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1.
《Journal of Plant Interactions》2013,8(3):238-247
We investigated the mycorrhizal associations in 31 adult wild or cultivated green orchids (22 epiphytic, 8 terrestrial, and 1 species with both epiphytic and lithophytic life-forms) from different vegetation types of Western Ghats, southern India. All the orchids examined were mycorrhizal with the extent of colonization varying with species and life-forms. Mycorrhizal association has been reported for the first time in 25 orchids. The entry of mycorrhizal fungi into the roots was mostly through root hairs. In certain epiphytic species, the fungal entry was directly through the epidermis. The fungi formed highly coiled hyphal structures (pelotons) within the root cortex, and their size was related to the cell size. The fungal invasion of the cortical cells was through cell-to-cell penetration. The cortical cells contained intact and lysed pelotons, and their ratio varied with species and life-forms. No significant relationship existed between root hair characteristics and the extent of colonization. Chlamydospores and microsclerotia-like structure were frequently found within the cortical and root hair cells. The liberation of fungal reproductive structures was by spiral dehiscence of the root hairs. 相似文献
2.
石松类及蕨类植物在高等植物中处于比较特殊的进化与系统发育地位, 同时具有孢子植物(孢子)与种子植物(维管束)的双重特征。附生蕨类植物是蕨类植物中占据独特生境的一个大类群, 其生活史策略及进化历史与其附生生长的森林生态系统紧密相关。大部分附生蕨类植物的克隆生长习性及克隆生活史性状在其生态适应中具有重要作用, 但这方面未引起广泛关注。本文主要综述了中国山地森林中附生蕨类植物的根状茎克隆生长、克隆性与生态适应性、不同克隆生长方式与进化等方面, 并展望了蕨类植物克隆性在森林生态系统过程与功能中的作用, 以及今后如何将蕨类植物生态学研究与气候变化、植被恢复、土地利用变化等全球变化的主流方向进行结合。 相似文献
3.
The rate of molecular evolution is not constant across the Tree of Life. Characterizing rate discrepancies and evaluating the relative roles of time and rate along branches through the past are both critical to a full understanding of evolutionary history. In this study, we explore the interactions of time and rate in filmy ferns (Hymenophyllaceae), a lineage with extreme branch length differences between the two major clades. We test for the presence of significant rate discrepancies within and between these clades, and we separate time and rate across the filmy fern phylogeny to simultaneously yield an evolutionary time scale of filmy fern diversification and reconstructions of ancestral rates of molecular evolution. Our results indicate that the branch length disparity observed between the major lineages of filmy ferns is indeed due to a significant difference in molecular evolutionary rate. The estimation of divergence times reveals that the timing of crown group diversification was not concurrent for the two lineages, and the reconstruction of ancestral rates of molecular evolution points to a substantial rate deceleration in one of the clades. Further analysis suggests that this may be due to a genome-wide deceleration in the rate of nucleotide substitution. 相似文献
4.
Ecology of the Pteridophytes on the Southern Slopes of Mt. Kilimanjaro. Part II: Habitat Selection 总被引:2,自引:0,他引:2
A. Hemp 《Plant biology (Stuttgart, Germany)》2001,3(5):493-523
Abstract: Based on the evalutation of 957 vegetation plots on the southern slope of Mt. Kilimanjaro, habitat preferences for 140 species of pteridophytes were evaluated. Using the average percentage cover value, and taking into account the pteridophyte flora's composition, life form spectra and its spectra of seasonal growth pattern, eight vegetation formations were recognized. Ferns contributed less than 1 % of the vegetation cover of salt marshes, ruderal vegetation, grasslands and (sub-)alpine heathlands. In contrast, pteridophytes constituted the most important vascular plant group on rocks, where 64 species were found, forming about two-thirds of the vegetation cover. With respect to alpha and beta diversity and fern biomass, luxuriant montane forest was the main habitat for pteridophytes on Mt. Kilimanjaro. Here 130 pteridophyte species (93 % of the whole pteridophyte flora of the study area), on average, contributed 16 % of the total vegetation cover. Epiphytic ferns, tree ferns and filmy ferns had their main distribution between 1900 and 2400 m, in a zone coinciding with the maximum rainfall on Mt. Kilimanjaro's southern slope.
Poikilohydrous species were typical of dry habitats, such as on rocks, in meadows or along roadsides, but they also occurred in the often sun-exposed epiphyte layer in moist montane forests. Deciduous species, which were in many cases fire resistant, had a similar distribution; however, inside the forest belt they were restricted to the lower and upper parts, where fires are a common phenomenon. Evergreen species were the dominant group in swamps, forests and forest clearings.
Compared to other volcanoes in East Africa, Mt. Kilimanjaro is distinctly richer in fern species in general and in filmy ferns, tree ferns and epiphytic ferns in particular, suggesting that the forest belt of the southern slope of Mt. Kilimanjaro is wetter than those of other high mountains in East Africa. 相似文献
Poikilohydrous species were typical of dry habitats, such as on rocks, in meadows or along roadsides, but they also occurred in the often sun-exposed epiphyte layer in moist montane forests. Deciduous species, which were in many cases fire resistant, had a similar distribution; however, inside the forest belt they were restricted to the lower and upper parts, where fires are a common phenomenon. Evergreen species were the dominant group in swamps, forests and forest clearings.
Compared to other volcanoes in East Africa, Mt. Kilimanjaro is distinctly richer in fern species in general and in filmy ferns, tree ferns and epiphytic ferns in particular, suggesting that the forest belt of the southern slope of Mt. Kilimanjaro is wetter than those of other high mountains in East Africa. 相似文献
5.
JEAN-YVES DUBUISSON SABINE HENNEQUIN FRANCE RAKOTONDRAINIBE HARALD SCHNEIDER 《Botanical journal of the Linnean Society. Linnean Society of London》2003,142(1):41-63
Among the basal fern families, the Hymenophyllaceae, with more than 600 species, display a high diversity in terms of their morphology and the habitats that they occupy. We have chosen to focus on Trichomanes L., a clearly defined genus for which a phylogeny is presently being developed, to investigate the appearance of the climbing and epiphytic habits, as well as the related supposed adaptive characters. In this study we present the first review of the different ecological types within the genus: terrestrial, climbing (divided into hemi-epiphytic forms and true lianas), and epiphytic types. The study of several features concerning stem morphology and leaf size allows a proposal on relationships between ecology and plant morphology. Terrestrial species display a thick monocaulous rhizome with robust roots and short internodes. Climbing species are characterized by a branched, thick, creeping rhizome with long internodes. Epiphytic species also exhibit long, creeping and branching stems with long internodes but the rhizome is fine to filiform. Under these circumstances, there is a reduction of root system and frond size leading to dwarfism in numerous instances. This may be related to an extreme hygrophilous epiphytic strategy. Finally, hypotheses on the evolution of these habits and hence on the evolutionary relationships between ecology and characters are presented and discussed. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 142 , 41–63. 相似文献
6.
Xishuangbanna lies in the south of Yunnan. The composition and distributive regulation of lycophytes and ferns in Xishuangbanna are studied in this paper. As a result, 363 species of wild lycophytes and ferns which belong to 76 genera and 31 families are found in this area. The six species rich families are Polypodiaceae, Athyriaceae, Thelypteridaceae, Aspleniaceae, Pteridaceae and Selaginellaceae. The geographical distribution of the species shows that this flora mainly consists of Tropical Asia elements. Terrestrial species are the richest of this flora, followed by epiphytic and lithophytic species. The lycophytes and ferns resources of Xishuangbanna are abundant. However, the exploitation and utilization of this group of plants are ignored. This study investigated lycophytes and ferns resources of Xishuangbanna. Medicinal, edible and ornamental ferns in Xishuangbanna have been clearly researched and their utilization and protection have been discussed. 相似文献
7.
The pattern of canopy distribution and some water relations characteristics of the epiphytic cacti Epiphyllum phyllanthus and Rhipsalis baccifera and the epiphytic ferns Polypodium crassifolium and Polypodium phyllitidis were examined in the tropical forest of Barro Colorado Island, Panama. The epiphytic cacti were 6-fold more succulent than the epiphytic ferns, which had a 9-fold higher root: shoot ratio. The four species, especially the cacti, were more abundant on the deciduous trees Ceiba pentandra, Platypodium elegans. and Tabebuia guayacan than on the evergreen Anacardium excelsum. The water-holding capacity of the bark was 2-fold higher for A. excelsum and T. guayacan than for C. pentandra and P. elegans; the main crotches of the latter species intercepted 2-fold more rainfall than those of the former. Well-watered plants of all epiphytic species showed similar total daily transpiration. After 2 weeks of drought, daily transpiration decreased an average of 48 percent for the cacti and 73 percent for the ferns. After 4 weeks of drought, daily transpiration decreased 80 percent for the cacti and was eliminated for the ferns; succulence then decreased an average of 29 percent for the cacti and 98 percent for the ferns, but all species recovered fully within 2 d after rewetting. The epiphytic ferns had a low relative capacitance (0.16 M/Pa), causing these presumably C3 plants often to be under water stress. A high relative capacitance (0.50 M/Pa) and crassulacean acid metabolism allowed the epiphytic cacti to occur most frequently on the driest sites of this tropical forest. 相似文献
8.
Question: Are differences in microhabitat preferences of co‐occurring epiphytic Hymenophyllaceae species (filmy ferns) correlated with differences in ecophysiological responses to light availability and humidity in the host tree? Location: The Andean foothills in south‐central Chile. Methods: We evaluated the distribution pattern of nine filmy fern species in microhabitats that differ in light availability and humidity in four host tree species. A DCA was developed to assess Hymenophyllaceae species microhabitat preference in terms of canopy openness (CO) and relative humidity. We assessed whether differences in chlorophyll content, maximum photochemical efficiency (Fv/Fm), photosynthetic capacity (Amax), evapotranspiration (E) and instantaneous water use efficiency (WUE) are consistent with any pattern. Results: CO and relative humidity differed significantly with height in the host trees. While CO increased with height in a host tree, relative humidity decreased. DCA analysis showed that filmy fern species distribution within and among trees was mainly explained by the relative humidity of the microhabitat. Chlorophyll content, chlorophyll a/b ratio, Amax and E differed significantly among filmy fern species. Amax and E were correlated with axis 1 scores from the DCA analysis. Conclusions: The vertical distribution and abundance of filmy fern species in Chilean temperate rain forest seems to be closely related to the different microhabitats offered by host trees. This pattern may reflect interspecific differences in ecophysiological traits related both to light availability and humidity. Our results suggest that humidity is the main environmental factor driving functional responses and habitat preferences of these filmy fern species. 相似文献
9.
Nicole Mandl Marcus Lehnert Michael Kessler S. Robbert Gradstein 《Biodiversity and Conservation》2010,19(8):2359-2369
We present a first comparison of patterns of alpha and beta diversity of ferns, mosses, liverworts and macrolichens in neotropical
montane rainforests, and explore the question whether specific taxa may be used as surrogates for others. In three localities
in southern Ecuador, we surveyed terrestrial and epiphytic species assemblages in ridge and slope forests in 28 plots of 400 m2
each. The epiphytic habitat was significantly richer in ferns, liverworts, and macrolichens than the terrestrial habitat;
mosses, however, were primarily terrestrial. Alpha diversity of ferns and of liverworts was congruent in both habitats. Mosses
were similar to ferns and liverworts only in the epiphytic habitat. Macrolichens did not share patterns of alpha diversity
with any other group. Beta diversity of ferns, mosses and liverworts (lichens excluded due to low species richness) was similar
in the terrestrial habitat, but not in the epiphytic habitat. Our results demonstrate that patterns of alpha diversity of
the studied taxa cannot be used to predict patterns of beta diversity. Moreover, diversity patterns observed in epiphytes
are different from terrestrial plants. We noted a general coincidence in species patterns of liverworts and ferns. Diversity
patterns of macrolichens, in contrast, were completely independent from any other taxonomic group studied. 相似文献
10.
A. M. F. Tomescu G. W. Rothwell M. L. Trivett 《Plant Systematics and Evolution》2008,270(3-4):209-216
Reiteration is a widespread component of plant growth whose evolutionary importance in ferns is not recognized widely. We
introduce and discuss the growth architecture of Kaplanopteris clavata, a fossil filicalean fern from the Pennsylvanian (ca. 305 million yeas old), focusing on types of reiteration exhibited by
this species and on the adaptive and phylogenetic significance of reiteration for ferns in general. Kaplanopteris clavata combines two types of reiterative growth where growth modules are borne on fronds: (1) entire fronds derived from primary
pinnae, and (2) epiphyllous plantlets. This combination of reiterative pathways, unique among fossil and living ferns, allowed
K. clavata to explore ecospace through an opportunistic combination of scrambling, climbing and epiphytic growth. Kaplanopteris clavata underscores the organographic importance of fronds (as opposed to stems) in the adaptive architecture of ferns, emphasizing
functional convergences between the different Baupla̋ne of ferns and angiosperms. This unique combination of reiterative pathways
is interpreted as a derived condition illustrating the structural and developmental complexity achieved by some filicaleans
during the first major evolutionary radiation of leptosporangiate ferns. 相似文献
11.
Dubuisson JY Hennequin S Bary S Ebihara A Boucheron-Dubuisson E 《Comptes rendus biologies》2011,334(12):880-895
To infer the anatomical evolution of the Hymenophyllaceae (filmy ferns) and to test previously suggested scenarios of regressive evolution, we performed an exhaustive investigation of stem anatomy in the most variable lineage of the family, the trichomanoids, using a representative sampling of 50 species. The evolution of qualitative and quantitative anatomical characters and possibly related growth-forms was analyzed using a maximum likelihood approach. Potential correlations between selected characters were then statistically tested using a phylogenetic comparative method. Our investigations support the anatomical homogeneity of this family at the generic and sub-generic levels. Reduced and sub-collateral/collateral steles likely derived from an ancestral massive protostele, and sub-collateral/collateral types appear to be related to stem thickness reduction and root apparatus regression. These results corroborate the hypothesis of regressive evolution in the lineage, in terms of morphology as well as anatomy. In addition, a heterogeneous cortex, which is derived in the lineage, appears to be related to a colonial strategy and likely to a climbing phenotype. The evolutionary hypotheses proposed in this study lay the ground for further evolutionary analyses that take into account trichomanoid habitats and accurate ecological preferences. 相似文献
12.
The study of the underground parts of plants is often difficult, and as a result roots are often treated as homogeneous physiological entities with respect to root respiration. In this study we demonstrate a partitioning of respiration within root tissues using nitro blue tetrazo-lium staining and an incident light optical system that permits detailed observations of intact roots. The assay is rapid and easy to perform, and reveals that respiratory activity in roots is not uniform in space and time. The results show that root hairs in particular may be regions of enhanced respiratory activity in some species or in certain developmental or physiological states. This fact has important implications for the role of root hairs in the overall respiratory budget of roots and the energetics of nutrient assimilation. The results suggest that root respiration studies should consider differential respiratory activities of root cell types within roots. 相似文献
13.
Ferns usually have relatively lower photosynthetic potential than angiosperms. However, it is unclear whether low photosynthetic potential of ferns is linked to leaf water supply. We hypothesized that there is an evolutionary association of leaf water transport capacity with photosynthesis and stomatal density in ferns. In the present study, a series of functional traits relating to leaf anatomy, hydraulics and physiology were assessed in 19 terrestrial and 11 epiphytic ferns in a common garden, and analyzed by a comparative phylogenetics method. Compared with epiphytic ferns, terrestrial ferns had higher vein density (Dvein), stomatal density (SD), stomatal conductance (gs), and photosynthetic capacity (Amax), but lower values for lower epidermal thickness (LET) and leaf thickness (LT). Across species, all traits varied significantly, but only stomatal length (SL) showed strong phylogenetic conservatism. Amax was positively correlated with Dvein and gs with and without phylogenetic corrections. SD correlated positively with Amax, Dvein and gs, with the correlation between SD and Dvein being significant after phylogenetic correction. Leaf water content showed significant correlations with LET, LT, and mesophyll thickness. Our results provide evidence that Amax of the studied ferns is linked to leaf water transport capacity, and there was an evolutionary association between water supply and demand in ferns. These findings add new insights into the evolutionary correlations among traits involving carbon and water economy in ferns. 相似文献
14.
Mycorrhizal symbioses were found in the roots of 45 out of 59 species of pteridophytes collected in Korea. The mycorrhizal
fungi were colonized in the root cortical cells, primarily in terrestrial species, but rarely in epiphytic or aquatic pteridophytes.
Mycorrhizae that are typically found in orchid colonized the roots of the epiphytic pteridophytes, but not in other species.
These were the first observations of orchid mycorrhizae in pteridophytes. Arbuscular mycorrhizal fungi were examined after
staining, then confirmed with PCR, using a specific primer. This is the first report of arbuscular mycorrhizal colonization
in the roots of pteridophyte species in Asia. 相似文献
15.
Most plant roots are associated with glomalean fungi forming arbuscular mycorrhizas (AM) and a wide range are also colonized
by ascomycetous dark septate endophytes (DSE). Bromeliaceae species can be epiphytic, rupicolous or terrestrial but their
mycorrhizal status is poorly studied. We examined the AM and DSE status of 5 epiphytic and 4 terrestrial Bromeliaceae from
an arid area of Central Argentina. The terrestrial species were either dually associated (AM and DSE) or non-associated whereas
the epiphytes were only DSE colonized. Terrestrial Bromeliaceae that formed AM-DSE associations were likely responding to
the arid conditions of the area and the availability of AM fungal (AMF) spores in the soil. The terrestrialBromelia ubaniana was not colonized either by AMF or DSE. This could reflect its root morphology and high number of root hairs. DSE are endosymbiotic
in the stressful ecosystems experienced by canopy epiphytes in the studied environment. The different fungal associations
are discussed in relation to the three Bromeliaceae subfamiles and we suggest that environmental features determinethe type
of association formed by species in this plant family. 相似文献
16.
We examined the roots of 27 epiphytic and terrestrial species of Piperaceae collected in primary and secondary habitats in Monteverde, Costa Rica. Terrestrial roots of only two of the nine Peperomia species, two of eight Piper species, and of Pothomorphe umbellatum contained internal vesicles and/or arbuscules. We did not find internal vesicles and/or arbuscules in 3024 cm of fine roots of epiphytic Piperaceae, even though 15% of these root segments had associated external typical glomalean hyphae. Glomus and Acaulospora spores, and Gigaspora auxiliary cells occurred in both canopy and terrestrial habitats. After inoculation of a low nutrient substrate, the facultatively epiphytic Peperomia costaricensis averaged 23% mycorrhizal root length. Relatively high atmospheric inputs of dissolved inorganic nutrients that alleviate the requirement for mycorrhizae, and heterogeneity of mycorrhiza inocula in the canopy may explain the absence of mycorrhizae from epiphytic Piperaceae. We suggest that the Piperaceae comprises predominantly facultatively mycotrophic species, and that facultative mycotrophism facilitates their radiation to the canopy. 相似文献
17.
Jean-Yves Dubuisson Harald Schneider Sabine Hennequin 《Comptes rendus biologies》2009,332(2-3):120-128
As for other vascular plants, numerous adaptive strategies have been selected in epiphytic ferns in order to survive in a constraining and desiccating environment and thus to prevent dehydration and/or to access to water and nutrients. Here we present some of the specializations that allow ferns to survive in this particular habitat. Some of the most spectacular epiphytic specializations are observed in the Polypodiaceae family, involving humus-collectors which entrap humus in specialized organs, and ant-plant mutualism strategies. We then address the question of epiphytism in an evolutionary context. There is little fossil evidence of vascular epiphytes. Inferring the evolution of epiphytism in extant ferns shows that diversification of major living epiphytic groups mostly occurred in the Tertiary. Finally, we focus on the Hymenophyllaceae family which provides an original example of hygrophilous epiphytic strategy that is unique in vascular plants. To cite this article: J.-Y. Dubuisson et al., C. R. Biologies 332 (2009). 相似文献
18.
We present a comparative analysis on the anatomy of roots, shoots, and leaves of three epiphytic Pleiochiton species and a species of the closely related Clidemia. The four species share similar anatomical characters, suggesting adaptations toward water storage in all the structures and, consequently, to the water-limited epiphytic habitat. All four species present succulent roots with up to 75% of its volume with cells that store water. The leaves have about 50% of the volume formed by a hypodermis that also stores water. They are very similar to leaves of epiphytic Peperomia and Gesneriaceae, suggesting evolutionary convergence. Leaf cells in all species have large vacuoles and compact mesophyll, with little intercellular spaces; all these traits are usually related to CAM photosynthesis. The anatomical features found in all four species agree with previous phylogenetic analyses that show Clidemia blepharodes, Pleiochiton ebracteatum and Pleiochiton micranthum as members of a same clade. 相似文献
19.
Emonet EG Tafforeau P Chaimanee Y Guy F de Bonis L Koufos G Jaeger JJ 《Journal of human evolution》2012,62(1):146-154
Although often preserved in the fossil record, mandibular dental roots are rarely used for evolutionary studies. This study qualitatively and quantitatively characterizes the three-dimensional morphology of hominoid dental roots. The sample comprises extant apes as well as two fossil species, Khoratpithecus piriyai and Ouranopithecus macedoniensis. The morphological differences between extant genera are observed, quantified and tested for their potential in systematics. Dental roots are imaged using X-ray computerized tomography, conventional microtomography and synchrotron microtomography. Resulting data attest to the high association between taxonomy and tooth root morphology, both qualitatively and quantitatively. A cladistic analysis based on the dental root characters resulted in a tree topology congruent with the consensus phylogeny of hominoids, suggesting that tooth roots might provide useful information in reconstructing hominoid phylogeny. Finally, the evolution of the dental root morphology in apes is discussed. 相似文献
20.
Gbenga F. Akomolafe Rusly Rosazlina Zakaria Rahmad Fatai A. Oloyede 《Ecology and evolution》2022,12(6)
Research on fern ecology has gained attention in the last decade, yet there is a paucity of information on the comparison of ferns communities across continents. This study focused on comparing the ferns community assemblages in some tropical forests of Malaysia and Nigeria, thereby assessing the patterns of species richness (SR) and phylogenetic diversity (PD) in relation to the bioclimatic drivers across the continents. The diversity and taxonomic compositions of ferns were assessed using 180 plots of 10 m × 10 m in each country. The species richness and other diversity indices were determined using the combined forests data for each country and for the individual forests. Also, the phylogenetic diversity of the ferns was assessed using the genus‐based molecular sequences downloaded from the GeneBank. The patterns of the ferns SR and PD in the two countries as driven by some bioclimatic factors were evaluated using the regression analysis. The observed and rarefied–extrapolated fern species richness is significantly higher in Malaysian forests than in Nigerian forests. Also, the other diversity indices are significantly higher in Malaysian forests except for the Shannon index which showed no significant difference between the two biogeographic regions. There is a very low similarity (7.41%) in the taxonomic composition of ferns between the two biogeographic areas, although the similarity in composition increased with increasing taxonomic levels (species: 7.41%, genus: 12.77%, family: 70.96%). Terrestrial and epiphytic ferns are more dominant than the other life forms in the two countries. The precipitation variables drive the phylogenetic structure of ferns in Nigeria, whereas both precipitation and temperature variables drive the phylogenetic structure of ferns in Malaysia. This indicates that ferns assemblages in Nigeria and Malaysia are driven by both climatic variables. Besides, we also hypothesize that these observed differences could be due to other historical and evolutionary processes. 相似文献