Miracle-dz/UniFAR-FTUs huggingface dataset:
Disturbance, succession, and maintenance of species diversity in an East Texas forest.

Vegetation change following selective logging and major natural disturbance was in- vestigated through the use of stand history reconstruction and population monitoring in an east Texas pine-hardwood forest. High frequencies of release in beech (Fagus grandifolia) and white oak (Quercus alba) occurred after apparently natural disturbances in 1800-1810, 1860-1870, and 1960-1970, and after selective logging beginning 1910. Pulses of recruitment occurred after all disturbances except the most recent one. Age data suggest that recruitment after the 1910 disturbance was asynchronous among species, with loblolly pine (Pinus taeda) regenerating first, followed sequentially by white oak, red maple (Acer rubrum), and beech. At present, only magnolia (Magnolia grandiflora) is showing significant new recruitment. After the 1910 disturbance, regenerating pines grew rapidly and became dominant in the re-forming overstory. Most hardwoods originating after the 19 10 disturbance did not reach the overstory. White oak initially outgrew maple and beech and is presently larger. Over the last 20 yr beech growth has been greater than white oak growth, resulting in a decline in the average size difference between individuals of these species. Presently, mortality rates of understory populations are high for sweetgum, blackgum, and the oaks, and are low for beech and magnolia. These latter two species are also the faster growing. Ifthese trends continue, beech and magnolia will become increasingly predominant in the forest understory and eventually in the overstory as well. Map data show that saplings and small trees are abundant under pine and oak, but not under beech and magnolia. Future disturbance is therefore likely to accelerate succession to more shade-tolerant species in parts of the forest now dominated by pine and oak, but is most likely to re-initiate new regeneration, including pine and oak, in areas now dominated by beech and magnolia. These results suggest a pattern of cyclical replacement driven by disturbance, a pattern which may help preserve species diversity in southern mesic forests.
Preliminary Microbiological Studies on the Preservation of Palm Wine

Palm wine is essentially a heavy suspension of yeasts and bacteria in fermenting palm sap. The water extract of a local preservative, from the bark of Sacoglottis gabonensis, failed to inhibit several yeasts and bacteria from palm wine. Sodium metabisulphite, diethylpyrocarbonate (DEPC) and sorbic acid inhibited to varying extents micro-organisms in palm wine. Sorbic acid was thought to be the most suitable preservative tested since DEPC left a residual pungent smell and sodium metabisulphite was not suitable because it is unacceptable to man above 0.35 mg/kg of body weight (Mossel, 1971). Pasteurization at 70° for 30 min was more effective than any of the chemical methods in reducing the microbial load of the wine. It is suggested that pasteurization at 70° for 30 min combined with subsequent treatment with sorbic acid may prove useful as a means of preserving palm wine.
Effects of cultivation, conditioning and isolate on sclerotium germination in Sclerotium cepivorum

Sclerotium germination in various isolates of S. cepivorum was studied following different cultivation and conditioning treatments. A simple and rapid laboratory test was developed to trigger sclerotial germination under unsterile conditions. In most isolates, sclerotia produced under sterile and unsterile conditions showed a constitutive dormancy immediately after maturing. In contrast to this, the sclerotia of some isolates germinated quite well as soon as they were mature. The dormancy of sclerotia from axenic cultures broke down after storage in soil for 12 weeks. In a few cases sclerotia produced under unsterile conditions germinated remarkably well. Freezing and thawing of sclerotia decreased the ability of most isolates to germinate.
Cell expansion in the epidermis: microtubules, cellulose orientation and wall loosening enzymes

Summary Two models of isolated epidermis were used to demonstrate that the net orientation of cellulose microfibrils in the cell wall is related to mechanical properties of the tissue, and can be used as an indicator for wall anisotropy. In the developing plant epidermis, cells expand in one or two directions in the plane of the plant surface. In epidermis cells actively expanding in one direction (elongation), the orientation of cortical microtubules closely matches the net cellulose orientation. In epidermis cells expanding in two directions, the orientation of the parallel microtubules does not coincide with the net cellulose orientation in the adjacent cell wall. The orientation of cortical microtubules is thus not always a reliable indicator of wall characteristics. In both types of epidermis, a high rate of expansion correlates with a high activity of xyloglucan endotransglycosylase (XET), as determined in situ . This high activity alone cannot explain unidirectional wall expansion.
Metal-specific and NADPH oxidase dependent changes in lipoxygenase and NADPH oxidase gene expression in Arabidopsis thaliana exposed to cadmium or excess copper.

Reactive oxygen species produced by NADPH oxidase and oxylipins derived from lipoxygenase activity can signal various stress conditions and have been implicated when plants are exposed to heavy metals. Transcriptional profiling of the 10 NADPH oxidase and 6 lipoxygenase genes was performed after exposure of Arabidopsis thaliana wild-type and NADPH oxidase mutants to 5 µM CdSO4 or 2 µM CuSO4 for 24 h. Under these short exposures to environmentally realistic concentrations of Cd or Cu, plants modulate signalling networks that regulate the onset of adaptive responses. Metal-specific NADPH oxidase genes were upregulated by Cd but downregulated by Cu, and metal-specific lipoxygenase gene expression was observed only after Cu exposure. Genes that are responsive to both metals were upregulated and may be responsive to general oxidative stress. For all metal-responsive genes except RBOHD, distinct responses were observed between leaves and roots, which may be due to different stress intensities and signalling mechanisms. Mutation of NADPH oxidase genes had opposing effects on gene expression after Cd or Cu exposure. Upregulation of LOX1 and LOX6 in the roots after exposure to Cd depended on NADPH oxidase gene expression, whereas LOX3 and LOX6 expression was induced more strongly in NADPH oxidase mutants after Cu exposure. Furthermore, NADPH oxidases regulated their own expression level and that of other members of the gene family when exposed to Cd or Cu. The results suggest interplay between reactive oxygen species and oxylipin signalling under Cd or Cu stress, and are useful as a basis for genetic studies to unravel metal-specific signalling mechanisms.
Trout Production in Prairie Ponds

Experimental plantings of rainbow trout (Salmo gairdneri) in prairie winterkill lakes commenced in 1968 to test the feasibility of their commercial production. These trials were highly successful and by 1970 a small but rapidly expanding trout farming industry had been established. Trout planted early in the spring as 5- to 8-cm long fingerlings grew to marketable size (200 g minimum), without supplementary feeding, in the 6-mo period of open water that prevails in this region. Recoveries as high as 86% of the fingerlings stocked have been achieved and the quality of the trout produced is usually excellent in flavor and color. These experiments are continuing to improve management techniques and to determine the long-term productive capacity of pothole lakes. Three serious problems — summerkill, muddy flavor, and harvest inefficiency — are also subjects of continuing investigations. Use of prairie winterkill lakes as nursery ponds for production of advanced fingerlings of walleye and whitefish for use in .
All creatures great and smaller: a study in cetacean life history energetics

This paper reviews some specific studies of cetacean life history energetics over the past 20–30 y that include one of the largest species, the baleen fin whale, Balaenoptera physalus, the medium-sized odontocete long-finned pilot whale, Globicephala melas, and one of the smallest marine odontocetes, the harbour porpoise, Phocoena phocoena. Attention is drawn to the decrease in longevity with size and the differences in biological parameters that reflect this and affect life history strategy and energy utilization. Data from the past whaling industry in Iceland for fin whales, the Faroese ‘grindedrap’ for pilot whales, and by-catches as well as some live captive studies for harbour porpoise have been used. The studies demonstrate how information can be gathered to compile energy budgets for individuals, relying on carcase measurement and analysis, dietary investigations, biochemical analyses of tissues, and general life history studies including reproduction; as well as from monitoring living animals. The individual examples presented show how food energy storage in the form of fat can be variously important in insulation in the smallest species to controlling reproductive efficiency in large migratory species. The paper concludes by noting that an understanding of energy use in the individual can be an important input in multi-species ecosystem modelling.
Basicranial anatomy of Syndyoceras cooki (Artiodactyla, Protoceratidae) and the need for a reappraisal of tylopod relationships

ABSTRACT Observations of the holotype of Syndyoceras cooki and comparative material indicate that protoceratid basicrania share no striking resemblances to those of camelids, a group purported to be closely related to the protoceratids. The protoceratid petrosal has a massive posterodorsal (canalicular) part with a strong dorsal crest separating the cerebral and cerebellar surfaces, like the petrosals of ruminants, and its endocranial surface lacks a fossa mastoidea, a feature of uncertain polarity found in camelid petrosals dating back at least as far as the Oligocene genus Poebrotherium. Furthermore, the subarcuate fossa of the petrosal is reduced in protoceratids (a derived condition found in pecoran ruminants). These results, while they cannot be analyzed completely with currently available data, indicate: 1) a pressing need for the reappraisal of interrelationships of “tylopod” artiodactyl taxa and their relationships with the ruminants, and 2) the potential that protoceratids themselves may be more .
Deleterious Mutations and the Evolution of Male Haploidy

In the Hymenoptera males develop directly from unfertilized ggs and produce gametes mitotically. Females are diploid and produce gametes by meiosis. A related phenomenon exists in other taxa in which males transmit only maternal genes but may have diploid somatic tissue. This life cycle was called paternal genome loss by Bull (1979). The hymenopteran life cycle is usually called arrhenotoky or haplodiploidy. Since Hamilton's seminal articles (Hamilton 1964a, 1964b), a tremendous amount of effort has been devoted to exploring the consequences of arrhenotoky but relatively little to its evolution (Whiting 1945; Brown 1964; Hartl and Brown 1970; Bull 1979; Borgia 1980). The articles by Whiting, Hartl and Brown, and Borgia emphasize cological factors that might favor arrhenotoky and the preconditions necessary to ease a transition from full diploidy. Hartl and Brown (1970), for example, derived the conditions for invasion of arrhenotoky assuming that sperm is limited and many eggs go unfertilized. Bull (1979), following Brown (1964), showed that arrhenotoky is favored if the fitness of the male haploids is at least half that of the diploids and mothers control the ploidy level of their male offspring. This twofold transmission advantage applies to any life cycle in which the paternal genome is not passed on through the male, whether or not it is expressed in the somatic tissue. Bull (1979) has called such life cycles male haploidy, but it seems that male genetic haploidy is a superior term because it emphasizes that males need not be haploid somatically. The transmission advantage is equivalent o a segregation distorter that acts only when passed through the mother and that completely blocks the transmission of wild-type alleles in the male (Bull 1979). This explanation of the origin of male genetic haploidy is especially attractive in light of recent findings that allelic activity can be influenced by the sex of the parent from which it was inherited (Solter 1988). In this note I investigate another inherent genetic factor, mutation to deleterious alleles, that is expected to influence the evolution of arrhenotoky. The arguments apply only to those male-genetic-haploid taxa in which the paternal genome is not expressed in males, such as arrhenotoky and some forms of paternal genome loss (Bull 1983). Both Hartl and Brown (1970) and Borgia (1980) note that male haploids are more sensitive to deleterious recessive alleles than diploids, and they conclude that such alleles must be low in frequency for arrhenotoky to evolve in response to advantages like the use of unfertilized ggs or close control of sex ratio. Therefore, they argue that close inbreeding would ease a transition to arrhenotoky. In the context of the transmission advantage, Bull (1979) points
Measurement versus estimation of condition in snakes

Because variation in fat reserves (i.e., condition) is expected to contribute to variation in survival and reproductive success, zoologists often wish to estimate the condition of the animals they study. The conventional condition estimates used for snakes are the residuals from a regression of body mass on body length. Because this estimate of condition is not independent of the variables used to estimate it (i.e., fat is a component of body mass), estimates derived in this fashion will be confounded whenever fat varies nonrandomly with length. To avoid this problem we used total lipid extraction to estimate percent body fat in a representative sample of northern water snakes (Nerodia sipedon). The conventional condition index explained less than half the variance in the measured percent body fat in this sample. An improved estimate of condition calculated as the difference between total body mass and predicted lean mass (based on the results of the lipid extraction) explained 70% of the variation in percent body fat in the original sample of snakes. 'This improved estimate also revealed that condition declined with body size in a large sample of male water snakes measured in early spring over a 4-year period. This last result, coupled with theoretical expectations that condition will not vary randomly with body size in snakes, suggests that researchers interested in condition should derive indices from direct measurements of body fat.
Differentiation in populations of Hordeum spontaneum along a gradient of environmental productivity and predictability: life history and local adaptation

Reciprocal introduction of seeds and seedlings of wild barley, Hordeum spontaneum , originating in four different environments of Israel was used to: (1) test for local adaptation, (2) make inferences about environmental effects on life-history and reproductive traits, and (3) identify trait combinations with recognizable ‘strategies’. The four populations examined represented the following environments: (1) desert − low productivity and predictability, drought stress; (2) semi-steppe batha − moderate productivity and predictability; (3) grassland − high productivity and predictability; and (4) mountain − high productivity and predictability but with severe frost stress. Significant genotype-by-environment interactions were observed for yield and reproductive biomass, seedling biomass and percentage germinated and survived seeds, suggesting local ecotype adaptation. Increasing productivity and predictability of environment in respect to rainfall, without concomitant frost stress, was found to select for high reproductive biomass and large seeds, a high fraction of germinating seeds and high vigour of seedlings. The optimal strategy changes with increasing productivity and predictability and involves a trade-off between seed size and number, with reduced yield but increased seed mass, consistent with competition selection (or K-selection sensu MacArthur & Wilson (1967)) type. No specific life-history adaptations to predictable frost stress were detected for the mountain ecotype, but there was higher survival of seedlings in their indigenous (mountain) environment compared with other ecotypes. The latter appears to be a physiological adaptation to frost, which is consistent with selection for stress tolerance (or S-selection sensu Grime (1977)) type. The other stress factor, drought, which is very unpredictable in deserts, was associated with high seed dormancy, small seed size and low vigour of seedlings, but relatively high yield, which is consistent with a stress-escape bet-hedging strategy. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 77, 479–490.
Contrasting effects of the cyanobacterium Microcystis aeruginosa on the growth and physiology of two green algae, Oocystis marsonii and Scenedesmus obliquus, revealed by flow cytometry

Summary Aquatic photosynthetic productivity is influenced by resource availability, resource use efficiency and interspecific interactions. In hypertrophic environments, interspecific interference is known to influence species succession. The effect of interference by phytoplankton on biomass production is very poorly understood. One hypothesis is that the development of cyanobacterial blooms is triggered by the excretion of allelopathic substances that inhibit the growth of other phytoplankton species. In this study, we analysed how the co-cultivation of the cyanobacterium Microcystis aeruginosa with two green algae (Oocystis marsonii and Scenedesmus obliquus) influences the resource use efficiency of each partner under nutrient-replete conditions. Using single-cell technologies, it was possible to quantify the efficiency of light use and the biomass gain for all three species under hypertrophic (non-limiting nutrient) conditions. The presence of M. aeruginosa resulted in growth inhibition, reduced metabolic activity and an increased quantum requirement for biomass assimilation in O. marsonii, whereas no changes were observed in S. obliquus. M. aeruginosa, on the other hand, showed an increased cell size in mixed cultures with O. marsonii. However, with respect to biomass production, M. aeruginosa did not profit from the growth inhibition of O. marsonii in the experimental period of 8 days. By contrast, the co-cultivation of M. aeruginosa with S. obliquus did not affect the physiological activity of either species. This study highlights the potential of flow cytometry to determine species-specific basic growth parameters, light-use efficiency and biomass gain during co-cultivation of different algal strains. It is further demonstrated that sorted cells can be used to analyse their macromolecular composition. The results of this study reveal very different species-specific patterns of growth kinetics and light-use-efficiency of green algae in co-cultivation experiments with a cyanobacterium.
Effect of constant light on male sterility in the cotton leafworm Spodoptera littoralis

Females of the cotton leafworm (Spodoptera littoralis) reared in long day conditions (LD 16:8 h) and mated to males kept throughout the whole period of development in continuous light (LL) oviposit very small numbers of mostly sterile eggs. It was found that in control males reared from the first larval instar in long day conditions there was a large accumulation of euperene sperm bundles in their testes on day 1 after imaginal moult. On day 10 of adult life the number of the sperm bundles was very small. In males kept from the first instar in continuous light there was also high number of sperm bundles on day 1 after imaginal moult but it did not decrease significantly on day 10 as was observed in controls. Transfer of different developmental stages of S. littoralis from long day conditions to continuous light resulted in a big difference in the density of eupyrene sperm bundles in their testes. In control insects reared through the whole of their development in long day conditions there was a significant decrease in the density of eupyrene sperm bundles on day 10 of adult life. By contrast, in males in continuous light, regardless of their developmental stage when transferred, there was either no change in density of sperm bundles in day 10 adults or there was a significant increase in comparison with day 1 adults. The highest density of eupyrene sperm bundles was observed in day 10 adults when they were transferred to continuous light shortly before moulting to the last instar (as day 4 larvae in the last stadium or day 1 pupae). Generally, the density of eupyrene sperm bundles on day 10 of adult development was about 2–2.5 times higher in males in continuous light then those under long day conditions. The results presented here indicate that the last larval instar and the pupa are the stages most sensitive to constant light treatment, which greatly reduces the amount of eupyrene sperm bundles released from the testes.
Effect of tazolol on β‐adrenoceptors in isolated preparations of the guinea‐pig and rat

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Ten-year results of strip clear-cutting in Quebec black spruce stands

Regeneration of first-cut strips in a two-cut system of strip clear-cutting was compared to that of large clear-cutting in four different areas representative of the black spruce (Picea mariana (Mill.) BSP) stands of the boreal forest of Quebec. Seedlings were more evenly distributed in clearcut strips than in large clearcuts. Differences of about 10 000 black spruce seedlings per hectare and 20% of stocking were observed in favour of clearcut strips compared to large clearcuts. Black spruce stocking was about 14% larger on lowland than on upland sites but height growth was better on upland sites. A regeneration problem similar to that of large clearcuts was observed when the second strips were cut. One year after cutting these second strips, winter harvesting resulted in a 23% gain in black spruce stocking as compared to summer harvesting. Even if black spruce stocking marginally increased during the years following winter harvesting, the height advantage of the preserved advance growth justifies the app.