Made available in DSpace on 2016-04-28T14:58:35Z (GMT). No. of bitstreams: 1 2008 - Thais Moreira Hidalgo de Almeida.pdf: 3286442 bytes, checksum: 491a402cc8bf5539730d0625fcbf7b31 (MD5) Previous issue date: 2008-02-28 / Germination, conservation and physical characteristics of seeds of four cacti species that occurs on Rio de Janeiro State coastal regions, Cereus fernambucensis Lem., Coleocephalocereus fluminensis (Miq.) Backeb., Pilosocereus arrabidae (Lem.) Byles & G.D. Rowley and Pilosocereus ulei (K. Schum.) Byles & G.D. Rowley were evaluated in this study. The first experiment, mounted in a completely randomized design and factorial system, tested two substrates (agar 1% and paper) and three temperatures (20?C, 25?C and 20-30?C) using four replicates of 40 seeds. The evaluation parameters were germination percentage (normal seedlings) and germination average time (ANOVA and Tukey; P<0,05). According to the germination analysis, the best combination of temperature and substrate is 20?C in agar for C. fernambucensis, 20?C and 20-30?C in paper or agar for C. fluminensis, 25?C in agar for P. arrabidae and 20, 25 and 20-30?C in paper, as well as, 20 and 25?C in agar for P. ulei. The use of agar 1% was suitable for germination of this cacti seeds, being necessary, however, studies that lead to reduction in the incidence of plant health problems. In another experiment the effects of storage and seed water content were evaluated on the germination percentage and germination average time of these four species. To better define the salts to be used in the seed drying process for this experiment, adsorption isotherms were built using static gravimetric method, with saturated salt solutions. The isotherms of all species showed a reverse sigmoidal pattern with increase of seed water content according to the increase in relative humidity. In the conservation experiment, also arranged in completely randomized design and factorial system, three different storage conditions (control, 30 days at 10?C and 30 days at -196?C) under three levels of water content, around 5, 7 and 9% (dry basis) were tested, with four replicates of forty seeds (ANOVA and Tukey; P<0,05) at the following conditions: C. fernambucensis in agar at 20?C, C. fluminensis and P. ulei in paper at 20?C and P. arrabidae in agar at 25?C. All four species showed dehydration and sub-zero temperature tolerance. Seed viability and four species showed dehydration and sub-zero temperature tolerance. Seed viability and vigour showed no changes when stored with water content around 7%, at 10?C and cryopreserved at -196?C. Cryopreservation can be recommended for the storage of this cacti species. / As caracter?sticas f?sicas, germina??o e conserva??o de sementes de quatro esp?cies de cact?ceas ocorrentes nas ?reas litor?neas do estado do Rio de Janeiro, Cereus fernambucensis Lem., Coleocephalocereus fluminensis (Miq.) Backeb., Pilosocereus arrabidae (Lem.) Byles & G.D. Rowley e Pilosocereus ulei (K. Schum.) Byles & G.D. Rowley foram avaliadas neste estudo. O primeiro experimento, montado em delineamento inteiramente casualizado e esquema fatorial, testou dois substratos (?gar 1% e sobre papel ) e tr?s temperaturas (20?C, 25?C e 20-30?C) utilizando quatro repeti??es de 40 sementes. Os par?metros de avalia??o foram porcentagem de germina??o (pl?ntulas normais) e tempo m?dio de germina??o (ANAVA e Tukey; P<0,05). De acordo com a an?lise de germina??o, as melhores temperaturas e substratos para a germina??o de sementes de C. fernambucensis s?o 20?C e ?gar; para C. fluminensis, 20?C e 20-30?C, tanto no substrato papel como em ?gar, para P. arrabidae, 25?C em ?gar e para P. ulei em papel a 20, 25 e 20-30?C e ?gar a 20 e 25?C. O uso de ?gar 1% se mostrou adequado a germina??o das sementes destas cact?ceas, sendo necess?rios, no entanto, estudos que levem a redu??o da incid?ncia de problemas fitossanit?rios. Em outro experimento foram avaliados os efeitos de armazenamento e teor de ?gua das sementes sobre o percentual e o tempo m?dio de germina??o destas quatro esp?cies. Para melhor defini??o dos sais a serem usados na secagem das sementes para este experimento, foram constru?das isotermas de adsor??o utilizando-se o m?todo gravim?trico, est?tico, com solu??es salinas saturadas. As isotermas de todas as esp?cies revelaram um padr?o sigmoidal inverso com o acr?scimo de teor de ?gua das sementes em fun??o do aumento da umidade relativa do ar. No experimento de conserva??o, tamb?m montado em delineamento inteiramente casualizado e esquema fatorial, foram testadas tr?s diferentes condi??es de armazenamento (controle, 30 dias a 10?C e 30 dias a -196?C) sob tr?s diferentes teores de ?gua, pr?ximos a 5, 7 e 9% (base seca), utilizando quatro repeti??es de 40 sementes (ANAVA e Tukey; P<0,05) e nas seguintes condi??es: C. fernambucensis em ?gar a 20?C, C. fluminensis e P. ulei em papel a 20?C e P. arrabidae em ?gar a 25?C. As quatro esp?cies demonstraram toler?ncia a desidrata??o e a temperatura sub-zero. A viabilidade e o vigor das sementes n?o apresentaram altera??es quando armazenados com teores de ?gua pr?ximos a 7%, tanto em c?mara fria a 10?C como criopreservado a -196?C. A criopreserva??o pode ser recomendada para o armazenamento das esp?cies estudadas.