Morphophysiological development of Tabeluia serratifolia Vahl Nich. seeds

Abstract

Tabebuia serratifolia is used for the reforestation of degraded areas. Despite protection by law for permanent preservation, the species is in danger of extinction due to improper exploitation. With the objective to aid preservation and long term storage of the species we evaluated morphophysiological alterations of T. serratifolia seeds during the maturation process in order to identify markers that can be used for harvesting and storage. Fruits were collected at anthesis and seven developmental stages from trees growing in Lavras, state of Minas Gerais, Brazil. At each harvest, fruits and seeds were evaluated for color and size, moisture content, dry matter, internal morphology (by X-ray analysis), germination parameters (in vitro and ex vitro), as well as sugar and polyphenol content and heat resistant proteins. During the maturation process the initially green fruits changed to a brownish color and grew from a length of 7 to 18 cm; cracks appeared at the beginning of seed dispersal. The seed color varied from leaf-green to brownish and the length from 1 to 3 cm. The first indicatior of physiological maturity should be observed at 39 days post-anthesis, when variations the color and size of both fruits and seeds were observed. Increase in the moisture content, dry matter and germination, percentage of seeds and embryos in vitro, as well as a reduction in sugar content and LEA proteins were also observed. The physiological maturity of T. serratifolia seeds was reached 53 days after anthesis, coinciding with a maximum of dry matter accumulation and germination (and index of germination speed ex vitro), decrease in phenol levels, higher intensity of heat-resistant protein bands and the beginning of fruit opening. Key words: forest seeds, maturation, seed quality, preservation DESENVOLVIMENTO MORFOFISIOLÓGICO DE SEMENTES DE IPÊ-AMARELO (Tabeluia serratifolia Vahl Nich.)RESUMO: Tabebuia serratifolia é utilizada no reflorestamento de áreas degradadas. Devido à sua exploração indevida, encontra-se em perigo de extinção, apesar de protegida por lei para preservação permanente. Foram investigadas as alterações morfofisiológicas de sementes de ipê-amarelo ao longo do desenvolvimento, para fins de auxiliar a conservação dessa espécie. Os frutos foram coletados a partir da antese, em sete estádios de desenvolvimento, em árvores localizadas na região de Lavras, MG, Brasil. Em cada coleta, as sementes foram submetidas às análises radiográficas e microscópicas, avaliando-se as colorações e tamanho, o grau de umidade e matéria seca tanto dos frutos como das sementes, a germinação in vitro e ex vitro, bem como os teores de açúcares, polifenóis e proteínas resistentes ao calor. Durante o desenvolvimento os frutos que inicialmente eram verdes passaram para amarronzados e o comprimento de 7 para 18 cm, apresentando fendas que iniciam a dispersão de suas sementes. As sementes tiveram sua cor variando de verde-folha a amarronzado e comprimento de 1 a 3 cm. As alterações iniciais indicativas da maturidade fisiológica de s...

In vitro and ex vitro germination of three Handroanthus species (Bignoniaceae)

“…Several species of Handroanthus have germination problems in natural habitats. The process is extremely variable and differs between species and with the site and conditions of seed formation (climate, phytosanitary status and physiological aspects) (Justiniano et al, 2000;Bocchese et al, 2008;Carvahlo et al, 2008;Nery et al, 2008). Sakai (2010) reports that most recalcitrant species are associated with Dicotyledons primitive or ancestral characters, such as large exalbuminous seeds and a tropical woody habit.…”

“…Morphological and physiological aspects of the germination of H. impetiginosus have been reported by Silva et al (2004). Morphological studies of the fruit, seed and seedlings have been reported by different authors (Corner, 1976;Carvahlo et al, 2008;Ferreira & Cunha 2000;Souza et al, 2005).…”

“…Even though most species of Handroanthus produce large quantities of seed, many of them have germination and conservation problems in their natural habitats (Bocchese et al, 2008;Carvahlo et al, 2008;Justiniano et al, 2000;Nery et al, 2008). In vitro germination has been little studied (Nery et al, 2008), however some studies have been carried out on the ex situ germination of several species of this genus (Silva et al, 2004;Ferreira & Cunha, 2000;Nery et al, 2008).…”

Acúmulo de matéria seca e óleo nas sementes de pinhão-manso e qualidade do óleo extraído

“…Nos estádios iniciais do processo de maturação o aumento das dimensões características dos frutos e sementes é comum, em razão do acúmulo de matéria seca e a menor perda de água (Mendes et al, 2006;Carvalho et al, 2008). Como não houve diferença significativa entre o teor de água dos frutos dos estádios E1, E2 e E3 é provável que tenha prevalecido, nesses estádios, o efeito do desenvolvimento com o aumento do tamanho dos frutos sobre o efeito de contração volumétrica, causado pela perda de água, diferentemente do que foi observado para as sementes que apresentaram médias decrescentes de teor de água.…”

Seedling survival of Handroanthus impetiginosus (Mart ex DC) Mattos in a semi-arid environment through modified germination speed and post-germination desiccation tolerance

“…Fruit and seed maturity were verified using morphological parameters (Carvalho et al, 2008). The seeds were extracted manually from the fruits, mixed, dried to a moisture content of 0.07 g H 2 O g -1 dw and stored for five months in plastic bags in a controlled environment room with 55% relative humidity and 5 °C.…”