Antonio Carlos de Souza Medeiros

Proposta de padrões de germinação e teor de água para sementes de algumas espécies florestais presentes na região sul do Brasil

In order to comply with the legislation on seeds and seedlings (Law n° 10.711, as of August 5th, 2003, and Decree n° 5.153, as of July 23rd, 2004), the REDE SEMENTE SUL {Southern Seed Network)} convened a working group to discuss and draft a document in order to collect and analyze research to be presented as a proposal for germination and water content standards for seeds and validity period of germination tests for 27 southern Brazilian native tree species. The data were collected from the records of seed analyses over the past 25 years at the Fundacao Estadual de Pesquisa Agropecuaria - FEPAGRO and 5-year records at the Fundacao Zoobotânica do Rio Grande do Sul - FZB/RS. The confidence criteria for species selection were the germination results of at least 10 batches obtained during the storage period. The germination standard (Sg), i.e., the minimum germination rate required to certify a batch of seeds, was defined based on the average (µ) and the respective standard deviation (SD) by applying the formula: Pg = µ - DP. Different criteria were used to determine the critical values of seed water content (U%), depending on the type of seeds with respect to their desiccation tolerance (orthodox seeds: maximum U% = µ + DP; recalcitrant seeds: minimum U% = µ - DP; intermediate-class seeds: min U% = µ - DP and maximum U% = µ + DP). The historical data survey from files belowed to FEPAGRO and FZB/RS alowed to set proposal for germination standards, moisture content and validity for the germination test, for 27 native forest species originary from the atlantic south region of Brasil.

Efeito do substrato e da temperatura na germinação de sementes de cataia (Drimys brasiliensis miers. winteraceae)

The aim of this research was to evaluate cataia (Drimys brasiliensis Miers. - Winteraceae) seed germination under different, temperatures, substrate and stratification times. Seeds were submitted to stratification method in green house, without controlled temperature, during 30, 60 and 90 days. Filter paper, sand, vermiculite and agar 1% were tested as substrates. Were compared constant temperatures of 17, 25 and 30oC under light, and alternate temperatures treatments of 20-30oC, adopting 20oC for 16 hours in absence of light and 30oC for 8 hours exposed to light. IVG (Germination Speed Index) was obtained additionally as a vigor test, by counting normal seedlings everyday after sowing. Cataia seeds showed 7% of moisture content (wet basis) at the beginning of the experiment. After 30, 60 and 90 days of sand stratification, these seeds presented 11,3%, 27,7% and 46,2% of moisture content, respectively. Treatments with 30 and 60 days of sand stratification at 17oC obtained the highest germination percentage, of 67% and 52%, respectively. The highest percentage of germination was obtained after 30 days of sand stratification corresponding to 68% for substrates like agar, sand and filter paper, and 61% for vermiculite. For the treatment with 60 days of sand stratification, the highest germination percentages were 56%, 58% and 54% in agar, sand and filter paper, respectively, without statistic difference. The vigor seeds (IVG) were those that were sand stratified for 60 days and were transferred to agar, sand and filter paper to germinate, at 17oC, presenting germination rate of 0,55, 0,61 and 0,65. It was possible to conclude that 60 days of sand stratification is an efficient method to broken cataia seed dormancy. The higher rate an percentage of germination were obtained at constant temperature of 17oC with agar, sand and filter paper as substrates.

Caracterização morfolóica de frutos e sementes de cataia (Drimys brasiliensis Miers. - Winteraceae)

The aim of this research was to characterize morphologically internal and external structures of Drimys brasiliensis Miers fruits and seeds. In order to describe the fruits, internal and external details related to texture, consistency, pilosity, brightness, shape and number of seeds per fruit were observed. Shedding was observed as well. Some external aspects of the seeds were analyzed including size, color, texture, consistency, shape, hilum and micropyle position. The following internal characteristics were observed the presence or absence of endosperm and cotyledon, embryo axes and plumule type, shape and color. The heart, torpedo and mature stages were identified during embryo development. The fruits of D. brasiliensis are multiple, free, constituted by five little fruits, indehiscence and polispermic. The seeds are kedney form and they have great amount of endosperm, and they present dormancy for embryonic immaturity.

Morphological characterization of fruits, seeds and germination of Allophylus edulis (St.- Hil.) Radlk. (Sapindaceae)

Os objetivos deste trabalho foram caracterizar morfologicamente as estruturas externa e interna dos frutos e das sementes, alem de descrever e ilustrar a morfologia externa da plântula de Allophylus edulis (St.-Hil.) Radlk.. Para a descricao dos frutos foram observados detalhes externos e internos do pericarpo, referentes a textura, consistencia, cor, pilosidade, brilho, forma, numero de sementes por fruto e deiscencia. Para as sementes foram analisadas as seguintes variaveis externas: dimensoes, cor, textura, consistencia, forma e posicao do hilo e da micropila. Para as caracteristicas internas, verificou-se presenca ou ausencia de endosperma, o tipo, a forma, a cor, a posicao dos cotiledones, o eixo-hipocotilo-radicula e plumula. A germinacao foi considerada desde a emissao da radicula ate a emissao dos protofilos e a plântula foi considerada estabelecida quando os protofilos ja estavam totalmente expandidos. Os frutos de Allophylus edulis sao do tipo coca, globosa, indeiscentes e monospermicos. As sementes sao ovoides, sem endosperma e o embriao ocupa toda a semente, mais ou menos encurvado e levemente comprimido. A germinacao das sementes tem inicio ao oitavo dia e pode ser encerrada no decimo quinto dia, apos a semeadura.

Physiological behaviour of Blepharocalyx salicifolius and Casearia decandra seeds on the tolerance to dehydration

The present work aimed to develop studies on the tolerance to dehydration of Blepharocalyx salicifolius and Casearia decandra seeds. In order to verify the effect of drying on the seeds, they were placed in desiccators containing a saline solution saturated with potassium acetate (23.5% RH) at temperature of 15 °C. After obtaining the desired moisture contents, the seeds were submitted to the germination, vigor, tetrazolium and electrical conductivity tests. It can be concluded that under slow drying conditions, the seeds of B. salicifolius and C. decandra were sensitive to moisture reduction of 29% to 25%, and lost viability at around 14% and 8% of moisture content, respectively. The physiological changes occurring during seed drying showed there was a decrease in viability and vigor and an increase in electrical conductivity values starting at 25% seed moisture content.

Fungos associados a frutos e sementes de imbuia (Ocotea porosa Ness. L. Barroso)

Ness. L. Barroso) e uma especie arboreaque ocorre nas Florestas Ombrofila Mista (Floresta com Araucaria) eOmbrofila Densa (Floresta Atlântica). E conhecida pela qualidade ealto valor comercial de sua madeira. Face a sua exploracaodescontrolada, encontra-se na lista oficial de especies da flora brasileiraameacadas de extincao e na lista vermelha, categoria rara, no Parana. Anecessidade de preservacao dessa especie requer a disponibilidade desementes. O objetivo deste trabalho foi detectar fungos associados afrutos e sementes de imbuia.Os frutos de imbuia foram coletados em arvores matrizes emCanoinhas- SC. Para a deteccao dos fungos usaram-se 100 frutos e400 sementes nao desinfestados, atraves do metodo do papel defiltro, em quatro repeticoes. Os frutos e sementes foram colocadosem caixas gerbox com duas folhas de papel de filtro umedecidascom agua destilada esterilizada. O material foi incubado a 20±1oC,sob 12 h luz negra/12 h escuro, por sete dias e, entao, av aliou-se aincidencia de fungos (%).O delineamento foi inteiramente casualizado e os dados foramanalisados pelo modelo linear generalizado, com funcao de ligacaologaritmica e distribuicao de Poisson; ajustou-se o modelo Poissonpara o delineamento inteiramente casualizado. O valor da deviance doresiduo foi proximo ao do numero de graus de liberdade do residuo,indicando que o modelo ajustou-se bem aos dados. Observou-sediferencas em relacao a incidencia de fungos entre os dois substratos(frutos e sementes), verificando-se valores mais elevados nos frutos.Encontraram-se os seguintes fungos potencialmentefitopatogenicos, tanto nos frutos quanto nas sementes:

Fungos associados às sementes de baguaçu

St. Hil) e uma especie arborea daFloresta Ombrofila Mista (Floresta Atlântica), encontrada na lista dasespecies ameacadas de extincao. E recomendada como prioritaria emregeneracao de mata ciliar. Suas flores e sementes tem papel namanutencao da fauna silvestre. Sua madeira e indicada para a construcaocivil e de artefatos; as flores para perfumaria; a casca em usos medicinais;e o oleo das sementes para a lubrificacao de equipamentos de altaprecisao.Ha falta de informacoes sobre a sanidade de sementes de baguacu.Assim, o objetivo deste trabalho foi comparar a ocorrencia de fungosentre as sementes com e sem arilo (estrutura carnosa que envolve asemente).As sementes de baguacu foram coletadas de arvores matrizes emAntonina-PR. Para a deteccao de fungos nas sementes empregou-se osmetodos do papel-filtro (PF) e batata-dextrose-agar (BDA). Para PFforam utilizadas 400 sementes nao desinfestadas, em quatro repeticoes,em caixas gerbox contendo duas folhas de papel-filtro esterilizadas eumedecidas com agua destilada esterilizada; enquanto para BDA foramusadas 200 sementes desinfestadas com hipoclorito de sodio 1% (por1 min), em quatro repeticoes. A avaliacao da incidencia de fungos (%)foi feita apos incubacao das sementes por sete dias a 20±1oC, sob 12h luz negra/12 h escuro.Em PF avaliou-se ainda a ocorrencia de fungos entre sementes comarilo e sem arilo e, tambem, a ocorrencia de fungos entre sementes comarilo normal e com injurias, de lotes dos anos 2004 e 2005. Considerou-se normal as sementes cujo arilo estava intacto, e com injurias aquelascujo arilo apresentava danos mecânicos ou escurecimento.No PF foram identificados os seguintes generos de fungospotencialmente fitopatogenicos: