In vitro collecting techniques for germplasm conservation

During the early 1980s, while searching for ways to more fully utilize the techniques of plant biotechnology, IPGRI (the International Plant Genetic Resources Institute, then the International Board of Plant Genetic Resources, IBPGR) suggested that germplasm be collected by means of in vitro methods. Between 1990 and today, research in this area has been performed by different groups, leading to the development and/or optimization of in vitro collecting techniques for various additional species including coconut, taro, tropical rainforest tree species and wild and endangered species. This technical bulletin comprises three separate parts. The first part (theoretical background to in vitro collecting), consists of three chapters regarding the rationale behind the development of in vitro collecting and its potential for the conservation of crops and wild or endangered species and the control of contamination, a critically important step which conditions the successful development of any in vitro collecting protocol. The second part (case studies) comprises nine chapters, each describing the work performed for the development of in vitro protocols for a particular species or group of species. The protocols described can be applied directly for collecting germplasm of any of the species concerned. However, circumstances will differ from one collecting mission to the next and it can be expected that these protocols will have to be adapted to these circumstances. Therefore, the aim of these chapters is to illustrate the range of protocols, from the simplest to the most sophisticated, which can be developed for in vitro collecting germplasm of a given species and to highlight the critical steps of such protocols. Such information should be used by the readers as a guide for the development of protocols for the species of their own interest. The last part (prospects) consists of a single chapter which analyses the future of in vitro collecting for improving the conservation and use of plant genetic resources. This technical bulletin includes references up to 2001. It includes both theoretical and practical aspects, aims to provide a resource for those wishing to understand the basic concepts of adapting plant tissue culture methods to field collecting

Seed conditioning of red oak: a recalcitrant North American seed Condicionamento de sementes de carvalho vermelho: semente recalcitrante da América do Norte

A ten day aerated water soak was developed as a seed conditioning treatment for red oak (Quercus rubra L.). Conditioned seeds had higher germination completeness, uniformity and speed compared to control seeds. Seeds could be conditioned under a wide range of temperatures and durations. Conditioned seeds were maintained at 7(0)C for 30 days without loss of seed quality. During conditioning, pericarps split in response to seed hydration. Split pericarps could be used as a pre-sowing indicator for high quality seeds. Seed conditioning was ineffective on dormant seeds. Increased crop uniformity and higher stand establishment can be realized by subjecting red oak acorns to an aerated water soak treatment followed by selecting seeds with split pericarps. These results are especially important in container production systems where limited numbers of value seeds are available.<br>Sementes de carvalho vermelho (Quercus rubra L.) foram condicionadas diretamente em água, sob aeração, durante 10 dias. As sementes condicionadas fisiologicamente apresentaram maior percentagem, velocidade e uniformidade de germinação, quando comparadas com a testemunha. O condicionamento das sementes pode ser efetuado sob ampla variação de temperaturas e períodos de exposição. Sementes condicionadas podem ser mantidas a 7ºC/30 dias, sem perda de qualidade. Durante o condicionamento ocorre ruptura do pericarpo, em resposta à hidratação da semente; essa ocorrência pode ser utilizada para estimar a qualidade da semente. O condicionamento não apresentou efeitos em sementes dormentes. O condicionamento das sementes de carvalho vermelho em água, com aeração, seguido pela seleção de sementes com ruptura do pericarpo, proporciona o rápido estabelecimento e uniformidade das plântulas

Indução de embriogênese somática em cupuaçu (Theobroma grandiflorum Schum.) Induction of somatic embryogenesis in cupuassu (Theobroma grandiflorum Schum.)

Folhas jovens de cupuaçu (Theobroma grandiflorum Schum.) foram empregadas para indução de embriogênese somática, as quais foram cultivadas inicialmente em meio MS suplementado com 6,0 mg/L BAP e 0,5 mg/L AIA (meio de estabelecimento), seguindo-se o cultivo em meio MS suplementado com 2,20 mg/L TDZ (meio de indução). A região da nervura mostrou intumescimento três dias após inoculação no meio de estabelecimento, o qual foi seguido pela formação de cachos de calos. As massas calosas foram transferidas para o meio de indução, e as estruturas com características pró-embriogênicas puderam ser observadas após uma semana. Estudos de microscopia eletrônica de varredura revelaram estruturas com características de embriões somáticos no meio com TDZ.<br>Young leaves of cupuassu (Theobroma grandiflorum Schum.) were used to induce somatic embryogenesis, which were cultivated initially in MS basal medium suplemented with 6.0 mg/L BAP and 0.5 mg/L IAA (established medium ) followed by MS basal medium supplemented with 2,20 mg/L TDZ (induction medium). Vascular region of explants showed intumescement three days after inoculation in established medium, which was followed by the formation of calli clusters. Calli mass were transferred to induction medium, and the structures with proembryogenic characteristics could be observed after one week. Scanning electron microscopy studies revealed structures with somatic embryos characteristics in the medium with TDZ