大白菜萝卜细胞质雄性不育系RC7的选育及其特性研究

利用甘蓝型油菜萝卜细胞质雄性不育材料RC97-1为不育源,采用种间杂交,将RC97-1的不育性导入大白菜,再通过连续回交转育和严格经济性状选择育成新的大白菜胞质雄性不育系RC7.RC7表现为:蜜腺正常,雌蕊功能健全,能吸引蜜蜂等昆虫正常采蜜传粉;在不同的生态区和播期条件下不育性稳定,不育株率和不育度均达100%,且自然结实性良好,配合力高;高抗霜霉病,抗病毒病和黑斑病;生长整齐,叶色正常,生育期85 d,株高58.6 cm,株幅45.3 cm,叶球纵径和横径分别为48.5和16.3 cm,球形指数2.98,单球质量3.6 kg左右.RC7的一代杂种金秋70和金秋90抗病性强,适应性广,优质、丰产、稳产.因此,RC7是优良的大白菜萝卜细胞质雄性不育系,具有较高的利用价值.     

Systematics of Crumomyia Macquart and Alloborborus Duda (Diptera: Sphaeroceridae)

ABSTRACT. The phylogenetic relationships of two sphaerocerid genera, Alloborborus Duda (1923) and Crumomyia Macquart (1835), are analysed, and their taxonomic status within the tribe Copromyzini (= Copromyza Fallén s.lat.) is clarified. Accepted here are a monotypic Alloborborus , which includes A.pallifrons (FalléAn) from northern and central Europe, and twenty-six species of the Holarctic Crumomyia. Within Crumomyia , five species-groups are recognized: pedestris group: pedestris (Meigen); annulus group: immensa (Spuler), maculipennis (Spuler), annulus (Walker), nipponica (Richards), pruinosa (Richards); notabilis group: glabifrons (Meigen), glacialis (Meigen), absoloni (Bezzi), notabilis (Collin), rohaceki sp.n., zuskai (Roháček); nitida group: nitida (Meigen); setitibialis group: setitibialis (Spuler), pilosa sp.n., nigra (Meigen), parentela (Séguy), deemingi (Hackman), pollinodorsata (Papp), subaptera (Malloch), gelida (Hackman), fimetaria (Meigen), roserii (Rondani); unplaced species: hentscheli (Duda), hungarica (Duda), promethei (Nartshuk). Apterina Macquart, Fungobia Lioy and Speomyia Bezzi are synonymized with Crumomyia , and the following nominal species are synonymized: tuxeni Collin with nigra, freyi Hackman with setitibialis , and annulipes Duda with annulus. C. pruinosa is considered distinct from annulus, and Copromyza subaptera is placed in Crumomyia. The identity of C.glacialis , the type species of Crumomyia , is clarified, and lectotypes are designated for five nominal species: rufoannulata Duda, annulipes, annulus, flavipennis Haliday and pallifrons. The cladistic relationships of the species of Crumomyia and Alloborborus are established and their phylogeny and biogeography are discussed. Keys to the species of Crumomyia and to the Holarctic genera of the Copromyzinae are provided.     

Neural coding in antennal olfactory cells of tsetse flies (Glossina spp.)

Spike trains from individual antennal olfactory cells of tsetse flies (Glossina spp.) obtained during steady-state conditions (spontaneous as well as during stimulation with 1-octen-3-ol) and dynamic stimulation with repetitive pulses of 1-octen-3-ol were investigated by studying the spike frequency and the temporal structure of the trains. In general, stimulation changes the intensity of the spike activity but leaves the underlying stochastic structure unaffected. This structure turns out to be a renewal process. The only independently varying parameter in this process is the mean interspike interval length, suggesting that olfactory cells of tsetse flies may transmit information via a frequency coding. In spike records with high firing rates, however, the stationary records had significant negative first- order serial correlation coefficients and were non-renewal. Some cells in this study were capable of precisely encoding the onset of the odour pulses at frequencies up to at least 3 Hz. Cells with a rapid return to pre-stimulus activity at the end of stimulation responded more adequately to pulsed stimuli than cells with a long increased spike frequency. While short-firing cells process information via a frequency code, long-firing cells responded with two distinctive phases: a phasic, non-renewal response and a tonic, renewal response which may function as a memory of previous stimulations.      

Why does the hoverfly Metasyrphus corollae migrate?

Abstract. 1. Migration pattern and mass appearance of the hoverfly Metasyrphus corollae (F.) (Diptera, Syrphidae) were investigated on the SE coast of Sweden in 1981. In total, 4433 hoverflies, belonging to fifteen species, were collected in water traps during 4–6 August. All but 2.2% were M.corollae , 3282 specimens being caught on 4 August, 1021 on 5 August and thirty-five on 6 August.
2. The sex ratios ( ♂/♀ ) on these dates were 1/1.6, 1/1.3 and 1/1.7. The average dry weights did not significantly differ between sexes (males 4.01 mg, females 4.02 mg).
3. M.corollae females were reproductively immature.
4. Females mostly had Senecio pollen in their guts while males mainly had Rubus pollen. The average number of pollen grains per specimen was 210 for females and 1100 for males.
5. In the summer 1980 aphids were numerous, forming a basis for a high abundance of adult hoverflies (with hibernating larvae) in 1981. Aphid density in 1981 was low and stimuli inducing egglaying were sparse. It is suggested that this pattern of aphid abundance triggers migration in M.corollae and in other aphidophagous species at irregular intervals.     

A Taxonomic Study of European and East African Species of the Genera Pelecopsis and Trichopterna (Araneae, Linyphiidae), with Descriptions of a New Genus and Two New Species of Pelecopsis from Kenya

On the basis of the results of an analysis primarily of the morphology of the male palps and palpal organs the delimitation of the erigonine genera Pelecopsis Simon and Trichopterna Kulczyński and the phylogenetic relationships between European and East African species of these genera are discussed. For the East African species Pelecopsis convexa (Holm), and P. bacelarae (di Caporiacco), together with two undescribed species from Nigeria, the new genus Locketia is established. Pelecopsis humiliceps sp.n. and P. albifrons sp.n., both from Kenya, are described and P. tenera (Holm, 1962), preocc. P. tenera (Schenkel, 1927), is replaced by P. tenuipalpis nom.n. Viewpoints are presented on evolutionary trends and phylogeny of European and East African Pelecopsis species.     

Pheromone deactivation catalyzed by receptor molecules: a quantitative kinetic model

A quantitative model of pheromone-receptor interaction and pheromone deactivation, the supposed rate-limiting processes underlying the receptor potential kinetics, is worked out for the moth Antheraea polyphemus. In this model, the pheromone interacts with the receptor molecule while bound to the reduced form of the pheromone binding protein. The receptor molecules--besides their receptor function-- catalyze the observed shift of the pheromone-binding protein from the reduced to the oxidized form (Ziegelberger, G., Eur. J. Biochem., 232, 706-711, 1995), which deactivates the pheromone bound to pheromone binding protein. With the following parameters, the model fits morphological, radiometric, electrophysiological and biochemical data: a maximum estimate of 1.7 x 10(7) receptor molecules/cell (with 40,000 units/micron 2 of receptor cell membrane), rate constants k1 = 0.2/(s.microM) for the association, k2 = 10/s for the dissociation of the ternary complex of binding protein, pheromone and receptor, and k3 = 10/s for the deactivation via the redox shift. With these parameters, the duration of elementary receptor potentials elicited by single pheromone molecules (approximately 50 ms) reflects the lifetime of the ternary complex, tau = 1/(k2 + k3). The receptor occupancy produced by the model for threshold stimuli fits the sensitivity of the receptor cell to single pheromone molecules.      

Flux detectors versus concentration detectors: two types of chemoreceptors

Dose-response curves relating the external stimulus concentration to receptor occupancy differ in two types of chemoreceptor organs. In 'concentration detectors' the receptor molecules at the receptor cell membrane are directly exposed to the external stimulus concentration; these organs exhibit the well-known hyperbolic dose-response relationship reflecting the association-dissociation of stimulus and receptor molecules. In contrast, 'flux detectors' accumulate the stimulus molecules in a perireceptor compartment. In flux detectors, deactivation of stimulus molecules may be in balance with arrival, as a prerequisite for producing a constant effective stimulus concentration at constant adsorptive flux of stimulus molecules. In a simple model of a flux detector in which receptor molecules themselves catalyze the deactivation, the dose-response relationship is linear. It reflects the rate of stimulus deactivation. If the deactivation is catalyzed by a separate enzyme, the dose-response relationship can be close to hyperbolic, or linear. In all cases, the receptor molecules are maximally occupied if the adsorptive flux equals or exceeds the maximum rate of stimulus deactivation. The time course of the receptor potential recorded from moths' pheromone receptors depends on the odor compound, which suggests that a peripheral process, possibly the stimulus deactivation, is the slowest, rate-limiting process of the transduction cascade. Further evidence comes from experiments with stimuli oversaturating the mechanism responsible for the decline of the receptor potential.