Métodos para avaliação do vigor de sementes de soja, incluindo a análise computadorizada de imagens

A velocidade e uniformidade de emergência de plântulas, determinantes do sucesso do estabelecimento do estande, representam etapas essenciais para a obtenção de alta produtividade na cultura da soja, de modo que o desenvolvimento de procedimentos para avaliar o potencial fisiológico tem recebido atenção contínua da pesquisa em Tecnologia de Sementes. O objetivo deste trabalho foi o de verificar a eficiência de um sistema computadorizado para análise de imagens de plântulas, em comparação com testes recomendados para determinação do vigor de sementes de soja como testes de tetrazólio, envelhecimento acelerado, condutividade elétrica e crescimento de plântulas,. Para tanto, lotes de sementes dos cultivares Pintado e TMG 113RR foram avaliados quanto à germinação (25oC aos 4 e 7 dias), envelhecimento acelerado tradicional (41oC durante 48 h), envelhecimento acelerado com solução saturada de sal (41oC durante 72 h) e emergência de plântulas. O sistema de análise computadorizada de imagens de plântulas (SVIS®), desenvolvido pela Ohio State University/EUA, forneceu dados referentes ao índice de vigor, à uniformidade de desenvolvimento e ao crescimento de plântulas, tanto aos três dias após a semeadura do teste de germinação sob condições ótimas como após o envelhecimento acelerado com solução de sal. O período experimental compreendeu três épocas de testes com intervalo aproximado de 30 dias. Constatou-se que o SVIS® é suficientemente sensível para avaliação do vigor de sementes de soja, com eficiência comparável à do teste de envelhecimento acelerado, constituindo alternativa interessante para a obtenção de informações consistentes sobre o potencial fisiológico.

Using Tomato Analyzer software to determine embryo size in x-rayed seeds

A primary interest of image analysis of X-rayed seeds is to identify whether the extent of fill in the embryo cavity is associated with to seed physiological quality. The objective of this research was to verify the accuracy of the freely available Tomato Analyzer (TA) software developed at The Ohio State University to determine the ratio of embryo size over total seed area. Seeds of pumpkin, watermelon, cucumber and cotton were X-rayed and analyzed by the software which defines seed and embryo boundaries and automatically generates numerical values to quantify that ratio. Results showed that the TA has the sensitivity to evaluate the extent of embryo growth within the cucurbits and cotton seeds and is a promising alternative for this assessment in other seed species.

HTLV-I associated myelopathy in the northern region of Brazil (Belém-Pará): serological and clinical features of three cases

Three patients (males, black, ages 37, 40 and 57) attended a university clinic with a progressive paraparesis of obscure origin. One patient who referred disease duration of more than 16 years, showed diminished deep reflexes, bilateral Babinski's sign, diminished sensation of vibration, abnormal bladder function and back pain. The other two patients (with one and six years of disease duration) complained of weakness in one leg, increased deep reflexes and back pain. Babinski's sign and bladder disturbance were also present in the patient with six years of disease. Blood samples tested by an enzyme immune assay and a discriminatory Western blot were positive for HTLV-I. The familial analysis of one patient showed a possible pattern of sexual and vertical transmission of the virus. To the best of our knowledge, these are the first cases of a proven association between HTLV-I and TSP/HAM in Belem, Para, and emphasize the need to actively look for cases of neurological disease associated to the virus.

Myxomycetes collection preserved in the herbarium of the Federal University of Roraima (Brazil)

First records of myxomycetes in the North region of Brazil go back to the 19th century. Nevertheless, the myxobiota of this region is still largely unexplored, with only 42 species recorded, distributed in 20 genera and seven families. The objectives of this paper were to characterize the Myxomycetes collection of the Herbarium of the Federal University of Roraima (UFRR) and to add new records for the myxobiota of this State. The collection holds specimens collected in fragments of Open Ombrophilous Forest, Seasonal Semi-deciduous Forest, Riparian Forest, deforested areas and urban home gardens in the state of Roraima. The 157 exsiccates were analyzed and identified or redetermined based on identification keys, descriptions and illustrations. The collection is in good conditions of preservation and includes all subclasses of Myxomycetes, 83% of its orders, 50% of its families, and 20 species. Trichiales, with one family, three genera and six species, represents 62% of all exsiccates. Cribraria aff. splendens, Metatrichia vesparia, Physarella oblonga, Stemonaria longa and Stemonitis splendens are new records for Roraima and Arcyria obvelata, Comatricha pulchella, Stemonitis pallida and Stemonitopsis aequalis are referred for the first time in the Northern Region, enlarging the knowledge of the Brazilian geographic distribution of these species.