Produção de painéis de madeira aglomerada de Grevillea robusta A. Cunn. ex R. Br.

Este trabalho teve como objetivo avaliar o comportamento da madeira de Grevillea robusta na produção de painéis de madeira aglomerada. Os painéis foram produzidos em densidades de 0,60 e 0,80 g/cm³ e conteúdo de resina de 6 e 8%. Os resultados de propriedades físicas e mecânicas dos painéis fabricados com densidade de 0,80 g/cm³ e conteúdo de resina de 8% evidenciaram que a madeira de Grevillea robusta pode ser utilizada como fonte alternativa de matéria-prima para produção de painéis aglomerados.

Seed bank from soil of coffee plantations associated with grevillea trees

This study aimed to study the composition and dynamics of seed bank from soil of coffee plantations associated with grevilea trees in the experimental fields of the Southwest Bahia State University, on Vitória da Conquista campus. The experiments were carried out from September 2006 to May 2007. The coffee trees (Coffea arabica) were sown at three x one m spacing, associated with grevillea trees (Grevillea robusta) and maintained at densities of 277, 139, 123, 69, 62 and 31 plants ha-1, under direct sunlight. One hundred grams of soil were taken from each treatment with four repetitions and later identified and counted with a 10x magnifying glass. To determine seedling emergence, four soil samples of 1000 g were collected from each experimental field and transported to the greenhouse. Seedling emergence was observed by counts after 15, 30 and 45 days. The experimental design was randomized blocks of seven treatments (soil from different tree densities) and four replicates; the experimental unit consisted of a plastic tray (0, 30 x 0.22 x 0.06 m) containing 1.000 g of soil. The variables utilized to characterize the bank and its dynamics were: relative frequency, relative density, relative abundance, importance index and species diversity (Shannon-Weaver index).Increased number of monocotyledon seeds and sprouts were verified in the treatments maintained under full sunlight.

Calibração de um equipamento TDR (Reflectometria por Dominio do Tempo) para a Determinação da Umidade da Madeira de Grevillea robusta (Cunn.)

This study aimed to establish a calibration model of a TDR equipment to determinate thewood moisture of Grevillea robusta (Cunn.). It was selected alleatory, 11 logs of Grevillea robusta (Cunn.), it was dried in a regulate electric greenhouse at 40o C. During the dry process, the moisture was determinate, periodically and systematically by gravimetric and TDR methods. Through the gravimetric method, moisture vary from 125,88% to 6,62% while the TDR method, the variation was from 119,83% to 5,79%. The best model adjusted to the wood moisture in the determination of the function of relative dielectric constant, using this technique, was the exponential 50,20 132,72 140,27 K U e − = − ⋅ , with a R2 = 0,96, with indicator of trust or performance 0,97 they were classified as very good, according to Camargo and Sentelhas (1997). The correlation between the gravimetric method (reference) and TDR, showed to be equivalent for both methodologies. It was concluded that the TDR can be used to the determination of wood moisture of Grevillea robusta (Cunn.), in a precise and fast way, once it was established it calibration.

Grevillea robusta

Von A. Sliwa

Grevillea.

Editor: 1872- , M. C. Cooke.

Effects of 6-benzylaminopurine treatments on the longevity of harvested Grevillea 'Sylvia' inflorescences

Exogenous treatments with cytokinins, such as 6-benzylaminopurine (BA), can delay senescence of some plant tissues. Grevillea 'Sylvia' inflorescences have a short vase life. BA supplied in vase solutions at up to 0.1 mM did not delay senescence of G. 'Sylvia' in florescences. However, BA applied by dipping at concentrations up to 10 mM extended their vase life (longevity). Senescence parameters of relative fresh weight, flower abscission, flower opening, flower discolouration and flower wilting were all suppressed by BA dips. Dip treatment with BA (1 mM) was effective on G. 'Sylvia' in florescences at three different maturity stages.

Development and senescence of Grevillea 'Sylvia' inflorescences, flowers and flower parts

To characterise the physiology of development and senescence for Grevillea 'Sylvia'. oral organs, respiration, ethylene production and ACC concentrations in harvested flowers and flower parts were measured. The respiration rate of harvested inflorescences decreased over time during senescence. In contrast, both ethylene production and ACC concentration increased. Individual flowers, either detached from cut inflorescences held in vases at 20degreesC or detached from in planta inflorescences at various stages of development, had similar patterns of change in ACC concentration and rates of respiration and ethylene production as whole inflorescences. The correlation between ACC concentration and ethylene production by individual flowers detached from cut inflorescences held in vases was poor (r(2)=0.03). The isolated complete gynoecium (inclusive of the pedicel) produced increasing amounts of ethylene during development. Further sub-division of flower parts and measurement of their ethylene production at various stages of development revealed that the distal part of the gynoecium (inclusive of the stigma) had the highest rate of ethylene production. In turn, anthers had higher rates of ethylene production and also higher ACC concentrations than the proximal part of the gynoecium (inclusive of the ovary). Rates of ethylene production and ACC concentrations for tepal abscission zone tissue and adjacent central tepal zone tissue were similar. ACC concentration in pollen was similar to that in senescing perianth tissue. Overall, respiration, ethylene and ACC content measurements suggest that senescence of G. 'Sylvia' is non-climacteric in character. Nonetheless, the phytohormone ethylene is produced and evidently mediates normal flower development and non-climacteric senescence processes.

Adventitious root formation in Grevillea (Proteaceae), an Australian native species

Grevillea (Proteaceae) is a native Australian plant genus with high commercial value as landscape ornamentals. There has been limited research on the culture and propagation of Australian native species. The effect of indole-3-butyric acid (IBA) on the rooting of G. 'Royal Mantle' and G. 'Coastal Dawn' in winter, spring and summer was evaluated at University of Queensland Gatton, Southern Queensland in order to determine the rooting ability of this species in different seasons. Both Grevillea cultivars showed seasonal rooting. The more difficult-to-root G. 'Coastal Dawn' had a reduced response to IBA application than G. 'Royal Mantle'. Stem and leaf indole-3-acetic acid (IAA) levels were not different between cultivars, therefore rooting ability between the two cultivars does not appear to be due to the differences in endogenous IAA levels. (c) 2005 Elsevier B.V. All rights reserved.

Vase treatments containing gibberellic acid do not increase longevity of cut Grevillea 'Sylvia' inflorescences

The longevity of Grevillea 'Sylvia' inflorescences can be very short and is influenced by exposure to ethylene. Gibberellic acid has the potential to delay senescence in some cut flowers by acting as an anti-ethylene treatment. Gibberellic acid was therefore applied to Grevillea 'Sylvia' inflorescences in vase solutions to determine its effects on longevity. Treatments with gibberellic acid did not prolong the longevity of inflorescences or influence 1-aminocyclopropane-1-carboxylic acid concentrations. Treatments at high gibberellic acid concentrations enhanced flower abscission and we therefore conclude that vase-applied gibberellic acid treatments are not suitable for extending the longevity of cut Grevillea 'Sylvia' inflorescences.

Stem End blockaged in Cut grevillea 'Crimson Yul-lo' inflorescences

Grevillea 'Crimson Yul-lo' inflorescences have cut flower potential, but their vase life is short. End of vase life is characterized by early wilting. The possibility of physiologically mediated stem end blockage was investigated. Hydraulic conductance of 2 cm long stem end segments declined rapidly and remained lower throughout vase life than that of 2 cm long stem segments from immediately above. Recutting daily to remove basal 2 cm stem ends increased solution uptake, delayed declines in inflorescence water potential and water content, and improved inflorescence vase life. S-carvone is a potential inhibitor of wound related suberin formation, via inhibition of phenylalanine ammonia-lyase. Vase solution treatments with S-carvone (0.318 and 0.636 mM) delayed the decline in hydraulic conductance of basal 2 cm long stem end segments and decreases in vase solution uptake and relative fresh weight of cut stems, and extended vase life. Treatments with the catechol oxidase inhibitor 4-hexylresorcinol (2.5-10 mM) also delayed stem end blockage. These findings suggest that stem end blockage in cut G. 'Crimson Yul-lo' stems is physiologically mediated. (C) 2006 Elsevier B.V. All rights reserved.

Seed dormancy and germination responses of nine Australian fire ephemerals

Fire ephemerals are short-lived plants with seeds that persist in the soil and germinate after a fire or physical soil disturbance. Ex situ germination of many Australian fire ephemerals has previously been difficult. Dormancy was present in most of the nine fire ephemerals examined. Alyogyne hakeifolia (Giord.) Alef. and Alyogyne huegelii (Endl.) Fryxell (Malvaceae) seeds had physical and possibly also physiological dormancy, Actinotus leucocephalus Benth. (Apiaceae) seeds had morphophysiological dormancy, Austrostipa compressa (R.Br.) S.W.L. Jacobs & J. Everett and Austrostipa macalpinei (Reader) S.W.L. Jacobs & J. Everett (Poaceae) seeds were either non-dormant or possessed physiological dormancy, and seeds of all remaining species possessed physiological dormancy. A proportion of the Alyogyne hakeifolia, Alyogyne huegelii, Austrostipa compressa and Austrostipa macalpinei seed populations were non-dormant because some seeds could germinate at the various incubation temperatures without further treatment. At 20 degrees C, artificial methods of inducing germination such as manual or acid scarification were among the optimal treatments for Austrostipa compressa, Austrostipa macalpinei, Alyogyne huegelii, Actinotus leucocephalus and Grevillea scapigera A.S. George (Proteaceae), and gibberellic acid induced maximum germination of Tersonia cyathiflora (Fenzl) J.W. Green (Gyrostemonaceae) seeds. Heat (70 degrees C for 1 h) and smoke water was one of the most effective treatments for germinating Actinotus leucocephalus and Codonocarpus cotinifolius (Desf.) F. Muell. (Gyrostemonaceae) seeds. Germination of Grevillea scapigera, Codonocarpus cotinifolius, Gyrostemon racemiger H. Walter (Gyrostemonaceae) and Tersonia cyathiflora did not exceed 40% and may require other treatments to overcome dormancy. Although the nine fire ephemerals examined require fire to germinate under natural conditions, a range of germination responses and dormancy types was observed.