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1.
A sclerochronological analysis was performed on Cladocora caespitosa corals from Late Pleistocene terraces near Taranto (Apulia, Italy) to reconstruct the main palaeoenvironmental conditions
at the time of their growth. The fossil corallites were sampled in the Santa Teresiola uplifted bank or ‘open frame reef’
attributed to the Last Interglacial Period. The typical, annual growth pattern of the temperate coral with two alternate high-
and low-density bands allowed the reconstruction of two multidecadal growth curves of 61 and 95 years. Trend analysis showed
oscillations in annual growth rates similar to those observed in recent, living colonies sampled along a north–south latitudinal
transect around the Italian and Croatian coasts as far as Tunisia. The mean growth rate of the fossil reef (4.2 ± 2 mm year−1) is comparable to those measured on colonies living in the coldest part of the Mediterranean Sea. The comparison with data
from living Croatian banks shows how fossil C. caespitosa lived in a semi-enclosed environment characterized by seasonal inputs of fresh, cold water. The greatest variations in decadal
growth rates of the fossil colonies support the hypothesis of larger amplitude of the seasonal cycles in the past. The death
of the fossil bank was probably due to a sudden alluvial input that suffocated the reef with a great amount of mud. Another
possible cause of the death of the bank was a prolonged increase in summer temperatures that caused colony mortality and enhanced
algal colonization. 相似文献
2.
Summary Anthers and ovaries of six grapevine cultivars (three Vitis vinifera L., two V × Labruscana L. H. Bailey, and one complex hybrid) were extracted from flower buds over 2 yr and cultured on three media reported to promote
somatic embryogenesis in Vitis tissues. The highest percent embryogenesis from the hybrid ‘Chancellor’ and V. vinifera ‘Chardonnay’, ‘Merlot’, and ‘Pinot Noir’ occurred on medium C [Nitsch and Nitsch, 1969, basal medium with 3.0% (w/v) sucrose,
0.01% (w/v) inositol. 0.3% (w/v) Phytagel, 2.5 μM 2.4-dichlorophenoxyacetic acid, 2.5μM β-naphthoxyacetic acid, 5.0μM N-(2-chloro-4-pyridyl)-N′-phenylurea, and 0.05% (w/v) glutamine]. Regardless of the media, the labrusca cultivars ‘Concord’ and ‘Niagara’ produced
soft non-embryogenic callus that was sometimes mixed with well-developed somatic embryos. Nine vinifera genotypes were further
tested for several different years on medium C. Embryogenic cultures suitable for transformation were obtained from all genotypes
in more than 1 yr. The average percent embryogenesis from ovaries was 7-fold higher than from anthers. There was significant
annual variation in percent embryogenesis, demonstrating the need for media comparisons to be replicated for more than one
season. Suspension cultures suitable for use in genetic transformation were initiated from ‘Chardonnay’, ‘Merlot,’ and ‘Pinot
Noir’ pro-embryogenic masses. ‘Chardonnay’ suspension cultures plated and grown under conditions developed for recovery of
plants after biolistic transformation yielded approximately 500 non-transformed embryos per plate after 4 mo. of culture,
with 68.6% of the embryos converting to plants. This is the first reported protocol for embryogenesis from ‘Concord,’ ‘Cabernet
Franc,’ and ‘Pinot Noir’ grapevines. 相似文献
3.
G. Coelho De Souza R. Kubo L. Guimarães E. Elisabetsky 《Biodiversity and Conservation》2006,15(8):2737-2746
The fronds of Rumohra adiantiformis, also known as ‘7-weeks-fern,’ ‘leatherleaf’ or ‘samambaia-preta,’ are used worldwide as florists’ greenery. Costa Rica and
the USA cultivate and export R. adiantiformis, whereas in South Africa and Brazil this trade is based on extractivism. In Brazil, R. adiantiformis is harvested in the Atlantic Forest biome; 50% of the production comes from the slopes of the ‘Serra Geral’ (state of Rio
Grande do Sul), where some 2000 families harvest and trade R. adiantiformis as their main source of revenue. However, harvesting, trading and transporting wild ornamental species is illegal in the
Atlantic Forest, This study evaluates R. adiantiformis extractivism in hilly areas of Rio Grande do Sul, from an ethnobotanical/ethnoecological perspective. The study reveals that
emic perceptions on the sustainability of R. adiantiformis extractivism are in agreement with relevant ecological data. The regeneration areas on the slopes of the Serra Geral have
the highest plant density ever reported for R. adiantiformis; its extractivism has low environment impact and generates significant income for local communities. Further studies of these
areas are important in order to support neoextractivism as a suitable form of use of the state's biodiversity. 相似文献
4.
A semi-field experiment was carried out in two peach orchards in northern Italy to assess mortality due to predators and parasitoids
on the exotic coccinellid Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) in comparison with the native coccinellid Adalia bipunctata L. (Coleoptera: Coccinellidae). The experiments were conducted in cages to avoid the possible escape of the exotic ladybird
(not yet established in Italy). Two kinds of cage experiments were included: ‘exclusion cages’ (access by walking predators
impeded) and ‘free cages’ (walking predators free to enter). The cages, containing all the stages of the two ladybird species,
were placed in two localities and left for 24 h. All ladybird stages used for the semi-field experiments came from a laboratory
rearing. The eggs of H. axyridis experienced less mortality than those of A. bipunctata. The ant workers were the most frequent predators in ‘free cages’ but A. bipunctata cannibalism on eggs was also detected. Larvae of both coccinellid species were predated equally but larval predation of L1
and L2 was higher in comparison to predation of L3 and L4. Pupae and adults of both exotic and native ladybirds were never
attacked by predators. Predation on younger larval stages was higher in the ‘free cages’ in comparison with ‘exclusion cages’.
No ladybird parasitisation was observed. The ‘free cage’ technique seems to provide a standardised and realistic estimation
of predation impact but more studies are needed to evaluate ladybird parasitisation in semi-field conditions. 相似文献
5.
Grant WS 《Genetica》2005,125(2-3):293-309
Genetic architectures of marine fishes are generally shallow because of the large potential for gene flow in the sea. European
anchovy, however, are unusual among small pelagic fishes in showing large differences among sub-basins and in harbouring two
mtDNA phylogroups (‘A’ & ‘B’), representing 1.1–1.85 million years of separation. Here the mtDNA RFLP dataset of Magoulas
et al. [1996, Mol. Biol. Evol. 13: 178–190] is re-examined to assess population models accounting for this subdivided population
structure and to evaluate the zoogeographical origins of the two major phylogroups. Haplotype and nucleotide diversities are
highest in the Ionian Sea and lowest in the Aegean and Black seas. However, this gradient is absent when ‘A’ and ‘B’ haplotypes
are examined separately. Neither the self-sustaining nor the basin population models adequately describe anchovy population
behaviour. Tests for neutrality, mismatch and nested clade analyses are concordant in depicting recent expansions of both
phylogroups. Unimodel mismatch distributions and haplotype coalescences dating to the last (Eemian) interglacial (‘B’) and
the Weichselian pleniglacial period (‘A’) indicate separate colonizations of the Mediterranean Basin. Phylogroup ‘A’ is unlikely
to have arisen through continuous long-term isolation in the Black Sea because of climate extremes from displaced subpolar
weather systems during the ice ages. Ancestors of both groups appear to have colonized the Mediterranean from the Atlantic
in the late Pleistocene. Hence, zoogeographic models of anchovy in the Mediterranean must also include the eastern (and possibly
southern) Atlantic. 相似文献
6.
Summary
Pentapora fascialis, one of the largest living bryozoan, is often a predominant part of the benthos on hard subtidal bottoms in the Mediterranean
Sea. Conversion factors calculated from laboratory measurements of colony size, biomass and skeleton weight, combined with
density of colonies and mean annual growth rate allowed the estimation of carbonate standing stock, biomass and carbonate
production ofPentapora fascialis in five sites in the Ligurian Sea. Carbonate standing stock ranged from 281 to 2490 g·m−2, colony biomass varied from 8.82 to 78.01 g·m−2, with a ratio biomass to carbonate standing stock of about 3%. Carbonate production of the bryozoan ranged in the five sites
from 358 to 1214 g·m−2·y−1. If compared with the few data available on carbonate production of bryozoans and other sublittoral benthic bioconstructors
in the temperate regions,Pentapora fascialis has to be considered one of the major contributors to the carbonatebudget. 相似文献
7.
Summary Use of lysozyme was tested for treatment of bacterial contaminations in in vitro shoot cultures of quince (Cydonia oblonga) ‘BA 29’ and the hybrid (Prunus persica × P. amygdalus) rootstock ‘GF 677’. Shoots which had been contaminated for about 1 yr by Bacillus circulans and Sphingomonas paucimobilis were treated in liquid culture, at pH 4.5, with 9–36 mg ml−1 egg white lysozyme (EWL), and compared to each other and to untreated cultures for their growth, proliferation, and number
of bacterial colony-forming units in the tissues. EWL did not negatively affect shoot growth up to 18 mg ml−1; furthermore, the proliferation rates of EWL-treated shoots were sometimes higher than those of controls. In contrast, the
concentration of 36 mg ml−1 had some deleterious effect on the regrowth capacity and shoot production of ‘GF 677’ at the first subculture to solid medium
after EWL, treatments. EWL had a simple bacteriostatic effect against Sphingomonas paucimobilis; in contrast, it was effective at 18 mg ml−1 in eliminating Bacillus circulans in both ‘BA 29’ and ‘GF 677’ cultures, after optimal treatment duration. 相似文献
8.
Biomass, carbonate standing stock and production of the mediterranean coralCladocora caespitosa (L.) 总被引:1,自引:0,他引:1
Summary The Mediterranean coralCladocora caespitosa often occurs in large beds, i.e. populations of hemispherical clonies with stock densities varying between 1.9 and 4 coloneis
·m−2. Laboratory measurements of volume, skeleton weight, surface and number of corallites per colony, coupled with mean annual
growth rates evaluated through sclerochronology, allowed for the estimation of biomass, skeleton bulk density, calcimass (carbonate
standing stock) and secondary production (both organic and inorganic) of twoC. caespitosa beds at 4 and 9 m depth. The mean colony biomass varied between 0.73 and 0.99 kg dw ·m−2, corresponding to a calcimass between 2 and 5 kg CaCO3·m−2. Organic secondary production was 215.5–305.4 g dw of polyps ·m−2·y−1, while the potential (mineral) production was 1.1–1.7 kg CaCO3·m−2·y−1, for the year 1996–1997.
These values show thatC. caespitosa is one of the major carbonate producers within the Mediterranean and one of the major epibenthic species originating stable
carbonate frameworks both in recent and past times. 相似文献
9.
Matsubara K Ando T Mizubayashi T Ito S Yano M 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,115(2):179-186
One outcome of hybrid breakdown is poor growth, which we observed as a reduction in the number of panicles per plant and in
culm length in an F2 population derived from a cross between the genetically divergent rice (Oryza sativa L.) cultivars ‘Sasanishiki’ (japonica) and ‘Habataki’ (indica). Quantitative trait locus (QTL) analysis of the two traits and two-way ANOVA of the detected QTLs suggested that the poor
growth was due mainly to an epistatic interaction between genes at QTLs located on chromosomes 2 and 11. The poor growth was
likely to result when a plant was homozygous for the ‘Habataki’ allele at the QTL on chromosome 2 and homozygous for the ‘Sasanishiki’
allele at the QTL on chromosome 11. The results suggest that the poor growth found in the F2 population was due to hybrid breakdown of a set of complementary genes. To test this hypothesis and determine the precise
chromosomal location of the genes causing the hybrid breakdown, we performed genetic analyses using a chromosome segment substitution
line, in which a part of chromosome 2 from ‘Habataki’ was substituted into the genetic background of ‘Sasanishiki’. The segregation
patterns of poor growth in plants suggested that both of the genes underlying the hybrid breakdown were recessive. The gene
on chromosome 2, designated hybrid breakdown 2 (hbd2), was mapped between simple sequence repeat markers RM3515 and RM3730. The gene on chromosome 11, hbd3, was mapped between RM5824 and RM1341.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
10.
C. M. Felland L. A. Hull B. A. Barrett A. L. Knight J. W. Jenkins P. A. Kirsch D. R. Thomson 《Entomologia Experimentalis et Applicata》1995,74(2):105-114
Mating disruption treatments for the tufted apple bud moth (TABM),Platynota idaeusalis (Walker), were tested in small plot trials in apple orchards in Pennsylvania. Treatments were evaluated by fruit injury and
by capture of male TABM in traps baited with synthetic pheromone sources or virgin females. The TABM pheromone is a two component
isomeric blend ofE-11-tetradecen-1-ol (E11-14:OH) andE-11-tetradecenyl acetate (E11-14:Ac). A 50∶50 ratio of these two components was used in standard monitoring septa and in mating
disruption treatments released from either hollow fibers (‘fiber’) or PVC tubes (‘PVC’). Other pheromone blends tested included
a 90∶10 ratio of E11-14: Ac and E11-14:OH (‘EAc’) and its reverse (‘EOH’), mixture ‘EAc’ with 30% of the Z-isomers (‘low AEc’),
and a blend similar to the preceding with 2% Z9-12:Ac (‘generic’). These other blends were released from multi tube tape (‘tape’)
or Shin-Etsu type rope (‘rope’) dispensers. Seasonal dispenser release rate in mg ha−1 h−1 was ca. 30 for the ‘rope’ dispensers, 14 for ‘PVC’ and 6 for ‘fiber’. ‘EAc-tape’ and ‘EOH-tape’ were equally effective in
reducing catches of males in traps baited with synthetic lures and in traps baited with virgin females. Both treatments also
reduced fruit injury. ‘EAc-rope’, ‘fiber’ and ‘PVC’ also were generally effective; whereas, the ‘low EAc’ and ‘generic’ treatments
reduced trap capture less than 90% and did not reduce fruit injury. Dispenser density was positively correlated with reduction
in trap capture for the ‘low EAc-rope’ and ‘genericrope’ treatments. Traps loaded with ‘fiber’ dispensers captured more male
TABM than the other treatments in non-pheromone permeated environments. Trap capture of other tortricids was reduced in pheromone
treatments. ‘EAc-rope’ and the ‘TABM’ treatments provided mean (s.e.) percent reduction in trap catch of 99.5 (0.4) and 42.9
(10.1), respectively, for the redbanded leafroller,Argyrotaenia velutinana (Walker), and 90.4 (6.8) and 90.4 (1.3), respectively, for the obliquebanded leafroller,Choristoneura rosaceana (Harris). 相似文献
11.
Summary An in vitro protocol has been developed for callus indiction, somatic embryogenesis, and plant regeneration from stigma-style culture
of grapevine. Four different grapevine cultivars (Vitis vinifera L.: cvs. ‘Bombino Nero’, ‘Greco di Tufo’, ‘Merlot’, and ‘Sangiovese’) were tested. Exlants were cultured on Nitsch and Nitsch
medium (NN) supplemented with various combinations of 6-benzylaminopurine (BA: 4.5 and 9.0 μM) and β-naphthoxyacetic acid (NOA; 5.0 and 9.9 μM). Sucrose (88 mM) was used as the carbon source. Somatic embryogenesis was induced within 3–7 mo. after culture initiation. Even though explants
of different origin (unfertilized ovules and anthers) regenerated somatic embryos, the higher embryogenic potential was observed
in stigma and style explants, with the exception of ‘Merlot’, which regenerated somatic embryos only from unfertilized ovules.
The percentages of stigma-style explants producing somatic embryos was 7% in ‘Bombino Nero’ (cultured on NN medium supplemented
9.0 μM BA and 9.9 μM NOA). 14% in ‘Greco di Tufo’ (4.5 μM BA and 9.9 μM NOA), and 8% in ‘Sangiovese’ (9.0 μM BA and 9.9 μM NOA). The presence of growth regulators (BA and NOA) in the medium was essential for induction of somatic embryogenesis.
Plants were regenerated on hormone-free NN medium containing 88 mM sucrose. 相似文献
12.
Xingguo Zhang Chaozhi Ma Tingdong Fu Yuanyuan Li Tonghua Wang Qingfang Chen Jinxing Tu Jinxiong Shen 《Molecular breeding : new strategies in plant improvement》2008,21(3):305-315
‘SI1300’ is a self-incompatible Brassica napus line generated by introgressing an S haplotype from B. rapa ‘Xishuibai’ into a rapeseed cultivar ‘Huayou No. 1’. Five S-locus specific primer pairs were employed to develop cleaved amplified polymorphic sequences (CAPS) markers linked the S haplotype of ‘SI1300’. Two segregating populations (F2 and BC1) from the cross between ‘SI1300’ and self-compatible European spring cultivar ‘Defender’, were generated to verify the molecular
markers. CAPS analysis revealed no desirable polymorphism between self-incompatible and self-compatible plants. Twenty primer
pairs were designed based on the homology-based candidate gene method, and six dominant sequence characterized amplified region
(SCAR) markers linked with the S-locus were developed. Of the six markers, three were derived from the SRK and SP11 alleles of class II B. rapa
S haplotypes and linked with S haplotype of ‘SI1300’. The other three markers were designed from the SLG-A10 and co-segregated with S haplotype of ‘Defender’. We successfully combined two pairs of them and characterized two multiplex PCR markers which could
discriminate the homozygous and heterozygous genotypes. These markers were further validated in 24 F3 and 22 BC1F2 lines of ‘SI1300 × Defender’ and another two segregating populations from the cross ‘SI1300 × Yu No. 9’. Nucleotide sequences
of fragments linked with S-locus of ‘SI1300’ showed 99% identity to B. rapa class II S-60 haplotype, and fragments from ‘Defender’ were 97% and 94% identical to SLG and SRK of B. rapa class I S-47 haplotype, respectively. ‘SI1300’ was considered to carry two class II S haplotypes and the S haplotype on the A-genome derived from B. rapa ‘Xishuibai’ determines the SI phenotype, while ‘Defender’ carry a class I S haplotype derived from B. rapa and a class II S haplotype from B. oleracea. SCAR markers developed in this study will be helpful for improving SI lines and accelerating marker-assisted selection process
in rapeseed SI hybrid breeding program. 相似文献
13.
In this study we use mtDNA ND2 gene (1041 bp) to evaluate the relationship between Menzbir’s (Anthus [gustavi] menzbieri) and Pechora (A. [g.] gustavi) pipits. Menzbir’s pipit is listed in the regional Red Data Book as a distinct, rare species with a small range. We obtained
18 Pechora pipit samples from two localities and 8 Menzbir’s pipit samples from a single locality. Sequences of the two taxa
appear reciprocally monophyletic and are separated by 6 substitutions (0.6% divergence). Differences between the taxa explained
62.4% of the variation in our dataset. Differences among individuals within localities explained 34.8%, whereas differences
between the two Pechora pipit localities explained only 2.8%. Mismatch distributions suggest that unlike the Pechora pipit
localities, which either have experienced recent population growth or sustain a stable population size, the Menzbir’s pipit
population may be declining. Our results suggest distinct taxonomic and conservation status for the Menzbir’s pipit. 相似文献
14.
Legumes as ground cover are regularly planted to increase nitrogen economy of crops and to improve soil. In the present study
various clover species were evaluated as vegetative ground cover in nursery field production of micropropagated red birch
(Betula pubescensEhrh. f. rubraUlvinen f. nova) in two 2-year experiments. The clover species and cultivars, Trifolium pratenseL. ‘Bjursele’, T. repens L. ‘Jogeva’, T. repens L. ‘Sonja’, T. hybridum L. ‘Frida’, T. incarnatum L. ‘Opolska’, T. resupinatum L. and T. subterraneum L. were compared to grass sod Festuca rubra L. ‘Ensylva’ and to a coverless ground (control). The last one was kept weed free by hand hoeing. Birch (leaves, stems, branches
and roots) and soil nutrient concentrations (N, P, K, Ca, Mg and Fe) were analysed and nutrient ratios in birch determined.
The annual clovers, T. incarnatumL., T. resupinatumL. and T. subterraneumL., provided about the same nutrient status in birch as did the control. Perennial clovers and grass were strong competitors
with trees. High levels of P and Mg in birch leaves relative to N concentration were typical for poorly growing seedlings.
Neither annual nor perennial clovers did generally improve soil nutrient status.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
15.
Experiments were conducted to quantify parasitism of Colorado potato beetle,Leptinotarsa decemlineata (Say), by the egg parasitoid,Edovum puttleri Grissell, on 3 different cultivars of eggplant,Solanum melongena L. Levels of parasitism were higher (P<0.05) on ‘Black Pride’ than on other cultivars. The percentage of egg masses that
were parasitized was 1.2-fold higher (P<0.05) on ‘Black Pride’ than on ‘Harris Special’ and ‘White’. The number of eggs per
mass that were parasitized was 1.3- and 1.4- fold greater (P<0.05) on ‘Black Pride’ than on ‘Harris Special’ and ‘White’,
respectively. The percentage of eggs that were parasitized per mass and percentage of emerged adult parasitoids did not differ
(P>0.05) among cultivars; between 2.1- to 2.6- fold more females than males emerged from eggs on all cultivars during the
growing season.Edovum puttleri suppressed the 2nd generation ofL. decemlineata on ‘Black Pride’ and ‘Harris Special’, but did not suppress populations on ‘White’.
相似文献
16.
Response of twenty eight cultivars of durum wheat (Triticum turgidum var. durum) to immature embryo culture, callus production and in vitro salt tolerance was evaluated. For assessment of cultivars to salt tolerance, growing morphogenic calli were exposed to different
concentrations of NaCl (0, 0.3, 0.6, 0.9, 1.2, 1.5, 1.8 and 2.1% w/v) added to the culture medium during two subsequent subcultures
(4 weeks each). Comparison of cultivars for callus induction from immature embryo was based on callus induction frequency
and fresh weight growth of callus (FWG). While, for salt tolerance, the relative fresh weight growth (RFWG) and necrosis percent
of callus were used. There were significant differences among cultivars for potential of regeneration from immature embryo,
and ‘Shahivandi’ a native durum wheat cultivar originating from western Iran was superior among the cultivars tested. The
FWG distinguished cultivars more than callus induction frequency did for callus induction evaluation. Hence, a range of FWG
from 1.23 to 14.65 g was observed in ‘Mexical-75’ and ‘Omrabi-5’ cultivars, respectively. Growing calli derived from cultivars
‘PI 40100’ and ‘Dipper-6’ showed superiority for tolerating salinity under in vitro conditions.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
17.
Patrick H. Brown Steven A. Weinbaum Geno A. Picchioni 《Trees - Structure and Function》1995,9(3):158-164
The influence of alternate bearing on nutrient utilization and total tree nutrient content was investigated in mature pistachio
(Pistacia vera L. cv Kerman trees). Removal of N, P and Zn in fruit and abscised leaves of cropping (‘on’) trees averaged 5, 6, and 2 times,
respectively, the removal in abscised leaflets of the non-fruiting, ‘off’ year trees. One hundred and thirty-five kg N, 131
kg K, 86 kg Ca, 39 kg Mg and 18 kg P per hectare were removed in fruits and abscised leaves in ‘on’ year trees. Tree nutrient
contents and, presumably, the size of nutrient storage pools in dormant trees varied between ‘on’ and ‘off’ years. There was
22% and 14% more N and P, respectively, in dormant trees following ‘off’ than ‘on’ years. The greater N and P accumulation
in ‘off’ year trees is depleted in support of the large fruit demand for N and P during ‘on’ years. In contrast to N and P,
there was greater K and Ca accumulation in perennial tree parts during ‘on’ years than during ‘off’ years. The greater K accumulation
in perennial tree parts and approximately 30% greater removal of K in annual organs during ‘on’ than ‘off’ years suggests
that K uptake could be 4 times higher in ‘on’ year trees than in (non-cropping), ‘off’ year trees. 相似文献
18.
Dr. Michaela Bernecker 《Facies》1996,34(1):41-76
Summary The Upper Triassic reefal limestones of the Oman Mountains were investigated with respect to their microfacies, palaeontology
and community structure. The reef fauna described and figured for the first time occurs in parautochthonous slope deposits
of the Arabian platform (Sumeini Group) and in allochthonous reefal blocks (‘Oman Exotics’, Hawasina Complex). The ‘Oman Exotics’
are tectonically dislocated blocks, derived from isolated carbonate platforms on seamounts in the Hawasina basin or in the
South Tethys Sea.
The lithofacies and fauna of these blocks comprise a cyclic platform facies with megalodonts, reef and reef debris facies.
The reefal limestones are dated as Norian/Rhaetian by benthic foraminiferal associations (Costifera, Siculocosta, Galeanella) and typical encrusting organisms (Alpinophragmium, Microtubus). Some small ‘Oman Exotics’ are of Carnian age.
The shallow-marine organisms include scleractinian corals of different growth forms, ‘sphinctozoans’, ‘inozoans’ chaetetids,
spongiomorphids, disjectoporids and solenoporacean algae as the main reef builders, various encrusters like microbes, foraminifers,
sponges and many different problematical organisms for the stabilisation of the reef framework and a group of dwellers including
benthic foraminifers, gastropods, bivalves and a few dasycladacean algae. The reef communities are characterized by the coverage
of organisms and distributional pattern.
Analogies with the coeval reef deposits from the European part of the Tethys have been recognized. Some species, now collected
in Oman, were also reported from American and Asian localities. 相似文献
19.
Ectomycorrhizal symbiosis in vitro between Tricholoma matsutake and Pinus densiflora seedlings that resembles naturally occurring ‘shiro’ 总被引:1,自引:0,他引:1
We established an in vitro ectomycorrhizal symbiosis between Tricholoma matsutake and Pinus densiflora. Mycorrhiza formed in a substrate of Modified Norkrans' C medium and granite-based soil had features similar to those observed
previously only in naturally occurring mycorrhizal system called ‘shiro,’ and promoted the growth of plants with smaller root/shoot
ratios. The in vitro formation of ‘shiro’ is essential for the development of T. matsutake system to produce mushrooms and is useful for the propagation and plantation of the mycorrhizal seedlings. 相似文献
20.
Reported crystallographic data and calculated molecular models indicated that chlorophyll (Chl) a and bacteriochlorophyll (BChl) a tend to bind the fifth ligand on the side of the macrocycle where the C132-(R)-methoxycarbonyl moiety protrudes (denoting the ‘back’ side). The crystal structures of 34 photosynthetic proteins possessing
(B)Chl cofactors revealed that most of Chl a and BChl a (and b) are coordinated by any peptidyl residue (e.g., histydyl-imidazolyl group), peptidyl backbone or water from the ‘back’ side.
Almost all the cofactors that bind a water molecule as the fifth ligand in these proteins have a ‘back’ configuration. Theoretical
model calculations for methyl chlorophyllide a (MeChlid a) and methyl bacteriochlorophyllide a (MeBChlid a) bound to an imidazole molecule indicated that the ‘back’ side is energetically favored for the ligand binding. These results
are consistent with the fact that ethyl chlorophyllide a (EtChlid a) dihydrate crystal consists of the ‘back’ complex. The modeling also showed that both removal and stereochemical inverse
of the C132-methoxycarbonyl group affect the relative stability between the ‘back’ and ‘face’ complexes. The effect of the C132-moiety on the choice of the macrocycle side for the ligand binding is discussed in relation to the function of P700.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献