Salix has many physiological features in common with other deciduous woody plants, e.g. C3 photosynthesis, occurrence of latitudinal photoperiodic ecotypes, and organic N (no ) flux to the shoot in the xylem. Special points about the physiology of Salix spp. which may have impact on their ecology and economic uses include: (i) relatively high (for woody plants) light-saturated rate of photosynthesis on a leaf area or leaf dry weight basis, (ii) sex differences in water (transpiration) costs of growth, (iii) very limited seed longevity and a wide range of temperature and light conditions permitting germination, and (iv) ready rooting and establishment of naturally or artificially detached twigs and branches. Areas in which work on Salix has been especially influential for the development of plant physiology include: (i) the analysis of phloem functioning using aphids, (ii) the role of photoinhibition under natural conditions, and (iii) the realisation that the woody habit need not constrain the achieved activity of enzymes and hence N-based metabolic rates.

The geological exploration of submarine canyons and valleys began late in the nineteenth century.Theories of canyon genesis are many, but the probable causes are turbidity currents or sediment slumps, or both. Recent biological investigations indicate that the faunal composition of canyons is quite different from adjacent depths without canyons. The predominance of motility in the fauna implies that canyons today are physically more dynamic than previously expected. Motility could be an adaptive strategy for survival in an unstable sedimentary environment, or the species may be trophic opportunists which are able to take advantage of the entrapment by canyons of large aggregates of organic detritus.

The hyperarid climate of the Rub' al-Khali strongly conditions plant life in this subtropical hot desert. There is fossil evidence of a more humid climate here in late Tertiary and Pleistocene times and of a lakeforming phase as recent as 9000–6000 BP. Today rain may not occur for years in some parts, with annual means less than 25 mm, yet the extensive sands provide more scope for plant growth than do some rock and gravel tracts in less arid northern Arabia. The sand vegetation is characterised by very diffuse shrub communities led respectively by an endemic subspecies of Calligonum crinitum, the endemic saltbush Cornulaca arabica and, locally, by Haloxylon persicum. Cyperus conglomeratus, Dipterygium glaucum, Limeum arabicum, and Zygophyllum mandavillei are widespread associates. Sand-free gravel floors or salt flats, relatively small in extent, are nearly or entirely sterile. Tree forms are absent except for rare individuals on some borderlands. Floristic diversity is very restricted; only about 37 species (listed), of which hardly 10 are important in the vegetation, are recorded from an area of 500,000 km2. Annual plants are virtually absent, a situation contrasting sharply with that in Arabia to the N where more than half the desert species are therophytes.

Diameter frequency distributions (dfds) of 197 tree species in Korup National Park and 118 tree species in Douala–Edea Forest Reserve (based on c. 41 000 and 25 000 trees ≥ 30 cm gbh in 135 and 104 plots along four transects at each site, respectively) were individually classified into four groups of species according to their maximum diameters (≥99% trees <50, <70 and <90cm dbh, and > 1% ≥90cm dbh), and separated into two abundance classes (n≥50 and n = 20–49 (or 15–49). A fifth group, from those species in 3 and 4, was defined by a relative lack of small stems and given detailed attention. Dfds were evaluated for all species together on a transect and site basis, and compared for individual species across transects, and between sites for those group 5 species in common.

Analysis focussed on three large ectomycorrhizal species in groups 3 and 4, Microberlinia bisulcata, Tetraberlinia bifoliolata and T. moreliana (Caesalpiniaceae), which were restricted to, and dominated, the forest on the nutrient-poor soils of transect P at Korup. M. bisulcata, the most abundant, was markedly group 5 in character, with very few small trees, whilst the Tetraberlinia species had strong replacement potential. Although there were 27 species (42% of groups 3 & 4) at Korup and 19 (48%) at Douala–Edea in group 5, M. bisulcata was unique in its combination of large size, dfd, mycorrhizal habit, spatial distribution and soil association. The potential replacement of this species was contrasted also with a non-ectomycorrhizal caesalp with similar dfd that occurred on nutrient-richer soils, Erythrophleum ivorense.

Knowledge of the Caesalpiniaceae-rich la forêt biafriéene of Letouzey (which includes Korup and Douala–Edea) is reviewed, and the distribution, ecology and regeneration of the caesalps discussed. Structure and inferred dynamics of the forest at Korup are discussed with special regard to the ectomycorrhizal species.

The reproductive biology of a wide variety of deep-sea echinoderms from the northeast Atlantic has been examined. Time series samples of asteroids, ophiuroids, echinoids and holothurians are available from Station “M” and the Scottish Marine Biological Association's Permanent Station in the Rockall Trough and from opportunistic sampling in other areas of the northern Rockall Trough. Examination of these time series samples has established three main reproductive patterns in these taxa and one example of protandric hermaphroditism. The dominant reproductive pattern is the aperiodic production of relatively few large eggs usually in excess of 600μm diameter. Although the oogenic pattern is similar in most of these species, the follicle cell distribution and breakdown of relict oocytes vary considerably, particularly at family level. A second reproductive pattern is the production of numerous small eggs c. 100μm diameter, indicative of planktotrophic development. The five species exhibiting this pattern show intra- and interspecific synchrony of egg production with a proliferation of young oocytes in February to April of each year, vitellogenesis during summer and autumn and a synchronous spawnout in January–April of each year. In the apparent constant conditions of the deep sea, this synchrony of reproduction is related to the rapid descent of surface primary production. Two rarer reproductive patterns observed are the production of intermediate sized eggs (c. 300–400μm diameter) suggesting the formation of a lecithotrophic larva, and lastly a single case of protandric hermaphroditism, and the subsequent production of a large egg. In none of the species examined have we found any evidence of brooding. The variation in the reproductive pattern of individual species is discussed in relation to the constancy of the physico-chemical environment of the deep-sea.

A vegetation survey comprising all major habitats has been used to examine the ecological range of pteridophytes in an area of varied geology, climate and land-use in northern England.

Pteridophytes occur most commonly in coniferous plantations, scrub, cliffs and acidic woodlands and are also frequent in broadleaved plantations, in unshaded mire and on walls and river banks. In marked contrast to the herbaceous angiosperms of the region, pteridophytes have failed to exploit habitats subject to high intensities of disturbance (e.g. arable fields, spoiled land, paths) and are relatively unsuccessful in herbaceous vegetation experiencing moderate intensities of orderly disturbance (pastures, meadows, road verges).

Strategy concepts have been applied to compare the range of ecological specialisation displayed by the pteridophytes with that of the herbaceous angiosperms within the area of study. It is concluded that the contribution of pteridophytes is restricted by the absence of ephemeral and vernal life-forms, the scarcity of shoot systems resilient under defoliation, the low relative-growth rates of many species and the susceptibility of gametophytes, and young sporophytes to competition from herbaceous angiosperms and to submergence by leaf litter from deciduous trees. Whilst some of these features are of recent importance in that increasingly they limit the capacity to survive current changes in land-use, others appear to have restricted the ecological amplitude of the Pteridophyta throughout their history.

Preliminary results from a winter and a summer cruise in 1984 to the area west of the U.K. continental slope are presented to discuss the structure and the spatial scales of convection. Winter convection events were found to reach a depth of 630 m with horizontal scales of the order of 50 km. The number of areas with actual convection to maximum depth was small at the particular time of the cruise, but the vertical structure in the investigated area indicated numerous convection events over a longer period. The principal vertical structure of the upper 600 m in winter was preserved until the following summer, which agreed with the age of the summer upper layer water estimated from the tritium/helium ratio. This characterises the area to be one of low advection, which can also be indirectly concluded from the fact that the northward flow of 4 Sverdrup of Atlantic Water through the Faeroe-Shetland Channel is supplied by 2 Sverdrup from the current over the continental slope west of U.K. and 2 Sverdrup of flow along the Arctic Front between Iceland and the Faeroes.

Findings from the first two years of a long-term study of conifer log decomposition are presented. Log decomposition is regulated by the physical and chemical states, and development of decomposer foodwebs. The functional group with the greatest initial effect on the log is the channelisers, represented in our study by ambrosia and bark beetles. They not only create multitudes of channels into the logs but vector the initial decomposer community. Ambrosia beetles exclude certain elements of the decomposer community from channels until they vacate the log, at the end of their reproductive phase. The foodweb during the early stages of decomposition includes nitrogen-fixing and other bacteria, fungi, protozoa, nematodes, and arthropods. Seasonal fluctuations of temperature and moisture are hypothesised to work in tandem to modulate the activities of the decomposer community.

The branchial apparatus of Lampetra fluviatilis has been studied to find out whether the inspiratory movement is brought about by muscular contraction. Differences between existing accounts of the anatomy are pointed out, and a description is given of diagonal muscles which span re-entrant curves of the gill bars. Extirpation and stimulation experiments provide evidence that none of the available muscle groups can have an inspiratory function. The pressure changes in the gill sac indicate that the momentum of the water-stream in forceful expiration leaves a region of low pressure which initiates the inspiratory flow.

The sediments of shallow and deep water areas of Loch Leven are, respectively, medium to very fine-grained sands and silty clays (muds). The largest area of more or less uniform sediment type (sands) occurs on the north-eastern shelf. The sediments with the finest grain size are found in an area to the south and east of Castle Island and Reed Bower. Here, the median grain size is less than 4 microns. The amount of sand in a sediment is very highly correlated with the median grain size of the sediment and may therefore most usefully be used to describe the general distribution of sediments in the loch. The distribution of organic carbon in the loch sediments is largely confined to deep-water areas. The southern deep area is more organic rich than the northern deep area. The amount of organic carbon in a sediment is positively correlated with the amounts of clay and silt in the sediment.

The planktonic movements of larval Chironomidae in Loch Leven, Kinross, are described, together with a provisional list of the species and age groups involved. The importance of this type of behaviour in determining the distribution of larval Chironomidae is discussed.

It was in 1878 that Ehrlich, with the aid of his triacid stain, described in terms of granulation of the cytoplasm six types of leucocytes. This marked the first real advance in our knowledge of the blood corpuscles. Present-day classification of cells in the blood-forming tissues gives six main groups with about thirty named types of cells. These fine subdivisions appear to represent different stages in different lines of development from one original type, chiefly by change in the shape of the resting nucleus. Divergence in opinion arises as to whether all these types of cell develop in the red bone marrow, or whether some arise elsewhere in the body.

In recent years considerable progress has been made in the investigation of the biochemistry and physiology of the root nodules of leguminous plants (Wilson, 1940). It now appears desirable that the anatomical structure of the nodule should be re-examined from the standpoint of the functions which the nodule is considered to discharge. Special interest attaches to the distribution within the nodule of endodermis, cork, and any other suberized layers, since on this will depend the facility with which materials may be exchanged between the tissues of the nodule and the environment. There is some confusion in the literature as to the distribution of such suberized tissues within the nodule, but it is clear that rather curious features are presented.

The physiological and biochemical features of plants that are responsible for determining susceptibility or tolerance to air pollutants have often proved hard to identify. In recent years, however, there has been new experimental evidence of responses which may be of critical importance. These include (a) changes in stomatal behaviour, affecting plant-water relations, (b) alterations in carbon and nitrogen assimilation and partitioning which can influence root growth, and (c) interference with the processes of winter hardening. Evidence of these changes to physiological processes, and the ways in which responses to pollutants may become more significant to plant survival in the presence of other environmental stresses, are discussed. The longer-term consequences, or secondary responses, such as effects on associations with other organisms, are also briefly reviewed. We have also examined the possibility that ecosystems may be overloaded with inputs of nitrogen from the atmosphere.

The Braithwaite system of agamospory is reviewed. The few ferns having this system are very diverse, both systematically and in their behaviour. It is concluded that this type of agamospory has arisen independently several times by different routes.

The return to air after periods of oxygen deprivation has long been known to be associated with injury from active radicals in a variety of animal tissues (post-ischaemic injury or reperfusion injury). In plants, a similar sequence of events has been suspected, but only on the basis of indirect evidence of peroxidative damage to membrane lipids. The role of free radicals in causing such injury was investigated in the rhizomes of two Iris species, one tolerant of anoxia (Iris pseudacorus) and one intolerant (Iris germanica). Rhizomes of both species were subjected to total anoxia for 7 days. In the following post-anoxic period, when normal air supply was restored, the generation of active radicals was detected by Electron Paramagnetic Resonance (EPR) only in the anoxia-intolerant I. germanica. Radical generation was exclusively in the rhizodermis and never observed in the rhizome cortex. The radicals were successfully scavenged with the antioxidants ascorbic acid and reduced glutathione. A direct parallel can therefore be drawn between post-ischaemic injury in animal tissues and post-anoxic injury in plants on the basis of direct observation of active radical generation in sensitive tissue. The avoidance of this type of injury is discussed in relation to variation in flooding tolerance, anoxia and other stresses in higher plants.

Like oxidation in a flame, oxidation in the atmosphere is mediated by free radicals. By far the most important radical in the troposphere is the hydroxyl radical, OH. It is generated photochemically, and reacts with most atmospheric trace gases, in many instances as the first, and rate-determining, step in the reaction chains leading to their oxidation. Usually these chains regenerate OH thus maintaining OH at relatively large day-time concentrations of the order of 106 cm−3.

The most important reactions controlling local concentrations of OH form the framework of a photochemical reaction model, the results of which are compared to OH concentrations measured in the field at locations with different concentrations of pollutant attributable to the activities of man. The model-predicted OH concentrations are based on the simultaneously measured concentrations and photolysis rates of those trace gases that dominate OH chemistry at the local level.

Predicted and measured OH concentrations correlate reasonably well where concentrations of atmospheric pollutants are small but not where they are large. Explanations are being sought.

In the Caridea, unlike the allied Euphausiacea and Penæidea, developing eggs are attached by means of a “cement” to specialized non-pinnate ovigerous setæ on pleopods 1–4; in Crangon also to periopods 4 and 5. The presence of these eggs does not prevent flexure of the abdomen and execution of backward escape movements. The form of the abdomen differs in relation to habit, and this, together with the disposition of the ovigerous setæ, which varies greatly in different genera and in different pleopods of the same species, conditions the arrangement of the egg-mass. Ovigerous setæ increase both in numbers and in length with age; so do the number of eggs which have to be attached. There is concentration in the pleopods of “cement” glands identical with the tegumental glands which secrete the epicuticle which the “cement” resembles in all respects. Ducts run into the ovigerous setæ but it remains obscure where the “cement” emerges; possibly it dissolves its way through the integument of the setæ to emerge at many places simultaneously. Attachment of eggs in the Caridea may be associated with the many different habits exhibited; the developing eggs are protected and hatch out in the often restricted environment of the parent.

The problem to be presented here emerges from the following groups of facts and more or less generally accepted opinions.

As heterochromatin we may define those parts of chromosomes which reach maximum nucleic acid charge in mitosis or meiosis in times other than metaphase. In salivary gland chromosomes (which are more conveniently called polytene chromosomes) of Drosophila melanogaster the proximal heterochromatic parts of all chromosomes come together and form a central undifferentiated mass, the chromocentre. Genetically heterochromatin forms the so-called inert regions of the chromosomes.

The geological structure and history of the Rockall Trough margin to the west of the Outer Hebrides (57°N-59°N) has been inferred from the analysis of bottom samples, seismic, sonar, magnetic, satellite altimeter and surface-ship gravity observations. Much of the continental shelf consists of a shallow platform of Precambrian Lewisian basement, covered by a thin (<300m) blanket of Cenozoic sediments. Apart from areas near the shelf break and immediately west of Lewis, the basement has not undergone the large-scale subsidence typical of many regions adjacent to the Rockall Trough. Beneath the outer shelf, the Lewisian dips steeply towards the deeper water and is covered by a westwardthickening succession (>3km) of Mesozoic and Cenozoic sediments.

The eastern margin of the Rockall Trough appears to have been well established as a site of deposition by the end of the Triassic. Further subsidence occurred during the late Jurassic and continued into the Cretaceous when the axial province of the Rockall Trough off the Hebrides was invaded by basic volcanic material. Subsequently, the region was profoundly affected by early Cenozoic igneous activity. The long-term buoyancy of the Lewisian basement under the Outer Hebridean platform and early-formed structural discontinuities within it have influenced the overall pattern of sediment accumulation and the distribution of volcanic activity along the margin. During the later stages of deposition, sedimentation was closely controlled by the presence of early Cenozoic volcanics, by bottom currents and by glacial processes.