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1.
Amy Bogaard 《Vegetation History and Archaeobotany》2002,11(1-2):155-168
Despite widespread criticism, the shifting cultivation model continues to inform discussion of Neolithic farming in Europe,
beginning with early Neolithic (Linearbandkeramik or LBK) communities concentrated in the loess belt of western-central Europe. Hundreds of LBK and later Neolithic sites have
been excavated in this region and many of them sampled for charred plant remains. Archaeobotanical data on the weed floras
harvested with crops provide the most direct archaeological evidence of crop husbandry practices, including the permanence
of crop fields, but have played a limited role in the debate over shifting cultivation. The Hambach Forest experiment, conducted
in the 1970s-80s near Cologne, Germany, provides valuable comparative data on the weed floras growing in newly cleared cultivation
plots in an area of longlived mixed oak woodland on loess-based soil. Correspondence analysis of the Hambach weed survey data
suggests that weed floras of fields managed under a shifting cultivation regime would be rich in perennial species, including
woodland perennials. Comparison of these results with Neolithic weed assemblages from the loess belt of western-central Europe
strongly suggests that Neolithic crop fields were not recently cleared of woodland vegetation but were long-established.
Received September 5, 2001 / Accepted February 26, 2002 相似文献
2.
Reconstruction of crop sowing time and cultivation intensity, based on arable weed ecology, can resolve archaeological questions
surrounding land use and cycles of routine activity, but crop processing may introduce systematic ecological biases in the
arable weeds represented in products and by-products. Based on previous ethnoarchaeological work, there is a predicted bias
against indicators of spring sowing and intensive cultivation in fine sieve products (and a corresponding over-representation
of such species in by-products). Recent work on modern weed floras using functional weed ecology has identified distinctive
functional attributes associated with different sowing regimes and cultivation intensity levels. Evaluation of the predicted
biases using functional attribute data for modern weed survey studies of different sowing regimes (in Germany) and cultivation
intensity levels (in Greece) suggests that there is a likely bias against spring sowing indicators in fine sieve products but not (apparently) against intensive cultivation
indicators. An archaeological case study is presented in order to illustrate how bias relating to crop sowing time may be
identified and interpreted. 相似文献
3.
Castor Muñoz Sobrino Pabio Ramil-Rego Manuel Antonio Rodríguez Guitián 《Vegetation History and Archaeobotany》2001,10(1):7-21
A new core taken from a site in the Sierra de Courel range of mountains in the northwest Iberian peninsula, Spain, enables
a palaeoenvironmental reconstruction to be made of the biological events resulting from climatic changes and human activities
during the last 17,000 years in the area. The sequence begins with a phase characterised by the dominance of Gramineae (Poaceae)
and Pinus. A markedly arid period with prevalence of Artemisia pollen occurred between 17,5000 and 15,500 uncal. B.P. Subsequently, a succession of woodlands with Betula, Pinus and other mesophilous and thermophilous trees was recognised during the period 15,500-13,500 uncal. B.P. Between 13,500 and
10,300 uncal. B.P. herbaceous vegetation formations indicating moister conditions dominated the pollen record, although a
maximum of Gramineae has been dated during the period 11,300-10,300 uncal. B.P. Comparison with other pollen data from neighbouring
mountains allows an interpretation of the vegetation changes during the glacial/interglacial transition in the mountains of
northwest Iberia. The Holocene pollen record from the site does not differ markedly from other records in the area, tree expansion
occurring before 10,000 uncal. B.P. and high values of deciduous Quercus mixed with other trees and shrubs persisting until 3500 uncal. B.P., when increased human activities are shown by a fall
of the tree pollen percentages.
Received July 7, 1999 / Accepted May 22, 2000 相似文献
4.
Wood formation in poplar: identification, characterization, and seasonal variation of xylem proteins 总被引:9,自引:0,他引:9
Proteins that are preferentially produced in developing xylem may play a substantial role in xylogenesis. To reveal the identity
of these proteins, comparative two-dimensional polyacrylamide gel electrophoresis was performed on young differentiating xylem,
mature xylem, and bark of poplar (Populus trichocarpa Hook. cv. `Trichobel') harvested at different times of the year. The most-abundant xylem proteins were identified by microsequence
analysis. For 17 of these proteins a putative function could be assigned based on similarity with previously characterized
proteins, and for 15 out of these corresponding expressed sequence tags (ESTs) were found in the poplar EST database. The
identified xylem–preferential proteins, defined by comparing the protein patterns from xylem and bark, were all involved in
the phenylpropanoid pathway: two caffeoyl-coenzyme A O-methyltransferases (CCoAOMT), one phenylcoumaran benzylic ether reductase (PCBER), one bispecific caffeic acid/5-hydroxyferulic
acid O-methyltransferase (COMT), five S-adenosyl-L-methionine synthetases, and one homologue of glycine hydroxymethyltransferase (GHMT). Remarkably, the biological function
of the two most-abundant xylem-preferential proteins (PCBER and a GHMT homologue) remains unclear. In addition, several housekeeping
enzymes were identified: two enolases, two glutamine synthetases, one 70-kDa heat-shock cognate, one calreticulin, and one
α-tubulin. In comparison to the xylem-preferential proteins, the housekeeping proteins were expressed at significant levels
in the bark as well. Also, several additional protein spots were detected for CCoAOMT, PCBER, and COMT by immunoblot. Our
data show that for the study of xylogenesis, two-dimensional protein gel comparisons combined with systematic protein sequencing
may yield information complementary to that from EST sequencing strategies.
Received: 28 June 1999 / Accepted: 3 September 1999 相似文献
5.
First archaeological evidence of banana cultivation in central Africa during the third millennium before present 总被引:1,自引:0,他引:1
Christophe Mbida Mindzie Hughes Doutrelepont Luc Vrydaghs Rony L. Swennen Rudy J. Swennen Hans Beeckman Edmond de Langhe Pierre de Maret 《Vegetation History and Archaeobotany》2001,10(1):1-6
Phytoliths recovered from refuse pits excavated in central Cameroon and dated to ca 2500 B.P. have been positively identified
for the first time in Africa as derived from Musa the cultivated banana, after a comparative study of Musa and Ensete phytoliths. This discovery provides archaeologists with unequivocal proof of early agriculture in central Africa. Furthermore,
the presence of banana in Cameroon much earlier than previously assumed could explain how agriculture spread through the rain
forest. Lastly, as Musa is of Asian origin, this study provides the first concrete evidence of contacts across the Indian Ocean a millennium earlier
than currently accepted.
Received July 12, 1999 / Accepted May 4, 2000 相似文献
6.
Anna Maria Mercuri Carla Alberta Accorsi Marta Bandini Mazzanti 《Vegetation History and Archaeobotany》2002,11(4):263-276
The cores from the Albano and Nemi lakes, near Rome, were studied within the European Union funded PALICLAS project and provided
high resolution records of the Late-glacial and Holocene. Pollen evidence of increasing human influence on vegetation was
recorded in the Holocene parts of both diagrams, and the Cannabis (hemp) curve was one of the major signs. In this paper we present unambiguous pollen evidence from the Cannabaceae records
for the cultivation of hemp in central Italy by the Romans. The oldest records of Cannabis and Humulus (hop) date from to the Late-glacial. Hop pollen values rise during the mid Holocene, while hemp pollen becomes more abundant
from ca. 3000 cal B.P. onwards. The highest earliest hemp peak (21%) is dated to the 1st century A.D. This ‘Cannabis phase’, with the abrupt rise of hemp pollen soon after the rise of cultivated trees (Castanea, Juglans and Olea) is associated with the increase in cereals and ruderal plants. This unambiguous proof of cultivation by Romans around 2000
B.P. occurs as well as a long lasting pre-Roman presence of hemp in the area, which is natural and possibly also anthropogenic.
Subsequent clear episodes of cultivation in the medieval period were found.
Received February 4, 2002 / Accepted September 13, 2002
Correspondence to: Anna Maria Mercuri, e-mail: mercuri.annamaria@unimo.it 相似文献
7.
Jaromir Beneš Jan Kaštovský Romana Kočárová Petr Kočár Klára Kubečková Petr Pokorný Petr Starec 《Vegetation History and Archaeobotany》2002,11(1-2):107-120
The stone fortification of Prague Old Town was constructed shortly after A.D. 1230. Large-scale archaeological and archaeobotanical
research has been carried out in this area in recent years. The deep moat and the drainage ditch have been excavated at several
places in front of a line of former ramparts. During the initial period of their existence, the moat and the ditch contained
only minimal waste. A sudden change in the management of these features occurred at the beginning of the 14th cent., when
they started to be filled with large amounts of rubbish. This article concentrates on the evaluation of these rubbish strata
at three profiles through the drainage ditch and one profile through the dry moat. The results of plant macro-remains (including
wood), pollen, and diatom analyses clearly demonstrate the development of the local (aquatic) environment from being relatively
clean to highly polluted. An actualistic (phytosociological) approach was adopted to reconstruct the local environment of
the town periphery in detail, and to distinguish a variety of habitats that were situated in the economic hinterland of the
city. Some species from the rich assemblages of plant remains are interpreted in terms of their use in High Medieval households.
Diatom analysis completes the picture by providing the proxy data on water quality history in the drainage ditch.
Received September 15, 2001 / Accepted May 21, 2002 相似文献
8.
Ahmed Gamal-Eldin Fahmy 《Vegetation History and Archaeobotany》2001,10(4):235-246
The Neolithic site at Hidden Valley, Farafra Oasis, Egypt (6028±150 – 5163±374 cal B. C.) on the shores of a playa (dry lake
basin in the desert), yielded a large quantity of carbonized plant remains from post-holes, hearths, querns and a corridor.
The plant remains could have become carbonised during food preparation, or when fuel included seeds. Rich and diverse floras
were retrieved from 40 soil samples, in all 534 seeds, grains, spikelets, culm fragments and leaflet fragments which were
attributed to 30 taxa in the flora of Egypt. Wild grasses from almost all samples represent 83% of the plant remains. Quantitative
correlation between plants remains and archaeological contexts is discussed. The highest density of plant remains was recorded
from pot-holes (in which pots were stood), while sediments recovered near querns show the lowest. The economy of the site
was apparently based mainly on herding associated with the gathering of grasses which suggests that the climate at Farafra
during the middle Holocene (6077–4511 cal B. C.) was wetter than today's, with winter and summer rainfall. A reconstruction
of the vegetation around the site comprises reed plant cover, aquatic and wetland plants and desert savanna.
Received March 8, 2001 / Accepted June, 2001 相似文献
9.
Ecological interactions between species that prefer different habitat types but come into contact in edge regions at the
interfaces between habitat types are modeled via reaction-diffusion systems. The primary sort of interaction described by
the models is competition mediated by pathogen transmission. The models are somewhat novel because the spatial domains for
the variables describing the population densities of the interacting species overlap but do not coincide. Conditions implying
coexistence of the two species or the extinction of one species are derived. The conditions involve the principal eigenvalues
of elliptic operators arising from linearizations of the model system around equilibria with only one species present. The
conditions for persistence or extinction are made explicit in terms of the parameters of the system and the geometry of the
underlying spatial domains via estimates of the principal eigenvalues. The implications of the models with respect to conservation
and refuge design are discussed.
Received: 10 June 1999 / Revised version: 7 July 2000 / Published online: 20 December 2000 相似文献
10.
The roles of gibberellins, abscisic acid and phytochrome B in the vernalization response were investigated by combining mutations
causing defects in their biosynthesis and response with the Arabidopsis thaliana (L.) Heynh. fca-1 mutation. The fca-1 mutation confers a very late-flowering phenotype which can be reversed to wild-type flowering if the seedlings are vernalized.
Vernalization was unaffected in ga1-3, gai, abi1-1, abi2-1, abi3-1 and phyB-1 backgrounds, suggesting that gibberellin action mediated via GA1 and GAI, abscisic acid action mediated through ABI1 and ABI2, and phytochrome B, function independently of vernalization. However, the mutations did interact with fca-1 to change flowering time in the absence of vernalization. The abi1 fca-1 and abi2 fca-1 double mutants flowered earlier than fca-1 implying a role for abscisic acid in floral repression. Combination of ga1-3 or gai with fca-1 unexpectedly resulted in opposite interactions, with gai partially suppressing the late flowering of fca-1.
Received: 17 July 1999 / Accepted: 11 October 1999 相似文献
11.
Lucyna Kubiak-Martens 《Vegetation History and Archaeobotany》2002,11(1-2):23-32
Roots and tubers, together with other plant storage organs such as rhizomes, bulbs, corms, etc. are known to be a source
of human food. Until very recently, however, remains of root foods were rarely identified from archaeological contexts in
temperate Europe. New evidence for the use of root foods has been recently recovered from the early Erteb?lle settlement at
Halsskov in Denmark. Remains included charred bulbs of Allium cf. ursinum and tubers of Conopodium majus. They were accompanied by charred remains of parenchymatous tissues derived from underground parts of other plants. All parenchymatous
remains were recovered from features that could be interpreted as pit-cooking depressions. A minimum of two periods of root
food gathering can be assumed, spring to early summer and autumn. The presence of charred seeds of Nuphar pumilum suggests that either the seeds or rhizomes (or both) were use as food.
Received September 4, 2001 / Accepted February 27, 2002 相似文献
12.
Phototolerance of lichens, mosses and higher plants in an alpine environment: analysis of photoreactions 总被引:8,自引:0,他引:8
Adaptation to excessive light is one of the requirements of survival in an alpine environment particularly for poikilohydric
organisms which in contrast to the leaves of higher plants tolerate full dehydration. Changes in modulated chlorophyll fluorescence
and 820-nm absorption were investigated in the lichens Xanthoria elegans (Link) Th. Fr. and Rhizocarpon geographicum (L.) DC, in the moss Grimmia alpestris Limpr. and the higher plants Geum montanum L., Gentiana lutea L. and Pisum sativum L., all collected at altitudes higher than 2000 m above sea level. In the dehydrated state, chlorophyll fluorescence was
very low in the lichens and the moss, but high in the higher plants. It increased on rehydration in the lichens and the moss,
but decreased in the higher plants. Light-induced charge separation in photosystem II was indicated by pulse-induced fluorescence
increases only in dried leaves, not in the dry moss and dry lichens. Strong illumination caused photodamage in the dried leaves,
but not in the dry moss and dry lichens. Light-dependent increases in 820-nm absorption revealed formation of potential quenchers
of chlorophyll fluorescence in all dehydrated plants, but energy transfer to quenchers decreased chlorophyll fluorescence
only in the moss and the lichens, not in the higher plants. In hydrated systems, coupled cyclic electron transport is suggested
to occur concurrently with linear electron transport under strong actinic illumination particularly in the lichens because
far more electrons became available after actinic illumination for the reduction of photo-oxidized P700 than were available
in the pool of electron carriers between photosystems II and I. In the moss Grimmia, but not in the lichens or in leaves, light-dependent quenching of chlorophyll fluorescence was extensive even under nitrogen,
indicating anaerobic thylakoid acidification by persistent cyclic electron transport. In the absence of actinic illumination,
acidification by ca. 8% CO2 in air quenched the initial chlorophyll fluorescence yield Fo only in the hydrated moss and the lichens, not in leaves of the higher plants. Under the same conditions, 8% CO2 reduced the maximal fluorescence yield Fm strongly in the poikilohydric organisms, but only weakly or not at all in leaves. The data indicate the existence of deactivation
pathways which enable poikilohydric organisms to avoid photodamage not only in the hydrated but also in the dehydrated state.
In the hydrated state, strong nonphotochemical quenching of chlorophyll fluorescence indicated highly sensitive responses
to excess light which facilitated the harmless dissipation of absorbed excitation energy into heat. Protonation-dependent
fluorescence quenching by cyclic electron transport, P700 oxidation and, possibly, excitation transfer between the photosystems
were effectively combined to produce phototolerance.
Received: 10 December 1999 / Accepted: 13 April 2000 相似文献
13.
Garcia RF Gazola VA Barrena HC Hartmann EM Berti J Toyama MH Boschero AC Carneiro EM Manso FC Bazotte RB 《Amino acids》2007,33(1):151-155
Summary. Our purpose was to determine the blood amino acid concentration during insulin induced hypoglycemia (IIH) and examine if the
administration of alanine or glutamine could help glycemia recovery in fasted rats. IIH was obtained by an intraperitoneal
injection of regular insulin (1.0 U/kg). The blood levels of the majority of amino acids, including alanine and glutamine
were decreased (P < 0.05) during IIH and this change correlates well with the duration than the intensity of hypoglycemia. On the other hand,
the oral and intraperitoneal administration of alanine (100 mg/kg) or glutamine (100 mg/kg) accelerates glucose recovery.
This effect was partly at least consequence of the increased capacity of the livers from IIH group to produce glucose from
alanine and glutamine. It was concluded that the blood amino acids availability during IIH, particularly alanine and glutamine,
play a pivotal role in recovery from hypoglycemia. 相似文献
14.
Aldona Bieniek 《Vegetation History and Archaeobotany》2002,11(1-2):33-40
Neolithic settlements in the Kujawy region of central Poland are represented by seven archaeological sites which have botanical
material archaeologically dated to the Linear Pottery culture (LBK) (ca. 5400-5000 cal. B.C.) and the Lengyel culture (ca.
4400-4000 cal. B.C.). The composition of plant remains suggests that Stipa pennata s.l. played a certain role in the economy of the Neolithic settlers. The presence of this xerothermic grass is best explained
by local gathering rather than distant transport or coming into the sediment by chance. The finding of Hierochlo? cf. australis grains represents the first identification of this plant in archaeobotanical material from Poland. This, now rare, plant
contains coumarin and for this reason could have been useful in prehistory. Other plants such as Bromus spp., Chenopodium album type, Fallopia convolvulus and Galium spp. were found in large quantities, and although common weeds now, they could also have been collected by the Neolithic
settlers. Plants such as Corylus avellana and Vaccinium vitis-idaea that are typically considered to be collected as foods are present in the studied material but in very small quantities.
Received September 17, 2001 / Accepted March 13, 2002 相似文献
15.
Two-year-old rosemary (Rosmarinus officinalis L.) plants were subjected to severe stress by exposure to prolonged drought during a Mediterranean summer. Severely stressed
plants recovered completely after the autumn rainfalls although the relative water content remained below 35% for 3 months
and the chlorophyll content of leaves was reduced by up to 85% during the drought. In severe stress: (i) α-tocopherol increased
9-fold per g dry weight and 20-fold per unit of chlorophyll; (ii) lutein and β-carotene contents decreased on a dry-weight
basis, but an 80% increase in lutein and constant levels of β-carotene were observed on a chlorophyll basis; (iii) there were
transient and sustained increases in the de-epoxidation state of the xanthophyll cycle; and (iv) the highly oxidised abietane
diterpene isorosmanol increased 8-fold as a result of the oxidation of carnosic acid. With the autumn rainfalls, water status,
α-tocopherol and violaxanthin recovered first and the levels of photosynthetic pigments and abietane diterpenes increased
later. The photoprotection conferred by the xanthophyll cycle and the antioxidant function of tocopherols, lutein and diterpenes
may help to avoid irreversible damage in severe drought, making possible the recovery of functional membranes after the autumn
rainfalls. Besides, chlorophyll loss reduces the amount of photons absorbed by leaves, which enhances the photoprotective
and antioxidant capacity of leaves per amount of photons absorbed, since the ratios of xanthophylls, α-tocopherol and abietane
diterpenes to chlorophyll increase.
Received: 12 July 1999 / Accepted: 25 November 1999 相似文献
16.
17.
Nikolic J Stojanovic I Pavlovic R Sokolovic D Bjelakovic G Beninati S 《Amino acids》2007,32(1):127-131
Summary. The existing interrelation in metabolic pathways of L-arginine to polyamines, nitric oxide (NO) and urea synthesis could be
affected in sepsis, inflammation, intoxication and other conditions. The role of polyamines and NO in the toxic effect of
mercury chloride on rat liver function was studied. Administration of mercury chloride for 24 h led to significantly elevated
plasma activities of Alanine transaminase (ALT) and Aspartate transaminase (AST). Malondyaldehyde (MDA) levels were unaffected
(p > 0.05) and arginase activity was significantly decreased (p < 0.05) while nitrate/nitrite production was significantly
elevated (p < 0.001) in liver tissue. Polyamine oxidase (PAO) and diamine oxidase (DAO) activities, enzymes involved in catabolism
of polyamines, were decreased. L-arginine supplementation to intoxicated rats potentiated the effect of mercury chloride on
NO production and it was ineffective on arginase activity.
Results obtained in this study show that mercury chloride-induced toxicity leads to abnormally high levels of ALT and AST
that may indicate liver damage with the involvement of polyamine catabolic enzymes and NO. 相似文献
18.
Inactivation of DNA replication origins by the cell cycle regulator, trigonelline, in root meristems of Lactuca sativa 总被引:4,自引:0,他引:4
The effects of trigonelline (TRG) on the cell cycle in root meristems of Lactuca sativa L. were examined in the knowledge that TRG is a cell cycle regulator that causes cell arrest in G2, and prevents ligation
of replicons in S-phase. The hypothesis was tested that continuous exposure to TRG would perturb DNA replication which, in
turn, would lengthen the cell cycle and impair root elongation. Using DNA fibre autoradiography, mean replicon size was 31
and 13 μm in the TRG (3 mM) and control treatments, respectively. Trigonelline also resulted in a lengthening of both S-phase
and the cell cycle and a decrease in primary root elongation. Hence, replicon inactivation was responsible for the protracted
S-phase. Trigonelline treatment also resulted in a 1.6-fold increase in fork rate (13.8 μm h−1) compared with the control (8.4 m h−1). The faster fork rate in the larger replicons is in accord with the highly significant positive relationship already established
between fork rate and replicon size for various unrelated higher plants.
Received: 11 October 1999 / Accepted: 23 December 1999 相似文献
19.
Summary. Accumulation of amino acids was studied in rice roots of 3-day-old seedlings subjected for 48 h to anaerobic conditions.
Alanine and Gaba were the main amino acids accumulated under anoxia. Their synthesis was strongly inhibited by MSX and AZA,
inhibitors of glutamine synthetase and glutamate synthase. These activities increased after 8 h of anaerobic treatment and,
by immunoprecipitation of 35S-labeled proteins, it was shown that glutamine synthetase and ferredoxin-dependent glutamate synthase were synthesized during
the treatment. These findings indicate that the glutamine synthetase/glutamate synthase cycle play an important role in anaerobic
amino acid accumulation.
Received April 5, 1999 相似文献
20.
Susanne Jahns 《Vegetation History and Archaeobotany》2001,10(2):97-104
A high-resolution Late Pleistocene and Middle to Late Holocene pollen profile of regional significance is presented. The
coring site is located in a mire between two lakes. Ober- and Unter-ückersee, in Brandenburg, north-eastern Germany. The study
was carried out in an archaeological context. It provides information about the history of vegetation, climate and human impact
in the ücker river valley and the surrounding hills, the Uckerm?rker Hügelland. Hence, it is an important contribution for
the reconstruction of the past vegetation of this area of Brandenburg. Seven AMS 14C-dates based on pollen concentrates provide a chronology for the middle Holocene part of the profile. Phases of intensive
human activity can be shown from the middle Neolithic times until the Roman Iron Age.
Received February 1, 2000 / Accepted January 18, 2001 相似文献