Browsing by Author "Santamaria, J.M."

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    Cultivating in vitro coconut palms (Cocos nucifera) under glasshouse conditions with natural light, improves in vitro photosynthesis nursery survival and growth
    (2005) Gabriela Fuentes; Francisco Espadas; Fernando Contreras; Carlos Talavera; Santamaria, J.M.
    Plantlets of coconut were cultured in vitro under three different ambient conditions including a standard culture room, a culture room inside a glasshouse with natural light but controlled temperature, and a standard glasshouse with natural light and natural fluctuations of temperature. Plantlets from the 3 treatments were compared in terms of growth, plant survival as well as net photosynthesis and efficiency of PSII (Fv/Fm ratio) both at the end of the in vitro stage and at 3 stages of ex vitro acclimatization. At the end of the in vitro stage, plantlets cultured in vitro under glasshouse conditions showed the best performance showing the highest photosynthesis rate, dry weight and number of leaves. Plantlets from the standard culture room showed the lowest photosynthesis and growth rate. After 6 months of ex vitro acclimatization, plantlets originally grown in vitro under glasshouse conditions maintained better field survival and growth rates in terms of fresh weight, dry weight and leaf number than plantlets originally grown in vitro in the standard culture room. Although more studies are required to define the reason for this effect, it is clear that the conditions of standard culture rooms are not the best for in vitro cultivation of coconut and perhaps other tropical species
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    Effect of medium sucrose on the photosynthetic capacity of coconut vitroplants formed from zygotic embryos
    (2007-02-08) Santamaria, J.M.; Talavera, C.; Lavergne, D.; Trabelsi, S.; Verdeil, J.L.; Huet, C.; Rival, A.; Hamon, S.; Nato, A.
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    High irradiance can minimize the negative effect of exogenous sucrose on the photosynthetic capacity of in vitro grown coconut plantlets
    (2005) Fuentes, G.; Talavera, C.; Desjardins, Y.; Santamaria, J.M.
    There is increasing evidence that the sucrose normally added to the culture medium affects negatively the photosynthetic capacity of plantlets. At the same time, however, sucrose cannot be eliminated from the medium, as it is required for normal in vitro growth. We argue that this is true only under the conventional light conditions of growth-rooms. In the present paper irradiance of growth-rooms was increased 10 times and although the sucrose-inhibitory effect was found at high sucrose concentrations, it was possible to grow coconut (Cocos nucifera L.) plantlets without sucrose. Those plantlets showed both high photosynthetic capacity and comparable in vitro growth to those grown with sucrose in the medium under conventional growth-room irradiance. Nevertheless, the best growth was achieved under mixotrophic conditions where at high irradiance and moderate sucrose concentrations plantlets accumulated 27 % more biomass than plantlets grown without sucrose under high irradiance and 43 and 73 % more biomass than their counterparts at low irradiance with or without sucrose, respectively.