Us | Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1-beta1
     

     

    Tweets by @Massey_Research
    Information PagesContent PolicyDepositing content to MROCopyright and Access InformationDeposit LicenseDeposit License SummaryTheses FAQFile FormatsDoctoral Thesis Deposit

    Browse

    All of MROCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Copyright © Massey University
    | Contact Us | Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1-beta1