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41.
IGNACIO M. SOTO ESTEBAN R. HASSON MAURA H. MANFRIN 《Biological journal of the Linnean Society. Linnean Society of London》2008,95(4):655-665
A central issue in evolutionary biology is to understand the mechanisms promoting morphological evolution during speciation. In a previous study, we showed that the Neotropical cactophilic sibling species Drosophila gouveai and Drosophila antonietae can be reared in media prepared with their presumptive natural host plants (Pilosocereus machrisis and Cereus hildmaniannus) and that egg to adult viability is not independent of the cactus host. In the present study, we investigate the effects of ecological and genetic factors on interspecific divergence in wing morphology, in relation to the pattern of wing venation and phenotypic plasticity in D. gouveai and D. antonietae, by means of the comparative analysis of isofemale lines reared in the two cactus hosts. The species differed significantly in wing size and shape, although specific differences were mainly localized in a particular portion of the wing. We detected significant variation in form among lines, which was not independent of the breeding cactus, suggesting the presence of genetic variation for phenotypic plasticity and wing shape variation in both species. We discuss the results considering the plausible role of host plant use in the evolutionary history of cactophilic Drosophila inhabiting the arid zones of South America. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 655–665. 相似文献
42.
We evaluated the role that endangered species reintroduction efforts can play in the larger context of ecosystem restoration. To do so, we examined interactions between endangered giant tortoises (Geochelone nigra hoodensis), currently being reintroduced to Isla Española, Galápagos, and an arboreal cactus (Opuntia megasperma var. megasperma), which is itself endangered and a keystone resource for many animals on the island. We collected information on spatial patterns of occurrence of cacti, tortoises, and woody vegetation and compared recruitment of juvenile cacti in areas occupied versus unoccupied by tortoises. Reintroduced tortoises appeared to suppress cactus recruitment near the few remaining adult cacti at the study site, but facilitate it at longer distances, with tortoise–cactus interactions mediated by the presence of woody vegetation, which likely alters tortoise movements and thereby patterns of cactus seed dispersal. The net effect of tortoises on cacti appeared to be positive insofar as tortoise presence was associated with greater recruitment of juveniles into cactus populations. Our study provides support for reintroducing endangered reptiles and other animals to aid ecosystem restoration in areas where they might once have played an important role in grazing upon and dispersing plants. 相似文献
43.
The xeric side of the Brazilian Atlantic Forest: The forces shaping phylogeographic structure of cacti
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Fernando Faria Franco Cecília Leiko Jojima Manolo Fernandez Perez Daniela Cristina Zappi Nigel Taylor Evandro Marsola Moraes 《Ecology and evolution》2017,7(22):9281-9293
In order to investigate biogeographic influences on xeric biota in the Brazilian Atlantic Forest (BAF), a biodiversity hotspot, we used a monophyletic group including three cactus taxa as a model to perform a phylogeographic study: Cereus fernambucensis subsp. fernambucensis, C. fernambucensis subsp. sericifer, and C. insularis. These cacti are allopatric and grow in xeric habitats along BAF, including isolated granite and gneiss rock outcrops (Inselbergs), sand dune vegetation (Restinga forest), and the rocky shore of an oceanic archipelago (islands of Fernando de Noronha). The nucleotide information from nuclear gene phytochrome C and plastid intergenic spacer trnS‐trnG was used to perform different approaches and statistical analyses, comprising population structure, demographic changes, phylogenetic relationships, and biogeographic reconstruction in both spatial and temporal scales. We recovered four allopatric population groups with highly supported branches in the phylogenetic tree with divergence initiated in the middle Pleistocene: southern distribution of C. fernambucensis subsp. fernambucensis, northern distribution of C. fernambucensis subsp. fernambucensis together with C. insularis, southern distribution of C. fernambucensis subsp. sericifer, and northern distribution of C. fernambucensis subsp. sericifer. Further, the results suggest that genetic diversity of population groups was strongly shaped by an initial colonization event from south to north followed by fragmentation. The phylogenetic pattern found for C. insularis is plausible with peripatric speciation in the archipelago of Fernando de Noronha. To explain the phylogeographic patterns, the putative effects of both climatic and sea level changes as well as neotectonic activity during the Pleistocene are discussed. 相似文献
44.
Regeneration from Phylloclade Explants and Callus Cultures of Schlumbergera and Rhipsalidopsis 总被引:1,自引:0,他引:1
Phylloclade explants of Schlumbergera and Rhipsalidopsis were cultured in vitro to produce axillary and adventitious shoots. The explants of both species, taken from greenhouse-grown plants, produced only
axillary shoots. There was a pronounced improvement in adventitious shoot formation in phylloclade explants of cultivar CB4
of Rhipsalidopsis by increasing numbers of subcultures of axillary shoots used as donor plants. The axillary shoots generated from the explants
were either subcultured to produce successive generations of axillary shoot cultures or made into phylloclade explants and
tested for adventitious shoot formation at each subculture. The duration of each subculture varied from 6 to 12 weeks. After
the first subculture, sporadic adventitious shoot formation began, and after the third subculture 87% explants of cultivar
CB4 produced adventitious shoots at a frequency of about 12 shoots per explant. In contrast, there was no improvement in regenerative
ability in explants of cultivar Thor-Olga of Schlumbergera up to third subculture. Adventitious shoots could be produced by callus culture too. Cultivar CB4 was highly regenerative,
producing as many as 10 adventitious shoots per square cm of callus. In vitro grown plantlets, when transferred to pots continued to show prolific growth. 相似文献
45.
The interaction of proteins bound at distant sites on a nucleic acid chain plays an important role in many molecular biological processes. Contact between the proteins is established by looping of the intervening polymer, which can comprise either double- or single-stranded DNA or RNA, or interphase or metaphase chromatin. The effectiveness of this process, as well as the optimal separation distance, is highly dependent on the flexibility and conformation of the linker. This article reviews how the probability of looping-mediated interactions is calculated for different nucleic acid polymers. In addition, the application of the equations to the analysis of experimental data is illustrated. 相似文献
46.
Association between cacti and nurse perennials in a heterogeneous tropical dry forest in northwestern Mexico 总被引:1,自引:0,他引:1
Abstract. The Sierra de La Laguna, Baja California Sur harbors the only tropical dry forest of the Peninsula. An inventory of the perennial plants was carried out at the eastern part of this mountain range. Plant spatial distribution was analyzed considering the species composition and vertical stratification of plant clusters in a study plot of 2 500 m2. A plant cluster was defined as a group of at least three individuals with a maximum distance between plants of 1 m. Soil physical-chemical characteristics and soil surface temperatures were compared between shade and sun conditions. The tropical dry forest of Baja California Sur presents a highly aggregated pattern of species distribution. Most of the perennial plants grow clumped, yet not all of the six cactus species recorded were significantly associated with them. Pattern analysis revealed that only Stenocereus thurberii and Ferocactus peninsulae were aggregated and associated to perennial plants. There is no replacement pattern between cacti and perennial plants. Nutrient content, including soil fertility, between shade and sun conditions does not seem to explain the patchy distribution of perennial plants, while the differences in solar radiation between these conditions appear to be restrictive and determinant of this spatial pattern of distribution. 相似文献
47.
Edgar Zenteno Lorena Vázquez Raúl Chávez Félix Córdoba Jean Michel Wieruszeski Jean Montreuil Henri Debray 《Glycoconjugate journal》1995,12(5):699-706
Sugar specificity of theMachaerocereus eruca isolectins, MeAI and MeAII, has been determined by comparing the capacity of glycans with well defined structures to inhibit their haemagglutinating activity. Both are galactose-specific isolectins with high affinity for O-glycans. However, the twoM. eruca isolectins recognize different oligosaccharidic sequences belonging to O-glycosidically linked glycans from porcine stomach mucin. The minimal structure recognized by MeAI on the porcine mucin glycans is the O-glycan core Gal1, 3GalNAc-ol, whereas MeAII has a more extended site and interacts with a biantennary O-glycan possessing the terminal trisaccharide Fuc1,2 (GalNAc1,3) Gal1,4. 相似文献
48.
Locereol (4α-methylcholesta-8,14-dien-3β-ol) and 5α-cholesta-8,14-dien-3β-ol, not previously isolated from plants, 24-methylenelophenol, lathosterol, 5α-campest -7-en-3β-ol and spinasterol are present in senita cactusin addition to the lophenol and schottenol described previously. 相似文献
49.
Z LATIFFAH K HARIKRISHNA S G TAN S H TAN F ABDULLAH Y W HO 《The Annals of applied biology》2002,141(2):133-142
Use of Crassulacean acid metabolism (CAM) plants in México and worldwide has a long history, but the morphological and photosynthetic aspects of these plants have only been considered recently. Emphasis in this article is on the daily net CO2 uptake ability by three species of agaves and three species of cacti that are currently extensively cultivated in México for beverages, food, fodder, and forage ‐ Agave mapisaga, A. salmiana, A. tequilana, Opuntia ficus‐indica, O. robusta and Stenocereus queretaroensis. Data under controlled conditions are used to help interpret seasonal net CO2 uptake patterns observed in the field. These CAM plants have instantaneous and total daily net CO2 uptake values similar to those for highly productive C3 and C4 crops. The future increase in the cultivated area of CAM plants will have both agronomical and ecological ramifications because of the ability of these plants to endure prolonged drought and to sequester carbon during extended dry periods when few C3 and C4 crops and non‐CAM native plants can fix atmospheric CO2. 相似文献
50.
Rodrigo Infante 《Plant Cell, Tissue and Organ Culture》1992,31(2):155-159
Yellow pitaya (Mediocactus coccineus) seeds were sown on Murashige and Skoog (1962) mineral salt medium. After germination, epicotyls were placed on media enriched with a combination of naphthaleneacetic acid (NAA) (0.05, 0.27 or 0.54 M) and benzyladenine (BA) (2.2 or 4.4 M). The apical tip was excised from half of the shoots and the other half were kept intact. Different values for proliferation rate, shoot length and thickness were observed on each medium. The cotyledons and roots were placed on MS medium supplemented with NAA (2.7 or 5.4 M) and embryogenic calluses were formed. Somatic embryos were induced on these media and then they normally developed on a growth regulator-free medium.Abbreviations BA
benzyladenine
- MS
Murashige and Skoog
- NAA
-naphthalenacetic acid 相似文献