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.

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.

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.

Ripening of tomato and other fruits involves changes in quality attributes that make them attractive to consumers. These alterations are brought about by the coordinated expression of specific genes. Ethylene, synthesised by cells of climacteric fruit at the onset of ripening, stimulates the expression of genes required for ripening to occur. Experiments with transgenic plants have shown that a 5′ flanking region from the fruit polygalacturonase (PG) gene directs the ripening-specific expression of foreign genes in tomato. Antisense genes have also been used to down-regulate expression of the PG gene, causing a reduction in pectin degradation during ripening. This reduction in PG has beneficial effects on fruit storage life and processing characteristics. Antisense technology has also been used to assign functions to previously unknown genes. This has led to the identification of the gene for ethylene forming enzyme (EFE) which catalyses the terminal step in ethylene synthesis. Detached fruit from tomato plants in which EFE is inhibited by antisense genes produce much less ethylene and ripening is greatly slowed. The rate of ripening can be restored by adding ethylene externally. These results raise the possibility of manipulating ripening of many fruits and also of controlling processes such as abscission and senescence of leaves and flowers.

An account of the pathology of Sitka spruce in northern Britain is given based on enquiries dealt with by the Pathology Branch of the Forestry Commission Research Division in the last fifteen years. Sitka spruce occupies the major proportion of our forest estate but has given rise to only 15% of enquiries concerning tree damage. The most frequently diagnosed injuries have been those due to frost and to root diseases caused by Heterobasidion annosum and Armillaria spp. Two other root pathogens, Rhizina undulata and Phaeolus schweinitzii, and two needle pathogens, Lophodermiun piceae and Rhizosphaera kalkhoffii, have also been recorded in Sitka spruce plantations as have several wound-infecting stem decay fungi. Only five other fungal diseases, those caused by Botrytis cinerea, Phytophthora citricola, Helicobasidium purpureum, Sirococcus strobilinus and Pythium spp. have been recorded, all in nurseries.

Evidence now points to the existence of common patterns of functional specialisation in green plants and fungi. It is predicted that further research will reveal the basis for a universal functional classification of organisms which can be used to analyse the assembly rules of communities and ecosystems.

The Turkish forests are a complex of Mediterranean, European, Euxine and Irano-Turanian influences. The boundaries between these 4 bioclimatic-biogeographical zones have, especially in the E of the country, been little studied and their limits are difficult to establish. Phytosociological and biogeographical aspects of these forest zones are discussed. In the bioclimatic-Mediterranean region, the forest and pre-forest structures are related to QUERCETALIA ILICIS in the thermo- and meso-Mediterranean stages, and to QUERCETALIA PUBESCENTIS in the supra-Mediterranean stage, except in southern Anatolia where they belong to QUERCO-CEDRETALIA LIBANI. In the prepontic bioclimatic region where the Mediterranean influence is still perceptible, they belong to QUERCO-CARPINETALIA ORIENTALIS and in the Euxine bioclimatic region to RHODODENDRO-FAGETALIA ORIENTALI and to PINOPICEETALIA ORIENTALIS. Some forest formations in NW Anatolia, with a European mountain influence, are related to FAGETALIA SYLVATICAE and to VACCINIO PICEETALIA.

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.