成長錐を用いた木片試料採取法の検討 : 道管形成の季節変化を調べる観点から

Feature : Impact on Ashiu forest ecosystem due to dee

Relationship between the timing of vessel formation and leaf phenology in ten ring-porous and diffuse-porous deciduous tree species

The goal of this study is to clarify how different aspects of plant function are coordinated developmentally for species of ring-porous versus diffuse-porous deciduous trees, comparing the timing of leaf phenology and vessel formation in twigs and stems from an ecophysiological viewpoint. Cylindrical stem cores and twigs were collected at intervals from early spring through summer from five ring-porous and five diffuse-porous species in a cool temperate forest, and leaf and vessel formation were observed simultaneously. We found that the first-formed vessels of the year were lignified in twigs around the time of leaf appearance and at or before full leaf expansion of each tree in both groups of species with flush-leaves. Vessels in stems were lignified 2 weeks before to 4 weeks after leaf appearance and before or around full leaf expansion of the tree in ring-porous species. This was significantly earlier than in diffuse-porous species, in which stem vessel lignification was 2–8 weeks after leaf appearance and at or after full leaf expansion of the tree. The timing of vessel formation in twigs compared to stems was significantly earlier in ring-porous species than in diffuse-porous species. Lignification of vessels in stems occurred within 2 weeks of lignification in the twigs of ring-porous species and 2–8 weeks after lignification in twigs of diffuse-porous species. These results indicate the order and time-lag of leaf and vessel formation. Ring-porous species showed intensive leaf/vessel production, whereas diffuse-porous species showed less intensive leaf/vessel production

Formation and distribution of calcium crystals in the trunk of Hopea odorata

Some of trees accumulate calcium crystals, which cause damage to cutting tools in wood machinery. For the fundamental information on the formation and distribution of calcium crystal in a trunk, Hopea odorata was very important to be studied. Three discs from lower, middle and upper positions of the trunk were collected. In each disk, radial strip from bark to pith was fixed with 3% glutaraldehyde. In each disc, small blocks from outer, middle, inner part and pith were cut and used for microscopic observation. Sections were stained with safranin and fast green. Morphology and distribution of calcium crystals in a trunk (radial and longitudinal) and quantitative analysis were carried out. Acid treatments with hydrochloric acid or acetic acid were also applied to investigate the chemical characteristic of the crystals. For comparison of morphology of calcium crystals between wood and bark, bark block was embedded in epoxy resin, and sections were stained with safranin. Crystals in wood were exclusively included in square/ upright ray cells with very rare cases of crystals in procumbent ray cells of ray parenchyma. Their morphology was prismatic crystals in wood and pith. In the bark, crystals showed druses form. Through chemical treatments, calcium crystals were identified as calcium oxalate. In the trunk, crystals were increased from outer to inner in the radial direction, but decreased in the pith. In the longitudinal direction, crystals showed an increase from lower to upper position in the outer and middle part, but decreased at inner part. Pith did not show much difference from lower to upper position of the trunk

Estimation of tree age in the humid tropics by vessel measurement: a preliminary study

We estimated the age of plantation-grown trees lacking distinct and consistent annual rings to examine whether an anatomical method for determining the vessel traits of wood is effective in the tropical rain forest climate. Stem disks from 1 Dipterocarpaceae and 2 Meliaceae species for which the planting year was known were collected, and radial strips were sawn out from 2 different radii on each disk. We measured mean vessel lumen area (MVLA) and vessel frequency (VF) and found that radial changes in the 2 variables showed cyclic variation in all samples. The cycle number of both MVLA and VF mostly matched the tree age when they were analyzed with proper radial resolution. The number and shape of the cyclic variations were different between the 2 radii; this inconsistency could partly be ascribed to asynchronous cambium activity. The result implies that (1) the selection of sample species is important and (2) more than 1 radius should be analyzed to increase the accuracy of estimation. Thus, we concluded that vessel traits are important growth-ring indicators in the humid tropics, but a single application of this method of ring analysis may not be sufficiently accurate in age estimation. Further research on the factors affecting vessel formation will make the method more effective

Anatomical structures and fiber morphology of new kenaf varieties

Kenaf plant is claimed as one of the fast-growing herbaceous plants with the high potential as a fiber material or lignocellulosic material. Nine kenaf varieties i.e., Q-Ping, KK60, V12, V19, V36, V132 and NS V133 and TK were introduced recently by Taman Pertanian Universiti, Universiti Putra Malaysia as one of the potential plant to replace tobacco plantation. Since, these nine kenaf varieties are new to Malaysia, therefore, there is a need to study their anatomical structures and fiber morphology as well as microscopic appearances to understand their different and similarity. Cell morphology and anatomical appearances were observed and evaluated under the image analysis system (Leitz DMRB). From the results, V19 and V12 had the wider ray among the nine varieties, whereas other varieties in their microscopic appearance were almost similar to those observed in many diffuse-porous hardwoods. The longest fiber length was observed in variety TK (2.96 mm) followed by V36. Q-ping showed the widest fiber diameter and lumen diameter amongst the nine varieties, with value of 28.64 μm in bast fiber and 28.06 μm in core diameter. However, Q-ping had the thinnest core cell wall with the thickness of 3.34 μm. In term of fiber length, all the kenaf varieties bast fiber has longer fiber than core fiber. The kenaf core of nine varieties has wider fiber diameter and fiber lumen diameter than the bast fiber. Conclusively, although kenaf exhibit similarity in some fiber morphology and anatomical structures, however, there still some distinction that can be used to differentiate these kenaf variety

Formation and anatomical characteristics of tension wood in plantation-grown Hevea brasiliensis (Willd.) Muell.-Arg.

Hevea brasiliensis wood is now widely utilized for wood industry. A problem of low yield or recovery has been pointed out. Tension wood is considered to be one of the possible causes for the low recovery. The characteristics of tension wood formation of three plantation-grown H. brasiliensis trees with different leaning angles were investigated. In a tree with strongly leaning stem, eccentric growth which is one of the typical characteristics of tension wood occurred in the upper (tension) side of the leaning stem. In the eccentric growth portion, almost all fibers except growth ring boundary showed gelatinous fibers with gelatinous layer. In a tree with weakly leaning stem, the eccentric growth did not occur. However, the upper side wood had gelatinous fibers. The opposite wood had partially gelatinous fibers. Three distribution patterns of gelatinous fibers were indicated. In a tree whose stem was in the upright position, the gelatinous fibers were distributed not in a fixed-direction but along the circumference of the disk. Their amount was not much compared to those of the upper side wood of leaning stems. The fibers in upright stems showed similar structure with gelatinous layer in leaning stems. The occurrence of gelatinous fibers in a weakly leaning stem or in the upright stem suggests the possibility of uneven distribution of plant hormones necessary and sufficient for the formation of gelatinous fibers

Radial variation of wood cell features under different stocking densities management of two new clones of rubberwood (Hevea brasiliensis)

Wood characteristics vary from pith to bark and this can influence the final use. These variations can be related to the effects of plantation management. The radial variation in fiber cells, vessel elements, and ray cells was investigated for a commercial and fast-grown species, the rubberwood (Hevea brasiliensis), at varying stocking densities. Nine-year-old trees of two new clones (RRIM 2020 and RRIM 2025) were categorized into four stocking densities of 500, 1000, 1500, and 2000 trees ha−1. The sample blocks were anatomically analyzed to determine the changes in wood cells from pith to bark. The results generally showed a centrifugal increase in fiber features, vessel diameter, ray height, and ray area. Vessel density and ray density showed a decreasing trend. Vessel areas revealed a radial irregular variation. The ray area showed a striking relationship with ray density and ray height. Ray cell pattern indicated enough variation for visual approval to ensure within and between stocking density changes. Most radial variation was explained by the effect of cambial age. Owing to different stem width and growth rates, the mean cell features were not at the same radial distances from the pith

II Coleoptera : Ciidae (Entomological Results from the Scientific Survey of the Tokara Islands) (MATHEMATICS AND NATURAL SCIENCE)

The material collected during the Tokara scientific survey contains 4 species of Ciidbeetles, one of which seems to be new to science and is described below. The specimens mentioned in this paper are preserved in the collection of the Osaka Municipal Museum of Natural History and of ours