<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Vidal, Nieves</style></author><author><style face="normal" font="default" size="100%">Viéitez, Ana M</style></author><author><style face="normal" font="default" size="100%">Fernández, M Rosario</style></author><author><style face="normal" font="default" size="100%">Cuenca, Beatriz</style></author><author><style face="normal" font="default" size="100%">Ballester, Antonio</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Establishment of cryopreserved gene banks of European chestnut and cork oak</style></title><secondary-title><style face="normal" font="default" size="100%">European Journal of Forest Research</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Castanea sativa</style></keyword><keyword><style  face="normal" font="default" size="100%">Cryopreservation</style></keyword><keyword><style  face="normal" font="default" size="100%">forest tree species</style></keyword><keyword><style  face="normal" font="default" size="100%">liquid nitrogen</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">Vitrification</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year></dates><volume><style face="normal" font="default" size="100%">129</style></volume><pages><style face="normal" font="default" size="100%">635-643</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Cryopreservation of selected genotypes of European chestnut and cork oak was carried out in two laboratories in a project involving conservation of ﬁeld collections. Plant material was selected on the basis of disease resistance (chestnut), growth habit, phytosanitary performance and cork quality (cork oak). The cryopreservation technique comprised of vitriﬁcation of shoot apices isolated from in vitro stock shoot cultures (chestnut) and somatic embryos (cork oak). Forty-three out of 46 chestnut genotypes assayed survived the freezing process, but only 63% recovered their capacity to produce new shoots. After completion of multiplication and rooting steps, the surviving shoots produced plants that were morphologically identical to those derived from non-supercooled material. All 51 cork oak genotypes withstood freezing and were able to produce new somatic embryos through a process of secondary embryogenesis. Multiplication and germination of the recovered embryos enabled production of plants that were morphologically identical to those derived from nonsupercooled material. In light of the results obtained, longterm cryopreservation of these species is feasible, thereby ensuring conservation of valuable genotypes during ﬁeld evaluation</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sánchez, M Concepción</style></author><author><style face="normal" font="default" size="100%">Martínez, M Teresa</style></author><author><style face="normal" font="default" size="100%">Valladares, Silvia</style></author><author><style face="normal" font="default" size="100%">Ferro, Enrique</style></author><author><style face="normal" font="default" size="100%">Viéitez, Ana M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Maturation and germination of oak somatic embryos originated from leaf and stem explants: RAPD markers for genetic analysis of regenerants.</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of plant physiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">DNA polymorphism</style></keyword><keyword><style  face="normal" font="default" size="100%">genetic stability</style></keyword><keyword><style  face="normal" font="default" size="100%">plant conversion</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus robur</style></keyword><keyword><style  face="normal" font="default" size="100%">Somatic embryogenesis</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2003</style></year></dates><volume><style face="normal" font="default" size="100%">160</style></volume><pages><style face="normal" font="default" size="100%">699-707</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Experiments were performed to determine the influence of maturation medium carbohydrate content on the rates of germination and plantlet conversion (root and shoot growth) of somatic embryos from four embryogenic lines derived from leaf or internode explants of Quercus robur L. seedlings. The conversion rate was favoured by high carbohydrate content as long as the maturation medium contained at least 2% sucrose, which was necessary for healthy embryo development. Given this, sorbitol and mannitol favoured the conversion rate more efficiently than sucrose, the highest rate, 32%, being achieved by medium with 6% sorbitol and 3% sucrose. Maturation treatment did not affect the root or shoot lengths of converted embryos. In supplementary experiments, 2 weeks of gibberellic acid treatment between maturation and germination treatments did not improve germination rates, but did reduce root length and the number of leaves per regenerated plantlet. In the four embryogenic lines tested, plant recovery rate was enhanced by inclusion of benzyladenine into the germination medium following culture of the embryos on maturation medium with 6% sorbitol and 2-3% sucrose. In embryogenic systems it is important to assess the uniformity of the regenerants. Random amplified polymorphic DNA (RAPD) analysis using 32 arbitrary oligonucleotide primers was performed to study variability in DNA sequences within and between four embryogenic lines. No intraclonal nor interclonal polymorphism was detected between embryogenic lines originating from different types of explant from the same seedling, but every one of the primers detected enough polymorphism among clones originating from different plants to allow these three origins to be distinguished. No differences in DNA sequences between regenerated plantlets and their somatic embryos of origin were detected, but a nodular callus line that had lost its embryogenic capacity was found to be mutant with respect to three other clones originating from the same plantlet. This study shows that high carbohydrate levels in the maturation medium significantly increase plant conversion of oak somatic embryos, which exhibit no variation in DNA sequences when proliferated by secondary embryogenesis.</style></abstract><accession-num><style face="normal" font="default" size="100%">12872492</style></accession-num></record></records></xml>