Coconut-Tissue culture
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Item Tissue Culture of Stem Explants of Coconut (Cocos nucifera L)(1977) Pimchai Apavatjrut; Blake, J.The authors have studied the conditions of induction of callus from the tissue of adult coconut stems, The aim is to find a method of vegetative propagation of the coconut by tissue culture, induction of callus was obtained on nutritive media of simple composition, in the presence of coconut water, at 31 C, and in the dark. The importance of the simultaneous presence of the ammonium and nitrate ions has also been shown. Cellular division produced cells of the embroid type. It now remains to study conditions for culturing these callus to find out whether the embroid cells can give rise to seedlings.Item Item Leaf development in ricinus communis during drought stress:Dynamics of growth processes, of cellular structure and of sink-source transtion(2000-09) Schurr, U.; Heckenberger, U.; Herdel, K.; Walter, A.; Feil, R.Dicot leaf growth is characterized by partly transient tip-to-base gradients of growth processes, structure and function. These gradients develop dynamically and interact with dynamically developing stress conditions like drought. In Ricinus communis plants growing under well-watered and drought conditions growth rates peaked during the late night and minimal values occurred in the late afternoon. During this diurnal course the leaf base always showed much higher rates than the leaf tip. The amplitude of this diurnal course decreased when leaves approached maturity and during drought stress without any significant alteration of the diurnal pattern and it increased during the first days after rewatering. Unique relationships between leaf size and cytological structure were observed. This provided the framework for the analysis of changes in assimilation, transpiration and dark respiration, chlorophyll, protein, carbohydrate, and amino acid concentrations, and of activities of sink–source related enzymes at the leaf tip and base during leaf development in well-watered and drought-stressed plants. Gas exchange was dominated by physiological rather than by anatomical properties (stomatal den sity). Tip-to-base gradients in carbohydrate concentra tions per dry weight and sink–source-related enzymes were absent, whereas significant gradients were found in amino acid concentrations per dry weight. During drought stress, growing leaves developed source function at smaller leaf size, before specific physiological adaptations to drought occurred. The relevance of the developmental status of individual leaves for the drought-stress response and of the structural changes for the biochemical composition changes is discussed.Item Revealing the potential of elite coconut types through tissue culture(2006) Samosir, Y.M.S.; Rillo, E.P.; Mashud, N.; Vu Thi My Lien; Kembu, A.; Faure, M.; Magdalita, P.; Damasco, O.; Novarianto, H.; Adkins, S.W.Low income, smallholder coconut farmers have been facing difficulties for decades due to the falling price of copra, their traditional cash product from coconut. These farmers are now looking towards new, higher value products from coconut to make their industry viable over the longer term. There are a number of elite coconut types that have either a soft, jelly-like endosperm or a flavoursome, aromatic drinking water. They have a high commercial value in the confectionary and ice cream industries (soft endosperm types) or the soft drink market (aromatic types). The soft endosperm types (‘makapuno’) are naturally occurring mutants which cannot germinate in nature as their endosperm cannot support the germination of the embryo. They are known from a number of countries and are called makapuno (the Philippines, Vietnam and Thailand), kopyor (Indonesia), garuk (Papua New Guinea) or dikiri pol (Sri Lanka), depending on their origin. For propagation, the embryo has to be removed from the fruit and grown in vitro to produce a seedling. The aromatic types are also thought to be naturally occurring mutants which can only germinate in nature at a very low rate. They are known from a number of countries including Thailand and Vietnam. For propagation, the same kind of embryo culture procedure has to be used. The first attempt at the embryo culture of these mutant coconut types was by De Guzman in the Philippines in the early 1960s (for the makapuno coconut). Subsequent studies have led to the commercialisation of a technique so it is now possible to mass produce seedlings of the Filipino makapuno. Other countries are now attempting to use the same or modified embryo culture techniques to develop their own soft-endosperm or aromatic coconut production industries. The common problems these projects encounter are the low rate of conversion of the isolated embryos to plantlets and the duration of the protocol, which can be as long as 1 year. These issues ultimately lead to high production costs for the elite seedlings, well above that possible for subsistence farmers. However, a recent collaborative project funded by the Australian Centre for International Agricultural Research (ACIAR) has made some impressive improvements to the standard embryo culture protocol. These improvements include the use of a CO2-enrichment step within a photoautotrophic culture system and the application of plant regulators NAA or IBA to promote seedling rooting. By using this protocol on the embryos of normal coconuts the in-vitro stage can be reduced from 10–12 months to 3–4 months and the success rate in transferring embryos to seedlings in the field can be improved from about 50% to 100%. The new improved protocol now needs to be refined and applied to the different mutant coconut types that are found around the world.Item Androgenic potential in coconut (Cocos nucifera L.)(2008) Verdeil, J.L.; Hocher, V.; Perera, P.I.P.; Yakandawala, D.M.D.; Bandupriya, H.D.D.; Weerakoon, L.K.Conditions for induction of androgenesis in coconut cv. Sri Lanka Tall were studied. Anthers collected from inflorescences at four maturity stages were given heat (38 C) or cold (4 C) pretreatments for 1, 3, 6 and 14 days, either prior to or post inoculation. Three different basal media and different anther densities were also tested. Androgenesis was observed only in anthers collected from inflorescences 3 weeks before splitting (WBS) and after a heat pretreatment at 38 C for 6 days. Modified Eeuwens Y3 liquid medium supplemented with 100 lM 2,4-dichlorophenoxyacetic acid (2,4-D), 0.1% activated charcoal and 9% sucrose was effective in inducing an androgenic response. The lowest anther density tested, 10 per petri plate, was found to be the optimal density. When androgenic calli or embryos were subcultured to Y3 medium containing 66 lM 2,4-D, followed by transfer to Y3 medium without plant growth regulators and finally to Y3 medium containing 5 lM 6-benzyladenine (BA) and 0.35 lM gibberellic acid (GA3), plantlets regenerated at a frequency of 7%. Histological study indicated that the calli and embryos originated from the inner tissues of the anthers. Ploidy analysis of calli and embryos showed that they were haploid. This is the first report of successful androgenesis yielding haploid plants from coconut anthersItem Changes in Key Aroma Compounds of Criollo Cocoa Beans During Roasting(2008) Felix Frauendorfer; Peter SchieberleApplication of a comparative aroma extraction dilution analysis on unroasted and roasted Criollo cocoa beans revealed 42 aroma compounds in the flavor dilution (FD) factor range of 1-4096 for the unroasted and 4-8192 for the roasted cocoa beans. While tne same compounds were present in the unroasted and roasted cocoa beans, respectively, these clearly differed in their intensity. For example, 2- and 3-methylbutanoic acid (rancid) and acetic acid (sour) showed the highest FD factors in the unroasted beans, while 3-methylbutanal (malty), 4-hydroxy-2,5-dimethy1-3{2H)-furanone (caramel-like), and 2- and 3-methylbutanoic acid (sweaty) were detected with the nighest FD factors in the roasted seeds. Quantitatton of 30 odorants by means of stable isotope dilution assays followed by a calcuiation of odor activity values (ratio of the concentration/odor threshold) revealed concentrations above the odor threshold for 22 compound^ in the unroasted and 27 compounds in the roasted cocoa beans, respectively. In particular, a strong increase in the concentrations of the Strecker aldehydes 3-methylbutana! and phenylacetaldehyde as well as 4-hydroxy-2,5-dimethyl-3(2H)-furanone was measured, suggesting that these odorants should contribute most to the chanyes in the overall aroma after roasting. Various compounds contributing to the aroma of roasted cocoa beans, such as 3-methylbutanoic acid, ethyl 2-methylbutanoate, and 2-phenylethanol, were already present in unroasted, fermented cocoa beans and were not increased during roasting.Item Recent lethal yellowing outbreak: why is the Malayan Yellow Dwarf Coconut no longer resistant in Jamaica?(2008) Berger, A.; Myrie, W.; Baudouin, L.; Lebrun, P.; Dollet, M.In Jamaica, the Maypan, a hybrid of Malayan Yellow Dwarf (MYD) and Panama Tall coconut, previously considered highly resistant, is currently being devastated by an epidemic outbreak of lethal yellowing disease. There are several possible causes for this change. In this study, we checked that affected planting material in Jamaica is genetically the same as the material shown to be resistant. We compared the deoxyribonucleic acid (DNA) of MYD sampled in four locations in Jamaica with a reference DNA of the same cultivar collected in five different countries. The results of our analyses showed more variation at 34 simple sequence repeat loci in Jamaica than in the rest of the world providing clear evidence for the presence of about 16% of alleles that do not match the usual typical MYD genotype. These alleles appear to have already been present in the introduced germplasm. This rules out a possible cause of the new outbreak: The observed heterogeneity may have caused some loss of resistance but is insufficient to explain a massive outbreak of the disease.Item Use of SSR markers to determine the anther-derived homozygous lines in coconut(2008) Perera, P.I.P.; Verdeil, J.L.; Hocher, V.; Perera, L.; Yakandawala, D.M.D.; Weerakoon, L.K.Anther culture was used to obtain dihaploid (DH) coconut plants and their ploidy level was determined by flow cytometric analysis. Simple sequence repeat (SSR) marker analysis was conducted to identify the homozygous diploid individuals. Ploidy analysis showed that 50% of the tested plantlets were haploid and 50% were diploid. Polymorphic fragments of the mother palm and their segregation patterns in anther-derived plantlets were used to determine the origin of the diploid plantlets. Using a diagnostic SSR marker (CNZ43), all the diploid plantlets tested were identified as being derived from microspores (i.e. were homozygous) and were thus candidates for use in coconut breeding programsItem Influence of form of activated charcoal on embryogenic callus formation in coconut (Cocos nucifera)(2010) Luis Saenz; Gaston Herrera-Herrera; Frank Uicab-Ballote; Jose Luis Chan; Carlos OropezaDevelopment of micropropagation protocols for Cocos nucifera has progressed slowly. Activated charcoal is included in the culture medium of each protocol, mainly to prevent tissue browning. Charcoal production procedures can affect the properties of different brands. In this study, eight types of activated charcoal were evaluated for their effects on free 2,4-dichlorophenoxyacetic acid level, pH, conductivity, and osmolarity of the culture medium and on the frequency of embryogenic callus induction. Moreover, the effect of particle size of the optimum charcoal type on embryogenic callus development was also studied. Charcoal type had a significant effect on (Y3) culture medium properties. Free 2,4-D was highest in Reactivos y Productos Quı´micos Finos-containing medium and pH was lowest in MERCK-containing medium. Charcoal type also influenced embryogenic callus induction, with acid washed for plant cell and tissue culture-, DARCO- and United States Pharmacopeia- containing media promoting*60% embryogenic callus, but with different optimal 2,4-D concentrations. Particle size profiles varied among all charcoal types, although small particle fraction (\\38 lm) was abundant in all. Use of small particle fractions produced higher frequencies of embryogenic callus (70%) than either large particle or whole charcoal fractions.Item Search of alternative substratum for agar in plant tissue culture(2010-01-10) Chitta Ranjan Deb; Aolemla PongenerIn plant tissue culture, agar has been the most commonly used gelling agent. But the exorbitant price and stress on its sources have necessitated the search for low cost alternatives. In the present study, a successful attempt has been made to standardize low cost plant tissue culture substratum. Different substratum like ‘polyurethane foam disc’, chopped coconut coir, betel nut coir and leaf litter were processed and used as substratum in place of agar and a comparative study was done. Successful asymbiotic immature seed germination and plant regeneration of Cymbidium aloifolium was achieved on different substratum like foam disc and coconut coir. Amongst the different substratum used, optimum germination, regeneration and multiple shoot buds formation was registered on polyurethane foam containing medium followed by agar medium and coconut coir containing media. The results of the present study offer a new possibilities of using low cost raw materials which will reduce production costs considerably and will help in popularizing plant tissue culture techniques.