Classificação fisiológica de sementes de espécies florestais quanto a tolerância à dessecação
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Data
2017-05-26
Autores
Barros, Hellen Síglia Demétrio [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A demanda por sementes florestais nativas vem crescendo, devido a produção de mudas que visam recuperar áreas abandonadas, degradadas e de reflorestamento, tornando-se imprescindível conhecer o comportamento dessas sementes quanto a tolerância à dessecação e armazenamento, visando sua conservação. O trabalho teve como objetivo classificar sementes de espécies florestais quanto à tolerância a dessecação e ao comportamento no armazenamento, através dos efeitos da redução do teor de água sobre o desempenho fisiológico das sementes. Testes de germinação e de determinação do teor de água foram feitos para cada espécie: com as sementes recém-beneficiadas, as submetidas ao processo de secagem e após três meses de armazenamento a -18°C, apenas para as sementes com teores de água inferiores a 5% de água que mantiveram a viabilidade. Com base resultados dos testes de germinação e de teor de água, as sementes foram classificadas em ortodoxas, recalcitrantes e intermediárias. As sementes de Parkia platycephala, Pseudopiptadenia suaveolens, Bowdchia nitida e Ptrocarpus rhorii foram classificadas como ortodoxas, as quais podem ser armazenadas à baixa temperatura (-18ºC) e com teores de água inferiores a 5% sem comprometer sua viabilidade. As sementes de Manilkara huberi e Swartzia laurifolia foram classificadas como recalcitrantes, não tolerando a secagem a baixos teores de água (12%), recomendando a conservação in situ dessas espécies. Enquanto que as sementes de Eriotheca globosa foram classificadas como intermediárias.
The demand for native forest seeds has been increasing, due to the increasing of projects aiming at to recover abandoned, degraded and reforested areas. For this is essential to know the behavior of these seeds in terms of tolerance to desiccation and storage. The objective of this study was to classify seeds of forest species in terms of tolerance to desiccation and storage behavior, through the effects of drying the followed by physiological performance of the seeds. Germination and water content tests were performed for each species: with newly-harvested seeds, submitted to the drying process and after three months of storage at -18°C, only for seeds with water contents below 5% of water. Based on the tests of germination and water content, the seeds were classified as orthodox, recalcitrant and intermediary. The seeds of Parkia platycephala, Pseudopiptadenia suaveolens, Bowdchia nitida and Ptrocarpus rhorii were classified as orthodox, which can be stored at low temperature (-18ºC) and with water contents of less than 5% for longs periods, without compromising their viability. The seeds of Manilkara huberi and Swartzia laurifolia were classified as recalcitrant and did not tolerate drying at low water contents (12%), recommending the in situ conservation of these species. The seeds of Eriotheca globosa, were classified as intermediates.
The demand for native forest seeds has been increasing, due to the increasing of projects aiming at to recover abandoned, degraded and reforested areas. For this is essential to know the behavior of these seeds in terms of tolerance to desiccation and storage. The objective of this study was to classify seeds of forest species in terms of tolerance to desiccation and storage behavior, through the effects of drying the followed by physiological performance of the seeds. Germination and water content tests were performed for each species: with newly-harvested seeds, submitted to the drying process and after three months of storage at -18°C, only for seeds with water contents below 5% of water. Based on the tests of germination and water content, the seeds were classified as orthodox, recalcitrant and intermediary. The seeds of Parkia platycephala, Pseudopiptadenia suaveolens, Bowdchia nitida and Ptrocarpus rhorii were classified as orthodox, which can be stored at low temperature (-18ºC) and with water contents of less than 5% for longs periods, without compromising their viability. The seeds of Manilkara huberi and Swartzia laurifolia were classified as recalcitrant and did not tolerate drying at low water contents (12%), recommending the in situ conservation of these species. The seeds of Eriotheca globosa, were classified as intermediates.
Descrição
Palavras-chave
Conservação de germoplasma, Secagem de sementes, Sensibilidade à dessecação, Conservation of germoplasm, Seed of drying, Desiccation to sensitivity