The paper deals with three problem areas in the taxonomy of British willows: (1) the widespread occurrence in Perthshire and neighbouring counties of an intermediate between Salix myrsinifolia Salisb. and S. phylicifolia L., apparently of hybrid origin, though growing in an area where typical S. phylicifolia has yet to be found; (2) the complex taxonomy of the British Sallows, where two common aggregate species, Salix cinerea L. and S. caprea L., are each represented by two segregates; a third, S. aurita L., may also comprise more than one segregate; all three species interbreed, as do the segregates within each aggregate; (3) the disputed identity of the Crack Willow, Salix fragilis L., and its nomenclatural implications.

The evolutionary significance of natural fire disturbance regimes in the development of post-fire fungal and herb communities is examined. Before a fire the soil microflora exhibits a general fungistasis, microbial competition is great, nutrients are limiting, and carbonicolous ascomycetes are in a dormant phase. Also in mature chaparral shrub communities the soil microflora is implicated in soil toxicity that prevents seeds of some species from germinating in the interval between burns. Fire results in the deposition of ash and charred wood, a release of nutrients, the elimination of competitors (e.g. shrub cover, soil microflora), an increase in soil alkalinity, the removal of soil toxicity/fungistasis, and cues the germination of constitutively dormant ascospores and seeds. The cue for germination of the chaparral fire annuals appears to be components of the hemicellulose fraction, produced during the charring of wood, but this fraction has not been tested for its ability to cue ascospore germination. Germination in the absence of fire would be “suicidal” because neither the carbonicolous ascomycetes nor the post-fire annuals are able to compete successfully in these pre-burn habitats. The frequency of burning and the uneven heating of the soil surface creates patchiness with a corresponding increase in the species richness of the post-burn community.

The main pollutants affecting materials are sulphur dioxide and sulphates, nitrogen oxides and nitrates, chlorides, carbon dioxide and ozone. In marine environments it is important to separate the effects of anthropogenic pollutants from marine sources of the same substances. The effects of paniculate matter, especially from diesel vehicle emissions is of increasing significance.

In buildings containing books, historical artefacts or other works of art indoor pollutants may cause significant degradation. These pollutants may either be lower concentrations of pollutants originating outdoors or other substances generated from synthetic materials, paints, varnishes and display cases as well as from combustion for heating.

The materials most sensitive to pollutants are calcareous building stones and ferrous metals. Manifestations of damage include losses of mass, changes in porosity, discoloration and embrittlement. In the case of stone it is difficult to (1) dissociate the effects of historical concentrations of pollution from current ones and (2) to establish background rates of erosion or decay in the absence of pollutants.

Damage to materials in polluted atmospheres can be attributed to dry or wet deposition of pollutants, or dissolution in rainfall in the case of stone. Estimates of the contributions of the different mechanisms of decay have been made in programmes in the U.S.A. and the U.K.

To obtain estimates of the economic cost of damage from acid deposition it is necessary to know how decay rates are related quantitatively to pollutants and meteorological parameters (damage functions), and the distribution of materials exposed in buildings and in geographical areas. There are few damage functions available and those in existence lack general applicability. There is. therefore, much importance attached to national and international exposure programmes that have been established to assess the responses of a range of materials to different environments. Such work is also of interest in predicting the potential effects of climatic changes on materials.

Methodologies have been developed to enable estimates of economic costs of damage to be made. These are being refined with better data on rates of decay obtained from mathematical models and from exposure programmes. The concept of target loads for damage, originally devised for the natural environment, is being introduced to help assess the action needed to reduce degradation of sensitive materials and buildings.

Sitka spruce grown from seed has a juvenile phase of about twenty years before coning commences; mature trees and grafted scions cone intermittently and produce good cone crops every three–five years. These characteristics have lengthened the breeding programme and reduced seed production in orchards. Production of male and female cones can be enhanced by treatments such as heat and drought and by application of a mixture of gibberellins A4 and A7 (GA4/7) to mature grafts. To enhance flowering consistently in container grown grafts the GA4/7 must be applied together with a cultural treatment, but with larger grafts in the field GA4/7 alone is often effective. Attempts to induce cone production in juvenile trees, however, have been less successful. Female cones initiated on field grown trees in response to inductive treatments yield seed of a similar quantity and quality to that from cones on untreated trees. The physiological mechanisms of coning, and cone induction techniques, are discussed.

Numerous investigations have already been made on the biology of Calanus finmarchicus. The main body of data, however, has been derived from field observations, and while many and important conclusions have been drawn from such work, confirmation of some of them is required by direct experimental methods. Accurate studies on the feeding, metabolism, and breeding of Calanus can only be made on living animals in the laboratory. Some such investigations have already been made by Crawshay, Clarke, Fuller, Marshall, Nicholls and Orr, Harvey and others, but the results have sometimes been obscure owing to the difficulties encountered in keeping Calanus in really healthy condition.

Hypotheses concerning diaspore behaviour are presented. It is suggested that in many plants, dispersal strategy involves alternative agents (2 or more vectors) and combination of distances. The hypotheses are substantiated by data compiled from observations of dispersal modes and mechanisms in herbaceous plant species of the Middle East. Two special modes, heterocarpy and amphicarpy, represent complex strategies with different propagules on the same individual. Amphicarpy resembles cryptophytic life-form in many respects. In several other cases the same propagule can be dispersed for various distances by a single vector or through alternative modes. Combination of long-range, short-range, and in situ dispersal is described for many species; Compositae of Turkey serve as a study case of the possible abundance of this strategy.

Several combinations of different vectors that can distribute the same diaspores, alternately or successively, are recorded. It seems that the combination of wind and temporary water currents is quite common in our region. Cruciferae of Israel serve as a study case of the possible abundance of this strategy and its various combinations. It is concluded that dispersal strategies with alternate modes are typical of many herbaceous species and probably adopted by most angiosperms. The one-to-one conservative relationships between adaptation and mode, mechanism and agent, are rather misleading. An adaptation or a syndrome should not be rigidly defined as they may function in more than one way. Often, the alternate mode can be more effective than the mode attributed to that particular syndrome. By such strategy a plant can better guarantee its distribution in space.

Photogeneration of singlet oxygen molecules (1O2), their vibrationally excited state and dimols (1O2)2 has been shown by measuring photosensitised delayed luminescence in pigment-containing media. All singlet oxygen species are formed as a result of energy transfer to O2 from triplet pigment molecules. Monomeric pigment molecules are the most efficient singlet oxygen generators. The 1O2 quantum yields are 40–80% in aerobic solutions of monomeric chlorophylls and pheophytins. Pigment aggregation causes a strong decrease in singlet oxygen production. The 1O2 quantum yield in chloroplasts has been estimated using literature and experimental data on formation of the chlorophyll triplet states in the photosynthetic apparatus. The most probable value is 0.1%. One of the major sources of singlet oxygen is likely to be the triplet states of newly formed pigment molecules which are not quenched by carotenoids and can be detected by measuring low-temperature pigment phosphorescence. Quenching of singlet oxygen by the thylakoid components has been analysed and the 1O2 lifetime estimated. The data suggest that carotenoids and chlorophylls are the most efficient physical 1O2 quenchers and the 1O2 lifetime is about 70 ns in thylakoids. The quantum yield of 1O2-induced pigment photodestruction was estimated to be about 10−6–10−5. This value is close to the quantum yield of chlorophyll photobleaching experimentally observed in aerobic suspensions of isolated chloroplasts. The intensity of pigment phosphorescence at 77 K correlates with the rate of chlorophyll photobleaching in plant materials. The data suggest that 1O2 generation by the pigment triplet states is the most likely reason for chloroplast photodamage. The intensity of pigment phosphorescence can be used as an index of the degree of plant photo-oxidative stress.

Data on the evolution of nitrogen gas and methane, and the utilisation of nitrate were obtained from sediment-water interface core samples obtained from Loch Leven, Kinross, and Windermere Esthwaite Water, Coniston Water and Ennerdale Water in the English Lake District. Differences in the rate of evolution and total quantity of the gases are discussed in relation to the trophic state of the lakes. The potential importance of nitrogen gas loss to the nitrogen budget of the lakes is considered.

The important macrophyte-feeding cyprinid fish Ctenopharyngodon idella Val., the White Amur or Grass Carp, is native to temperate climates. The present paper is concerned with its biology when transplanted to Malacca, a tropical research station in latitude 2° 17′ N.

At this station, the fish has a faster growth-rate, and may mature at an earlier age and smaller size, than in its native habitat. There are no marked seasonal changes at Malacca, and in these conditions the Grass Carp shows no spawning cycle, but some fish are ripe at any time of the year. While the testes of the males appear to develop normal milt, the ovaries in the fish examined seldom produced as many eggs as in their native habitat, and the eggs themselves have been shown to be mostly defective and to undergo early atresion.

Consequently, though the ovulation of eggs of normal size was induced by pituitary injection in nineteen out of forty-eight trials, no success was got in the artificial fertilization of the eggs, though elsewhere success has been got in 25 per cent and more of trials. It is suggested that this fish may need the external stimuli which are associated with its natural spawning season to develope normal fertile eggs.

The occurrence of a population of the spionid polychaete Marenzelleria viridis (Verrill 1873) in the middle reaches of the Tay Estuary is reported. This is a new British and European record of a North American species, and its principal characteristics are described and compared with earlier accounts. Size frequency analysis of the population showed it to be dominated by large animals from July 1984 to May 1986. The population matured coelomic gametes during winter 1985–86 and spawned in March 1986 to produce a heavy settlement in May, which subsequently grew rapidly. The distribution of M. viridis in relation to other species, sediment and other ecological parameters is described from a single survey of the Invergowrie Bay mudflats. Marenzelleria population densities of up to 1500 m 2 were negatively correlated with all other species of a low diversity macrofaunal community dominated by predatory polychaetes and filter feeding bivalves. Marenzelleria was abundant down to sediment depths of 20–30 cm. The significance and origin of this population is discussed.

A front on the Great Plateau separates tidally mixed water of the North Channel from quieter less saline surface layers of the Outer Firth. These water bodies exchange about 1·6 × 104m3 s−1, leading to a residence time of two months in the Outer Firth surface layers. The position of the front is determined by the balance of mixing and buoyancy supply. The wind modulates weak tidal currents in the Outer Firth by driving surface currents and setting up deeper compensation flows. Deep water in the Arran Deep and Kilbrannan Sound is irregularly renewed by inflow of dense water over the Eastern Plateau from autumn to spring of about 1 × 104m3 s−1 but stagnates in summer below a thermocline. A minor part of this renewal comes over the Davaar sill into Kilbrannan Sound.

Bottom water of the fjordic sea-lochs is isolated in summer and renewed during the winter. The renewals occur by density currents flowing in from the sills and these produce a characterising grading of the bottom sediments from coarse to fine away from the sills.

The forest zone of West and Central Africa comprises the coastal and adjacent inland regions bounded the semi-deciduous forests in the west and the equatorial forests in central Africa and the Congo basin. Sedimentary plains, developed mostly on weathered sandy materials, lie along the coastal stretches and cover vast areas of the Congo basin. Behind the coast the plain rises gradually to hills and plateaus of much lower elevation than those of the highlands of East Africa. Two great rivers, the Niger and the Congo, which discharge huge volumes of fresh water to the Atlantic Ocean, are major contributors to the hydrological cycles of the rain forests ecosystems of the Guinea–Congo Region. The Niger originates from the forested highlands of Guinea and discharges its waters into the Bight of Benin by way of a large delta in southern Nigeria. The Congo basin occupies an immense area of 750 000 km2, surrounded by Pre-Cambrian uplands. The alluvial floor of the saucer-shaped basin is flat, and marshes and swamps comprise a large proportion of the total area. The highlands and plateaus along the rim are low to the west and north and higher to the south. To the east, they merge with the mountains of the Great Rift Valley of East Africa (Gann & Duignan 1972; Hance 1975; Grove 1978; Hamilton 1989).

The production of fruitbodies of mycorrhizal fungi associated with Betula spp. in an experimental site was observed to occur in a pattern ordered in time and space. Certain species of Inocybe, Hebeloma and Laccaria and Thelephora terrestris appeared in the first five years after planting: they were followed by species of Leccinum, Cortinarius and Russula. Usually more fungi were associated with B. pendula than with B. pubescens. More toadstools of Laccaria tortilis developed in association with one clone of B. pubescens than with another which favoured instead the development of Inocybe petiginosa.

The idea of a fungal succession is supported by below-ground observation of mycorrhizas. Early- and late-stage fungi formed mycorrhizas on seedlings growing in sterile conditions whether inoculated with mycelia or spores. However, only early-stage fungi formed mycorrhizas in unsterile conditions.

The concept of succession is based on observations made when treeless sites were planted with Betula spp. However, experimental planting of seedlings into soil with intact roots of older trees with mycorrhizas of Lactarius pubescens resulted in mycorrhizas on the seedlings: but no mycorrhizas formed if the roots of the older tree had been severed. This suggests that the pattern or sequence of mycorrhizal fungi associated with seedlings regenerating within natural stands is likely to differ from that associated with Betula spp. colonizing previously treeless sites.

The title to the talk this afternoon, “Abiogenic Information Coupling, or, How protein and DNA were married”, is, indeed, an excerpt from the much broader subject to which your President referred, namely chemical evolution of life on the surface of the earth, with some speculation about elsewhere as well. Actually, the “elsewhere” portion is more than a hopeful addition because it may provide a check on the speculations on the origin of life on the surface of the earth, which is very difficult to obtain inany other way.

Various species of the lamellibranch Gryphœa have received much attention from palæontologists in the past twenty years, partly because careful collecting appears to have produced continuous series of forms (lineages) and partly owing to the problems which are raised by their progressive development from more normal oysters.

Thin sections of the spinal ganglion of the rat were cut and examined with the electron microscope. Two main types of nerve cell are described. Type A with equal electron density of nucleus and cytoplasm. The cytoplasm contains large aggregates of Nissl's substance discretely scattered throughout the cell, mitochondria and osmophilic granules. Type B with a “light” nucleus and a “dark” cytoplasm. The cytoplasm is closely packed and homogeneous so that it is difficult to separate out the various cytoplasmic elements.

There is a well-marked nuclear membrane about 500 Å thick and characteristic strawberry nucleolus.

The capsular cells are closely applied to the nerve cell with no intervening boundaries. A system of cytoplasmic filaments—the “endoplasmic reticulum”—is present in the intercellular regions.

There are nerve fibres with lamellated myelin sheath, axolemma, Schwann cells and Schwann membrane.

A cytological analysis of a number of Sealyham, Spaniel, and Spaniel × Manchester Terrier dogs was undertaken in order to determine the number and structure of chromosomes during both mitosis and meiosis in each breed, and to ascertain the differences between them in respect of chromosome number and behaviour.

In Dutch coastal dunes, geomorphological and geohydrological processes have been adversely affected by intensive utilisation of the dunes. In the past, wide-scale stabilisation, notably for reasons of coastal defence, stopped nearly all aeolian activity. Rejuvenation did not take place and succession to mature-type ecosystems increased. Artificial infiltration with eutrophic river water and extraction of groundwater for drinking water catchment modified the geohydrology of the wet-dune environment.

Today, actions are being taken to restore geomorphological and geohydrological processes. Managing authorities join forces with universities and policy makers to strike the right balance between conflicting interests. Applied research helps to develop management strategies.

Two types of research are discussed: (a) geomorphological work on the development of blow-outs; (b) geohydrological work on the development of dune slacks. Questions considered are: do blow-outs grow to an unlimited extent or do they have optimum size and shape corresponding to aerodynamic conditions? Are there natural stabilisation mechanisms for blow-outs? What is the ecological impact of drinking water catchment? Which aspects should be considered to restore the dune slack environment in catchment areas?

Our findings are that blow-outs in The Netherlands have an optimum length:width ratio of about 2 with a blow-out length varying between 20 and 30 m. After 10–15 years without artificial stabilisation measures, the areas studied present an average of about one blow-out per hectare. Natural stabilisation mechanisms include algae which colonise deflation sites inside the blow-out and low secondary dunes which develop at the immediate leeward side of the blow-out. Blow-outs situated at or near downhill slopes of 6–12° may easily extend into larger deflation surfaces. Water erosion, probably caused by the water-repellency of humus-rich top soil, often precedes wind erosion on south- and south-east oriented slopes.

Drinking water production caused dessiccation of dune slacks and the disappearance of associated vegetation. In areas where infiltration with river water from outside the dunes is also applied, inudation and eutrophication drastically changed the dune environment. Nitrophilous plants appeared, especialy along banks of infiltration ponds, but also in seepage ponds. The plant cover depends on nutrient concentration of the (infiltrated) groundwater but especially on the flux of the groundwater. A high rate of flux leads to high nutrient loads, encouraging the growth and eventually dominance of nitrophilous plants. Restoration of dune slacks depends on the quality and the flux of the groundwater, on the streamlines of the groundwater flow in the dune body in relation to the orientation of the seepage ponds, on the presence of peaty or clayey adsorptive layers in the subsoil and possibly also on the presence of a rainwater lens occurring on top of the infiltration water.

The major antioxidants present in the essential (volatile) oils of oregano (Origanum vulgare, L.), summer savory (Satureja hortensis, L.) and thyme (Thymus vulgaris, L.) have been identified as carvacrol and thymol which have both been demonstrated to possess fungicidal and bactericidal properties. EPR spectra produced upon oxidation are inconsistent with the expected phenoxy free radicals (RO), but resemble those of galvinoxyl and anthronyl radicals. The EPR spectrum, in the case of carvacrol, is a pair of quintets with isotropic splittings, 0.325 and 0.080 millitesla (mT). ENDOR and TRIPLE resonance experiments have been performed and are indicative of the paramagnetic species being a substituted anthronyl. Further studies are being conducted to characterise these species and to investigate their potential roles during oxidative stress.

The Outer Hebrides comprise approximately 1·3% of the land area but 15·8% of the area of standing waters of Great Britain. Streams there are generally small and only three are as large as fifth order. The majority of the lochs occur below 200 m altitude and are less than 25 ha in area. A total of 1375 stream systems enter the sea, and drain the land mass through 9240 stream segments. There are just over 6000 lochs, of which less than half are connected to these networks. Most of the water systems are on geologically base-poor rock or soil, and less than 3%, situated on machair, are base-rich and eutrophic. The islands, due to their situation, receive precipitation in the form of very dilute sea water (with some non-marine sulphate probably derived from fossil fuel combustion) and this leads to unusual concentrations of chloride in the inland waters. Metamorphic rocks are resistant to weathering, so there is usually little variation in the composition of fresh waters except in the machair areas, where calcareous sands affect calcium concentrations and alkalinities.

The flora and fauna reflect the aqueous conditions and there are some unique successions of species from high to low salinities even in the same water body. The lochs provide a wide range of habitats for aquatic vegetation, ranging from the rich machair lochs to the oligotrophic peaty lochs (which show marked similarities with their counterparts on the mainland). Three broad categories can be delineated on the basis of their water quality and vegetation: brackish lochs with varying degrees of marine influence, calcareous machair lochs which may also be affected by sea connections, and the peaty lochans of low alkalinity. A few brackish water animals are sufficiently euryhaline to exist in the machair lochs, which are otherwise dominated by freshwater species. The occurrence of chloride in inland waters enables some crustaceans, e.g. Neomysis integer, Gammarus duebeni and Diaptomus wierzejskii to extend into what are poor freshwater habitats. The main constituents of the freshwater fauna are molluscs and arthropods, and a few species of euryhaline fishes, i.e. salmon, sea and brown trout, three-spined and ten-spined sticklebacks and eels. There are some populations of non-migratory charr. No amphibians are present.