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1.
Over 1500 root-nodule bacteria were isolated from a range of uninoculated soybeans, and one cowpea, trap-hosts, sown in 1985 into traditional soybean-growing areas of soybean-growing areas of northern Thailand. Most isolates were slow-growing Bradyrhizobium japonicum. Using a modified bottle-jar technique, 586 of the isolates were tested with a range of soybean hosts and one cowpea host. The results indicated:
(a)  a very high level of infectiveness, with only one isolate failing to nodulate one host, and 95% forming \s>20 nodules per plant;
(b)  a high level of effectiveness of fixation of nitrogen by the local rhizobium populations with soybeans;
(c)  evidence of selection of effective strains by both soybean and cowpea hosts in the field;
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2.
1.  The effects of the odorant compounds adenosine-5-monophosphate (5AMP), ammonium, betaine, L-cysteine, L-glutamate, DL-succinate, and taurine and of mixtures of these comounds on binding of taurine and 5AMP to dendritic membrane from the olfactory organ of spiny lobsters (Panulirus argus) were quantified to evaluate the contribution of inhibition of odorant-receptor binding to the generation of physiological responses to mixtures.
2.  Taurine binding sites belong to two affinity classes, while 5AMP binding sites belong to a single affinity class. Binding of either taurine or 5AMP was partially inhibited in an apparently noncompetitive, concentration dependent fashion by most odorant compounds, with 25–40 % inhibition by 1 mM of odorant. Mixtures of two or more odorant compounds also inhibited binding of taurine or 5AMP to its sites. However, the inhibition by mixtures was often significantly less than expected from the inhibition produced by a mixture's components assuming either a noncompetitive or competitive mechanism.
3.  By including this binding inhibition between compounds into models for predicting physiological responses to mixtures from the responses to the components, the predictive power of the models is significantly improved. This result strongly suggests that binding inhibition can influence the physiological responsiveness of chemoreceptor cells to mixtures.
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3.
The angular distribution of the optical axes of the ommatidia in the eyes of waterstriders (Gerris lacustris) has been investigated using antidromic illumination.
1.  Each eye contains about 920 ommatidia arranged in approximately 40 nearly horizontal rows (Figs. 5, 6).
2.  There is an acute zone (visual streak) of ±5° around the eye equator with high vertical resolution (Fig. 9).
3.  The horizontal interommatidial angle oh varies little with altitude and is in the frontal parts of the eye equal to the (horizontal) interrhabdomere angle rh (Fig. 10).
4.  Above and below the visual streak the eye is adapted to the perception of relative height or depth constancy (Fig. 13).
5.  Reconstruction of the viewing directions of the rhabdomeres in the visual streak reveals that characteristic groups of rhabdomeres in different ommatidia coincide in their receptive fields. Optical prerequisites for two types of neural superposition can be found: one of medium neural summation but highest sampling frequency, the other of highest neural summation at the cost of resolution (Fig. 11).
6.  The correspondence of the limits of resolution due to diffraction and finite sampling frequency is discussed.
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4.
1.  To determine the specificity of the goldfish (Carassius auratus) olfactory system to the reproductive pheromone 17,20-dihydroxy-4-pregnen-3-one (17,20P), and to determine if related sex steroids might also function as pheromones, electro-olfactogram (EOG) responses were recorded from mature male goldfish.
2.  Of the 24 steroids tested, 17,20P was the most stimulatory. It had a detection threshold of 10–12 M and at a concentration of 10–8 M elicited an EOG response 3 times that elicited by 10–5 M L-serine
3.  17,20,21-triol-4-pregnen-3-one, a metabolite of 17,20P, was the only other highly stimulatory steroid. Its threshold was 10–11 M.
4.  In cross-adaptation experiments EOG responses to all 21-carbon steroids were inhibited during adaptation to 17,20P: responses to this pheromone are transduced by a single receptor/transduction mechanism.
5.  To verify the biological relevance of EOG recording whole animal responsiveness was determined by measuring blood gonadotropin. When goldfish were placed into homogeneous steroid solutions endocrine responsiveness strongly correlated with EOG recording. However, when steroids were added to aquaria containing fish, responses were less specific indicating that transient wisps of steroids trigger endocrine responses.
6.  Although the extreme sensitivity and specificity of the goldfish olfactory system to 17,20P gives it the potential to serve as a highly specific cue, realization of this potential is probably determined by the dynamics of pheromone exposure.
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5.
1.  The neurons of the pyloric network of the lobster (Panulirus interruptus) stomatogastric ganglion organize their rhythmic motor output using both chemical and electrical synapses. The 6 electrical synapses within this network help set the firing phases of the pyloric neurons during each rhythmic cycle. We examined the modulatory effects of the amines dopamine (DA), serotonin (5HT) and octopamine (Oct) on coupling at all the electrical synapses of the pyloric network.
2.  Electrical coupling within the pacemaker group [anterior burster (AB) to pyloric dilator (PD), and PD-
3.  Dopamine decreased or increased the coupling strength of all the pyloric electrical synapses: the sign of the effect depended upon which neuron was the target of current injection. For example, DA decreased AB PD coupling (i.e., when current was injected into the AB) but increased coupling in the other direction, PD AB. Dopamine decreased AB to VD coupling when current was injected into either neuron. Serotonin also had mixed effects; it enhanced PDAB coupling but decreased AB to VD and PD to VD coupling in both directions. Octopamine's only effect was to reduce PD VD coupling. li]4.
5.  The characteristic modulation of electrical coupling by each amine may contribute to the unique motor pattern that DA, 5HT and Oct each elicit from the pyloric motor network.
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6.
1.  Interspecific diversity in the visual pigments of stomatopod crustaceans was characterized using microspectrophotometry. We examined the 10 visual pigments in main rhabdoms in retinas of 3 species of each of two genera of stomatopod crustaceans of the superfamily Gonodactyloidea, Gonodactylus (G. oerstedii, G. aloha, and G. curacaoensis) and Odontodactylus (O. scyllarus, O. brevirostris, and O. havanensis). Species were selected to provide a matched diversity of habitats.
2.  In each genus, visual pigments varied in max in several regions of the retina, as revealed by analysis of variance. The variation within closely related species of the same genus implies that visual pigments can evolve rapidly in stomatopods.
3.  In photoreceptors of the peripheral retina, which are devoted to spatial vision, visual pigment max decreased as the depth range of the various species increased, a typical pattern for marine animals. In contrast, visual pigment max in photoreceptors of retinal regions devoted to polarization vision (midband Rows 5 and 6) is not obviously correlated with the spectral environment, implying that polarization information may be confined to particular spectral ranges. Visual pigments of the tiered rows of the midband, which are committed to spectral analysis, span a larger spectral range in shallow-water than deepwater species.
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7.
Coxal hair-plate sensilla in the spider Cupiennius salei are described with respect to their innervation, central projection pattern, electrical response to mechanical stimulation, and putative behavioral function.
1.  Hair plates, each comprising 25–70 hairs, are situated on the ventrolateral leg coxae close to the prosomal joint; during coxal movements they are deflected by the bulging joint membrane. Each plate hair is innervated by one sensory cell.
2.  Threshold sensitivity lies at 0.5° to 1° of hair deflection. Only distalward deflection excites. During maintained deflections the spike rate declines slowly. These hairs differ from hair sensilla of insects in that we measure no standing potential, nor do we measure a receptor potential accompanying a mechanical stimulus.
3.  The central projection areas of both hair plates are limited to neuropil of the ipsilateral neuromere.
4.  Natural stimulus situation and the spike response to maintained deflection suggest that these hairs are used in proprioception and graviception. Yet behavioral changes following selective hair-plate ablations are not very pronounced. Unilateral removal of hair-plates produced significant increases in average body height in 7 of 10 animals, while the angular orientation of the long body axis with respect to gravity remained unchanged after hair-plate removal.
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8.
1.  When Xenopus laevis embryos swim into an obstruction they usually stop. This stopping response to stimulation on the head is present from stage 28 to 45. At stage 37/38 it is more reliable in restrained than in free-swimming animals, and to stimuli to the cement gland than to the head skin. Fictive swimming also stops reliably after the same stimuli but struggling and fictive struggling do not.
2.  Discharge of deformation-sensitive trigeminal sensory neurons in response to pressure on the cement gland or head skin precedes the fictive stopping response. When the embryo hangs from cement gland mucus, trigeminal neurons are active and the embryo is less responsive to stimulation.
3.  Lesions of the central nervous system have allowed us to draw the following conclusions about this inhibitory pathway: (a) either the cement gland or the head skin must be intact; (b) one trigeminal ganglion is both sufficient and necessary; (c) the pathway is independent of the forebrain and midbrain; (d) it can take an ipsilateral or contralateral route through the hindbrain; (e) at least two hindbrain interneuron components are involved.
4.  A similar stopping response is present in embryos and larvae of the urodele Ambystoma mexicanum.
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9.
1.  We have investigated a physiological component of the gravitaxis of Paramecium using established mechanisms of ciliate mechanosensitivity. The horizontal, up and down swimming rates of cells, and the sedimentation of immobilized specimens were determined. Weak DC voltage gradients were applied to predetermine the Paramecium swimming direction.
2.  An observed steady swimming rate is the vector sum of active propulsion (P), a possible gravity-dependent change in swimming rate (), and rate of sedimentation (S). We approximated P from horizontal swimming. S was measured after cell immobilization.
3.  Theory predicts that the difference between the down and up swimming rates, divided by two, equals the sum of S and . is supposed to be the arithmetic mean of two subcomponents, a and p, from gravistimulation of the anterior and posterior cell ends, respectively.
4.  A negative value of (0.038 mm/s) was isolated with a(0.070 mm/s) subtracting from downward swimming, and p(0.005 mm/s) adding to upward propulsion. The data agree with one out of three possible ways of gravisensory transduction: outward deformation of the mechanically sensitive lower soma membrane. We call the response a negative gravikinesis because both a and p antagonize sedimentation.
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10.
1.  The physiology and morphology of olfactory interneurons in the brain of larval Manduca sexta were studied using intracellular recording and staining techniques. Antennal olfactory receptors were stimulated with volatile substances from plants and with pure odorants. Neurons responding to the stimuli were investigated further to reveal their response specificities, dose-response characteristics, and morphology.
2.  We found no evidence of specific labeled-lines among the odor-responsive interneurons, as none responded exclusively to one plant odor or pure odorant; most olfactory interneurons were broadly tuned in their response spectra. This finding is consistent with an across-fiber pattern of odor coding.
3.  Mechanosensory and olfactory information are integrated at early stages of central processing, appearing in the responses of some local interneurons restricted to the primary olfactory nucleus in the brain, the larval antennal center (LAC).
4.  The responses of LAC projection neurons and higher-order protocerebral interneurons to a given odor were more consistent than the responses of LAC local interneurons.
5.  The LAC appears to be functionally subdivided, as both local and projection neurons had arborizations in specific parts of the LAC, but none had dendrites throughout the LAC.
6.  The mushroom bodies and the lateral protocerebrum contain neurons that respond to olfactory stimulation.
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11.
Somatic embryos and adult plants were regenerated from mesophyll protoplasts of a clone of chicory 474 (Cichorium intybus L. x Cichorium endivia L.). Embryos were obtained in three different ways:
–  - plating of 7-day-old protoplast cultures on PM-3 solid induction medium with 2.5 M 2-isopentenyladenine (2-iP) and 0.5 M naphthaleneacetic acid (NAA);
–  - transfer of 1–2 mm microcolonies into liquid M-17 induction medium with 2.5 M (2-iP) and 0.1 M (NAA);
–  - transfer of well-established protoplast-derived calluses onto M-17.
Development of embryos was accomplished in agitated liquid Heller medium with 0.15 M gibberellic acid and germination on solid Heller medium without growth regulators. The total time for plantlet (4-leaves stage) recovery, following protoplast isolation, was 13 to 15 weeks. After acclimatization all protoplast-derived plants of Cichorium 474 were phenotypically normal and fertile.  相似文献   

12.
Comparing the properties of young and senescent (aged) O+ erythrocytes isolated by applying ultracentrifugation in a self-forming Percoll gradient, we demonstrate that the sialic acids of membrane glycoconjugates control the life span of erythrocytes and that the desialylation of glycans is responsible for the clearance of the aged erythrocytes. This capture is mediated by a -galactolectin present in the membrane of macrophages. The evidence supporting these conclusions is as follows:
(1)  Analysis by flow cytofluorimetry of the binding of fluorescein isothiocyanate labelled lectins specific for sialic acids shows that the aged erythrocytes bind less WGA, LPA, SNA and MAA than young erythrocytes. The binding of DSA and LCA is not modified. On the contrary, the number of binding sites of UEA-I specific for O antigen and of AAA decreases significantly. PNA and GNA do not bind to erythrocytes.
(2)  RCA120 as well asErythrina cristagalli andErythrina corallodendron lectins specific for terminal -galactose residues lead to unexpected and unexplained results with a decrease in the number of lectin binding sites associated with increasing desialylation.
(3)  The glycoconjugates from the old erythrocytes incorporate more sialic acid than the young cells. This observation results from the determination of the rate of transfer by -2,6-sialyltransferase of fluorescent or radioactiveN-acetylneuraminic acid, using as donors CMP-9-fluoresceinyl-NeuAc and CMP-[14C]-NeuAc, respectively.
(4)  Microscopy shows that the old erythrocytes are captured preferentially by the macrophages relative to the young ones. Fixation of erythrocytes by the macrophage membrane is inhibited by lactose, thus demonstrating the involvement of a terminal -galactose specific macrophage lectin.
(5)  Comparative study of the binding of WGA, LPA, SNA and MAA to the aged erythrocytes and to thein vitro enzymatically desialylated erythrocytes shows that the desialylation rate of aged cells is low but sufficient to lead to their capture by the macrophages
These results were presented at the Jacques Monod Conference on Glycoconjugates (La Londe-les-Maures, 25–29 April 1994) and at the International Conference Romania and Romanians in Contemporary Science (Sinaia, 24–27 May 1994).  相似文献   

13.
With the aim of clarifying the role of screening pigments in photoreceptor optics of the compound eye, a comparative study of the optical properties of the honeybee eye in the visible region of the spectrum was carried out using wild-type bees and eye colour mutantssnow, snow laranja, ivoryumberandchartreuse with total or partial blockage of the tryptophane-ommochrome pathway.
1.  The electroretinogram (ERG) of mutant eyes displayed a sharp on-peak, this component being absent from normal heterozygote eyes (Fig. 6).
2.  The ERG of newly emerged bees (a) lacked the above on-peak and showed oscillations in mutants, and (b) lacked the off-peak which always occurs in the ERG of adults in all the genotypes studied when stimulated by visible light.
3.  The resting potentials of the receptor and cone cells were not found to be affected by mutations la, and the receptor potential ins/s ands la/slaphotoreceptors appeared to be similar to that in +/+
4.  Analysis of the amplitude characteristics of the whole eye of eight genotypes showed that the relative numbers of photons absorbed from an extended light source (4.5°×16.5°) and needed to elicit a standard ERG amplitude of 1 mV were as follows:s/si u/iusla/slach1/ch1(+/+; s/+ iu/+; sla/+)=14.38.612.2(100–250). These ratios are believed to reflect the progress in ommochrome formation in these strains.
5.  Spectral sensitivity curves (SSC) were obtained using an automatic spectrosensitometer and a spectral scan method which gave accurate results. The SSC of the whole eye in+/+ peaked at a max of 543±7 nm (SD,n=6), whereas max ins/s ands la/slashifted to 528±6 nm (n=9) and 548 ±3nm (n=6) respectively. The SSC ins/+ was the same as that in+/+. The bandwidth (width at 50% of peak sensitivity) of the SSC proved to be similar in+/+ ands/+ (126±10 nm and 128±8 nm), although ins/s the SSC appeared to be significantly narrower (106±7 nm;P<0.01; fig.=" 8,=" table=" 2).=">
6.  The peak spectral sensitivity of long-wave (LW) receptors lay at 541±5 nm (SD,n=14) in+/+ and at 526±5 nm (n=13) ins/s; the spectral distributions of the peaks in these genotypes were different. The bandwidth of the SSCs of the photoreceptors were 109±11 nm in+/+ and 103±4 nm ins/s, the difference being insignificant (Fig. 8, Table 2). The SSCs ins/s fit the absorption spectrum of pigment 526 (P 526) rather well whereas those in+/+ are noticeably distorted. The same is true for the whole-eye data.
7.  A theory is advanced to account for the acceptance functions of the photoreceptors of eyes with imperfect pigmentation. Light scattering in imperfectly screened eyes was estimated using a factor which the termed we parasitic absorption coefficientp (see Theory).
8.  The acceptance functions of LW photoreceptors were measured by three methods, and the results were similar to those predicted from the theory. On this basis the coefficientp was estimated; fors/s photoreceptors it lay between 0.65 and 0.76 according to experiments with a point light source (method 1), and was as great as 2.5 according to measurements with an extended light source (method 2). The latter technique, an integral method, made it possible to detect light scattering in normal bee eye, the coefficientp reaching 0.02 (Fig. 1, Table 3).
9.  In genotypes+/+ ands la/slathe absorption spectra of screening pigments were recorded by microspectrophotometry (MSP), and greater transmission of red light than blue-green was found (Fig. 11).
10.  Taking into account the screening effect of ommochromes, it is suggested that the visual pigment of LW photoreceptors in the honeybee eye is P 526; the absorption spectrum of this is highly similar to the SSC of LW photoreceptors in thes/s eye.
11.  On the basis of our theory and experimental results, the contrast transfer function (CTF) for the white honeybee eye was estimated to be only 0.1 (for white and black patterns with the spatial wavelength sp, the acceptance angle). Thus, the absence of screening pigments from the compound eye ofsnow mutants causes the great decrease in image contrast, and this serious sensory defect may be responsible for the fact that these mutants fail to find their way home.
Dedicated to Professor H. Autrum on the occasion of his 80th birthday  相似文献   

14.
The rich deciduous woodland at Loi, Luster, Inner Sogn, 61° 20 N., was traditionally used for fodder production from both tree and field layer. After more than nearly 40 years of disuse and secondary forest succession, experimental efforts were made to restore the traditional agricultural meadow woodland. Following a detailed preliminary registration of the vegetation the following measures were taken:
1.  The understory tree layer, mainly Alnus incana was removed.
2.  The old Ulmus glabra pollards were pruned back to traditional shape, as were some tall shurbs of Corylus avellana.
3.  The field layer was mown once or twice yearly.
The main results are:
1.  The pollarded elms have developed bundles of new twigs at the pruning points and are in good condition.
2.  After an expansion of tall, nitrophilic herbs, e.g. Urtica dioica, Impatiens noli-tangere and Rubus idaeus, low and medium sized herbs and grasses have increased both in numbers, frequency and abundance. Helio- and thermophilic forest margin species are also more prominent. The moss layer has also become more dense and varied.
3.  The average number of species in permanent plots has nearly doubled.
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15.
1.  Responses of single olfactory receptor neurons to pheromones were recorded with tungsten microelectrodes on the antennae of male Helicoverpa (Heliothis) zea. Recordings were obtained from the male specific sensilla trichodea type 1.
2.  More than half (49/91 units) could be classified as olfactory receptor neurons, 35 of which were selective for pheromone components of the heliothine moths H. zea and Heliothis virescens. The majority (31/35) were most responsive to the principal component (Z)-11-hexadecenal (Z11-16AL). The other 4 were tuned to (Z)-9-tetradecenal (Z9-14AL), which is a pheromone component in the sympatric species H. virescens, and also interrupts attraction of H. zea males.
3.  The specificity and sensitivity of these neurons were similar to the corresponding neurons in H. virescens, suggesting homologous populations of neurons in the two species. No other neurons selective for other pheromone compounds were identified.
4.  Receptor neurons of both types (tuned to Z11-16AL and Z9-14AL respectively) showed variations in temporal response characteristics. Some responses showed a pronounced phasic spiking component, a rapid decay, and return to background activity after stimulation. Other responses were more prolonged, far outlasting the stimulation period. Phasic neurons also followed short, rapid stimulus pulses better than tonic neurons, suggesting that they may encode different features of an intermittent pheromone plume.
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16.
Ipsilateral retino-tecto-tectal (IRTT) units were recorded extracellularly in the rostral optic tectum of the frog (Rana esculenta). The activity of 79 superficial units (II type) was quantified in response to black disks of various sizes, moved vertically at various angular velocities and against a white background. The contrast ¦C¦ was constant during the experiments. Neuronal activity was analysed by two methods, yielding identical results:
(1)  I1 units responded transiently to moving and movement gated stationary stimuli; these units did not seem to be directionally sensitive nor responsive to changes in background illumination. Fifty-three % of units had a low spontaneous activity.
(2)  A power function relating mean firing frequency (¯R) and angular velocity (v) was established in the majority (78%) of units. The exponent and the constantk were 0.44–0.8 and 8.9–20, respectively.
(3)  The relationship between¯R and stimulus diameter (D) was best expressed by a logarithmic function. The maximum response occurred forD= 2–4. The optimal stimulus diameter was found to be independent of stimulus velocity.
(4)  When stimulated repetitively under steady conditions, I1 units showed about 10% fluctuations in mean response, which seemed to increase with stimulus diameter.
The results show that qualitatively and quantitatively, the properties of I1 units are very similar to R1–R2 (sustained) ganglion cells.  相似文献   

17.
1.  Underwater downwelling quantal irradiance spectra were measured in estuarine and coastal areas under various tidal and rainfall conditions. At midday the available spectrum near the bottom has maximal irradiance in the region of about 570 to 700 nm in the estuary, whereas in offshore coastal areas greatest irradiance occurs between 500 and 570 nm. At twilight in an estuary, maximal underwater downwelling irradiance shifts to the 490–520 nm region.
2.  The visual pigment absorption maxima of 27 species of benthic crustaceans from semi-terrestrial, estuarine and coastal areas have values ranging from 483 to 516 nm. There is no obvious shift in the max from long wavelengths in estuarine species to shorter wavelengths in coastal species. The only match between max and midday spectrum was for a continental shelf species,Geryon quinquedens.
3.  The Sensitivity Hypothesis is predicted to account for the visual sensitivity of benthic crabs from estuarine and coastal areas. To assess the match between visual spectral sensitivity and environmental spectra, photon capture effectiveness was calculated for a range of idealized visual pigment absorption functions operating in the measured environmental spectra.
4.  All crab species are poorly adapted for maximal photon capture at midday, since pigments having max longer than 540 nm function best under all daytime spectral conditions. Photon capture of visual pigments with max near 500 nm improves dramatically at twilight, particularly at lower visual pigment densities and shallow depths. However, pigments having max at wavelengths longer than those for the crabs are equally or more efficient at photon capture. Therefore the Sensitivity Hypothesis is not supported for crustaceans.
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18.
1.  The light-dependent demolition of rhabdoms induced by a protein phosphatase inhibitor, okadaic acid (OKA) in retinas of a crab (Leptograpsus variegatus) is examined to determine whether the effects of OKA merely amplify the endocytosis of normal phototransductive membrane turnover, or are distinct from it.
2.  OKA-induced demolition by dawn retinas maintained in vitro is partially blocked by either of two protein kinase C inhibitors, staurosporine and H-7. It is similarly blocked by a Ca2+-channel blocking agent, diltiazem.
3.  Large night rhabdoms illuminated at 40 lux for up to 20 min are reduced by pinocytosis which is not inhibited by either staurosporine or diltiazem, each in the absence of OKA.
4.  Pinocytosis is not blocked by a high concentration of a specific tyrosine kinase inhibitor, genistein in absence of OKA.
5.  It is inferred that (i) phosphorylations of rhabdomeral proteins drive light-dependent, OKA-induced endocytosis; (ii) phosphorylations (including that of rhodopsin) do not drive normal, light-dependent endocytosis; (iii) tyrosine phosphorylations of a notional, minor population of rhabdomeral proteins are unlikely to determine, normal, light-dependent endocytosis of phototransductive membrane; (iv) entry of Ca2+ into R1-7 photoreceptors via either light-dependent or other channels is necessary for events provoked by OKA, but irrelevant to normal light-dependent endocytosis.
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19.
1.  Action potentials of the mesothoracic tympanic organ's two receptor units (Al and A2) were recorded extracellularly. The impulse activity of both receptor units rises beyond resting activity when stimulated by airborne sound.
2.  The time course of the excitation of both receptor units appears to be phasic-tonic (Fig. 4).
3.  The influence of stimulus intensity and its time course on the excitation of both receptor units was studied (Figs. 5–8).
4.  The threshold curves of the receptor units Al and A2 for airborne sound were determined in the frequency range between 0.3 to 20 kHz. The two receptor units differ. Receptor unit Al shows a distinct threshold minimum, whereas the threshold curve of the less sensitive receptor units A2 appears more flat (Fig. 9).
5.  The threshold curves of the receptor units on the left body side differ from those on the right. The threshold minimum of unit Al left is absolutely lower than that of Al right and lies at higher frequencies (Fig. 10).
6.  As observed under the light microscope, vibrations of the organ's base and bulb differ from one side of the body to the other (Fig. 11).
7.  Removing the bulb influences the mode of oscillation of the base as well as the threshold curves of the receptor units.
8.  A hypothesis is proposed regarding the function of integumentary structures on the membrane in stimulus transformation.
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20.
Studies on the division of labour in honeybees have mainly been focused on behaviour that is performed by workers of different ages or genetic background. However, little is yet known about behavioural differenceswithin groups of honeybee workers. The aim of this paper is to establish whether queen attendance in honeybee colonies is a function of specialists among the workers within one age cohort in colonies with a natural number of partilines. Furthermore, I want to assess whether the duration of contact of individual workers with the queen is correlated with their involvement in other behaviour and, in the long term, with their differentiation into laying and non-laying workers after the colony becomes queenless.The individual involvement in queen attendance was studied by investigation of three parameters:
–  the number of separate bouts of performing the behaviour
–  the total duration of queen-worker contact
–  the constancy of the relative individual involvement.
I hardly found any indications that there is a significance differentiation for queen attendance.  相似文献   

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