Browsing by Author "Nyende, A.B."

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    Evaluation of Endogenous Phytocomponents and Amino Acids Associated with Direct Somatic Embryogenesis of Coffee (Coffea arabicaL.)
    (Journal of Advances in Agriculture, 2022) Mayoli, R.N.; Isutsa, D.K.; Nyende, A.B.; Mweu, C.M.; ; ;
    Coffee is one of the mostimportant cropscultivated in the world for use in beverages and confectionaries. Embryogenesis is a complex process that begins with a single cell and ends with the formation of mature embryos. Somatic embryo development involves accumulation of complex metabolites and storage reserves. This present experimentidentifiedandquantifiedendogenous phytocomponents and amino acidspresent during somatic embryogenesis of ‘Ruiru 11’.Laboratory experiments for this study were set up in the Coffee Research Institute, Kenyaat Ruiru.Third leaf pair explants were excised from 8-month-old greenhouse-grown mother plants sterilized and cultured in half strength Murashige and Skoog basal salts augmented with Thidiazuron. Once embryos had developed, the cultures were analysed for phytocomponents using GCMS andHPLC. The results showed that palmitoleic and stearic acids were highest (23.3 μg/g and 69.9 μg/g respectively) in brown embryogenic cultures. Cis 7,8 epoxy-2-methyl octadecane was highest(253μg/g) in green embryogenic cultures. (Z)-3-Tetradecene washighest(25 μg/g)in brown non-embryogenic cultures. Z,Z-3,13-Octadecedien-1-ol and (Z)-7-Hexadecenalwere highest (32.1 μg/g and 70.2 μg/g respectively) in green embryogenic cultures. Alanine content washighest (4.4μg/g) in embryos of brown cultures. Amino acids, fatty acids and their derivatives are potential biomarkers for embryogenesis.Other phytocomponentsshould be identified and their role in coffee somatic embryogenesis determined. Further studies regarding the status of the phytocomponentsidentified in the present study, especially in particular stages of embryo development are needed to propose treatments to improve coffee somatic embryo development.
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    Relationships of Selected Endogenous Factors Associated with Direct Somatic Embryogenesis of Coffee (Coffea arabica L.)
    (Journal of Advances In Agriculture, 2018-05-30) Mayoli, R.N.; Isutsa, D.K.; Nyende, A.B.; Mweu, C.M.; ; ;
    Coffee is one of the most important cash crops produced in the world with great economic returns to growers and national gross domestic product. Somatic embryogenesis is a morphogenetic processes leading to plantlet regeneration and these processes are coupled with changes in the levels of primary metabolites. The present experiment established relationships of endogenous substances with direct somatic embryogenesis of coffee ‘Ruiru 11’. Laboratory experiments were set up at Coffee Research Institute, Ruiru-Kenya between 2014 and 2017. The set up was in a completely randomised design, replicated three times and repeated once. Third leaf pair explants were excised from 8-month-old greenhouse-grown mother plants and cultured in half strength Murashige and Skoog basal salts augmented with Thidiazuron. Once embryos had developed, the cultures were analysed for endogenous substances using HPLC and GCMS. Sucrose, phenolics, alkaloids, amino acids, fatty acids and their derivatives correlated positively, whereas fructose and glucose correlated negatively with the other biochemical components.Endogenous sucrose, chlorogenic acid, caffeine amino acid, fatty acids and their derivatives are potential biomarkers for coffee somatic embryogenesis, whereas endogenous fructose and glucose are inhibitors of the same. Further studies regarding the status of the biochemical components, especially in particular stages of embryo development should be conducted to establish treatments that can improve coffee direct somatic embryo development.