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1.
A new lichen, Waynea hirsuta is described from the Tunkinsky range, Lake Bajkal region, Central Siberia. It has a squamulose, sorediate thallus, (0-) 1 (-3) septate spores, labriform soralia, and positive reactions to K and to N of epithecium, excipulum and upper cortex. The thalline squamules have a dense cover of hyaline hairs. The material was collected on the bark of old Populus balsamifera trees in a close stand of Pinus sibirica. The affinities with the other three species of the genus, and with some Hypocenomyce species are discussed. 相似文献
2.
On the basis of multi-year data, the intrapopulation and individual variability of nesting terms, number of eggs, oomorphological parameters, and success of reproduction are analyzed for great and azure tits in the Baraba forest-steppe near Chany Lake. The reproductive parameters of both tit species are characterized by a strong seasonal and yearly variability. The species differ in nesting terms, fertility, and reproductive features. The obtained data are compared with the literature data for other parts of their geographic ranges. 相似文献
3.
1. 1.Thermal parameter of the four Gerbillurus species measured in the laboratory were examined in relation to their micro-environments in a xeric habitat. 2. 2.Basal metabolic rates (BMR) were lower than predicted, while thermoneutral zonds (TNZ) were narrow and exceeded burrow temperatures. 3. 3.Body temperatures (Tb) were regulated over a range of ambient temperatures (Ta). Evaporative water loss was used as a short-term cooling mechanism to reduce hyperthermia above the TNZ. 4. 4.Conductance was low below the TNZ to reduce heat loss. 5. 5.Adaptation to low temperatures is important for gerbils when active at night. 6. 6.The adaptive significance of the thermal biology of Gerbillurus is discussed in relation to phylogeny, distribution, food availability and nocturnal activity. Author Keywords: Gerbillurus; thermal preferences; temperature regulation; oxygen consumption; conductance; evaporative water loss; behavioural avoidance 相似文献
4.
The effectiveness of geographical isolation, ecological isolation, temporal isolation, mechanical isolation, ethological isolation, cross-incompatibility, hybrid inviability, hybrid sterility and hybrid breakdown as practical barriers to gene flow in the field between Conospermum taxifolium, C. ericifolium, C. ellipticum and C. longifolium has been quantified. The barriers to gene flow between C. ericifolium and C. ellipticum are completely effective, owing to their allopatric distributions. The barriers to gene flow between C. taxifolium and these two species are only partially effective, as their ecological separation breaks down in intermediate habitats, and partially-fertile F 1 plants can grow in the areas of overlap. The barriers to gene flow between C. longifolium and the other three species are almost completely effective, as cross-incompatibility is very high and the F 1 plants are female-sterile. 相似文献
5.
* The carbon costs of reproduction were examined in four subalpine herbaceous plant species for which number and size of flowers respond differently under a long-term infrared warming experiment. * Instantaneous measurements of gas exchange and an integrative model were used to calculate whole-plant carbon budgets and reproductive effort (RE). * Of the two species for which flowering was reduced, only one (Delphinium nuttallianum) exhibited higher RE under warming. The other species (Erythronium grandiflorum) flowers earlier when freezing events under warming treatment could have damaged floral buds. Of the two species for which flowering rates were not reduced, one (Helianthella quinquenervis) had higher RE, while RE was unaffected for the other (Erigeron speciosus). Each of these different responses was the result of a different combination of changes in organ size and physiological rates in each of the species. * Results show that the magnitude and direction of responses to warming differ greatly among species. Such results demonstrate the importance of examining multiple species to understand the complex interactions among physiological and reproductive responses to climate change. 相似文献
8.
Rare plant species of Central Siberia, included in the regional Red Lists, are considered in the context of their population
strategies. The potential possibilities and positions of species populations have been analyzed. The functional approach to
the evaluation of rare plants behavior is proposed. The functional typology of rare plants and specific features of their
behavior is recommended to be used for the development of measures for their protection. 相似文献
9.
Breeding soundness evaluation (BSE) of stallions is a routine component of stud farm practice. Guidelines for assessing satisfactory breeding potential have been developed using data derived from stallions of full-size breeds. In view of the increasing popularity of miniature stallions, knowledge of normal semen parameters of these stallions is important. Therefore, testicular measurements and semen parameters from 216 sexually rested miniature stallions were obtained. Semen was collected twice, 1.5 to 3 h apart, using an artificial vagina. Values were averaged over the 2 collections because of the sexual inexperience of the stallions. The smaller stallions (Group A, 72 to 86 cm; Group B, 87 to 96 cm) had smaller testicles (P<0.05), and Group A stallions had the lowest ejaculate volume (P<0.05) compared with Group C (97 to 104 cm) stallions. Thus, although there was no difference in the concentration of spermatozoa per milliliter between groups of stallions, Group A stallions had fewer total spermatozoa in their ejaculate than Group C stallions (4.31+/-0.47x10(9) vs. 5.41+/-0.30x10(9), P<0.05). Moreover, miniature stallions had smaller testicles and fewer total spermatozoa in their ejaculate than is commonly accepted as normal in full-size stallions. Average total scrotal width of miniature stallions was found to be 7.13, 7.38 and 7.95 cm for Groups A, B and C, respectively. The average total number of spermatozoa in the ejaculates of miniature stallions in this study was 4.94+/-0.22x10(9) cells, with 1.75+/-0.09x10(9) total normal, motile spermatozoa. When only stallions <96.5 cm in height were considered (conforming to requirements of the American Miniature Horse Association Registry), the average total number of spermatozoa in the ejaculates was 4.59+/-0.30x10(9) cells, with 1.70+/-0.11x 10(9) total normal, motile spermatozoa. Based on these findings, different criteria should be used to evaluate the potential breeding soundness of miniature stallions than are commonly applied to full-size stallions. 相似文献
10.
Waterlogging tolerance of four Brassica species, Brassica campestris L., B. carinata A. Br., B. juncea (L.) Czern and Coss., and B. napus L. was assessed after 4 weeks growth in greenhouse at two waterlogging treatments, unflooded control soil, and fully waterlogged soil.Shoot fresh and dry biomass, in both mean and relative terms, was highest in B. juncea and lowest in B. napus at waterlogging treatment. B. carinata was as good as B. juncea in mean shoot fresh and dry matter but it had almost same relative shoot fresh matter as that in B. campestris, but was second highest in relative shoot dry weight.Waterlogging treatment caused a marked reduction in chlorophyll content in all four species but the species difference was not evident. However, B. juncea and B. napus had lower relative total chlorophyll than the other species.A marked increase in soluble protein content of B. juncea and a significant increase in total amino acids in B. carinata was observed under waterlogged conditions as compared to the other species.At the waterlogging regime, an increase in iron content in both shoots and roots was observed in all four species. B. juncea accumulated lower amount of iron in both shoots and roots as compared to the other species, whereas B. carinata had also lower iron in the roots. The species did not differ for shoot manganese content but B. carinata had significantly higher manganese in the roots as compared to the other species. 相似文献
11.
The Brazilian Atlantic Forest has experienced a reduction in its original area since the discovery of Brazil. Over the last 30 years, studies and techniques for forest recovery have advanced. Establishing a self-sustainable reforested area with adequate biodiversity is the main parameter for any reforestation program. Thus, knowledge of the ecophysiological behavior of the species to be used is crucial. Our hypothesis is that certain tools are efficient in determining the ecophysiological characterization of native species within different functional groups. Filling group plants show fast growth, intense gas exchange, present mechanisms of water deficit tolerance and show high efficiency in radiation capture, so they are first planted in a reforestation area. While plants pertaining to the diversity group do not exhibit these characteristics, thus are plants after the establishment of the first group of species. To test this hypothesis, two experiments were installed using young plants of four species native to the Atlantic Forest, grown in 9-L pots. Leaf water potential, gas exchange, chlorophyll fluorescence and certain biochemical parameters of leaf metabolism were evaluated. In the first experiment, plants were maintained under two forms of light availability for 15 days, full light (control) and shaded (shade). The species Inga sp. and Brosimum guianensis presented the most contrasting responses on day 15, principally in the variables leaf water potential, gas exchange, leaf soluble sugar content, Ftextv¢ / Ftextm¢ F_{text{v}}^{prime } /F_{text{m}}^{prime } and F v/ F m. In the second experiment, plants were divided into two groups: a well-hydrated group (control) and one that underwent irrigation suspension for 7 days (drought); measurements were performed on day 8 of drought. Again, Inga sp. and Brosimum guianensis plants showed responses characterizing them as pertaining to distinct functional groups for the experimental parameters previously described. Thus, Inga sp. was classified as pertaining to the filling group and B. guianensis to the diversity group. The performance of the species Cinnamomum zeylancium and Tapirira guianensis under the conditions studied suggests that these are intermediate species with potential for use as filling group species. 相似文献
12.
During the last 40 years, few species of African birds have undergone more taxonomic revision than the olive thrush Turdus olivaceus. This is due to disagreement on how to partition the striking phenotypic variation among allopatric populations. The current consensus is to recognise one species T. olivaceus , split into three assemblages: (1) the olivaceus group restricted to southern Africa, (2) the swynnertoni group of the Zimbabwean and southern Malawi highlands, and (3) the abyssinicus group of the montane highlands of eastern and central Africa. Mitochondrial DNA sequences from 63 individuals were analysed to investigate the phylogenetic relationships among 16 taxa (species and subspecies) in the olivaceus species complex (plus seven outgroup species), with, particular emphasis on the relationships and taxonomic status of the endangered Taita thrush ( helleri ). Phylogenetic hypotheses generated using parsimony, maximum likelihood, and Bayesian inference identified a number of discrete clades corresponding to recognised subspecies. Northern ( abyssinicus clade) and southern populations ( olivaceus + swynnertoni clade) of olive thrush differ by 9–10% in sequence divergence. Furthermore, all analytical methods suggested that helleri (Taita Hills) and roehli (Usambara and Pare Mountains) are reciprocally monophyletic with respect to mtDNA, and 2.5 to 10.5% divergent from all other forms of olive thrush. Both helleri and roehli are surrounded in adjacent highlands by populations of olive thrush that represent a more recent radiation, suggesting that helleri and roehli may be relict taxa which have been able to maintain their genetic integrity. The results of this study support previous arguments for recognizing the arid/woodland T. smithi as a species distinct from other southern African forest populations of T. olivaceus (including the swynnertoni group). Results further suggest that T. abyssinicus , T. helleri , and T. roehli be accorded species rank. 相似文献
13.
The pools of nitrogen in different blocks of forest ecosystems and its cycle in the soil are considered. It is shown that the bulk of nitrogen concentrates in the soil and dead organic matter (necromass) of an ecosystem. The nitrogen pool of forest litters and soils consists by 83–93% of the inert compounds that cannot be involved in the biological cycle. Mineralization of organic nitrogen-containing substances in the litters and soils usually yields ammonium as an end product. The amount of nitrogen mineralized over the growing season is partially expended for annual plant increment (30–65%) and immobilization (12–17%), with its large proportion being found in the soil. 相似文献
14.
The reproduction and stature of the red algae Callophyllis cristata (C. Ag.) Kuetz., Membranoptera alata (Huds.) Stackh., Phycodrys rubens (Huds.) Batt., and Ptilota serrata Kuetz. were recorded from subtidal populations at Appledore Island, Maine, U.S.A., with respect to time and depth. Only Membranoptera alata exhibited a conspicuous seasonal fluctuation of reproduction. A vertical gradient of reproduction was evident, with reduced levels of reproduction in shallow populations of Phycodrys rubens and Ptilota serrata, as well as deep populations of Phycodrys rubens, Membranoptera alata and Callophyllis cristata. Differential stratification of the reproductive phases of Ptilota serrata occurred with higher frequencies of tetrasporic plants in deep populations and of cystocarpic plants in shallow populations. In contrast, the haploid and diploid plants of the other three species showed similar distributional patterns. Membranoptera alata, Phycodrys rubens, and Callophyllis cristata showed a conspicuous decrease in stature during maximum reproduction. 相似文献
15.
Four new species of blackflies (Diptera: Simuliidae) are described. Helodon rezidentsii Yankovsky, sp. n., Khabarovsk Territory, differs from all known species of the genus with morphology of eyes consisting only of microommatidii in male; from related species H. kamtshaticus (Rubzov, 1940) with large triangular posteromedial lobes of branches of genital fork in female; with number of rays of primary fan of premandibles (20-22, when in H. kamtshaticus 30-32) in larva. Helodon submulticaulis Yankovsky, sp. n., Transbaikalia, differs from related species H. multicaulis (Popov, 1968) with number of rays of primary fan of mandibles (36-40, when in H. multicaulis 26-28), narrow anterior branches of anal sclerite, number of rows of hooks in posterior attachment organ (88-92, when in H. multicaulis 78-80) in larva; with morphology of respiratory organ, consisting of 5-8 lobes bearing 40-60 tune filaments (in H. multicaulis 3-4 lobes bearing more than 150 filaments) in pupa. Sch. samarkandica Yankovsky, sp. n., Uzbekistan, differs from related species Sch. pseudopusilla Rubzov, 1956 with 3 (not 2 as in Sch. pseudopusilla) hooks in parameres, bifurcated lateral branches of X sternite, long projection of gonostyles in male. Schoenbaueria ivdelensis Yankovsky, sp. n., Middle Ural, differs from related species Sch. rangiferina (Rubzov, 1956) with prolonged gonostyles bearing narrow projection in male; with number of rays of secondary fan of premandibles (20-28, when in Sch. rangiferina 44-48), deep ventral groove of cephalic capsule, number of rows of hooks in posterior attachment organ (80-82, when in Sch. rangiferina 70-72) in larva; with morphology of respiratory organ (very long stems of 2 and 3 pairs of filaments) in pupa. 相似文献
16.
The assessments of the carbon pool and rate of plant biomass production, phytodetritus destruction, new formations of humic
matters, and removal of water-soluble decomposition products for the forest ecosystems of the forest tundra and the northern
and southern parts of the Central Siberian taiga were given. The rates of the main processes (organic-matter production and
degradation) were demonstrated to be balanced in the ecosystems of the forest tundra. The larch forests of the northern taiga
serve as a stock for a C atmosphere, which are equivalent to 32–34% of net primary production (NPP). The secondary birch growth
where the understory needle-leaved trees have been formed and the primary old-growth fir forests are characterized by the
balance of the main carbon fluxes in the southern taiga. The birch forests where the understory trees are just being formed
and the fir forests at the age of 50–90 years serve as a stock for an average of 26% of carbon extracted as dioxide to make
NPP. 相似文献
17.
Although sexual interactions between species (reproductive interference) have been reported from a wide range of animal taxa, their potential for determining species coexistence is often disregarded. Here, we review evidence from laboratory and field studies illustrating that heterospecific sexual interactions are frequently associated with fitness loss and can have severe ecological and evolutionary consequences. We define reproductive interference as any kind of interspecific interaction during the process of mate acquisition that adversely affects the fitness of at least one of the species involved and that is caused by incomplete species recognition. We distinguish seven types of reproductive interference: signal jamming, heterospecific rivalry, misdirected courtship, heterospecific mating attempts, erroneous female choice, heterospecific mating, and hybridization. We then discuss the sex-specific costs of these types and highlight two typical features of reproductive interference: density-dependence and asymmetry. Similar to competition, reproductive interference can lead to displacement of one species (sexual exclusion), spatial, temporal, or habitat segregation, changes in life history parameters, and reproductive character displacement. In many cases, patterns of coexistence might be shaped by reproductive interference rather than by resource competition, as the presence of a few heterospecifics might substantially decrease reproductive success. Therefore, interspecific sexual interactions should receive more attention in ecological research. Reproductive interference has mainly been discussed in the context of invasive species or hybrid zones, whereas its influence on naturally-occurring sympatric species pairs has rarely been addressed. To improve our knowledge of the ecological significance of reproductive interference, findings from laboratory experiments should be validated in the field. Future studies should also focus on ecological mechanisms, such as temporal spatial, or habitat partitioning, that might enable sexually interacting species to coexist. Reproductive interference also has implications for the management of endangered species, which can be threatened by sexual interactions with invasive or common species. Studies of reproductive interference might even provide new insights for biological pest control. 相似文献
18.
A comparative study was carried out on the seasonal variation in egg and body volumes of four species of rotifers, Brachionus calyciflorus, Brachionus angularis, Keratella quadrata and Anuraeopsis fissa, from ponds near Sevilla and in Doñana National Park. Temperature and food concentration significantly affected egg volume in all four species; clutch size significantly affected egg volume in A. fissa, B. calyciflorus and B. angularis, but not in K. quadrata. As temperature increased, egg and body volumes declined in A. fissa and B. angularis but increased in K. quadrata and B. calyciflorus due, perhaps, to complex interactions between temperature, food level and clutch size.All four rotifer species responded similarly to changes in food concentration: below a certain food level, egg and body volumes were small but increased to a maximal size, which differed in the four species, as the food concentration was raised. At higher food levels, there was a reduction in egg and body volumes. The food levels for maximum egg and body volumes are interpreted as optimal ones; below these, food limitation reduces the size of the reproducing adult and, consequently, the size of eggs. Above this optimal level, higher food levels accelerated the rotifer life cycles, resulting in adults maturing at smaller sizes with a larger number of smaller eggs. 相似文献
19.
Paramecium strains collected in Central Russia, Western Siberia (the West Siberian Lowland and the Altai Mountains in the south) were studied. The presence of P. caudatum, P. bursaria, P. multimicronucleatum, P. polycaryum, and four species of the P. aurelia complex, i.e. P. primaurelia (in Omsk), P. biaurelia (in Krasnoyarsk and the Altai Mountains), P. triaurelia (in Krasnoyarsk), and P. pentaurelia (in Novosibirsk, Altai Foreland, and Altai Mountains) was revealed. P. triaurelia and P. pentaurelia were found for the first time in Asia. 相似文献
20.
This paper reports reproductive parameters for 9 female grey-cheeked mangabeys kept in a captive colony over a 17-year period. Birth seasonality has shown a consistent trend towards an autumn peak. Oestrous cycles had an average length of 31.2 days: however 'short-cycle' (29.9 days) and 'long-cycle' (37.7 days) groups could be discriminated. Gestation was 175 days, with little variability. Variability in interbirth interval is mainly due to varying length of the cycling phase preceding the next gestation, suggesting influences of social factors. All these reproductive parameters are compared to those of baboons and macaques. Some conclusions about mangabey breeding colony management are drawn. 相似文献
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