ALBERT

Notes: Summary The concentrations of heavy metals, including zinc, cadmium, and copper were studied in the xylem rings of Pinus sylvestris trees and in the soil of three heavily polluted sites and one non-polluted site. There was a high correlation between the concentration of heavy metals in the soil and recently produced xylem rings. However, the initiation of industrial pollution did not abruptly increase heavy metal concentrations in the xylem rings. There was a high correlation between the zinc content of trees growing near a zinc smelter and the values obtained by other investigators for pine trees growing on the same site.

Notes: Summary A number of structural variables influence the conductivity of simple and scalariform perforation plates, and of vessel lumina. Using a previously developed computer model, the effects on conductivity of over 8,000 permutations of different lumen radii, perforation plate angles, perforation plate rim widths, scalariform slit pore heights, and scalariform bar thicknesses are considered. By taking advantage of basic patterns of similarity in the data, and by using scaling techniques, it has proved possible to calculate a series of factors which may be used to predict the conductivity of a vessel element or perforation plate of known dimensions. A number of previous workers have sought relationships between element structure and evolutionary or adaptive trends. Some important variables have been ignored in these studies in the past.

Notes: Summary Mature leaves of Mimosa pudica L. or parts of them were exposed to 14CO2, and translocation was recorded by macroautoradiography. It was observed that considerable amounts of labelled photoassimilates were accumulated in pulvini when the leaf was stimulated. In non-stimulated leaves, no such accumulation of label was observed. Microautoradiographs of pulvinar regions of the non-stimulated leaf showed 14C- label restricted to the phloem. When stimulated, the 14C- label was unloaded from the phloem of the pulvini. Labelled photoassimilates appeared most concentrated in the walls of the collenchymatous cells and beyond in the extensor region of the motor cortex. There, label was accumulated in the apoplastic compartments. Stimulation causes a sudden phloem unloading of sucrose, and its accumulation in the apoplast lowers the water potential which eventually exceeds the osmotic potential of the extensor cells of the motor cortex. By removal of cytoplasmic water the motor cells lose turgidity which results in the closing movement of the leaflets, and — some seconds later — in the bending down of the petiole. In late afternoon night-stimulation triggers sucrose unloading in secondary pulvini. During phases of relaxation, labelled material is taken up by motor cells of the extensor, which concomitantly gain turgor.

Notes: Summary Adenosine diphosphate (ADP), adenosine triphosphate (ATP) and orthophosphate were determined in non-stimulated, stimulated and relaxed pulvini of mature Mimosa pudica L. leaves. Additional determinations were made with leaflets, rhachillae, petiole and the stem in the stimulated condition. Results show that the content of adenine nucleotides is approximately twice as high in the pulvini as in the tissues between the pulvini. Orthophosphate, in contrast, occurs at higher concentrations in the connecting tissues than in the pulvini. ATP content is highest in the primary pulvini (0.8 μmol/mg dry wt.) and lowest in the tertiary pulvini. Stimulation causes consumption of ATP with a simultaneous increase in ADP content; however, the response is different in each type of pulvinus. This difference is best expressed in the ATP∶ADP ratio. Stimulation causes the most marked reduction of the ratio (9.5-1.4) in the secondary pulvini which react nyctinastically. Orthophosphate content is reduced by stimulation in all types of pulvini, and is increased during the recovery phase. By using a stylet bundle severed from a feeding aphid by a laser shot as tip for the microelectrode, changes of sieve tube membrane potentials were recorded. The changes of the electropotentials following stimulation show that the sieve tube is the pathway for the transmission of the excitation signal in the form of an action potential.

Notes: Summary Adventitious bud formation was induced on detached cotyledons and on cotyledons attached to excised embryos of Pinus caribaea and Pseudotsuga menziesii. The embryonic tissue was exposed to the cytokinin 6-benzyl amino purine contained within an agar medium. This exposure resulted in the formation of a meristematic zone, involving both epidermal and sub-epidermal cells, and then nodules on the tissue surface. Some of these nodules were induced to differentiate into bud primordia, and thence shoots, following exposure to a combination of auxin (IAA) and cytokinin. Shoots were produced over the entire surface of detached cotyledons of Ps. menziesii but predominantly on the adaxial surfaces of detached cotyledons of Pi. caribaea and the tips and adaxial surfaces of the cotyledons on the entire embryos of both species. Thus, inter-specific differences in the distribution of competent areas for adventitious bud production were detected in embryos.

Notes: Summary The influence of vesicular-arbuscular mycorrhizal symbiosis on cytokinin activity in Citrus jambhiri Lush, seedlings was investigated. C. jambhiri inoculated with cultures of Glomus caledonium (Nicol. and Gerd.), G. epigaeum (Dan. and Trappe), G. etunicatum (Becker and Gerd.), G. fasciculatum Thaxt. (Gerd, and Trappe) or G. mosseae (Nicol and Gerd.) was grown from seed for 105 days in a glasshouse. Cytokinin activity in roots and leaves of seedlings was analyzed using high-performance liquid chromatography, mass spectrometry and a bioassay. Seedling leaf tissue had greater cytokinin activity than root tissue. Zeatin, zeatin riboside, and their dihydro- and glucoside derivatives were isolated from leaves of 105-day-old seedlings inoculated with G. fasciculatum and G. mosseae. Cytokinin activity in roots and leaves was associated with differences in seedling total dry weight and vesicular-arbuscular mycorrhizal colonization. The ribose moiety and the saturated side chain apparently influence cytokinin transport and physiological activity in Citrus seedlings.

Notes: Summary The extractable monoterpenes from needles of two groups of trees — 4-year-old clonal and 20-year-old wild trees — were studied with respect to the influence of individual constitution, needle age, whorl position, and position on branch. Leaf terpene amounts from clonal trees are significantly affected by age and position of the whorl, whereas position on the branch is of minor importance. Developing needles of clonal trees are most strongly affected by age and whorl position and they differ markedly from mature needles in quantitative terpene composition. Wild trees exhibit a very high variation from tree to tree, which obscures the influence of needle age and position. For this reason meaningful tree leaf terpene data will only be derived if large samples of needles of different ages are collected from distinct positions. When comparing different trees, needles should be selected that not only have the same state of development, but also originate from identical positions and have been subjected to the same light treatment.

Notes: Summary The concentration of 20 elements (including eight nutritional elements) in spruce needles was monitored by taking samples at nine different dates in a single year. On each date the youngest and the 1-year-old needles were collected at four different sites. The needles were washed with an organic solvent to remove surface contamination before analysis by instrumental neutron activation. Although the sites showed widely different concentrations for the same element, they could be treated as a uniform population using normalized concentration values. Taking the time dependence of the concentration and the ratio of the concentrations in new and old needles as criteria, the following three groups of elements could be distinguished: 9 group I —Ca, Sr, Ba, and Mn; group II — Al, Br, Co, Fe, Hg, La, Sc, Sb, and Zn; group III — K, Rb, Cs, P, and Cl. Mg and Na did not fit into any of these groups. Within group I and III elements the strongest variations occur during the growing season (late spring and early summer) and the weakest during the dormant season; the variation is greater in the younger needles. Group II elements show an approximately linear increase throughout the year in both the younger and older needles. The concentrations of elements of groups I and II increase with time, while those of group III decrease. Na is unique insofar as its concentration is influenced by foliar uptake of road de-icing salt. The concentration of elements belonging to the same group shows strong inter-element correlations. The grouping of elements deduced here shows similarities with the chemical nature of the elements and with their transportability within the plant.

Notes: Summary The concentrations of heavy metals, including zinc, cadmium, and copper were studied in the xylem rings ofPinus sylvestris trees and in the soil of three heavily polluted sites and one non-polluted site. There was a high correlation between the concentration of heavy metals in the soil and recently produced xylem rings. However, the initiation of industrial pollution did not abruptly increase heavy metal concentrations in the xylem rings. There was a high correlation between the zinc content of trees growing near a zinc smelter and the values obtained by other investigators for pine trees growing on the same site.

Notes: Summary Mature leaves ofMimosa pudica L. or parts of them were exposed to14CO2, and translocation was recorded by macroautoradiography. It was observed that considerable amounts of labelled photoassimilates were accumulated in pulvini when the leaf was stimulated. In non-stimulated leaves, no such accumulation of label was observed. Microautoradiographs of pulvinar regions of the non-stimulated leaf showed14C- label restricted to the phloem. When stimulated, the14C- label was unloaded from the phloem of the pulvini. Labelled photoassimilates appeared most concentrated in the walls of the collenchymatous cells and beyond in the extensor region of the motor cortex. There, label was accumulated in the apoplastic compartments. Stimulation causes a sudden phloem unloading of sucrose, and its accumulation in the apoplast lowers the water potential which eventually exceeds the osmotic potential of the extensor cells of the motor cortex. By removal of cytoplasmic water the motor cells lose turgidity which results in the closing movement of the leaflets, and — some seconds later — in the bending down of the petiole. In late afternoon night-stimulation triggers sucrose unloading in secondary pulvini. During phases of relaxation, labelled material is taken up by motor cells of the extensor, which concomitantly gain turgor.

Notes: Summary A number of structural variables influence the conductivity of simple and scalariform perforation plates, and of vessel lumina. Using a previously developed computer model, the effects on conductivity of over 8,000 permutations of different lumen radii, perforation plate angles, perforation plate rim widths, scalariform slit pore heights, and scalariform bar thicknesses are considered. By taking advantage of basic patterns of similarity in the data, and by using scaling techniques, it has proved possible to calculate a series of factors which may be used to predict the conductivity of a vessel element or perforation plate of known dimensions. A number of previous workers have sought relationships between element structure and evolutionary or adaptive trends. Some important variables have been ignored in these studies in the past.

Notes: Summary Adventitious bud formation was induced on detached cotyledons and on cotyledons attached to excised embryos ofPinus caribaea andPseudotsuga menziesii. The embryonic tissue was exposed to the cytokinin 6-benzyl amino purine contained within an agar medium. This exposure resulted in the formation of a meristematic zone, involving both epidermal and sub-epidermal cells, and then nodules on the tissue surface. Some of these nodules were induced to differentiate into bud primordia, and thence shoots, following exposure to a combination of auxin (IAA) and cytokinin. Shoots were produced over the entire surface of detached cotyledons ofPs. menziesii but predominantly on the adaxial surfaces of detached cotyledons ofPi. caribaea and the tips and adaxial surfaces of the cotyledons on the entire embryos of both species. Thus, inter-specific differences in the distribution of competent areas for adventitious bud production were detected in embryos.

Notes: Summary Adenosine diphosphate (ADP), adenosine triphosphate (ATP) and orthophosphate were determined in non-stimulated, stimulated and relaxed pulvini of matureMimosa pudica L. leaves. Additional determinations were made with leaflets, rhachillae, petiole and the stem in the stimulated condition. Results show that the content of adenine nucleotides is approximately twice as high in the pulvini as in the tissues between the pulvini. Orthophosphate, in contrast, occurs at higher concentrations in the connecting tissues than in the pulvini. ATP content is highest in the primary pulvini (0.8 μmol/mg dry wt.) and lowest in the tertiary pulvini. Stimulation causes consumption of ATP with a simultaneous increase in ADP content; however, the response is different in each type of pulvinus. This difference is best expressed in the ATP∶ADP ratio. Stimulation causes the most marked reduction of the ratio (9.5-1.4) in the secondary pulvini which react nyctinastically. Orthophosphate content is reduced by stimulation in all types of pulvini, and is increased during the recovery phase. By using a stylet bundle severed from a feeding aphid by a laser shot as tip for the microelectrode, changes of sieve tube membrane potentials were recorded. The changes of the electropotentials following stimulation show that the sieve tube is the pathway for the transmission of the excitation signal in the form of an action potential.

Notes: Summary The influence of vesicular-arbuscular mycorrhizal symbiosis on cytokinin activity inCitrus jambhiri Lush, seedlings was investigated.C. jambhiri inoculated with cultures ofGlomus caledonium (Nicol. and Gerd.),G. epigaeum (Dan. and Trappe),G. etunicatum (Becker and Gerd.),G. fasciculatum Thaxt. (Gerd, and Trappe) orG. mosseae (Nicol and Gerd.) was grown from seed for 105 days in a glasshouse. Cytokinin activity in roots and leaves of seedlings was analyzed using high-performance liquid chromatography, mass spectrometry and a bioassay. Seedling leaf tissue had greater cytokinin activity than root tissue. Zeatin, zeatin riboside, and their dihydro- and glucoside derivatives were isolated from leaves of 105-day-old seedlings inoculated withG. fasciculatum andG. mosseae. Cytokinin activity in roots and leaves was associated with differences in seedling total dry weight and vesicular-arbuscular mycorrhizal colonization. The ribose moiety and the saturated side chain apparently influence cytokinin transport and physiological activity inCitrus seedlings.

Notes: Summary The extractable monoterpenes from needles of two groups of trees — 4-year-old clonal and 20-year-old wild trees — were studied with respect to the influence of individual constitution, needle age, whorl position, and position on branch. Leaf terpene amounts from clonal trees are significantly affected by age and position of the whorl, whereas position on the branch is of minor importance. Developing needles of clonal trees are most strongly affected by age and whorl position and they differ markedly from mature needles in quantitative terpene composition. Wild trees exhibit a very high variation from tree to tree, which obscures the influence of needle age and position. For this reason meaningful tree leaf terpene data will only be derived if large samples of needles of different ages are collected from distinct positions. When comparing different trees, needles should be selected that not only have the same state of development, but also originate from identical positions and have been subjected to the same light treatment.

Notes: Summary The concentration of 20 elements (including eight nutritional elements) in spruce needles was monitored by taking samples at nine different dates in a single year. On each date the youngest and the 1-year-old needles were collected at four different sites. The needles were washed with an organic solvent to remove surface contamination before analysis by instrumental neutron activation. Although the sites showed widely different concentrations for the same element, they could be treated as a uniform population using normalized concentration values. Taking the time dependence of the concentration and the ratio of the concentrations in new and old needles as criteria, the following three groups of elements could be distinguished: 9 group I —Ca, Sr, Ba, and Mn; group II — Al, Br, Co, Fe, Hg, La, Sc, Sb, and Zn; group III — K, Rb, Cs, P, and Cl. Mg and Na did not fit into any of these groups. Within group I and III elements the strongest variations occur during the growing season (late spring and early summer) and the weakest during the dormant season; the variation is greater in the younger needles. Group II elements show an approximately linear increase throughout the year in both the younger and older needles. The concentrations of elements of groups I and II increase with time, while those of group III decrease. Na is unique insofar as its concentration is influenced by foliar uptake of road de-icing salt. The concentration of elements belonging to the same group shows strong inter-element correlations. The grouping of elements deduced here shows similarities with the chemical nature of the elements and with their transportability within the plant.

Notes: Summary Using energy-dispersive X-ray microanalysis, the concentrations of ions, especially potassium and chlorine, were determined in different tissues of primary and tertiary pulvini of Mimosa pudica. It was shown that stimulating the leaf was followed by ion displacements which were most striking in the outer extensor cells, resulting in turgor loss. Since Ca concentration remains relatively constant in cell walls of collapsed cells, the changes of K concentration are best described by the K:Ca ratio. After stimulation the K:Ca ratio dropped in the outer extensor of the primary pulvinus from 775.3 to 2.37 in the cytoplasm, and from 542.2 to 9.25 in the cell wall. Changes in chlorine content were less striking in the primary pulvinus. The K∶Cl ratios in some cases were lower than 1.0, which indicates that Cl content can increase, while K content is diminished. In the non-stimulated tertiary pulvini the outer extensor cells show high concentrations of Cl, but much lower Cl concentrations were found after stimulation. In contrast to the primary pulvinus the K content of the tertiary pulvini is very low. In the vascular tissues of both primary and tertiary pulvini stimulation is followed by a release of K and Cl out of the sieve element cytoplasm into the apoplast. K then appears accumulated in the cell walls of the collenchymatous tissue. These displacements lead to the assumption that the collenchymatous apoplast temporarily functions as a reservoir for K and to a lesser extent for Cl. With regard to the mechanism of leaf movement after stimulation, the accumulation of ions in the apoplast seems to be initiated by the decrease of water potential triggered by an apoplastic accumulation of unloaded sucrose (Fromm and Eschrich 1988a). The resulting turgor release in the outer extensor is accompanied by an efflux of ions.

Notes: Summary During the period of leaf senescence in fall, the minerals Mg, Ca, K, P, Cl, S, and Si were compared for occurrence and density in tissue compartments of leaf blade, petiole, and subtending stem of beech (Fagus sylvatica L.). Measurements were made by energy-dispersive X-ray microanalysis. The plant material was collected on 2,9, 16 and 23 October, and showed green, greenyellow, yellow, and red-brown autumn leaf coloration. Mg, K, and P were retrieved from the leaf blade prior to shedding, and deposited mainly in cortex and pith tissues of the stem. S and Ca remained in the leaf, and Si and Cl appeared to accumulate in the leaf prior to shedding. During the four stages of leaf senescence, the phloem compartments of the petiole showed considerable changes in mineral content. In addition, leaf senescence in several cases was accompanied by ion shifting from symplastic to apoplastic compartments and vice versa.

Notes: Summary Water willow and grey alder were grown on a raised sphagnum bog in central Sweden. The stands were intensively treated by daily irrigation and fertilization during the growing period in order to improve site fertility. After a 2-year establishment period high production rates were achieved in willow stands, 0.8 kg stem dry weight m−2 year−1 on current plus one (C+1) year old shoots. In these stands the canopy was closed with a leaf area index (LAI) that peaked at approximately 7. The canopy in the alder stand did not close during the initial 3 years of growth and the measured production rate was relatively low, at approximately 0.4 kg dry weight m−2 year −1 in the last year. The leaf nitrogen content was 3%–4% of dry weight during the summer and the other studied mineral elements were in almost optimal proportion to nitrogen. This was considered to be an effect of the intensive fertilization regime. Above-ground production close to maximum yield was attained in the prevailing conditions of soil, climate and biomass partitioning.

Notes: Summary A measuring device is described that allows the monitoring of fogwater deposition on to small spruce trees. The mass of fogwater deposition ranged from 41.9 to 60.5 ml/m2 of needle surface area. Fogwater was collected, and ion concentrations in fogwater and calculated masses of deposited ions are presented.

Notes: Summary Two alternative estimators of individual tree leaf area (A1) area are used to derive estimates of leaf-area index (L) for 40 plots in Pinus contorta Dougl. stands. One estimator of A1 is based on the common assumption of a constant ratio between A1 and sapwood cross-sectional area at breast height (As). The second estimator of A1 accounts for tree-to-tree variation in the relation between A1 and As. The apparent relationship between stand growth and leaf-area index is strongly dependent on the way leaf area is estimated. When L is derived from a constant A1∶As ratio, stand growth appears to be strongly correlated with L. However, when L is based on estmates of A1 that account for tree-to-tree variation in the A1 — As relation, stand growth is seen to be only weakly related to L. Stand structure, quantified as percent live-crown, accounts for a great deal of the observed variation in leaf-area efficiency. These contrasting relationships illustrate the importance of unbiased estimates of L in interpreting the link between stand-level processes and leaf area.

Notes: Summary Recovery from winter depression of photosynthesis was studied in Pinus sylvestris, Pinus conforta and Picea abies by means of chlorophyll fluorescence and gas exchange measurements. During the winter 1986–1987 the fluorescence yield was low and no variable fluorescence was detectable before the end of March. In the field recovery of variable fluorescence/maximum fluorescence (Fv/Fm) during spring was slow for all three species studied. The temperature dependence of recovery was confirmed from measurements of the potential rate of recovery of Fv/Fm at different temperatures in the laboratory. At 20° C, Fv/Fm increased from 0.1 to 0.8 within 3 days. Recovery of Fv/Fm was paralleled by an increase in apparent photon yield. No significant differences could be demonstrated between the studied tree species in potential rate of recovery in the laboratory or in actual recovery in the field.

Notes: Summary A novel stable isotope labelling procedure for microbeam analysis was developed to monitor exchange and uptake of nutrients, primarily Mg, K and Ca, by root tips at the cellular level. Initially root samples were analysed from 2-year-old spruce trees, originating both from a nursery and from a polluted forest site, (1) for the cortex cell wall accessibility and nutrient binding properties, (2) for the influence of low pH and elevated aluminum concentrations on Ca binding to cortex cell walls, and (3) for long-range transport into the secondary xylem, proximal to the labelled root tip. In nursery control plants, Ca is localized mainly in the apoplast of the cortex. Exchange of Mg, K, Ca in the cell wall of the cortex and the primary xylem with label in incubation solutions is almost completed to equilibration within 30 min. In the secondary xylem we could detect Mg, K, and Ca from labelling solutions in minute amounts after 30 min, and as a major fraction after 48 h. This indicates that stable isotope labelling can be used to study both ion-exchange properties of the apoplast and long-range transport. Slight acidification of the labelling incubation media to pH 4.5 reduced Ca binding to the cortex cell walls slightly, but acidification to the extreme value of pH 2.3 reduced binding 41%. A combination of pH 4.5 and increased free aluminum reduced the binding by 83%. In a preliminary attempt to analyse the nutrient binding capability of the root-tip apoplast from pollution affected trees, we exposed fine roots of 2-year-old spruce from an acidified and polluted site showing typical low levels of Ca and Mg in the cortical cell walls to Ca-enriched media. Under these conditions the Ca content of cortex cell walls doubled upon incubation at pH 4.7, reaching 40% of the total binding capacity of our nursey control plants.

Notes: Summary Mycorrhization of Picea abies has been achieved, for the first time, with six strains of Suillus grevillei by a new culture method, using activated charcoal paper and liquid medium as a substrate. Mycorrhization of P. abies and Larix decidua was compared, and the process was found to be significantly different in the two tree species. S. grevillei is not incompatible with P. abies, but it forms mycorrhizae more readily with L. decidua. Hyphal growth was clearly stimulated on the surface of roots of Larix but retarded on Picea. A well organized Hartig net was formed with both tree species, but wall protuberances were frequently observed on the outer cell walls of Picea cortex cells when the Hartig net was not fully developed. No conspicuous cell wall reactions occurred in Larix roots. Cell wall protuberances may be comparable to those in transfer cells and are interpreted as an alternative to Hartig net development. Anatomical differences between roots of Larix and Picea, and physiologically active substances such as recognition factors on the root surfaces, are discussed with respect to their responsibility for the different reactions of S. grevillei.

Notes: Conclusion Mangrove forests are of major ecological and commercial importance, yet the future of these resources is threatened by pollution, development and over-exploitation. There is an urgent need to develop sound management practices based on a functional understanding of the physical and biological processes underlying mangrove ecosystem dynamics. Such biological processes include dispersal (Rabinowitz 1978), herbivory (Smith 1987) and the physiological bases of species interactions and responses to environmental factors. Understanding these processes is essential for the development of more comprehensive and predictive modelling of mangrove ecosystem dynamics than has previously been possible.

Notes: Summary A method for the rapid determination of the lengths and surface areas of very large samples of needles of Picea abies (L.) Karst. using a computer-aided image analysis system was developed. Two independent methods for measuring non-destructively the volumes of individual needles and of all needles attached to a twig were devised. The surface areas and lengths of about 38000 needles sampled from the three youngest needle age-classes (1986, 1985, 1984) of 48 trees approximately 130 years old at four sites in the Fichtelgebirge mountains (N. E. Bavaria, FRG) were measured. The frequency distributions of lengths and areas for each site and age-class are given. Variability of needle size was fairly large. Even though the sites differed in climate, soil, and air pollution levels no consistent effect of these factors on needle size could be detected. Needle lengths and surface areas did not correlate with either the total chlorophyll content of the needles or the degree of crown thinning. The needle surface area (in mm2) of fully developed P. abies needles can be estimated by the empirical equation surface area = 4.440 x needle length -24.8 (r = 0.937), and the needle volume (in mm3) by needle volume = 0.208 x projected needle area 1.353 (r = 0.969).

Notes: Summary The relationships between the amounts of foliage and heights of trees were studied for the dominant understory tree species, including three evergreen and three deciduous species, in a secondary forest of Chamaecyparis obtusa Endl. The relationships showed two phases: leaf increasing and stationary phases. In the leaf-increasing phase, the height growth allowed these species to expand the canopy by increasing the number of leaves. In the stationary phase, the number of leaves was relatively constant number irrespective of tree height from 160 to 400 cm. The number of leaves in the stationary phase represents the maximum number of leaves that can be supported by trees under shady conditions. From the analyses of vertical distributions of leaves in six species, mono- and multi-layer foliage distributions were detected. Two evergreen species, Eurya japonica and Cleyera japonica, showed multi-layer foliage distributions, whereas three deciduous species, Lyonia ovalifolia, Rhododendron reticulatum and Vaccinium hirtum, and one evergreen species, Pieris japonica, showed mono-layer foliage distributions. The relationships between the weights of non-photosynthetic and photosynthetic organs of the six species were examined. The proportion of non-photosynthetic organs increased with tree height. The understory species attained the stationary phase and were maintained by minimizing their investment in non-photosynthetic organs, i.e. their height growth was arrested by the shady conditions under the crown trees.

Notes: Summary Shoot development was investigated on branches of Larix laricina (Du Roi) K. Koch trees growing in their 8th year in two plantations and in a natural stand approximately 12 years old. Expansion of throughout-crown series of short and long shoots was measured weekly, and later colour change and natural fall of leaves were assessed. Similar shoots were collected at intervals and dissected, the long shoots by 25-leaf segments. Leaf area and weight, as well as time of bud formation, were determined. Increasing acropetal trends were evident in time to bud burst: duration of short-shoot leaf-cluster expansion; size of leaf clusters and number, area and weight of leaves per cluster; duration and rate of long-shoot elongation; number, area and weight of leaves on long shoots; time to terminal-bud formation on long shoots. Along each long shoot, stem and leaf elongation and lateral-axis formation progressed acropetally. Lateral axes were most numerous on second to fourth 25-leaf segments. On longer shoots, some axes in middle segments developed as sylleptic short shoots rather than as lateral buds. Leaves of short shoots and basal leaves on long shoots turned yellow and abscissed sooner than axial leaves on long shoots. Colour change and loss among axial leaves were acropetal along shoots and up the crown. Thus, last-formed leaves, in axils of some of which lastformed lateral buds occurred, were held longest.

Notes: Summary The effects of exposure to magnesium or potassium deficiency on spruce needle photosynthesis were studied before symptoms of damage were visible, and recovery was followed. Water content, pigment content and O2 evolution rate were chosen as parameters of physiological activity in addition to chlorophyll fluorescence. In the case of exposure to Mg deficiency, the first symptoms detected by all the physiological parameters were observed in older needles. An effect on chlorophyll fluorescence [decrease in fluorescence index (Rfd) and photochemical quenching (qQ), and increase in non-photochemical quenching (qE)] was detected in younger needles at the beginning of the deficiency treatment with little effect on the other physiological parameters [decrease in water content to 96.5%, and in photosynthetic rate expressed over dry weight (PSDW) to 90.7%]. No recovery was observed. After a K-deficiency exposure, both kinds of needles were affected, but a high recovery rate was observed, especially in the current-year needles, where a complete recovery from damage was detected by fluorescence and confirmed later by visual inspection. Finally, these results indicate the possibility of an important early diagnosis of damage in forest decline and suggest that chlorophyll fluorescence can be used, at least in the laboratory, as a qualitative test of plant health.

Notes: Summary The ultrastructure of plastids in xylem ray parenchyma cells of Pinus sylvestris L. was studied and compared with the glycolipid composition of the stemwood. Seasonal changes of the ultrastructure were studied by taking samples regularly throughout the year. The plastids resemble amyloplasts. They usually have one large starch grain, and considerable variation in structure and starch content was observed, especially in the innermost sapwood and in the sapwood-heartwood transition zone. Electron-dense deposits were observed attached to the plastid membranes and envelopes, especially in the transition zone, from April to November. The plastids were aggregated near the nucleus and the starch disappeared during the winter (January–March). The glycolipids, monogalactosyldiacylglycerol (MGDG) and di-galactosyldiacylglycerol (DGDG), were present only in the sapwood, in trace amounts. The glycolipid content was slightly greater in the outer sapwood than in the sapwood-heartwood transition zone. DGDG was the dominant lipid of the two.

Notes: Summary A comparative analysis of three Norway spruce genotypes by two-dimensional gel electrophoresis is presented. This study has led to the identification of approximately 970 gene products for each genotype. Significant qualitative and quantitative differences have been identified, and qualitative and quantitative divergence indices between genotypes have been computed. Two-dimensional electrophoresis appears to be an efficient tool for studying modifications of gene expression in Norway spruce in response to climatic and pollution stresses.

Notes: Summary Many long-lived plant taxa are characterized by relatively high genetic load levels. This genetic load is manifested as the proportion of offspring that are physiologically handicapped to various degrees. It is proposed that the majority of this load is mutational load and is a consequence of the higher per generation mutation rates that occur in long-lived plants. Higher per generation mutation rates are a result of the chemostat-like accumulation of mutations in the apical initials as the plant grows. Genetic load, therefore, is a function of the postzygotic accumulation of mutations as well as mutations inherited from previous generations.

Notes: Summary The concentrations of 23 elements have been determined by instrumental neutron activation analysis in the needles and axes of 1-year-old spruce twigs from 12 different sites. Although the twigs had been washed with toluene and tetrahydrofuran prior to analysis, it was found that the amounts of eight elements (Al, Cr, Eu, Fe, La, Sc, Th and V) present were predominantly due to aerosol particles still being retained on the surface of the axes. The results of the remaining 15 elements (Ba, Br, Ca, Cl, Co, Cs, Hg, K, Mg, Mn, Na, P, Rb, Sr and Zn) were not or only slightly influenced by this effect and are considered to represent their inherent concentrations within the axes. With most of these latter 15 elements there are highly significant and linear correlations between the concentrations in the needles and in the axis, which testify to the great similarity of needles and axis of a twig. The axis/needles ratios are constant for every element (except K), but the individual elements show considerable differentiation, as evidenced by their ratios, which have values between 0.5 and 2.8. Inter-element correlations in the axes are mainly found within two groups of elements. With Na, Cl and Br these correlations are probably due to different pollution levels of the different sites, whereas with Mn, Co, Rb and Cs they are due to the pH of the soil. The activity of 137Cs from the Chernobyl fallout represents independent confirmation of the results obtained with the stable elements. With twigs sprouted before the deposition of the fallout, 137Cs acts as a tracer for aerosol particles, whereas it forms a tracer for the stable Cs inherent to the plant with twigs sprouted after the deposition.

Notes: Summary This study addresses the question of whether gaseous air pollutants are capable of damaging spruce foliage. For this purpose, several twig pairs of an adult tree in a natural stand from the western part of the Bavarian Forest were supplied with pure and ambient air and gas exchange was monitored. With the exception of insignificant and unexplained differences during winter, the gas exchange of the twigs showed no negative deviation due to the influence of gaseous air pollutants. Because visible damage arises only in older needles, the duration of measurement is not sufficient to exclude a long-term influence of gaseous air pollutants.

Notes: Summary Shade needles of hybrid larch (Larix decidua × leptolepis) had the same rates of photosynthesis as sun needles per dry weight and nitrogen, and a similar leaf conductance under conditions of light saturation at ambient CO2 (Amax). However, on an area basis, Amax and specific leaf weight were lower in shade than in sun needles. Stomata of sun needles limited CO2 uptake at light saturation by about 20%, but under natural conditions of light in the shade crown, shade needles operated in a range of saturating internal CO2 without stomatal limitation of CO2 uptake. In both needle types, stomata responded similarly to changes in light, but shade needles were more sensitive to changes in vapor pressure deficit than sun needles. Despite a high photosynthetic capacity, the ambient light conditions reduced the mean daily (in summer) and annual carbon gain of shade needles to less than 50% of that in sun needles. In sun needles, the transpiration per carbon gain was about 220 mol mol−1 on an annual basis. The carbon budget of branches was determined from the photosynthetic rate, the needle biomass and respiration, the latter of which was (per growth and on a carbon basis) 1.6 mol mol−1 year−1 in branch and stem wood. In shade branches carbon gains exceeded carbon costs (growth + respiration) by only a factor of 1.6 compared with 3.5 in sun branches. The carbon balance of sun branches was 5 times higher per needle biomass of a branch or 9 times higher on a branch length basis than shade branches. The shade foliage (including the shaded near-stem sun foliage) only contributed approximately 23% to the total annual carbon gain of the tree.

Notes: Summary CO2- and H2O-gas exchange of 20- to 25-year-old spruce trees from a plantation in the Hunsrück mountains were investigated over a period of 3 years. All measurements were made as pair comparisons, i.e., in each case the gas exchange of a damaged tree and of a relatively healthy tree in its immediate vicinity was measured simultaneously. A second plantation in the Westerwald mountains consisted of 18-year-old apparently healthy spruce trees. Pair comparison at this location meant comparison of two healthylooking trees. The investigations at both locations included diurnal course measurements of photosynthesis and transpiration, and light saturation curves and CO2-saturation curves of photosynthesis. The reduced photosynthesis parameters of the phenotypically damaged trees at the Hunsrück location indicates massive damage to the photosynthetic apparatus. Measurements of H2O-gas exchange showed that there are disturbances in stomatal regulation of the needles of damaged trees. As a result, the water use efficiency of these needles proved to be significantly lower. In addition, apparent photorespiration of the damaged trees was decreased, whereas their light- and CO2-compensation points and their dark respiration were increased. In contrast to the Hunsrück plantation, no such effects were detectable when the healthy-looking Westerwald trees were subjected to pair comparison of gas exchange. Reduced photosynthetic capacity and disturbances of the stomatal regulation of the phenotypically damaged Hunsrück trees may be due to damage in the cellular membranes. Furthermore, a comparison of three growing seasons led to the conclusion that the gas exchange of spruce trees in their natural habitat is markedly influenced by climatic conditions.

Notes: Summary The efflux of sugars from parenchyma cells into the apoplast has been studied in the wood of Populus × canadensis “robusta” in relation to the sugar level of the tissue and the sugar content of the tracheal sap during all physiological stages of the year. In poplar, the spring maximum in sugar content of the tracheal sap is clearly not the result of continuous exosmosis during winter but is reached within a short period in spring. The seasonal patterns of starch and sugar content of the wood and of the sugar content of the tracheal sap are described. The efflux of sugars from tissue sections changes drastically over the year, i.e., from 0.3 to 8.3 μg mg−1DWT day−1. In general, it is high in fall and winter, and low during late spring and summer. However, high tissue sugar levels proved not always to be correlated with high efflux rates or with high sugar levels in the tracheal sap, indicating that the intracellular compartmentalization of sugars, their passive and catalysed release into, and their re-uptake from the apoplast are all essentially involved in determining the actual sugar content of the sap. Sucrose, which is the dominant sugar in the tracheal sap during winter (pH 7.0–7.5) and in the efflux experiments at pH 7.5, in contrast to the hexoses which prevail in the spring sap (pH around 5.5) and also in the efflux experiments at pH 5.6, is considered to be preferentially released in poplar and to become extraplasmatically hydrolysed. The reasons for tree-specific differences are discussed.

Notes: Summary A microcomputer-controlled heat-pulse system for the measurement of sap velocity in trees is described. Several published methods for determining sap velocity from the temperature rise measured either above or below a heater inserted into the stem were compared and evaluated. All methods could be improved by the use of curve-fitting procedures, with a particularly useful approach involving direct estimation of the parameters of the diffusion equation using the non-linear curve-fitting package maximum likelihood programme. An alternative approach that was based on measurement of the value of the maximum temperature was proposed and tested. This was found to be particularly robust and sensitive to changes in flow rate. Although sap-flow velocity varied markedly with depth in the stem (as shown by the rate of dye movement), the maximum temperature at any given flow rate was found to be relatively insensitive to sensor depth. Estimated sap-flow velocities were compared with evaporation rates estimated either by weighing (for potted trees) or by the Penman-Monteith equation. Several independent methods were used for estimating the values of boundary layer resistance and net radiation that were required for application of the Penman-Monteith equation. There was a close relationship between flow and evaporation with some evidence for hysteresis. Although absolute calibration of the sap-flow estimates is difficult, the methods described are all useful for relative studies and all responded rapidly to altered flow rates caused by changing weather conditions.

Notes: Summary The nuclei of mesophyll cells of olive trees contain numerous sizeable crystalloid inclusions. Cytochemical examination using epoxy resin-embedded, semithin-sectioned tissue indicated the presence of proteins and oligoor polysaccharides in these inclusions. Their electron microscopical analysis revealed a crystalline substructure consisting of intersected subunits of high order. The spacing of the lattice fibrils and the angles of intersection were determined and used to establish a model of the unit cell of crystallization. It is suggested that the nuclear crystalloids of olive trees consist of glycoprotein molecules. They differ from the intranuclear crystalloids observed in other species predominantly in the high density of their subunit arrangement.

Notes: Abstract This paper is concerned with the problem of animating computer drawn images of speaking human characters, and particularly with the problem of reducing the cost of adequate lip synchronisation. Since the method is based upon the use of speech synthesis by rules, extended to manipulate facial parameters, and there is also a need to gather generalised data about facial expressions associated with speech, these problems are touched upon as well. Useful parallels can be drawn between the problems of speech synthesis and those of facial expression synthesis. The paper outlines the background to the work, as well as the problems and some approaches to solution, and goes on to describe work in progress in the authors' laboratories that has resulted in one apparently successful approach to low-cost animated speaking faces. Outstanding problems are noted, the chief ones being the difficulty of selecting and controlling appropriate facial expression categories: the lack or naturalness of the synthetic speech; and the need to consider the body movements and speech of all characters in an animated sequence during the animation process.

Notes: Abstract We propose a two-level hierarchy for planning collision-free trajectories in time varying environments. Global geometric algorithms for trajectory planning are used in conjunction with a local avoidance strategy. Simulations have been developed for a mobile robot in the plane among stationary and moving obstacles. Essentially, the robot has a global geometric planner that provides a coarse global trajectory (the path and velocity along it), which may be locally modified by the low-level local avoidance module if local sensors detect any obstacles in the vicinity of the robot. This hierarchy makes effective use of the complementary aspects of the global trajectory planning approaches and the local obstacle avoidance approaches.

Notes: Abstract OnO(n 2) exact algorithm is given for computing the volume of a set ofn spheres in space. The algorithm employs the Laguerre Voronoi (power) diagram and a method for computing the volume of the intersection of a simplex and a sphere exactly. We give a new proof of a special case of a conjecture, popularized by Klee, concerning the change in volume as the centres of the spheres become further apart.

Notes: Abstract Although jewelry has historically been equated with hardware, the advent of the single-chip CMOS microcomputer allows a redefinition in terms of software. A radically different new kind of jewelry is presented, based on LCD graphics controlled by an on board microcomputer. The revolutionary potentials of this new jewelry, along with its unique requirements and problems, are illustrated by examples from the author's personal experiences in developing this novel medium.

Notes: Abstract A recent computer-aided study identified the model immortalized in Leonardo da Vinci's celebratedMona Lisa to be none other than the artist himself. A follow-up investigation empolying similar techniques identifies the subject of asecond “Hidden”Mona Lisa by the same artist. Analysis of photographic and x-ray images indicates that Leonardo first created a sketch of Isabella, Duchess of Aragon, which he later painted over with theMona Lisa, using himself as the model.

Notes: Summary The existence of a worker caste in Prorhinotermes inopinatus was determined with the help of biometrical analyses and morphological observations. No dichotomy between alate and worker lines was detected among the young larval instars. Mandible sclerotization and wear show that the larvae become active by the fourth instar in mature colonies, and by the third in incipient ones. Prothoracic finger-shaped expansions characterize the most dependent larval instars. The antennal structure is the best feature for distinguishing late instars. The developmental schema is very flexible: the late larvae of stages 5 to 8 (at least) can give rise to wing-padded nymphs, to the next larval instar, to presoldiers, or most likely to neotenic reproductives as well; the wing-padded individuals (nymphs) normally moult direct to alates, but they can also undergo a regression of their wing pads and revert to worker-like individuals or differentiate into soldiers or neotenics. Slight variations in alate size and antennal morphology result from their origin in different larval instars. Whole-colony censuses revealed that the major part of the colony's work force is composed of pseudergates, i.e. late larvae that do not follow the most direct pathway to the alate. The pseudergates of Prohinotermes do not constitute a distinct worker caste irreversibly diverted from the alate developmental pathway. For this reason the caste system of Prorhinotermes is analogous to that of the Kalotermitidae and Termopsidae and much more primitive than those of the other Rhinotermitidae so far studied, Reticulitermes, Schedorhinotermes and Coptotermes.

Notes: Summary Euplokamis has coiled tentilla on its tentacles, which can be discharged, flicking out at high velocity, when triggered by contact with prey. The tentillum adheres to prey by means of numerous colloblasts. Discharge, which takes 40–60 ms, is accomplished by contraction of striated muscles, found only in this genus among the Ctenophora. Restoration of the coiled state is attributable to passive, elastic components of the mesogloea. Rows of “boxes” (fluid-filled compartments) along the sides of the tentillum appear to stiffen the structure so that it does not collapse, kink or buckle during discharge. Smooth muscle fibres present in the tentillum may help pull the tentillum tight after prey have been captured. In addition to the rapid discharge response, the tentillum can perform slower, spontaneous, rhythmic movements which, it is suggested, resemble the wriggling of a plank-tonic worm, enabling the tentillum to function as a lure. These movements appear to be executed by contraction of two sets of myofilament-packed cells which differ in several important respects from conventional smooth muscle. They belong to a novel and distinct cytological subset (“inner-ring cells”), other members of which are packed with microtubules and seem to be involved in secondary structuring of the collagenous component of the mesogloea. Study of tentilla in different stages of development shows that the striated muscle fibres, originally nucleated, become enucleate as they differentiate and that the colloblasts form in association with accessory cells, as proposed by K. C. Schneider and G. Benwitz. The refractive granules which adhere to the outside of all mature colloblasts derive from these accessory cells. The colloblast nucleus undergoes changes during development suggestive of progressive loss of its role in transcription and protein synthesis, but it remains intact, contrary to statements in the literature. The tentillum of Euplokamis can be regarded as a true food-capturing organ and it is probably the most highly developed organ in the phylum.

Notes: Summary Scypha ciliata is a syconoid sponge. Its oocytes differentiate from choanocytes located near the apopyle of a flagellated chamber, and initially they remain in that location, in a trophic complex with neighbouring choanocytes. When this first growth phase is completed, the oocyte migrates to the periphery of the sponge. There it undergoes a second growth phase, in which it phagocytizes choanocytes and mesenchyme cells. Fertilization of the mature egg is assisted by a converted choanocyte, the sperm carrier cell. This cell penetrates the oocyte and transfers to it the sperm contained in a carriercell vacuole. No meiotic events have yet been observed. Cleavage is asynchronous, with holoblastic, approximately equal divisions. After the first cleavage steps the blastomeres often contain multiple nuclei. The single-layered blastoderm of the stomoblastula consists of many micromeres with flagella that project into the blastocoel, a few macromeres and four cruciform cells. There is no development of a follicle epithelium. The stomoblastula develops into the amphiblastula by inversion; with the assistance of the maternal choanocyte epithelium, the hollow sphere turns inside out, simultaneously moving out of the mesoderm and into the lumen of the adjacent flagellated chamber. In this process, the blastocoel of the stomoblastula is lost. The flagellated cells that form the wall of the amphiblastula now have their flagella extending outward; the amphiblastula also comprises four cruciform cells, macrogranular and agranular cells. The larval cavity of the amphiblastula is a newly formed structure.

Notes: Summary The different chaetal types of three eidonomically very similar, closely related polychaete species (Microphthalmus carolinensis, M. nahantensis and M. listensis) were ultrastructurally investigated and compared with one another. Characteristic substructures are regularly arranged channels, the course and number of which were analysed in cross-sections. The intraspecific variability of the number of these channels is low in the individual chaetal type. Between the species, however, distinct differences exist, facilitating separation and identification of the species at the level of ultrastructure in certain chaetae.

Notes: Summary The Mediterranean sponges Reniera mucosa, Haliclona mediterranea, Reniera fulva, Dendroxea lenis and Reniera sarai and the Caribbean species Callyspongia sp., Niphates digitalis, Niphates sp. and Amphimedon compressa are the subjects of this study of the arrangement of the choanocyte chambers between the canal systems and their relation to the mesenchymal tissue. The phylogenetic significance of the different organizational features is discussed.

Notes: Summary In flight the wings of the blowfly Calliphora erythrocephala are driven by the indirect dorso-longitudinal (downstroke) and dorso-ventral muscles (upstroke). There are two “turning points” on the ventral wing joint, the anterior and posterior. The former consists of the pleural klöppel and its “fit” on the ventral anterior wing base. The connecting point between the anterior ventral peak of pterale II (wing base sclerite) and the underside of the dorsal end of the pleural wing joint forms the latter. A longitudinal axis going through the anterior and posterior turning point forms the “turning axis” for the wing-beat movements. The pleural wing joint ends in a heart-shaped structure with three peaks. A groove in the tooth of the ventral radial vein, which is part of the ventral wing base, connects with one of these peaks, where it remains for several downstroke cycles. Cross sections through the stem of the pleural wing joint show a V-shaped configuration. The pull of the first subunit of the pleuro-tergal muscle bends this stem outward like a torsion rod. Inward movement is effected by its own elasticity and the pull of the subalar tendon. Outward movement enables the groove of the tooth of the ventral radial vein to contact one of the peaks if the wing base and the tooth are turned anteriorly by the combined pull of basalar muscles 1 and 2 onto the anterior wing edge. The wing is turned backward by the pull of the pterale III muscle 1 onto the posterior wing edge. This contact can be used in two ways: 1. If the wing-base elements of one wing meet, the joint will click upward and the groove of the tooth loses its contact with a peak. Thus the downstroke amplitude of this wing will increase and the fly will turn contralaterally from this side where the wing-base elements meet. This movement works like a gear, extending the “wing-drive-independent” downstroke power unilaterally. 2. The joint does not click upward and the groove of the tooth remains in contact with a peak. The downstroke amplitude on this side now decreases and the fly turns ipsilaterally to this side. This would be a wing-beat stop (cf. Miyan and Ewing 1985a, b), which diminishes the wing-drive-independent downstroke power unilaterally. Besides an increase and decrease of flight power, the geometrical angles of attack may also have been altered (Pfau 1985). The upstroke occurs normally, passing over the anterior and posterior turning point — forming a turning axis — during flight regardless of whether contact (1) or (2) is used. In flies, both right- and left-wing driving systems are coupled morphologically by the scutellum. Even while the stroke movements of the wings are synchronous, the direct muscles on one side of the thorax work independently of those on the other side, i.e., their function is wing-drive-independent.

Notes: Summary By means of light and electron microscopical studies on Nautilus pompilius and Nautilus macromphalus, special basal cells within the alveolary enlarged terminal parts of the tubules of the midgut gland were revealed. Their abundant rough endoplasmic reticulum (RER) with enlarged cisterns synthesizes ring-shaped macromolecules that resemble the hemocyanin molecules within the bloods-paces in size and form and seem to be secreted throughout the lamina basalis, locally discharged into the adjacent blood sinus. The hypothesis that this cell type represents a site of hemocyanin synthesis was confirmed by Zeeman AAS and ASTEM analyses of the content and distribution of copper within the glandular tissue, especially the different compartments of this cell type.

Notes: Summary The spinning apparatus of the uloborid spider Polenecia producta was studied to complete previous studies on the same family of spiders. The structure of spinnerets and spigots, under scanning electron microscopy, and the main anatomical and histochemical characteristics of the spinning glands of adult females and males are described. In addition some observations on the spinning apparatus at three successive stages of development are made. There are nine kinds of silk glands in Polenecia, i.e. one more (aciniform — B glands) than found in other uloborids. The spinning apparatus of Polenecia is, therefore, the most complex so far known. It is also more complex than that presently known of Araneoidea. The characteristics of the spinning glands of Polenecia are compared with those of other uloborids. Present knowledge of the spinning apparatus of uloborids leads to a renewed discussion of the origin of the orb web in this family and in araneids. It is concluded that these two types of orb webs emerged from independent evolutionary processes.

Notes: Summary In Ephydatia fluviatilis young oocytes already appear in autumn. They pass the winter in the highly reduced sponge, but vitellogenesis and further development do not take place before following spring. The fact that the young oocytes appear before the normal period of reproduction makes E. fluviatilis different from all other local freshwater sponges, which reduce totally in autumn. E. fluviatilis seems to be a gonochorist. The oocytes originate from archaeocytes and during the first growth phase they reach a diameter of approximately 40 μm. In the second growth phase the oocyte is enclosed in a single-layered follicle epithelium and grows to 170–180 μm by phagocytosis of trophocytes. The fully developed egg cell finally shows a distinct layering of the incorporated yolk material. Cleavage is totally equal to unequal so that macro- and micromeres appear in some cleavage stages. Cleavage leads to a solid embryo consisting of uniform cells. At this stage of development the first scleroblasts appear. As the cells develop they are surrounded by companion cells, managing the transport of the scleroblasts. The further development to the larva is marked by the appearance of the larval cavity, typical for larvae of Spongillids, which finally occupies about half the volume of the larva at emergence. The periphery of the larva consists of a single-layered ciliated epithelium. After emergence the larva forms flagellated chambers, which are integrated into the primordia of the excurrent canal system. This system connects with the larval cavity and ensures that it becomes part of the excurrent canal system of the young sponge. Particularly in the region of the larval cavity the ciliated epithelium of the free larva is reduced. Here a new larval surface epithelium is formed by pinacocytes.

Notes: Summary Tubificoides benedii [=Peloscolex benedeni] a ubiquitous tubificid from poorly oxygenated, often polluted coastal muds, is known to be exceptionally well adapted to sulphidic sediments. However, almost nothing is known about its structural peculiarities, such as the conspicuously papillate body surface and possible relations to its unusual ecology. As a consequence, a study of this abundant but extraordinary marine worm has been made with the use of light and electron microscopy. While many internal structures correspond to the general pattern of marine tubificids and are not mentioned here, the epidermis — cuticle complex is unusual. The thick cuticle forms numerous high leaf-shaped papillae covered by condensed, almost solid mucus caps. The intermediate furrows usually harbour many different bacteria embedded in mucus. This mucus cover is rich in precipitates containing sulphur and other xenobiotic substances. Together with the cuticular papillae it can be sloughed off in a “moulting process”. Epicuticular projections, usually typical of oligochaetes, are absent from most parts of the body except from the first and last segments. The epidermal cells often contain numerous extremely long and abnormally shaped mitochondria. The significance of the peculiar structure of the body wall and the distinct “moulting” are discussed in the light of the ecological situation of these tubificids.

Notes: Summary Olfactory receptor molecules are assumed to be integral membrane proteins which may be visualized on fracture faces of the membrane as intramembrane particles (IMPs). In the present study, the plasma membrane of the receptor dendrites and ciliated epithelial cells in the teleost fish Alburnus alburnus were studied by freeze-fracture electron microscopy. The IMP diameters on the membrane P-faces of both receptor dendrites and ciliated epithelial cells ranged from 5 nm to 11 nm. The average IMP densities on membrane fracture faces of the ciliated and microvillous sensory dendrites were 3130±780 for the cilia, 2070±550 for the microvilli, 2390±1190 on the knob regions and 3050±1130/μm on the lateral dendrite membranes. The IMP densities on the P fracture faces of the cilia and knob regions were compared with the densities found on the lateral membranes of each individual dendrite. The ratios ranged from 0.5 to 0.96 in the case of the cilia/lateral membrane and from 0.5 to 0.90 in that of the knob/lateral membrane, indicating that, in contrast to the average densities, it is the lateral membrane which has the higher IMP densities and not the cilia. The great variations in the average IMP densities, as well as the considerable variety of the ratios, may be explained by the maturation and turnover of the olfactory sensory neurons.

Notes: Summary The protonephridial terminal organ in the nemertean Pantinonemertes californiensis is composed of two cells that are similar in size and shape and are mirror images of each other. Basally in the organ the two cells combine to form a binucleate cytoplasmic mass. Apically they are intimately joined to form a subcylindrical thin-walled weir apparatus; this part is supported by two opposed cytoplasmic columns running the length of the weir region, one originating from each of the two cells, and by a number of regularly spaced circular bars that arise from the two columns. The ciliary flame consists of 94–114 cilia that originate in the bases of the two cells, and it is surrounded by a palisade of incomplete circlets of long, straight microvilli. The convoluted protonephridial tubule is rich in structures that indicate intensive reabsorption from the primary urine. It is argued that the terminal organs in Pantinonemertes and Geonemertes are fundamentally similar and differ only in the amount of microtubules present in the longitudinal supports.

Notes: Summary The complex, erupting nematocyst batteries of Nanomia cara are described. In addition to the cnidoband, the battery has a central axis containing longitudinal muscles and nerves that run right through to the terminal filament. In addition, an elastic strand lies coiled within the battery. After eruption of the battery, this strand keeps the prey attached to the tentacle. The strand bears hook-like spicules, equipped with barbs that project beyond the surface. Electron microscopy shows that the elastic strand is a mesogloeal structure tunnelled through and through with cellular processes deriving from both ectoderm and endoderm and that the spicules lie in cellular pockets in the interior of the elastic strand. There is nothing in the structure of the spicules or their cellular sheaths to suggest an origin from nematocysts. Energy dispersive X-ray microanalysis shows strong peaks for calcium and for phosphorus in the spicules, indicating that the mineral present in them is an apatite. An organic matrix is also found in the form of fine filaments and a granular axial structure. The spicules are arranged in a linear series along the elastic strand showing progressive increase in size and structural elaboration.

Notes: Summary Phyllodoce trochophores have a system of large, multipolar, nerve-like cells similar to the larval reticulum of the much-studied larva of Lopadorhynchus. The Phyllodoce reticulum is described here by means of light and electron microscopy and Golgi-Cox preparations. The cells appear to be secretory, and contain numerous large vesicles approximately 1 ώm in diameter. Their nuclei are large and distinctive, with a dense, granular nucleoplasm containing unusual hollow tubules, 40 nm in diameter, arranged in tangled masses and parallel arrays. The cells are nerve-like in that they possess surface processes that ramify irregularly throughout the larval tissues and thinner, basal processes that run along the larval nerves. They differentiate in close association with nerve cells of conventional type, the principal centres being in the apical region, on either side of the apical organ, and in the oral region, on either side of the mouth. The latter are centres of nerve differentiation in species with a metatroch. Phyllodoce larvae lack a metatroch, but the band itself could have been lost secondarily during evolution without loss of the neural elements associated with it. The precise function of the reticular system is not known. Basal processes connect it to the larval nerves, suggesting its cells receive neural input and, presumably, release their secretion from surface processes. There is no obvious evidence of secretory release during the larval phase, but the system disappears entirely at metamorphosis, suggesting a role in this process, possibly related to the histolysis of larval tissues.

Notes: Summary The apical scolopidial organ (ASO) in the labial palp of six species from four families of Lepidoptera was studied in pupal and imaginal stages using electron microscopy. The organ houses three sensory units, each of which consists of one sensory cell and two enveloping cells at early pupal stage in all the species studied. The distal part of the ASO is connected with the epidermis of the tip of the labial palp. Proximally it is attached to the primordium of the palpal nerve. The axons of the sensory cells run within this nerve to the central nervous system. There are two main differences in the differentiation of the ASO in the species examined during postembryonic development: (1) the sensory cells of the ASO degenerate at different rates; and (2) the ASO may or may not change its position within the palp. In Pieris brassicae and Pieris napi (Pieridae), all three sensory cells undergo stepwise degeneration. Consequently, no sensory cells are left in the imago in these species. However, in the Rhodogastria sp. (Arctiidae), only one sensory cell of the ASO degenerates during pupal life. Two remain, therefore, in the imaginal stage. Their dendritic outer segments and axons are normal, and their appearance does not differ from that in early pupal life. The same process was also observed in Rhodogastria bubo (Arctiidae), Autographa gamma (Noctuidae) and Aglais urticae (Nymphalidae). In addition to the degeneration of the sensory cells the ASO turns through about 180° in P. brassicae and P. napi so that its tip points to the base of the palp in the imagines of these species.

Notes: Summary Transmission electron microscopic studies were carried out on the ventral pharyngeal organs in Ctenodrilus serratus and Scoloplos armiger. The pharyngeal organs are composed of a muscle bulbus and a tongue-like organ. In both species the muscle bulbus consists of transverse muscle fibres and interstitial cells with voluminous cell bodies and dorsoventral tonofilaments; the investing muscle runs into the tongue-like organ; the nuclei of the investing muscle fibres are located in caudal bulges; salivary glands are not present, but numerous gland cells occur in the bulbus epithelium. The tongue-like organ, however, is formed by lateral folds (C. serratus) or a bridge-like structure (S. armiger). The specific structure of the bulbus muscle is probably a homologous characteristic also occurring in several other polychaete families. The phylogenetic importance of this ventral pharynx is discussed and a hypothesis is suggested to explain the differentiation of certain other ventral pharyngeal organs from this probably primitive type.

Notes: Summary In the present report the functional morphology of the planarian gastrodermal phagocytic cells is examined in feeding animals. A functional interpretation of some of the morphological findings is given. The events in the fine-structure modifications of the phagocytic cells in the course of phagocytosis and intracellular digestion of food particles were followed through five post-feeding stages in the planarian Dugesia gonocephala. Light and electron microscopical observations demonstrate that there is preliminary intraluminal digestion of food particles; their phagocytosis takes place quickly. Beef hepatocytes that served as food are found engulfed at first in food vacuoles near the apical border of the phagocytic cells, and are clearly recognizable. The vacuoles increase in number to occupy most of the cytoplasm of these cells. Progressive breakdown and disappearance of phagocytosed hepatocytes occurs. In time the vacuoles move deeper into the cells, their contents lose their identity, and condense to homogeneous or heterogeneous residual bodies. These are returned to the distal surface of the cells, and then voided into the intestinal lumen. At the same time, synthesis and accumulation of numerous lipid droplets occurs, probably as a final product resulting from metabolism of the digested material. When feeding is over, the phagocytic cells are filled with lipid droplets, acquiring their typical appearance. It is suggested that disintegration of phagocytic cells during starvation is balanced by proliferation and differentiation of neoblasts into new phagocytic cells during the feeding-starvation cycle.

Notes: Summary Muscles are generally attached to the skeleton by interconnecting tendons. Each tendon necessarily has a junction with the muscle and another with the skeleton. The ultrastructure of the skeleton is identical in all echinoderm classes. Nevertheless, we found three different types of muscle-skeleton junctions. (1) In Crinoida the muscles are attached almost directly to the calcite trabeculae. (2) Asteroida and Ophiuroida have tendons that arise from the basal laminae of the muscle bundles. They consist of unstriated microfibrils that are attached on the muscle side to electron-dense areas below the sarcolemma of the fingershaped muscle ends. On the skeleton side they embrace the outermost calcite trabeculae. (3) In Echinoida the strong muscles are joined to the skeleton by means of composite tendons. They consist of unstriated tendon cords that adhere to the muscles and of bundles of striated fibrils coiled around the calcite trabeculae. Both kinds of tendons are interconnected in the same way as the links of a chain. Composite tendons are found in junctions that are exposed to multidirectional stress. In Holothuroida there are no true muscle-skeleton junctions and the muscles are apposed to connective tissue. The muscle-tendon junctions in Echinodermata differ fundamentally from the junctions in the protostome Arthropoda or Mollusca, but they were found to be very similar in structure to the muscle-tendon junctions in Vertebrata. This coincidence may refer to a phylogenetic relationship of the two deuterostome phyla. But the tendon-skeleton junctions of the two phyla are dissimilar, for Echinodermata and Vertebrata differ fundamentally in their skeletons. Vertebrate bone consists of extracellular fibrils combined with minute crystals of hydroxylapatite. Echinoderm ossicles are intercellular in origin. They are nothing but the calcified vacuolar system of syncytial sclerocytes, and extracellular fibrils never enter the mineral phase.

Notes: Summary The hitherto unknown anatomy of Afropomus balanoideus is described. Its systematic position within the Ampullariidae is indicated by the possession of the following autapomorphic characters of the Ampullariidae: presence of a lung sac, an ampulla-shaped aorta anterior, a bipartite copulatory organ of pallial origin, a left-sided zygoneur nervous system, a bipartite kidney, a lamellate osphradium, labial tentacles, an ingestion and an egestion sipho and a radula with strong teeth. The pallial vas deferens is completely closed, while the pallial oviduct is anatomically open in its distal part but functionally closed, because it is embedded in the surrounding mantle tissue. The copulatory organ is of pallial origin and innervated by the right pleural ganglion. The plesiomorphic states of some characters indicate that Afropomus balanoideus might represent the adelphotaxon of the remaining Ampullariidae. The morphological structures show that this species is adapted to an amphibious mode of life and to aestivation, as has been shown for other species of Ampullariidae.

Notes: Summary A rich engineering literature exists that is applicable to many aspects of vertebrate jaw mechanics and has been referred to in many studies in this sector. But mechanical engineering technology has provided few theoretical bases that are directly helpful in the study of predator teeth. Hence, analyses of puncturing and slicing functions of these teeth have lacked a firm physical technology as a background. Predator teeth have evolved to pierce and cut animal tissues that are usually compliant in that they readily undergo relatively large deformations under applied stress before they actually yield. The bulk of engineering theory is directed toward such noncompliant materials as wood and metal, the design of tools that cut them, and the mechanics involved in this. The purpose of the present paper is to scan the mechanical implications of different tooth designs, pose hypotheses that relate to primary considerations of the physics of cutting compliant substrates, and offer a preliminary approach that is intended as a useful guide to further studies on sharks and on other vertebrate groups. Thus, in this paper I have attempted to formulate some tentative and preliminary generalizations concerning the mechanics of cutting compliant materials. Then comes a survey of the teeth of a particular group of predators, three families of sharks, in terms of these preliminary formulations. The approach views the shark teeth in isolation from the complex cranial mechanism (presently under study) that functionally integrates with the teeth. Therefore, adaptive conclusions are minimal, because the evolutionary significance of tooth form cannot properly be assessed outside of an integrated study. However, certain correlations do exist between structural tooth characteristics and mechanics. Slender, smooth-edged (or nearly so) teeth can readily pierce prey, but are of less use in slicing it. Such teeth are typical of the lower jaw dentition in many sharks and, in a few species, they are present in both upper and lower jaws. Usually these slender teeth display a reversed curvature at their tips, so that although most of the tooth's crown is curved inward toward the mouth cavity, the tip is turned outward. This outward turning of the tip can enhance the probability of initial prey penetration, without much compromising the prey-retaining properties of the inward curvature of the greater, more proximal portion of the tooth. Many sharks possess upper teeth with serrations along the edges. The serrations vary from one species to another in coarseness and in distribution along tooth edges. Serrated teeth can make greater use of the available biting forces, and they have a greater cutting effect than do smooth-edged teeth. These latter depend upon friction which, because the coefficient friction is always less than 1.0 (often very much less), can make use of only a fraction of the total bite force. However, smooth tooth blades can pierce prey with less resistance and are less prone to binding (becoming immobilized) in the prey tissue. In many shark species serrations are concentrated along the proximal portions of the tooth crown, where the bases of adjacent teeth are in near contact along the jaw margin. In these regions food can be pressed during feeding, resulting in a binding of the teeth in the prey. Release of the binding must be accomplished by cutting the jammed food, to permit clearance of the prey material so it can slip past the tooth rows. The more prominent serrations in such regions may act to puncture and slice the jammed tissue. It is noted that commercial saws are typically designed in various ways to promote clearance between adjacent saw teeth. The pitch or rake of the teeth of sharks is discussed, as is the overall form of the tooth rows along the jaw margins. The relationship between the distribution of teeth along the jaw margins and surface irregularities of the prey surfaces is also considered.

Notes: Summary The chromatophore system on the tracheal bladders of the phantom larva of Chaoborus crystallinus has been investigated by light and electron microscopy. The pigment cells are attached to a restricted region of the outer surface of the bladders and have the capacity to change both their shape and position on the bladder in response to changes in background illumination. The whole pigment system is tightly spanned by an extracellular membrane, which is in contact with two small muscles inserting at the anterior inner wall of the bladders.

Notes: Summary The three-dimensional organization of the canal system in two sponge species, Petrosia ficiformis and Chondrosia reniformis, was studied using corrosion casts. Casts were made of live animals, in situ, and canal replicas were analzyed by scanning electron microscopy (SEM). In P. ficiformis the incurrent system consists of a superficial canal network giving rise to large radial canals, which ramify and anastomosize forming an internal web. Excurrent canals are arranged into modular ramified systems radiating from atrial cavities opening to the exterior. Main excurrent canals run at various depths within the sponge, even through the superficial incurrent network. Both incurrent and excurrent canal replicas show smooth, blind-ending capillaries. Some large incurrent canals merge with excurrent ones, thus bypassing choanocyte chambers. In C. reniformis there is a cortical collagen layer crossed by three-like incurrent canals, the “twigs” of which communicate with groups of inhalant pores. The stems of tree-like canals penetrate into the sponge medulla where they ramify and anastomosize to form a web. Main excurrent canals arise from large cloacal ducts leading to the oscular openings. They give rise to a sequence of branches intersecting the incurrent web. Both incurrent and excurrent canals have sharp, blind-ending capillaries. Morphometric data functions show that diameter scaling in canal branches is exponential in Petrosia and linear in Chondrosia. Structural differences and homologies between the two species are discussed.

Notes: Summary As a deterrent against predators, larvae of Zygaena trifolii release droplets of fluid containing cyanoglucosides from segmentally arranged cuticular cavities. Histological examinations show that during the moulting period, the old cuticle, including the cavities and the secretion within them, is degraded, with the exception of a thin mesocuticular layer forming the exuviae. When the endocuticular layer of the new cuticle is deposited, the cuticle detaches from the underlying epidermis in specific areas, which leads to the formation of the cuticular cavities. During a moult-intermoult sequence the concentration of cyanoglucosides in both the haemolymph and the defensive secretion shows specific changes. These changes seem to be related to the formation and degradation of the cavities. We suggest that during the moult the cyanoglucosides are transported through the epidermis into the haemolymph to prevent them from being wasted with the exuviae and, after ecdysis, are retranslocated into the newly formed cavities.

Notes: Summary The proprioceptors of the musculature moving the second antennal segment in the collembolan Allacma fusca were examined with the electron microscope. There are five muscles, the most important of which appear to be a levator and a depressor muscle. Only these two muscles are monitored by proprioceptors. These proprioceptors, the scolopidia, are referred to here as the levator (l-) and the depressor (d-) scolopidium. The former contains two, the latter one sensory cell. Both scolopidia deviate from the usual pattern in that they have unmodified dendritic outer segments (no dilatations, no electron-dense material) and are enveloped by only one cell. But l- and d-scolopidia also differ from one another. The dendritic inner segments of the l-scolopidium are branched to an h-shaped pattern, with one branch ending on the levator muscle and the other running to the antennal nerve where the perikarya are located. In the d-scolopidium a muscle fiber of about 1 μm diameter (140–320 myosin filaments) accompanies the scolopidium for a distance of about 0.5 μm. On the basis of the structural features it is hypothesized that (1) the mechanical forces possibly act on the membranes of the dendritic inner segments, (2) the small muscle parallel to the d-scolopidium is a receptor muscle, and (3) both scolopidia are highly derivative.

Notes: Summary The penial stylets of Haloplanella longatuba and Vejdovskya pellucida are formed intracellularly and in a successive mode starting from the distal end. However, there are obvious differences in the mode of formation. In H. longatuba, a double-walled, tube-shaped hard structure develops in a stylet-forming cell, which is also tubular. In the cytoplasm, numerous irregularly shaped hard elements are formed close to microtubules, and these later fuse with the outer wall layer of the stylet. This wall is built up by the accumulation of electron-dense material at the inner side of the peripheral cell membrane. The inner layer enclosing the lumen of the hard structure is differentiated at the central membrane of the forming cell without individual elements. In V. pellucida, a rather electron-dense substance condenses freely in the cytoplasm of the style-forming cell. Afterwards, a very thin homogeneous layer of the same material develops on the inner sides of the cell membranes. Finally, the walls are strengthened by the deposition of further hard substances. In both H. longatuba and V. pellucida the stylet bases show a porous structure and are embedded in an intracellular matrix. Although both modes of stylet formation are obviously successive, they may be derived from the holo-synchronous formation mode, which is probably part of the ground pattern of the Rhabdocoela.

Notes: Summary The inner ears of representatives of all six gymnophionan families, as well as an ontogenetic series of one species, were studied in order to understand the origin and changes of the amphibian and basilar papillae. The amphibian papilla is in close proximity to the papilla neglecta in some adult gymnophionans. During ontogeny, both epithelia are adherent before they are separated by the formation of the utriculosaccular foramen. The nerve fibers to both epithelia run together, and both epithelia show a comparable variation in size and position among amphibians (amphibian papilla) and among vertebrates (papilla neglecta). Based on these arguments we propose that the amphibian papilla is a translocation of a part of the papilla neglecta specific to amphibians. Present in all primitive gymnophionans, the basilar papilla is lost in all derived gymnophionans. In contrast to anurans, but similar to some urodeles, amniotes, and Latimeria, the basilar papilla rests partly on a basilar membrane. Because of similarities in structure, topology, and innervation, the basilar papilla is suggested to be homologous in Latimeria and tetrapods. The structural differences of most amphibian basilar papillae, compared to those of amniotes and Latimeria, may be due to the different course of the periotic system and the formation of a basilar papillar recess rather than to a separate evolution of this epithelium. In addition to loss of the basilar papilla, some derived gymnophionans have lost the lagena, presumably independently, and the amphibian papilla is extremely reduced in the only genus without a stapes (Scolecomorphus). The papilla neglecta is, for unknown functional reasons, relatively large in aquatic gymnophionans, whereas it is almost lost in some thoroughly terrestrial gymnophionans. The regressive changes in the inner ear are not reflected in obvious changes in the pattern of eighth nerve projection. However, there is a rearrangement of cell masses in the rhombencephalic alar plate of derived gymnophionans, which may be related to the partial or complete loss of lateral line afferents. We propose that the presence of a basilar papilla is a synapomorphy of tetrapods and Latimeria, that the translocation of the papilla neglecta is related to the unique course of the amphibian periotic canal, and that regressive changes in the inner ear are related to the primitive absence of a tympanic ear.

Notes: Summary The process of egg segregation in the tunic of the ovoviviparous ascidian Diplosoma listerianum was studied by light and electron microscopy. One egg at a time was seen to mature in each zooid. The eggs had large yolk and grew on the ovary wall enveloped in four layers: (1) outer follicle cells (OFC), long and rich in RER (rough endoplasmic reticulum) and with dense granules in the Golgi region; (2) flat inner follicle cells (IFC); (3) a loosely fibrillar vitelline coat (VC); (4) test cells encased on the egg surface. The growing egg protrudes from the ovary wall and presses on the contiguous epidermis. Granulocytes enter the space between the epidermis and the egg and insinuate cytoplasmic protrusions, disrupting the continuity of the OFC layer. At ovulation, OFC and IFC are discharged and form a post-ovulatory follicle (corpus luteum). The epidermis shrinks and closes, possibly by activation of microfilaments, causing the egg to be completely surrounded by the tunic. In the zooid, the wound caused by the passage of the egg is repaired both by contraction of the epidermis and by phagocytic activity. Altered spermatozoans are found in phagocytosing cells in the lumen of the ovary. These are presumably remnants of those which entered to fertilize the egg before segregation.

Notes: Summary Fine structural changes in the egg and sperm are described during gamete interaction in Oikopleura dioica, an appendicularian tunicate. The unfertilized egg has a vitelline layer 80 nm thick and a perivitelline space about 5 μm wide. In the peripheral cytoplasm are a few cortical granules 0.6×0.7 μm in diameter and areas rich in parallel cisternae of rough endoplasmic reticulum alternating with areas rich in long mitochondria. In the deeper cytoplasm the predominant organelles are multivesicular bodies. From 25 s to 60 s after insemination, the egg transiently elongates, although with no obvious cytoplasmic rearrangement, and the egg surface becomes bumpy. During this interval sperm enter the egg, and the cortical granules undergo exocytosis. After expulsion into the perivitelline space, the cortical granule contents do not appear to change their shape or blend with the vitelline layer, which neither elevates further nor loses its ability to bind sperm. On encountering the egg, the sperm undergoes an acrosome reaction involving exocytosis of the acrosome and production of an acrosomal tubule. The acrosomal contents bind the sperm to the vitelline layer, and the posterior portion of the acrosomal membrane and the anterior portion of the nuclear envelope evaginate together to form an acrosomal tubule, which fuses with the egg plasma membrane to form a fertilization cone. By 45 s after insemination, the sperm nucleus, centriole, mitochondrion and at least the anterior portion of the axoneme are within the fertilization cone. By 60 s sperm entry is complete. In having eggs with a cortical reaction and sperm with an acrosome reaction, O. dioica resembles echinoderms and enteropneusts and differs markedly from ascidian tunicates, which lack both these features. The relatively unmodified pattern of gamete interaction in O. dioica in comparison with the highly modified pattern in ascidians is difficult to reconcile with the neoteny theory that appendicularians have evolved via ascidian ancestors. The present results are more consistent with the idea that an appendicularian-like ancestor gave rise to ascidians.

Notes: Summary Pycnophyes kielensis possesses one pair of protonephridia. The single excretory organ of a female consists of 25 cells: 22 terminal cells, 2 canal cells, and 1 nephroporus cell. Generally, all cells exhibit two cilia, the only exception being the nephroporus cell, which contains a diplosome instead. The slashed peripheral cytoplasmic walls of the 22 terminal cells altogether constitute one compound filter and a common filtration area. The protonephridia discharge via cuticularized cavities and six cuticularized tubes. Two accessory cells with modified cilia penetrate the nephroporus cell. These cells are considered to be receptor cells. The protonephridium of the first juvenile stage of P. kielensis is built up of only 5 cells: 3 terminal cells, 1 canal cell, and 1 nephroporus cell. It opens to the outside via 1 cuticularized tube. The protonephridia within both the Kinorhyncha and the Bilateria are discussed. Presumably excretory organs with compound filters developed independently within Bilateria.

Notes: Summary Mukudai and Yata have shown in the previous reports an interpretation of mechano-sorptive behavior that characteristic of viscoelastic behavior of wood under moisture change may be resulted from redistribution of applied stress in the cell wall because of change of friction between the S1 and S2 layers induced by moisture content change due to the looseness between the both layers, and have proposed a mechano-sorptive model based on the interpretation. In this report, to find out evidence supporting the interpretation that mechano-sorptive behavior is resulted from the looseness between the S1 and S2 layers, surfaces of specimens fractured by increasing load during creep under moisture content change were observed with electron microscopes. And, characteristic features of mechano-sorptive creep and recovery deflection curves at 15%, 30% and 45% stress levels which were obtained by computer simulation were checked by comparison with those of the corresponding experiments. As the results, it could be observed that fractures took place at the interface of the S1 and S2 layers in cells of the tension side of beams, and splits at the interface of the S1 and S2 layers took place here and there in the fractured surfaces. Furthermore, the characteristic features of creep and recovery deflection curves obtained by the simulations agreed well with those of the experiments.

Notes: Summary Thirteen clones of Populus tremuloides (Michx.) from central Alberta, Canada, were sampled to determine variation patterns within and among clones for benzene-alcoholwater extractives. Significant differences among clones were present; however, the broadsense heritability for extractive content was low (0.13). Extractive content was highest near the pith and decreased outward. Genetic and phenotypic correlations between rate of growth (ring widths) and extractive content indicated that faster growing clones or trees tend to exhibit less benzene-alcohol-water extractives.

Notes: Summary Modeling of the kinetic of moisture adsorption by wood has been studied by using cubic samples. The model is based on an explicit numerical method with finite differences. Experiments have been carried out either for determining the data necessary for calculations (diffusivity, amount adsorbed at equilibrium) and for testing the validity of the model. Two different experiments have been done in case of the longitudinal adsorption: the one by increasing the relative humidity of the atmosphere following a discontinuous step by step process. The other by determining the kinetic adsorption of moisture by samples previously equilibrated under the same conditions when they are contacted with atmosphere at various R. H. Good correlations are obtained between calculated values and experiments in both cases. Although the actual paper is concerned with constant diffusivity, the model is capable to use concentration-dependent diffusivities.

Notes: Summary The ultrastructure of holocellulose and alpha-cellulose from Pinus radiata D. Don was examined after treatment with cellulase for either 24 hours or 7 days. A procedure for localising the enzyme in situ using phosphotungstic acid is described. The pattern of degradation differed between the two substrates with alpha-cellulose being much more susceptible to hydrolysis than holocellulose. In both substrates the primary wall showed evidence of hydrolysis after 24 hours and was completely hydrolysed after 7 days. In holocellulose after 7 days treatment, hydrolysis of the secondary wall was confined to localised areas of the S3 layer sometimes penetrating into the S2 region. In contrast, alpha-cellulose showed uniform degradation across the secondary wall. Enzyme did not appear to penetrate the holocellulose but full penetration occurred in alpha-cellulose, the enzyme being closely associated with individual microfibrils. The reasons for these differences in degradation pattern are discussed.

Notes: Summary Transmission electron microscopy observations of hemlock sawdust that had been incubated with concentrated filtrate from Postia placenta showed that wood was degraded despite the absence of weight loss and release of reducing groups. These results are contrary to the prevailing views that enzyme preparation from brown-rot fungi are unable to degrade wood.

Notes: Summary Radial distribution of thujaplicins in western red cedar (Thuja plicata Donn) trees of varying ages was studied in order to assess relative decay resistance of their wood. Samples were extracted with ethanol: benzene (1: 2), and the extractives were analyzed for thujaplicin codtent by a new method utilizing capillary gas chromatography of their methylated derivatives. The combined concentration of thujic acid and methyl thujate was also determined for each sample. Distribution of extractives, thujaplicins and thujic acid, generally increased from pith to outside heartwood, then decreased in the sapwood. Maximum extractive and thujaplicin contents were also related to tree age. This suggests that products made from the wood of younger trees will be less resistant to decay than similar products made from the wood of old trees.

Notes: Summary The ultrastructure of steam-exploded wood from the softwood Pinus radiata D. Don was examined by electron microscopy in order to determine the reasons for increased porosity and enhanced susceptibility to enzymatic hydrolysis. Ultrastructural changes were observed in the form of lignin redistribution and swelling of the cellulose framework. Lignin showed evidence of melting, having contracted into well defined agglomerates suspended in a web of cellulose. Using lanthanum and gold tracers of known particle size the pores in the microfibrillar cell wall have been examined. Cellulose regions were shown to contain numerous pores greater than 2 nm, while lignin agglomerates did not contain such pores. Treatment with NaOH resulted in lignin being smeared over the porous cell wall material — hence blocking pores and reducing digestibility.

Notes: Summary A new approach for continuous and non-destructive drying strain measurement was formulated. It was based on the hypothesis that the effect of drying stress on shrinkage decreases with a decrease in board width. Tests performed at 30°C on tangentially sawn E. grandis specimens provided sufficient evidence to support the hypothesis and to merit its further investigation.

Notes: Summary Physicochemical analysis are carried out on samples of torrefied pine obtained at 260°C in inert atmosphere. Gaseous effluents which evolve in the first moments of the pyrolysis as well as liquid phase are analyzed by gas-chromatography. It appears from the solid analysis, that the chemical structure of pine is strongly altered by the process. The roasted wood exhibits particular properties: pronounced hydrophobic character, improved energetic power, a noticeable increase in ash content, a decrease of the volatile components and a decrease of those extracted by neutral solvents. It is shown that the more substantial change occurs at the beginning of heating.

Notes: Summary A mathematical model based on numerical method with finite differences is able to describe the process of absorption and desorption by wood contacted with various atmospheres. The relative humidity of the atmosphere can either be kept constant or varied with a constant rate, at the same temperature of 30°C. The transverse transport of moisture is controlled by transient diffusion with a concentration-dependent diffusivity. The model takes this fact into account, as well as the dependence of the moisture content at equilibrium with the relative humidity. Not only the model gives kinetics in good agreement with experiments, but also it is able to attain the profiles of concentration of moisture developed throughout the wood.

Notes: Summary Thermogravimetry-mass-spectrometry (TGMS) as a sophisticated analytical instrument is described for the thermal analysis of milled wood lignins from spruce (Picea abies L.), beech (Fagus sylvatica L.) and bamboo (Bambus sp.). The samples were heated on the thermobalance in an inert gas atmosphere (Ar) with 20°C/min heating rate. The weight loss curves (TG) and their 1st derivatives (DTG) were recorded. The evolution of 10 low mass degradation products with m/z below 44 was monitored as a function of the temperature by means of a quadrupol mass spectrometer. Thus the intensity profiles of H2, CH3 •, H2O, CO, CHO•, HCHO, CH3O•, CH3OH, CH3CO• and CO2 were recorded and interpreted in terms of lignin structure and the course of carbonization. The results are in agreement with the results of differencial scanning calorimetry (DSC) and pyrolysis-gas-chromatography mass-spectrometry (PyGCMS) of the phenolics.

Notes: Summary The interpretation of data from scanning electron microscopy (SEM) combined with energy dispersive analysis of X-rays (EDAX) is dependent on the size of the excitation volume, the magnitude of which for organic materials such as wood has been little studied. From the analysis of a model system comprised of a thin layer of gold sandwiched between two layers of an epoxy plastic, it was shown that about 90% of all excitations arise from a volume about 6 μm wide and 4 μm deep. However, these dimensions vary with the orientation of the gold relative to the specimen surface, and the specimen tilt. Theoretical predictions based on these data support, but not conclusively, the previously published SEM/EDAX evidence of the penetration of urea formaldehyde resins into the wood cell wall in particleboard manufacture.

Notes: Summary A description of flake orientation in OSB is presented by means of standard distribution cut at the length interval π. The root of variance of this distribution is indicated as the parameter which characterizes the degree of flake orientation. Using the anisotropy of microwave attenuation caused by wood, a non-destructive method of determining this parameter has been elaborated. The method is based on the conviction, that particleboards have properties which correspond to the averaged density dependent properties of wood. The averaging procedure is discussed and a system of equations is stated that enables to determine the mean orientation direction and the degree of flake orientation. The results of a preliminary verification of the method, carried out with a wood-veneer-model of the OSB-properties are encouraging. Substantial correlation between the degree of flake orientation and the anisotropy of microwave attenuation has also been ascertained.

Notes: Summary A number of workers have noted a marked decrease of wood permeability with increasing specimen length, and to date a model proposed by Bramhall has been used to explain the phenomenon. This describes the effect of random blockages on the permeability of an anisotropic porous medium. However, the model does not allow for the fact that transverse flow may allow longitudinal flow paths to circumvent blockages to some extent, so some deviation from it can be expected. The issue is an important one if laboratory experiments are to be used as a basis for the prediction of the behaviour of wood during impregnation or drying on a commercial scale. A modified model which allows for transverse flow is therefore developed. New experimental evidence which cannot be explained by the Bramhall model, but which can be explained by the new model, is presented.

Notes: Summary Oligoesterification reaction of wood with phthalic anhydride and glycidyl methacrylate (GMA) was investigated. The reaction proceeded smoothly at 90°C. The products obtained consisted of acetone-insoluble and soluble parts. The insoluble parts were novel oligoesterified woods with oligoester chains having methacrylate double bonds. The soluble parts were viscous liquids consisting mainly of free oligoesters not linked with the wood matrix, and contained small amounts of GMA and oligoesterified wood components which were dissolved out. The products (the oligoesterified wood-containing mixtures), when subjected to hotpressing, gave plasticized crosslinked wood boards whose surfaces are smooth, glossy, and plasticlike. In this case, plasticization of wood components and thermal polymerization of the methacrylate double bonds in the oligoester chains occurred simultaneously even in the absence of radical initiator. The soluble parts worked as a plasticizer for the wood components. The crosslinked wood boards exhibited outstanding properties in tensile strength (∼ca. 700 kg/cm2), flexural strength (ca. 900–1030 kg/cm2), and Rockwell hardness (ca. 120).

Notes: Summary Laboratory scale cement-bonded particleboards were made from mixed particles of three tropical hardwoods. Boards were three-layered comprising of 2 mm thick sawdust face and 4 mm thick core layers made from flakes of three lengths-12.5 mm, 25.0 mm and 37.5 mm and two thicknesses of 0.25 mm and 0.50 mm. The panels were fabricated at three density levels of 1,050 kg/m3, 1,125 kg/m3 and 1,200 kg/m3. From the statistical factorial analysis carried out, flake length, flake thickness and board density had significant effects at 1% level of propability on the properties of the tested panels. Mean MOR ranged from 5.22 to 11.15 N/mm2; MOE-2,420 to 4,820 N/mm2; water absorption and thickness swelling following 144 hours soak in water, 32.95 to 46.00% and 0.35 to 5.47% respectively. The longer and thinner the flakes, the stronger, stiffer and more dimensionally stable the experimental cement-bonded particleboards. Similarly, the higher density panels generally exhibited higher strength values in terms of MOR and MOE and were more dimensionally stable. MOR, MOE, water absorption and thickness swelling were found to be highly correlated with flake length, flake thickness and panel density. Correlation coefficients (R) for these relationships were 0.888 to 0.986 for the combined variables; and 0.574 to 0.992 for the individual factors. In all the cases tested, the regression relationships were linear.

Notes: Summary The observed axial flow of an inert fluid (heptance, octane, etc.) in Scots pine and spruce over lengths between 0.05 m and 0.4 m was correctly represented by a phenomenological model consisting of series of elements in which flow takes place, each element comprising a stagnant zone. Moreover, there is partial recycling of the fluid from the final to the initial element. The volume fraction occupied by the stagnant zone increases sharply with the length of the sample and this variation is probably the reason for the increased lineic pressure drop with the length of the samples. Test using pentachlorophenol as a tracer showed that there is no irreversible fixation of this compound on sapwood of Pinus sylvestris.

Notes: Summary Oligoesterification of wood was investigated by alternately adding esterification reactions of wood with maleic anhydride and allyl glycidyl ether. The products obtained consisted of acetone-insoluble and soluble parts. The insoluble parts were novel oligoesterified woods with oligoester chains having polymerizable double bonds. The oligoester chain length showed a tendency to decrease with increase in wood content in feed. The soluble parts were free oligoesters which were not linked with the wood matrix. The products (the oligoesterified wood-containing mixtures), when subjected to hot-pressing in the presence of a peroxide, gave plasticized crosslinked wood boards whose surfaces are smooth, glossy, and plasticlike. In this case, the free oligoesters which were hardening worked as a plasticizer for the wood components and were combined, by the crosslinking, with the oligoesterified woods, resulting in the formation of the network structure. The crosslinked wood boards exhibited outstanding properties in heat distortion temperature (〉165°C) and compressive strength (ca. 1,600–2,300 kg/cm2).

Notes: Summary The thermal stability of papermaking pulps under conditions of accelerated aging and at pyrolytic temperatures was examined. Degradation was found to be extremely complex and influenced by both the technical processes of papermaking and by the experimental methods used. At moderate temperatures, as used for accelerated aging, the folding endurance test was found to be a sensitive measure of degradation. Methods of reducing the variability of the test were considered, and a new technique capable of handling widely different results was developed and evaluated. Several papermaking pulps were artificially aged and the resultant loss of strength attributed to the interaction between a gradual fiber strength reduction and a rapid increase in interfiber bonding. Excessive initial inter-fiber bonding decreased handsheet stability. Softwood sulfite and kraft pulps were more stable than a birch kraft pulp, but the behavior of sulfite pulps varied greatly. The presence of lignin or a high hemicellulose content was not of itself sufficient to cause rapid aging. The pyrolytic behavior of pulps was investigated using thermogravimetric analysis. Papermaking pulps had mean pyrolytic activation energies between 30–45 kcal/mole. The activation energy decreased as the reaction proceeded. Correlation of these activation energies with the rate of loss of physical properties during accelerated aging was not good. The results indicated that the rate determining reactions for pyrolysis and for low temperature degradation are different but that the pyrolytic behavior is partially determined by the supramolecular structure. Empirical stability indices, based on both the integral and differential thermograms, were calculated, and these correlated well with the relative rates of loss of physical properties.

Notes: Summary Selected tropical hardwoods from Cameroon were impregnated with methyl methacrylate and polymerized in situ using a catalyst-heat technique. The fractional volumetric retentions of monomer and polymer were determined and expressed in terms of the fraction of voids filled by the impregnant. Of the three species tested, Movingui and Bilinga were easily treatable and therefore considered suitable for wood-polymer composites; on the other hand Sapelli was difficult to treat.

Notes: Summary Tests on tempered hardboard in tension were made with the purpose to study the effect of combined mechanical and moisture loading (mechano-sorption). The tests were performed both in a conventional way with constant load during the test period, and in quasirelaxation with the strain of each specimen prescribed during the test. In both cases the moisture content was varied. The tests show that the mechano-sorptive effects in the studied hardboard are small under constant load. In the relaxation tests the effects was found to be more significant. A constitutive model was suggested and quantified on the basis of test data from the constant load experiments. It was then checked independently against the other tests. The model was found to give good agreement with creep type experiments. When the model was checked against the relaxation type experiments, however, it showed poor agreement.

Notes: Summary The utilization of lignin from Pinus radiata black liquor, as a copolymer in ligninphenol-formaldehyde resin binders was studied. Methylolation, demethylation and ultrafiltration separation of high molecular-weight fractions were carried out in order to increase lignin reactivity. The different modified lignins were tested in preparation of lignin-phenolformaldehyde resin binders. Mechanical properties and water resistance were evaluated through testing particleboard panels manufactured with the resins obtained. The best resin was composed of 18,8% ultrafiltrated high molecular weight lignin, 22,9% phenol and 58,3% formaldehyde and had comparable properties with typical commercial resins prepared only with phenol and formaldehyde. An economic analysis was made in order to compare possible benefits obtained through the replacement of phenol by lignin products. The ultrafiltrated lignin copolymer was significantly less costly than a phenol-formaldehyde resin and had comparable physical and chemical properties.

Notes: Summary Ezo spruce (Picea jezoensis) wood meal and milled wood lignin were successively reduced with sodium borohydride, methylated with methanol-HCl, oxidized with Fremy's salt, reduced with sodium dithionite, and methylated with diazomethane. Permanganate oxidation of the treated milled wood lignin showed that 0.08–0.1/C9 units of 3,4,5-trimethoxyphenyl groups were introduced into the softwood lignin. Although hardwood meal (beech, Fagus crenata) methylated with diazomethane gave a purple-red colour with the Mäule test, the treated softwood meal gave only a dark brown colour. The aromatic nuclei of lignin were broken down by the Mäule treatment. The consumption of permanganate by treated softwood lignin was higher than by hardwood lignin, which suggests that the guaiacyl nuclei were broken down severely. It is proposed that the purple-red colour obtained from methylated hardwood lignin with the Mäule colour test is generated by reaction of syringyl groups which were liberated by β-ether cleavage under the permanganate oxidation conditions.