首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 514 毫秒
1.
1.  Transepithelial potential differences (PDte) and acidification rates of the bath chamber were measured on isolated perfused posterior gills of the fiddler crabUca tangeri adapted to dilute seawater.
2.  The PDte decreased to almost zero when Na+ was substituted by choline or when ouabain was added to the perfusion saline in high concentrations (10 mmol·l–1). Thus, the rheogenic NaCl-transport across the gill epithelium seems to be totally Na+-dependent.
3.  When Cl– was replaced by gluconate, a bath positive PDte occurred which was insensitive to ouabain. This PDte could also be observed when, in addition to Cl– removal, Na+ was replaced by TMA+.
4.  Bath acidification under normal conditions could be abolished by ouabain, indicating that there is H+ excretion via electrically silent Na+/H+ exchange. In contrast, bath acidification under Cl–-free conditions is only partially blocked by ouabain.
5.  It is concluded that under Cl–-free conditions a rheogenic H+-pump in the apical membrane is responsible for the ouabain-insensitive bath acidification as well as for the PDte.
Parts of this study had been published earlier in abstract form  相似文献   

2.
Müller  D. G.  Frenzer  K. 《Hydrobiologia》1993,(1):37-44
Culture studies with healthy and virus-infected isolates of Ectocarpus siliculosus, Feldmannia simplex and F. irregularis gave the following results:
–  Virus particles are produced in deformed reproductive organs (sporangia or gametangia) of the hosts and are released into the surrounding seawater.
–  Their infective potential is lost after several days of storage under laboratory conditions.
–  New infections occur when gametes or spores of the host get in contact with virus particles. The virus genome enters all cells of the developing new plant via mitosis.
–  Virus expression is variable, and in many cases the viability of the host is not impaired. Infected host plants may be partly fertile and pass the infection to their daughter plants.
–  Meiosis of the host can eliminate the virus genome and generate healthy progeny.
–  The genome of the Ectocarpus virus consists of dsDNA. Meiotic segregation patterns suggest an intimate association between virus genome and host chromosomes.
–  An extra-generic host range has been demonstrated for the Ectocarpus virus.
–  Field observations suggest that virus infections in ectocarpalean algae occur on all coasts of the world, and many or all Ectocarpus and Feldmannia populations are subject to contact with virus genomes.
  相似文献   

3.
Flight metabolism of locusts has been extensively studied, but biochemical and physiological methods have led to conflicting results. For this reason the non-invasive and non-destructive method of 31P NMR spectroscopy was used to study migratory locusts, Locusta migratoria, at rest and during flight.
1.  In the flight muscle of resting locusts the ratio of phosphoarginine to ATP was the same whether determined by NMR (1.76) or biochemically, but the NMR-visible content of inorganic phosphate (Pi) was only 40% of ATP, i.e., much lower than total Pi as determined biochemically. This suggests that most of the Pi in flight muscle is not free, and hence not available as substrate or effector for cytosolic enzymes. Similarly, the free content of ADP and AMP in resting muscle was calculated to be much lower than the total content.
2.  Flight brought about a marked increase in Pi and a decrease in phosphoarginine in flight muscle although there was no change in intracellular pH.
3.  At the initiation of flight a new steady state of ATP, Pi, and phosphoarginine was rapidly established and minimal changes occurred after the first 2 s of flight.
4.  From the free contents of ATP and phosphoarginine in working flight muscle the flight-induced fractional increases in free ADP and free AMP were calculated to be 5.0-fold and 27.4-fold, respectively. As Pi, ADP, and AMP are substrates and potent effectors of enzymes, the flight-induced increase in their contents is likely to have marked effects on metabolic flux in working muscle.
5.  After short-term flight as well as prolonged flight, phosphoarginine, ATP, and Pi returned rapidly to their preflight levels, indicating that metabolic recovery from flight is rapid.
6.  The locust appears to be an appropriate model for the study of metabolic regulation in aerobic muscle during exercise.
Dedicated to Professor Dr. Ernst Zebe (University of Münster) on occasion of his 65th birthday.  相似文献   

4.
Thiolutin was found to inhibit the utilization of glucose and other growth substrates in Escherichia coli. The inhibition was detected by a sharp drop of the respiration rate after addition of the antibiotic. The actual function affected was allocated to the cytoplasmic membrane of the bacterial cells by the following evidence:
–  - spheroplasts were affected like intact cells,
–  - individual reactions of either the electron transport chain or the glycolytic pathway were not inhibited,
–  - glucose consumption in the culture stopped and the cells accumulated guanosine tetraphosphate as under starvation conditions,
–  - activation of the cell's apo-glucose dehydrogenase restored respiration via bypassing the glucose phosphotransferase system.
It was concluded that the transport of certain substrates across the membrane was inhibited.  相似文献   

5.
1.  The effect of outward and inward water flows through the membrane on outward potassium currents of dialyzedHelix pomatia neurons was studied.
2.  An outward water flow increased the peak and sustained outward potassium currents and accelerated the kinetics of their activation. An inward water flow had quite opposite effects—it decreased the peak and sustained potassium currents and delayed the kinetics of their activation.
3.  The analysis of the effect of water flow on the conductance of potassium channels showed that an outward water flow increased both the potassium conductance at a given potential (gk) and the maximum potassium conductance (g k max ). An inward water flow again had the opposite effect—it decreased the potassium conductance at given potential and the maximum potassium conductance.
4.  Neither an outward nor an inward water flow significantly affected the fraction of open potassium channels at a given potential [n (V)].
5.  These data suggest that in dialyzed neurons the changes of outward potassium current during water flow through the membrane are due mainly to the changes in single-channel conductance and the time constant of current activation.
  相似文献   

6.
Food concentration supplied during subchronic and chronic toxicity tests, is one of the most important factors that might influence the response of test organisms to toxicants. The green microalga Scenedesmus incrassatulus was used as food for the cladoceran Daphnia magna, in a chronic toxicity test with the toxicant sodium dodecyl sulphate (SDS). Test concentrations were 0.625, 1.25, and 2.5 mg l-1 of SDS, equivalent to 1/40, 1/20, and 1/10 of the average 48-h LC50 previously determined. Food concentrations were 9.5, 19, and 38 mg l-1 (dry wt.). Survival and reproduction were recorded, and the data were analyzed using a life-table approach. After 55 days, the main findings were as follows:
1.  Average clutch size decreased as food concentration increased and there was a negative interaction between the toxicant and the algal concentration.
2.  The Net Reproductive Rate (R 0) of the controls fed the lowest food concentration was approximately 10 times higher than the controls fed the highest food concentration.
3.  R 0's for the treatments with SDS fed the lowest food concentration, were 2.5 to 5 times higher than those fed the highest food concentration.
4.  Reproduction in controls and treatments with the same SDS concentrations, became similar as food level increased.
According to these results, the food concentration to be supplied in chronic toxicity tests should be accurate, as an incorrect food concentration might negatively affect the survival and reproduction of test organisms, thus masking or confounding the effects of the toxicant being examined. A concentration around 10 mg l-1 (dry wt.) of S. incrassatulus seems to be appropriate for D. magna economic toxicity tests.  相似文献   

7.
1.  A 28-kDa peptide from the brain of the tobacco hornworm,Manduca sexta, was purifiedvia HPLC. The peptide copurified with the insect neurohormone, prothoracicotropic hormone (PTTH), through two HPLC columns.
2.  Immunocyctochemistry using polyclonal antibodies against the 28-kDa peptide revealed that the peptide was produced in the same protocerebral neurons that produce PTTH. Western blot analysis demonstrated that the 28-kDa peptide and big PTTH are different molecules.
3.  A PTTHin vitro bioassay indicated that despite having chromatographic properties similar to those of big PTTH and being produced by the same neurons, the 28-kDa peptide did not have PTTH activity.
4.  Amino acid sequence analysis yielded a 27 N-terminal amino acid sequence that had no similarity with known peptides.
5.  Immunocytochemical studies revealed that the 28-kDa peptide is present as early as 30% embryonic development and is absent by adult eclosion. This is in contrast to big PTTH, which is expressed throughout theManduca life cycle.
6.  These data suggest that the 28-kDa peptide is another secretory phenotype of the lateral neurosecretory cell group III (L-NSC III) which may have functions distinct from those for big PTTH or may act synergistically with big PTTH.
  相似文献   

8.
In this report we describe the most suitable protocol for callus formation and plant regeneration for cotton. We screened 15 cotton (Gossypium hirsutum L.) genotypes for metal resistance and two of them, Nazilli M-503 (M503) Nazilli 143 (N-143) selected as Cd, Cu and Ni resistant. The cotyledonary nodes from these genotypes were the best explants for regeneration of shoots (more than 90 %) and roots (50 to 70 %). Shoot apex also gave good shoot regeneration (more than 90 %) but their root regeneration efficiency was low (35 %). These results show that Murashige and Skoog (MS) media containing 0.44 μM naphthaleneacetic acid (NAA) and 0.98 μM indole-3-butyric acid (IBA) was the most suitable recipe for getting high shoot and root regeneration from cotyledonary nodes of N-143 and M503 cotton genotypes.Abbreviations
2,4 D  2,4-dichlorophenoxyacetic acid
BAP  6-benzylaminopurine
GA  gibberellic acid
IBA  indole-3-butyric acid
MS medium  Murashige and Skoog medium
NAA  naphthaleneacetic acid
This work was supported by the Textile Industry grant No. F000301 given to A.R. Memon.  相似文献   

9.
The foraging pattern ofPolyrhachis vicina Roger, the composition of food collected, and the abundance and distribution of food sources were studied. Results showed:
1.  The food collected by workers was mostly honeydew secreted by Homoptera supplemented by small insects and plant secretions. The successful foraging rate was 35% in April, 74% in June, 91 % in August, and 83 % in October.
2.  The variety of food collected by workers increased from April to August and decreased from August to November, reflecting changes in the abundance of different food sources.
3.  The area foraged by workers increased from 112 m2 in March to a maximum of 1196 m2 in August and decreased again to 19 m2 in November. This depended on the demand for food (number and size of colonies), the time available for foraging determined by air temperature, and the abundance and distribution of food sources.
4.  Clearly, foraging for honeydew was directly related to the number of aphids at the source and inversely related to the distance from the nest to the source.
  相似文献   

10.
1.  Responses of 73 fibers to dorso-ventral vibration were recorded in the saccular and utricular branchlets of Rana pipiens pipiens using a ventral approach. The saccular branchlet contained nearly exclusively vibration-sensitive fibers (33 out of 36) with best frequencies (BFs) between 10 and 70 Hz, whereas none of the 37 fibers encountered in the utricular branchlet responded to dorso-ventral vibrations.
2.  Using a dorsal approach we recorded from the VIIIth nerve near its entry in the brainstem and analyzed responses to both sound and vibration stimuli for 65 fibers in R. pipiens pipiens and 25 fibers in Leptodactylus albilabris. The fibers were classified as amphibian papilla (AP), basilar papilla (BP), saccular or vestibular fibers based on their location in the nerve. Only AP and saccular fibers responded to vibrations. The AP-fibers responded to vibrations from 0.01 cm/s2 and to sound from 40 dB SPL by increasing their spike rate. Best frequencies (BFs) ranged from 60 to 900 Hz, and only fibers with BFs below 500 Hz responded to vibrations. The fibers had identical BF's for sound and vibration. The saccular fibers had BFs ranging from 10 to 80 Hz with 22 fibers having BFs at 40–50 Hz. The fibers responded to sound from 70 dB SPL and'to vibrations from 0.01 cm/s2.
3.  No differences in sensitivity, tuning or phase-locking were found between the two species, except that most BP-fibers in R. pipiens pipiens had BFs from 1.2 to 1.4 kHz, whereas those in L. albilabris had BFs from 2.0 to 2.2 kHz (matching the energy peak of L. albilabris' mating call).
4.  The finding that the low-frequency amphibian papilla fibers are extremely sensitive to vibrations raises questions regarding their function in the behaving animal. They may be substrate vibration receptors, respond to sound-induced vibrations or bone-conducted sound.
  相似文献   

11.
1.  The action of melatonin was investigated in a colonial anthozoan, the sea pansy Renilla koellikeri, in which rhythmic contractions underlying peristalsis were previously shown to be potentiated by serotonin (5-HT) and cAMP analogues (Anctil 1989).
2.  Melatonin (2–1000 mol·1-1) consistently and reversibly depressed the amplitude of rhythmic contractions, the latter all but vanishing at the most effective concentration (10 mol·1-1). In addition, the frequency of rhythmic contractions incurred a 25% reduction in some preparations exposed to melatonin (10–20 mol·1-1). Vaseline gap experiments showed that this response was restricted to tissues directly exposed to melatonin.
3.  The potentiating effect of 5-HT on rhythmic contractions was eliminated in a reversible manner in the presence of melatonin. The latter also caused a 50% reduction of the amplitude of contractions elicited by field electrical stimulation.
4.  Dibutyryl or 8-bromo cGMP, as well as the phosphodiesterase inhibitor IBMX, mimicked the melatonin-induced response and the effects of melatonin on the 5-HT potentiation or contractile response to electrical stimulation. cGMP levels, measured by radio-immunoassay (RIA) in rachidial tissues, increased 3-fold above basal levels in the presence of melatonin (0.01 mmol·1-1) and 2-fold with IBMX (1 mmol·1-1). In contrast, RIA measurements of cAMP levels showed the latter to fall to 50 and 40% of control values in the presence of melatonin (0.01 mmol·1-1) and IBMX (0.1 mmol·1-1), respectively. These results and other findings suggest that a cGMP-mediated melatonergic mechanism participates in an antagonistic fashion with 5-HT in the modulation of rhythmic contractions and peristalsis of the sea pansy.
  相似文献   

12.
1.  The effects of three barbiturates and the local anesthetic procaine on the ion channel function of mouse nicotinic acetylcholine receptor (nAChR) muscle subtype expressed inXenopus laevis oocytes were examined by whole-cell voltage-clamp technique.
2.  A concentration-response curve for the specific nicotinic agonist dimethylphenylpiperazinium iodide (DMPP) was first determined. This agonist produced increasing whole-cell currents up to a concentration of 100µM (EC50 = 13µM), then decreased responses at higher concentrations.
3.  The barbiturates (amobarbital, secobarbital, pentobarbital) and procaine produced reversible inhibition of DMPP-induced currents at clinically used concentrations. The two classes of drugs differed in the voltage dependence of the inhibition: procaine-induced inhibition was increased at more negative transmembrane holding potentials (-90 vs. -45 mV); whereas amobarbital-induced inhibition did not vary at different transmembrane potentials.
4.  Mutant forms of the nAChR, containing single amino acid changes in the M2 regions of and subunits, showed increased sensitivity to procaine but no change in sensitivity to amobarbital-induced inhibition.
5.  These electrophysiologic studies provide further evidence that barbiturates and local anesthetics produce inhibition of the nAChR at different sites.
  相似文献   

13.
Methyl jasmonate (JA-Me) promoted leaf abscission of succulent plant, Crassula lycopodioides, and exudation from stems and leaves after leaf abscission when it was sprayed in whole plants. Major component of the exudate was identified as sucrose based on the results described below.
(1)  The reaction of the excudate was not positive in the Somogyi-Nelson method but in the phenol-sulfuric acid method.
(2)  The exudate was hydrolyzed with invertase of Candida utilis, after that showing a positive reaction in the Somogyi-Nelson method.
(3)  Only glucose and mannose were identified in the exudate after hydrolysis with trifluoroacetic acid using a gas-liquid chromatograph (GLC).
(4)  A single peak corresponding to the retention time of sucrose was observed using a high performance liquid chromatograph (HPLC).
In addition, potassium and sodium were found in the exudate as major inorganic cations. These results suggest that exudate of Crassula lycopodioides is phloem sap, and JA-Me promotes the excudation due to the inhibition of the synthesis of callose in sieve tubes of succulent plants.  相似文献   

14.
Glycolytic intermediates and related metabolites were measured in the fat body of the American cockroach (Periplaneta americana) to locate the rate-limiting reactions that regulate glycolysis during the action of the corpus cardiacum (CC) in vitro.
1.  The concentrations of glucose 1-phosphate, fructose 6-phosphate, and fructose 1,6-bisphosphate were approximately doubled after 30 min treatment with CC extract, whereas that of glucose 6-phosphate increased more than four-fold. Slightly lower increases occurred after 10 and 60 min treatment.
2.  Triose phosphates, 2-phosphoglyceric acid, phosphoenolpyruvate and pyruvate were unaffected by CC extract.
3.  Glycerol 3-phosphate, which is 20\2-200 times more concentrated than any of the other measured metabolites in the unstimulated tissue, is increased more than two-fold by CC extract.
4.  NAD, NADP, and ATP were not significantly affected by CC extract. ADP was increased significantly by the gland extract.
  相似文献   

15.
The basic idea of the source simulation technique is to replace the scatterer (or radiator by a system of simple sources located within the envelope of the original body. The extent to which the simulated field reproduces the original field depends on the degree of correspondence between the simulated and the given boundary conditions. Numerical simulations have shown that: (1) the shape of the auxiliary surface, (2) the number of sources, and (3) the way the sources are distributed are the most relevant parameters to ensure an accurate solution for the problem. In the case of the single-layer method, sources should not be positioned close to the center of the body, because the problem becomes ill-conditioned. The auxiliary surface and the scatterer should be as similar as possible in order to minimize the boundary error. With respect to the number of sources (N), there are two opposite effects: (1) if (N) is too small, the sound field is not reproduced accurately; (2) if (N) is too large, computing time increases and solution accuracy decreases. The method beaks down when excitation frequency coincides with the eigenfrequencies — a narrow range of frequencies — of the space formed by the auxiliary surface. As the auxiliary surface is frequently represented by simple surfaces (cylinder, sphere), one can easily calculate the eigenfrequencies and therefore avoid them.
PDF (545 K)
View More Related Articles
View Record in Scopus
doi:10.1078/1439-1791-00125
Copyright © 2003 Urban & Fischer Verlag Published by Elsevier GmbH
Pre-dispersal seed predation and seed limitation in an annual legume
Arpád Szentesia, , and Tibor Jermya
aZoology Department, Plant Protection Institute, Hungarian Academy of Sciences, Budapest, Hungary  相似文献   

16.
Olfactory interneurons in the brain of the larval sphinx moth Manduca sexta     
Dr. H. Itagaki  J. G. Hildebrand 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,167(3):309-320
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.
  相似文献   

17.
Structural aspects of the cytochromeb 6 f complex; structure of the lumen-side domain of cytochromef     
W. A. Cramer  S. E. Martinez  D. Huang  G. -S. Tae  R. M. Everly  J. B. Heymann  R. H. Cheng  T. S. Baker  J. L. Smith 《Journal of bioenergetics and biomembranes》1994,26(1):31-47
The following findings concerning the structure of the cytochromeb 6 f complex and its component polypeptides, cytb 6, subunit IV and cytochromef subunit are discussed:
(1)  Comparison of the amino acid sequences of 13 and 16 cytochromeb 6 and subunit IV polypeptides, respectively, led to (a) reconsideration of the helix lengths and probable interface regions, (b) identification of two likely surface-seeking helices in cytb 6 and one in SU IV, and (c) documentation of a high degree of sequence invariance compared to the mitochondrial cytochrome. The extent of identity is particularly high (88% for conserved and pseudoconserved residues) in the segments of cytb 6 predicted to be extrinsic on then-side of the membrane.
(2)  The intramembrane attractive forces betweentrans-membrane helices that normally stabilize the packing of integral membrane proteins are relatively weak.
(3)  The complex isolated in dimeric form has been visualized, along with isolated monomer, by electron microscopy. The isolated dimer is much more active than the monomer, is the major form of the complex isolated and purified from chloroplasts, and is inferred to be a functional form in the membrane.
(4)  The isolated cytb 6 f complex contains one molecule of chlorophylla.
(5)  The structure of the 252 residue lumen-side domain of cytochromef isolated from turnip chloroplasts has been solved by X-ray diffraction analysis to a resolution of 2.3 Å.
  相似文献   

18.
Light-evoked walking in crayfish: Behavioral and neuronal responses triggered by the caudal photoreceptor     
Ted W. Simon  Donald H. Edwards 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,166(6):745-755
The caudal photoreceptors (CPRs) of crayfish (Procambarus clarkii) can trigger walking and abdominal movements by their response to light.
1.  In a restrained, inverted crayfish, illumination of A6 evoked a CPR discharge followed by leg movements and bursting from the abdominal tonic flexor (TF) motoneurons. Intracellular electrical stimulation of a single CPR at high frequency (80 Hz) evoked similar responses.
2.  Responses only occurred when a single CPR axon was driven at 60 Hz or more and outlasted the stimulus.
3.  CPR stimulation also excites the pattern-initiating network (Moore and Larimer 1987) in the abdomen.
4.  The axon of the CPR projects from ganglion A6 to the brain. Terminal branches occur in the subesophageal ganglion and the brain. A small descending interneuron is dye-coupled to CPR in the subesophageal ganglion.
5.  In animals with cut circumesophageal connectives, the CPRs can evoke walking and the abdominal motor pattern.
6.  The relationship of the abdominal motor pattern to walking is altered by restraint and/or inversion. In freely moving crayfish, the cyclic abdominal motor pattern is only observed with backward walking. In restrained, inverted crayfish, the motor pattern occurs with both forward or backward walking.
  相似文献   

19.
Innervation of buccal muscles by multifunctional MA1 neurons in Aplysia kurodai     
Tatsumi Nagahama  Mitsuru Takata 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,167(1):1-10
1.  Spikes in Aplysia MA1 neurons produced excitatory (EJPs), inhibitory (IJPs), and diphasic inhibitory-excitatory junction potentials in different fibers of the buccal muscles.
2.  The IJPs following the MA1 spikes were recorded in the muscle fibers innervated by the jaw-closing motoneurons. The depolarization of muscle fibers produced by the motoneurons was largely suppressed by simultaneous MA1 firing, suggesting that the MA1 neurons make a direct connection to a part of the muscle fibers innervated by these motoneurons and inhibit them.
3.  The excitatory and inhibitory components of the junction potentials produced by MA1 were reversibly blocked by hexamethonium and d-tubocurarine, respectively. In contrast, the EJPs produced by the jaw-closing motoneurons were blocked by an amino acid antagonist, suggesting that the MA1 neurons and the jaw-closing motoneurons use different transmitters in the nerve-muscle junctions.
4.  The jaw movement produced by the jaw-closing motoneurons was suppressed by simultaneous MA1 firing, and the suppression was released by d-tubocurarine, suggesting that the IJPs produced by MA1 may contribute to the suppression of jaw movement. The firing of MA1 produced the vertical movement of the buccal muscles, which was blocked by hexamethonium, suggesting that the EJPs produced by MA1 may contribute to the vertical movement.
  相似文献   

20.
Vegetation dynamics of grazing succession in the Stipa baicalensis steppe in Northeastern China     
Wang Yusheng 《Plant Ecology》1992,98(1):83-95
(1)  The influence of sheep grazing of moderate grazing (MG), heavy grazing (HG), inordinate grazing (IG), over grazing (OG), and extinct grazing (EG) on vegetation succession was studied in the Stipa baicalensis steppe during 1984–1986.
(2)  The relationships between the relative sum of dominance ratio (RSDR) and the degree of succession (DS) at all stages of grazing succession in the Stipa baicalensis steppe were revealed in terms of the method of mathematical analysis under five grazing intensities mentioned above.
(3)  The dynamic models of grazing succession that are based on accurate grazing intensities in relation to succession courses were constructed using RSDR5, and DS. The models may explain the rules of grazing succession in the Stipa baicalensis steppe.
  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号