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1.
Soil and climate are major constituents of the French notion of Terroir. This concept implies that there is a strong relationship
between the composition of the grape, the characteristics of the wine and the territory of production. To study this link,
a new method of characterization of the Terroir, including geological and pedological factors, was investigated. It uses a
field model based on depth and clay content of soil, together with the degree of weathering of the parent rock. Consequently,
for every type of parent rock belonging to a given geologic stage, there are a series of soils that show different stages
of pedological evolution. According to the model, three kinds of soils are distinguished with regards to the weathering intensity
of the parent rock, that are named weakly weathered rock (WWR), moderately weathered rock (MWR) and strongly weathered rock
(SWR). By hypothesis, each soil type is considered as a homogeneous unit for vine production from the viewpoint of ecophysiological
factors. Each terroir unit defined by this method is called a Basic Terroir Unit (BTU). To validate this hypothesis, experimental
plots planted with Chenin and Cabernet Franc vines were studied over three consecutive seasons (2000–2002), in the Anjou vineyard
(Loire Valley – France). The major BTUs developed on the two most important geological systems of Anjou (Brioverian and Ordovician–Devonian),
were studied. Results showed that the berries of vines cultivated in WWR were significantly smaller, richer in sugars and
anthocyanins and had a Total Phenolic Index higher than those of the vines cultivated in SWR. They also had a lower titratable
acidity. Cabernet Franc vines cultivated in MWR had berries with sugar and anthocyanin contents but also total phenolics very
close to those of WWR. With Chenin vines there was a good relationship between the global pool of free aromas of berries and
the BTU type. The study showed significant relationships between the quality of grapes and the measured values of several
ecophysiological variables such as the water supply regime or the timing of budburst. 相似文献
2.
Several aspects of a diel vertical migration (DVM) of adultEudiaptomus gracilis in Lake Maarsseveen (The Netherlands) are described. The period of DVM lasted from the end of May until the middle of August. On May 21, 1989, the population was found divided into a deep dwelling part and a part in the upper five meter. Large shoals of juvenile perch were observed in the open water for the first time. On June 7, the whole population was down below 10 m and concentrated in a zone of high chlorphyll-a concentrations. One week later, a regular DVM was performed. The amplitude of this migration gradually decreased towards the end of the migration period. The ascent in the evening and the descent in the morning took place after sunset and before sunrise, respectively. The movements coincided with high relative changes in light intensity. Population size increased rapidly during the period of DVM but decreased again before the end of this period. 相似文献
3.
The semidian rhythm in flowering response of Pharbitis nil in relation to dark period time measurement and to a circadian rhythm 总被引:1,自引:0,他引:1
When seedlings of Pharbitis nil Choisy, cv. Violet, are exposed to a single inductive dark period at 27°C, brief interruptions with red light (R) can be promotive after 2–3 h of darkness but increasingly inhibitory to flowering up to the 8–9th h of darkness. This rhythmic response to R interruptions can be advanced in phase by > 1 h when the preceding light period is interrupted with far-red (FR) 2 h before darkness (FR -2 h) or with FR – 15 h, whereas FR –8 h or FR–22 h retard the rhythm. These shifts in the R interruption rhythm are paralleled by equal shifts in the length of the dark period required for flowering. Brief FR interruptions of darkness displayed a similar rhythm which was also advanced by FR –2 h and retarded by FR –8 h. We conclude therefore that the semidian rhythm in the light, which we have previously described, continues through at least the first 12 h of darkness, is manifested in the R interruption rhythm, and determines the critical night length. A circadian rhythm with a marked effect on flowering was also identified, but several lines of evidence suggest that the circadian and semidian rhythms have independent additive effects on flowering and do not appear to show phase interaction. 相似文献
4.
5.
Discrimination of jittered sonar echoes by the echolocating bat,Eptesicus fuscus: The shape of target images in echolocation 总被引:2,自引:0,他引:2
James A. Simmons Michael Ferragamo Cynthia F. Moss Scott B. Stevenson Richard A. Altes 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,167(5):589-616
1. Behavioral experiments with jittering echoes examined acoustic images of sonar targets in the echolocating bat, Eptesicus fuscus, along the echo delay or target range axis. Echo phase, amplitude, bandwidth, and signal-to-noise ratio were manipulated to assess the underlying auditory processes for image formation. 2. Fine delay acuity is about 10 ns. Calibration and control procedures indicate that this represents temporal acuity rather than spectral discrimination. Jitter discrimination curves change in phase when the phase of one jittering echo is shifted by 180 degrees relative to the other, showing that echo phase is involved in delay estimation. At an echo detectability index of about 36 dB, fine acuity is 40 ns, which is approximately as predicted for the delay accuracy of an ideal receiver. 3. Compound performance curves for 0 degrees and 180 degrees phase conditions match the crosscorrelation function of the echoes. The locations of both 0 degrees and 180 degrees phase peaks in the performance curves shift along the time axis by an amount that matches neural amplitude-latency trading in Eptesicus, confirming a temporal basis for jitter discrimination. 相似文献
6.
The evolution of phage lysis timing 总被引:17,自引:0,他引:17
Summary The effect of host quantity and host quality on the evolution of phage lysis timing is analysed using marginal value theorem of optimal foraging theory. Both factors have been shown to strongly influence the latent period. A high host density selects for short latent period, which is the same result as previous investigators have found. A good host quality also promotes a short latent period. However, elasticity analysis shows that these two factors exert their influences under different sets of conditions. When host density is low, the host density is more important in determining the length of latent period, whereas when host density is high, the host quality is more important. 相似文献
7.
N. B. Cherfas Y. Peretz N. Ben-Dom B. Gomelsky G. Hulata 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,89(2-3):281-286
The results of a series of experiments conducted in our laboratory on the ornamental common carp (koi), aimed at optimizing heat-shock chromosome-set manipulation procedures, are described. The timing of heat-shock initiation was expressed in the relative unit of embryological age (0) in order to standardize this parameter, the absolute time for heat-shock initiation being calculated from duration of one 0 at two different pre-treatment water temperatures. Heat shocks were applied within the periods of 0.05–0.60 0 and 1.20–2.20 0 which, respectively, cover the successive phases of the 2nd meiotic division and the 1st cleavage. The highest production of diploid gynogenetic offspring was observed when heat shocks were initiated at 0.15–0.25 0 and at 1.5 0, after insemination, corresponding to anaphase of meiosis-II, and metaphase of the 1st cleavage, respectively. Similar results were obtained irrespective of the different pre-treatment water temperatures, thus confirming the possibility of standardizing heat-shock timing by 0. 相似文献
8.
PASCALE CHEVRET LAURENT GRANJON JEAN-MARC DUPLANTIER CHRISTLANE DENYS FRANÇOIS M. CATZEFLIS 《Zoological Journal of the Linnean Society》1994,112(4):425-442
Within the Murinae (Muridae: Rodentia), the African rats of the Praomys group, whose systematics has been studied through different approaches, have raised numerous taxonomic problems. Different taxa related to Praomys have successively been described, among which Mastomys, Myomys and Hylomyscus were considered either as separate genera or subgenera of Praomys. In order to clarify the relationships within the Praomys group, we conducted a series of DNA/DNA hybridization experiments involving different species of Praomys, Mastomys, Myomys and Hylomyscus plus other Murinae and a Cricetomyinae. This study indicates that the Praomys complex is a monophyletic entity clearly separated from the other African and Asian Murinae. If Mastomys and Hylomyscus appeared to be independent genera, the taxonomic situation of Praomys and Myomys is more difficult to ascertain. Indeed, Praomys tullbergi appears more closely related to Myomys daltoni than to another species of Praomys , namely P. jacksoni , suggesting paraphyly for Praomys. Furthermore, P. jacksoni is as distant from P. tullbergi as from any species of Mastomys. Additional species of Praomys and, especially, of Myomys , are needed for reaching a definitive conclusion on these latter taxa. The Praomys group is more related to Mus than to Rattus. To calibrate our molecular distances with geological time, we used a dating of 10 Myr for the Musi Rattus dichotomy. The inferred rate of molecular evolution suggests a dating of c. 8 Myr for the separation of the Praomys group from the Mus lineage. 相似文献
9.
Over two vegetation cycles we compared the recovery of macrophytes from flood disturbances that occured at different seasons (July vs December) on patches of a former channel of the Rhône River, France. Some patches were disturbed twice; others were disturbed either in summer or in winter; others were never disturbed and were used as controls.The recovery rate of the vegetation was estimated from the duration of recolonization of the disturbed areas and of growth of the recolonizing species. The influence of the summer disturbance appeared to be strong because the disturbance occurred when the development of the vegetation was maximum. The influence of the winter disturbance was apparently much lower since most species had already declined at this time because of their phenology. The repetition of the two disturbances on the same patch had little influence on the vegetation community.In all cases, the recovery of the vegetation occurred rapidly, both for total vegetation cover and species richness. By the following spring, no significant differences appeared between disturbed and reference patches. The effect of the disturbances varied according to the phenology of the plants, and the macrophyte community studied was more sensitive in summer than in winter. 相似文献
10.
Naoki Koyama Yukio Takahata Michael A. Huffman Koshi Norikoshi Hisayo Suzuki 《Primates; journal of primatology》1992,33(1):33-47
Over a 30-year period from 1954 to 1983, 975 live births were recorded for Japanese macaque females at the Iwatayama Monkey
Park, Arashiyama, Japan. Excluding unknown birth dates, primiparous mothers gave birth to 185 infants (182 cases with age
of mother known) and multiparous mothers gave birth to 723 infants (603 cases with age of mother known). The peak month of
birth was May with 52.3% of the total births occurring during the period. Multiparous females who had not given birth the
previous year did so earlier than multiparous females who had given birth the previous year and also earlier than primiparous
females. Among the females who had given birth the previous year, females whose infant had died gave birth earlier than females
who had reared an infant the previous year. The offspring sex ratio (1:0.97) was not significantly different from 1:1, and
revealed no consistent association with mother's age. Age-fecundity exhibited a humped curve. The annual birth rate was low
at the age of 4 years but increased thereafter, ranging between 46.7% and 69.0%, at between 5 and 19 years of age, but again
decreased for females between 20 and 25 years of age. Some old females displayed clear reproductive senescence. The infant
mortality within the first year of age was quite low (10.3%) and the neonatal (less than 1 month old) mortality rate accounted
for 49.0% of all infant deaths. There was no significant difference between the mortality rates of male and female infants.
A female's rank-class had no apparent effect on the annual birth rate, infant mortality, and offspring sex ratio. These long-term
data are compared with those from other primate populations. 相似文献