Performance of Citric Acid-Bonded Oriented Board from Modified Fibrovascular Bundle of Salacca ( (Gaertn.) Voss) Frond.

The fibrovascular bundle (FVB) in palm plants consists of fiber and vascular tissue. Geometrically, it is a long fiber that can be used as an oriented board raw material. This research aimed to examine the performance of citric acid-bonded orientation boards from modified FVB salacca frond under NaOH + NaSO treatment and the bonding mechanism between the modified FVB frond and citric acid.

Winter-spring temperature pattern is closely related to the onset of cambial reactivation in stems of the evergreen conifer Chamaecyparis pisifera.

Temperature is an important factor for the cambial growth in temperate trees. We investigated the way daily temperatures patterns (maximum, average and minimum) from late winter to early spring affected the timing of cambial reactivation and xylem differentiation in stems of the conifer Chamaecyparis pisifera. When the daily temperatures started to increase earlier from late winter to early spring, cambial reactivation occurred earlier.

Changes in cambial activity are related to precipitation patterns in four tropical hardwood species grown in Indonesia.

Premise: Cambial activity in some tropical trees varies intra-annually, with the formation of xylem rings. Identification of the climatic factors that regulate cambial activity is important for understanding the growth of such species. We analyzed the relationship between climatic factors and cambial activity in four tropical hardwoods, Acacia mangium, Tectona grandis, Eucalyptus urophylla, and Neolamarckia cadamba in Yogyakarta, Java Island, Indonesia, which has a rainy season (November-June) and a dry season (July-October).

Stem gravitropism and tension wood formation in Acacia mangium seedlings inclined at various angles.

Background And Aims: In response to a gravitational stimulus, angiosperm trees generally form tension wood on the upper sides of leaning stems in order to reorientate the stems in the vertical direction. It is unclear whether the angle of inclination from the vertical affects tension wood formation. This study was designed to investigate negative gravitropism, tension wood formation and growth eccentricity in Acacia mangium seedlings inclined at different angles.

Effect of epicuticular wax crystals on the localization of artificially deposited sub-micron carbon-based aerosols on needles of Cryptomeria japonica.

Elucidation of the mechanism of adsorption of particles suspended in the gas-phase (aerosol) to the outer surfaces of leaves provides useful information for understanding the mechanisms of the effect of aerosol particles on the growth and physiological functions of trees. In the present study, we examined the localization of artificially deposited sub-micron-sized carbon-based particles on the surfaces of needles of Cryptomeria japonica, a typical Japanese coniferous tree species, by field-emission scanning electron microscopy. The clusters (aggregates) of carbon-based particles were deposited on the needle surface regions where epicuticular wax crystals were sparsely distributed.

Cavitation of intercellular spaces is critical to establishment of hydraulic properties of compression wood of Chamaecyparis obtusa seedlings.

Background And Aims: When the orientation of the stems of conifers departs from the vertical as a result of environmental influences, conifers form compression wood that results in restoration of verticality. It is well known that intercellular spaces are formed between tracheids in compression wood, but the function of these spaces remains to be clarified. In the present study, we evaluated the impact of these spaces in artificially induced compression wood in Chamaecyparis obtusa seedlings.

Localized cooling of stems induces latewood formation and cambial dormancy during seasons of active cambium in conifers.

Background And Aims: In temperate regions, trees undergo annual cycles of cambial growth, with periods of cambial activity and dormancy. Environmental factors might regulate the cambial growth, as well as the development of cambial derivatives. We investigated the effects of low temperature by localized cooling on cambial activity and latewood formation in two conifers, Chamaecyparis obtusa and Cryptomeria japonica.

Gibberellin mediates the development of gelatinous fibres in the tension wood of inclined Acacia mangium seedlings.

Background And Aims: Gibberellin stimulates negative gravitropism and the formation of tension wood in tilted Acacia mangium seedlings, while inhibitors of gibberellin synthesis strongly inhibit the return to vertical growth and suppress the formation of tension wood. To characterize the role of gibberellin in tension wood formation and gravitropism, this study investigated the role of gibberellin in the development of gelatinous fibres and in the changes in anatomical characteristics of woody elements in Acacia mangium seedlings exposed to a gravitational stimulus.

Methods: Gibberellin, paclobutrazol and uniconazole-P were applied to the soil in which seedlings were growing, using distilled water as the control.

Gibberellin is required for the formation of tension wood and stem gravitropism in Acacia mangium seedlings.

Background And Aims: Angiosperm trees generally form tension wood on the upper sides of leaning stems. The formation of tension wood is an important response to gravitational stimulus. Gibberellin appears to be involved in the differentiation of secondary xylem, but it remains unclear whether gibberellin plays a key role in the formation of tension wood and plant gravitropism.