Miracle-dz/UniFAR-FTUs huggingface dataset:
Temperature Response of Vernalization in Wheat: A Developmental Analysis

Abstract The vernalization response of wheat (Triticum aestivumL.) was reinterpreted from a developmental perspective, using current concepts of the developmental regulation of wheat morphology and phenology. At temperatures above 0 °C, the effects of the process of vernalizationper sein wheat are confounded by the effects of concurrent vegetative development. These effects are manifested by differences in the number of leaves initiated by the shoot apex prior to floral initiation, which in turn affects the subsequent rate of development to ear emergence and anthesis. Leaf primordia development during vernalization and total leaf number at flowering were used to develop criteria to define both the progress and the point of saturation of the vernalization response. These criteria were then used to reinterpret the results of Chujo (Proceedings of the Crop Science Society of Japan35: 177–186, 1966), and derive the temperature response of vernalizationper sefor plants grown under saturating long day conditions. The rate of vernalization increased linearly with temperature between 1 and 11 °C, such that the time taken to saturate the vernalization response decreased from 70 d at 1 °C to 40 d at 11 °C. The rate declined again at temperatures above 11 °C, and 18 °C was apparently ineffective for vernalization. Total leaf number at saturation, however, increased consistently with temperature, as a result of the balance between the concurrent processes of leaf primordium initiation and vernalization. Total leaf number at saturation increased from 6 at 1 °C to 13.3 at 15 °C, which in turn influenced the time taken to reach ear emergence. The advantages of using this developmental interpretation of vernalization as the basis for a mechanistic model of the vernalization response in wheat are discussed.
Colonising Strategies and Diapause of Planktonic Rotifers (Monogononta, Rotifera) during Aquatic and Terrestrial Phases in a Floodplain (Lower Oder Valley, Germany)

The floodplains of the River Oder are inundated in winter and spring and are desiccated during summer. The plankton community developing towards the end of winter is dominated by monogonont rotifers. Some species maintain populations on the flooded areas as well as in the remaining permanent waters after flooding. Other species are found during the inundation period only. These species produce drought-resistant diapause stages, beginning at low population densities between 5 to 36 females L -1 . Experiments showed that 9 out of 10 species, which were observed to produce resting eggs during the aquatic phase, were able to survive the terrestrial phase through dormancy in the desiccated floodplain soils. Other species colonise the temporarily inundated areas from the permanent waters again during each flooding period.
Chitinases in root nodules

The abundance of chitinases in plants is surprising in view of the fact that plants do not contain chitin. However, plant chitinases have been shown to play a role in defense, growth and developmental processes. They are also involved in plant-bacterial symbioses. Two groups of plants, legumes and actinorhizal plants, are able to enter root-nodule symbioses with nitrogen fixing bacteria, rhizobia and Frankia strains, respectively, and plant chitinases are involved in these interactions. None of these bacteria contain chitin in their cell walls but rhizobia produce chitinaceous signal factors. To find out whether symbiosis-related chitinases belonged to phylogenetically distinct subgroups, a phylogenetic analysis was performed including all chitinases of one dicot, Arabidopsis, and one monocot, rice. The results show that conserved class I- and class III-chitinases were recruited in both types of root nodule symbioses. Since no chitinaceous signal molecules are formed by Frankia, a role of chitinases in the control of microbial signaling is unlikely. Alternative roles of chitinases in root nodules are discussed.
The Patch Dynamics Concept of Stream Community Ecology

Stream ecologists are faced with the problem of recognizing patterns in community organization and explaining the processes that determine these patterns. I argue that streams conform reasonably closely to the patch dynamics explanation of community organization which emphasizes temporal phenomena and focusses on the importance of history and chance. Even where competition or predation have been shown to play a role in shaping stream communities, the temporal phenomena of disturbance and colonization are invariably also of fundamental importance. In most cases, temporal variation is probably the factor of overriding significance, and species with weedy characteristics are a particularly prominent feature of streams. I highlight the critical role played by refugia as sources of recolonization after spates, and therefore as buffers against disturbance. A theoretical framework based on the patch dynamics view of community ecology may provide a unifying theme in stream ecology.
Bears and ants: myrmecophagy by brown bears in central Scandinavia

To determine general patterns of myrmecophagy in bears, we tested hypotheses regarding selection of ant species, factors important to bears when selecting ant species, factors influencing seasonal use of ants, and foraging behavior of brown bears (Ursus arctos) in central Sweden. Ants were an important food for these bears, constituting 12, 16, and 4% of fecal volume in spring, summer, and autumn, respectively. Ants were abundant, 30.5-38.5 tonnes per bear, and bears excavated 8-33% (mean 23%) of the mounds of red forest ants annually. Carpenter ants (Camponotus herculeanus) were highly preferred. Among mound-building red forest ants, the Formica aquilonia/polyctena complex was preferred over Formica exsecta and Formica lugubris. The ants selected by bears had high digestible energy and low formic acid content and behaved passively when the colony was disturbed. Colony size and density may also have influenced the selection of ants. Seasonal use of ants was related not to the availability of pupae or the .
The significance of symbiotic nitrogen fixation in plant production

Fixed nitrogen is probably the main plant nutrient that limits agricultural production worldwide. For most developed countries this limitation can be alleviated by the use of nitrogenous fertilizers. The increased cost of fertilizer nitrogen, concern about nitrates in water supplies, and the limited availability of fertilizer in developing countries are major factors influencing a desire to obtain more fixation by biological means. It is likely that nearly all plant species benefit from nitrogen fixation by bacteria associated with their roots. How much they benefit appears to be related directly to the degree of complexity of the interaction between the plant and nitrogen‐fixing bacteria. For example, some leguminous plants, which have root nodules containing rhizobia, can fix more than 100 kg N per hectare per annum, whereas some grasses which have nitrogen‐fixing bacteria associated with their roots may only support fixation of 10 kg N per hectare per annum or less. The role of biological nitrogen fixa.
Soil nutrients and beta diversity in the Bornean Dipterocarpaceae: evidence for niche partitioning by tropical rain forest trees

1 The relative importance of niche‐ and dispersal‐mediated processes in structuring diverse tropical plant communities remains poorly understood. Here, we link mesoscale beta diversity to soil variation throughout a lowland Bornean watershed underlain by alluvium, sedimentary and granite parent materials (c. 340 ha, 8–200 m a.s.l.). We test the hypothesis that species turnover across the habitat gradient reflects interspecific partitioning of soil resources. 2 Floristic inventories (≥ 1 cm d.b.h.) of the Dipterocarpaceae, the dominant Bornean canopy tree family, were combined with extensive soil analyses in 30 (0.16 ha) plots. Six samples per plot were analysed for total C, N, P, K, Ca and Mg, exchangeable K, Ca and Mg, extractable P, texture, and pH. 3 Extractable P, exchangeable K, and total C, N and P varied significantly among substrates and were highest on alluvium. Thirty‐one dipterocarp species (n = 2634 individuals, five genera) were recorded. Dipterocarp density was similar across substrates, but richness and diversity were highest on nutrient‐poor granite and lowest on nutrient‐rich alluvium. 4 Eighteen of 22 species were positively or negatively associated with parent material. In 8 of 16 abundant species, tree distribution (≥ 10 cm d.b.h.) was more strongly non‐random than juveniles (1–10 cm d.b.h.), suggesting higher juvenile mortality in unsuitable habitats. The dominant species Dipterocarpus sublamellatus (> 50% of stems) was indifferent to substrate, but nine of 11 ‘subdominant’ species (> 8 individuals ha−1) were substrate specialists. 5 Eighteen of 22 species were significantly associated with soil nutrients, especially P, Mg and Ca. Floristic variation was significantly correlated with edaphic and geographical distance for all stems ≥ 1 cm d.b. h. in Mantel analyses. However, juvenile variation (1–10 cm d.b.h.) was more strongly related to geographical distance than edaphic factors, while the converse held for established trees (≥ 10 cm d.b.h.), suggesting increased importance of niche processes with size class. 6 Pervasive dipterocarp associations with soil factors suggest that niche partitioning structures dipterocarp tree communities. Yet, much floristic variation unrelated to soil was correlated with geographical distance between plots, suggesting that dispersal and niche processes jointly determine mesoscale beta diversity in the Bornean Dipterocarpaceae.
Predation by house cats, Felis catus (L.), in Canberra, Australia. II. Factors affecting the amount of prey caught and estimates of the impact on wildlife

Information on the amount of vertebrate prey caught by house cats in Canberra was collected by recording prey deposited at cat owners’ residences over 12 months. The amount of prey taken was not significantly influenced by cat gender, age when neutered, or cat breed. Nor did belling or the number of meals provided per day have a significant influence on the amount of prey caught. The age of the cat and the proportion of nights spent outside explained approximately 11% of the variation in the amount of prey caught by individual cats. In all, 43% of variation in predation on introduced species (predominantly rodents) was explained by distance from potential prey source areas (i.e. rural/grassland habitat) and cat density. The mean number of prey reported per cat over 12 months (10.2) was significantly lower than mean predation per cat per year based on estimates made by cat owners before the prey survey began (23.3). Counts of the amount of prey caught by house cats were highly positively skewed. In all, 70% of cats were observed to catch less than 10 prey over 12 months, but for 6% of cats, more than 50 prey were recorded. Estimates of predation by house cats, particularly extrapolated estimates, should be treated with caution. The total number of prey caught by house cats in Canberra estimated using the sample median was approximately half the estimate based on the sample mean. Predation estimates alone do not prove that prey populations are detrimentally affected, especially in highly disturbed and modified environments such as suburbs. Impacts on native fauna are likely to be most significant in undisturbed habitat adjacent to new residential developments.
Size‐related factors causing individual variation in seasonal reproductive success of fluvial male Dolly Varden (Salvelinus malma)

– Reproductive activities of individually identified fluvial Dolly Varden (Salvelinus malma) were observed during a breeding season in a small stream. Males and females both established dominance hierarchies based on body size. Females spawned from late October to late November, with no apparent peak, and larger females spawned earlier than small ones. Males competed for access to females by adopting two types of mating tactics: pairing and sneaking. The tactic used depended on the male's position in the dominance hierarchy of the breeding group. Seasonal reproductive activity and mating success of males were positively correlated with body size, with only the largest male monopolizing most of the mating opportunities, and the small males were rarely successful in mating. Smaller males, however, lost as much weight as large males during the breeding season. Females preferred the largest male in the breeding group as a mate, while males courted females of any size. It is suggested that the polygynous mating pattern is a consequence of size-related differences in competitive ability among males, and the degree of monopolization is affected by both the temporal distribution and the spawning tactics of the females.
Extraordinary accuracy in floret position of Helianthus annuus

Divergence angles were measured for inﬂorescences of Helianthus annuus with several hundreds to more than a thousand disk ﬂowers. Quantitative analysis showed that the angles are robustly ﬁxed in the vicinity of the ideal golden angle 137.508° as accurately as ~0.001°. The mean deviation from the ideal value varies for each sample. The results have important implications for phyllotaxis models, which are discussed by referring to a necessary modiﬁcation proposed by Roberts.
Larvicidal and ovipositional preference test of copper solution for mosquitoes

: In the previous studies, we demonstrated that larvae of Anopheles stephensi died within two weeks after the exposure of the larvae to 2.4 ppm of copper solution. The ability of copper to kill mosquito larvae prompted us to examine its applicability to ovitraps. We demonstrated in this study that 10 ppm of copper killed more than 90% of larvae ( Anopheles stephensi , Aedes albopictus and Culex pipiens pallens ) in 96 hours. At 3.3 ppm, Cx. pipiens was more sensitive than An. stephensi and Ae. albopictus . Fifty percent of Cx. pipiens larvae died within 24 hours but An. stephensi and Ae. albopictus survived more than 50% at 48 hours. We also observed that gravid mosquitoes of An. stephensi , Ae. albopictus , and field-collected An. sinensis did not detect nor avoid 10 ppm copper solution for laying eggs under laboratory conditions. These results suggest that copper could be used in ovitraps as a low cost alternative and the eradication of mosquito-borne diseases.
The effect of variations in osmotic pressure upon a free-living soil nematode

1. The osmotic pressure of the medium in which the nematodes were cultured has been shown to be equivalent to that of about 30 mM. NaCl. 2. The effects of immersion in a saline solution isotonic with the above, in glass-distilled water, and in hypertonic saline solutions, have been described. Particular attention was paid to changes in the length of the body, in the appearance and behaviour of the alimentary canal, and in the movement of the body. 3. The results obtained have been discussed, and the following tentative conclusions reached: (a) The main aqueous exchanges occur through the cuticle and protoplasm covering the periphery of the body, and are controlled by the protoplasm rather than by the cuticle. The cuticle thus does not act as aja impermeable outer covering which insulates the animal from its environment. (b) The species normally lives in an environment which is hypotonic to the body fluids, and maintains its internal osmotic pressure by means of an active method of osmotic regulation. The alimentary canal is probably partially, but not wholly, responsible for this regulation. (c) Swelling occurs in distilled water because the removal of water in the initial stages is not rapid enough to cope with the extra inflow. Later the excess water is removed. (d) In concentrated solutions, water is removed from the body, and the internal osmotic pressure may also be increased to some extent by the penetration of osmotically active substances to the body, through the cuticle and hypodermis of the body wall. Penetration through the hypodermis is slower than through the cuticle. (e) During recovery in concentrated solutions, there is a slow removal of osmotically active material from the body. The hypertrophy of the lateral and post-anal organs, which sometimes occurs under these conditions, may be connected with this removal.
Tolerance of Sphagnum to water level

AbstractFour species of Sphagnum which occur on ombrotrophic mires were grown at different levels above the water table. In one experiment the species were grown at constant water levels in a bog pool and, in another, at fluctuating water levels in a transplant experiment. A general trend was found of decreasing photosynthetic capacity with increasing height above the water table. This indicates that the hollow species (S. balticum and S. tenellum) are unable to tolerate the hummock sites, whereas the hummock species (S. fuscum and S. rubellum) could well survive the environmental conditions of the hollows but are absent because of biotic factors.
Vascular smooth muscle cell‐specific regulation of cyclin‐dependent kinase inhibitor p21WAF1/Cip1 transcription by Sp1 is mediated via distinct cis‐acting positive and negative regulatory elements in the proximal p21WAF1/Cip1 promoter

Smooth muscle cells (SMC) play a central role in common vascular pathologies such as atherosclerosis and restenosis. Understanding the molecular regulation of SMC proliferation at a transcriptional level may provide important clues for the targeted control of vascular hyperplasia. We recently reported the capacity of the transcription factor Sp1 to down‐regulate p21WAF1/Cip1 production thereby reducing p21WAF1/Cip1–cyclin D1–Cdk4 complex formation and inhibiting vascular SMC proliferation (Kavurma and Khachigian [ 2003 ] J. Biol. Chem. 278, 32537–32543). We have now localized the Sp1‐response elements in the p21WAF1/Cip1 promoter responsible for p21WAF1/Cip1 repression in WKY12‐22 SMCs. The proximal region of the p21WAF1/Cip1 promoter contains five distinct Sp1‐binding elements that we have termed A, B, C, D, and E. Electrophoretic mobility shift analysis revealed that SMC nuclear Sp1 interacts with all five Sp1‐binding sites, and each of these sites is critical for Sp1 repression of the p21WAF1/Cip1 promoter, since mutation in any one element ablates repression, and in some cases results in activation. In contrast, only elements C, D, and E are bound by Sp1 in endothelial cells. Sp1 overexpression activates the p21WAF1/Cip1 promoter in this cell type. Furthermore, mutation in any of these five elements is not sufficient to prevent activation of the p21WAF1/Cip1 promoter by Sp1 in endothelial cells. Surprisingly, double mutations of elements C and E facilitates superactivation by Sp1 in both cell types, whereas triple mutations of C, D, and E inactivate the promoter. These findings demonstrate cell type‐specific regulation of p21WAF1/Cip1 transcription by Sp1 via distinct cis‐acting positive and negative regulatory elements in the proximal p21WAF1/Cip1 promoter. © 2004 Wiley‐Liss, Inc.
Effects of Increases in Freshwater Temperature on Loss of Smolt Characteristics in Atlantic Salmon (Salmo salar)

Two-year-old (2+) Atlantic salmon (Salmo salar) raised under ambient temperature and simulated natural photoperiod (45°N) completed smolting between February and May, exhibiting significant increases in gill Na+, K+-ATPase activity and salinity tolerance (96 h, 37.5 ppt) but no significant changes in plasma osmolality. On May 2 the smolts were divided into four groups (each n = 80) and subjected to a rapid (2–3 h) increase in temperature from ambient (5 °C) to 10, 13, or 16 °C or remained ambient (control) which rose to 12 °C by the end of the experiment on June 5. In the 10, 13, and 16 °C groups, mean gill Na+, K+-ATPase activity (micromoles inorganic phosphorus per milligram protein per hour) declined significantly from 6.6 units on May 2 to 4.3, 3.6, and 2.3 units, respectively, on May 23. In the control group, Na+, K+-ATPase activity showed no significant changes during the study. Plasma osmolality was maintained in all groups between 290 and 304 mosmol∙kg−1. Salinity tolerance tests revealed a signif.
Impact of Salinity on Soil Biological Activities: A Laboratory Experiment

In a laboratory study, the impact of sodium chloride (NaCl) on soil quality was examined through the monitoring of soil biological activity. Artificially salinized samples were prepared from the nonsaline soil by adding NaCl at electrical conductivities (EC) 2, 4, and 8 dS·m−1 in saturated extracts. The samples were kept at 25 °C and at 50% field capacity during an incubation period of 40 days. The ATP, soil basal respiration, protease, amylase, alkaline phosphatase, dehydrogenase, and catalase activities were monitored. The biological index of fertility (BIF), the enzyme activity number (EAN), and the metabolic potential (MP) were calculated. A regression analysis was used to calculate parameters from cumulative data of carbon dioxide (CO2) evolution. The size of microbial biomass, measured throughout the determination of ATP, was decreased by increasing salinity. Increasing concentrations of salt up to an EC of 4 dS·m−1 led to an increase of soil respiration. During incubation, protease and dehydrogenase were inhibited by NaCl; however, amylase, alkaline phosphatase, and catalase were not affected by the salt addition. Between indices, EAN confirmed the general depressive effect of NaCl on the biological properties of soil, while MP showed a pattern similar to that of soil respiration. Results of this study chiefly indicate that ATP, soil respiration, protease, dehydrogenase, EAN, and MP were able to put in evidence the effects of NaCl on soil biological activity and may be regarded as suitable tools to show the physiological reaction of soil microbial biomass under saline stress.
Forest buffalo prefer clearings to closed-canopy forest in the primary forest of northern Congo

During 1993–2000 the conservation status of forest buffalo Syncerus caffer was investigated in the Nouabalé-Ndoki National Park region, northern Congo. Data from dung counts collected during a number of ecological reconnaissance surveys in and around the National Park showed that the preferred buffalo habitat was open canopy swamps and forest clearings associated with watercourses. Buffalo abundance was very low in terra firma forest more than 250 m from water, and signs were restricted to large elephant trails connecting watercourses and clearings. The clumped distribution of the buffalo appeared to be a result of the highly patchy distribution of their food resources. In terra firma forest preferred food species were poorly represented, whereas in open swamp and sedge clearings they were more abundant. Low overall numbers, highly patchy distribution, small group size, and low effort-high return for hunters, including sport hunters, mean that buffalo must be considered a conservation priority in this environment.