首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Two new species of Gentianella (Gentianaceae, Gentianeae, Swertiinae), G. grantii and G. wayqecha, are described from Departamento Cusco, Peru. These two species differ from other Peruvian species of Gentianella in a combination of stems 10–100 cm long; no rosette of basal leaves; cauline leaves 10–75 mm long; flowers in thyrses; and corollas 14–26 mm long, campanulate, and adaxially glabrous. The leaves of G. grantii consist of an appressed pseudopetiole and a spreading, narrowly elliptic-oblong to linear blade; the corollas are lavender; and the corolla lobes are 0.6–0.7× as long as the tube. Gentianella grantii is similar to G. lythroides, of Bolivia, but differs in having more closely spaced leaves and less deeply lobed corollas. The leaves of G. wayqecha are sessile, lanceolate to ovate; the corollas are rose-violet; and the corolla lobes are 0.75–1.35× as long as the tube. Gentianella wayqecha is similar to G. rapunculoides, of Colombia and Ecuador, and G. ruizii, of Peru, but differs from both in its adaxially glabrous corollas and from G. rapunculoides in its less deeply lobed corollas. Both G. grantii and G. wayqecha grow in moist habitats near tree line, and are known only from a area northeast of the city of Cusco.  相似文献   

2.
Myrcia incompleta, from the northern Brazilian states of Amazonas and Rondônia, is described and illustrated. This species is apparently related to Calyptranthes paniculata and C. speciosa, from which it is distinguished mainly by its narrower leaves with midvein strongly raised adaxially and shorter, pauciflorous inflorescences. Conservation status for the species is proposed.  相似文献   

3.
Escherichia coli can hardly grow anaerobically on glycerol without exogenous electron acceptor. The formate-consuming methanogen Methanobacterium formicicum plays a role as a living electron acceptor in glycerol fermentation of E. coli. Wild-type and mutant E. coli strains were screened for succinate production using glycerol in a co-culture with M. formicicum. Subsequently, E. coli was adapted to glycerol fermentation over 39 rounds (273 days) by successive co-culture with M. formicicum. The adapted E. coli (19.9 mM) produced twice as much succinate as non-adapted E. coli (9.7 mM) and 62% more methane. This study demonstrated improved succinate production from waste glycerol using an adapted wild-type strain of E. coli with wild-type M. formicicum, which is more useful than genetically modified strains. Crude glycerol, an economical feedstock, was used for the cultivation. Furthermore, the increase in methane production by M. formicicum during co-culture with adapted E. coli illustrated the possibility of energy-saving effects for the fermentation process.  相似文献   

4.
Several species of predatory mites, especially those of the family Phytoseiidae, are potentially useful for the control of pest mites and insects. Among the phytoseiids, Euseius concordis (Chant), a species commonly found in South America, has been studied for possible use as biological control agent of pest mites. Given that Euseius species are known to feed on plant leaves and on pollen, the objective of this study was to determine plant species and pollen sources suitable to establish a pilot method of production of that species, based on a set of comparisons in the laboratory. Out of four plant species evaluated in the study, higher survivorship of E. concordis females in the absence of supplementary food was observed on leaflets of Canavalia ensiformis L. Out of two pollen types, higher survivorship was obtained on pollen of Typha domingensis L. In a subsequent step, the population of E. concordis increased 19.3× within 21 days when that pollen of T. domingensis was offered to the predator on plantlets of C. ensiformis, at 25.0 ± 1 °C, 70.0 ± 10% RH and 12 h photophase. Future studies may confirm the economic viability of this setup for the mass production of E. concordis.  相似文献   

5.
A new and rare species collected in Amazonian Ecuador, Sloanea jaramilloi, is described, illustrated, and its morphological similarities with other species of Sloanea is discussed. It resembles S. geniculata but is distinguished by the absence of persistent, adaxially concave stipules in the young branchlets, 4–6 sepals not covering entirely the reproductive organs of the flower, entire leaves, and the large, rigid, stout bristles sparsely distributed on the fruits.  相似文献   

6.
The success of an invasive plant species could be explained by trade-off between growth and defence. The aim of this paper was to explore the responses of two non-native aquatic macrophytes Elodea canadensis and Elodea nuttallii to herbivores in their introduced range. We assessed the palatability of the two phylogenetically close aquatic plant species in field and their responses to gammarid consumption in spring, summer and autumn in a microcosm experiment. We measured the variation of functional traits for each season. The traits selected were those judged most closely related to the allocation of resources to growth or to resistance against herbivores. We clearly established that the strategies of the two species were different and that their consumption rate differed in summer. In summer, E. canadensis allocated more of its resources to structural defence (leaf toughness). The increase in leaf thickness reduced the palatability of E. canadensis, whereas E. nuttallii stimulated its growth. Moreover, a decrease in dry matter content in E. nuttallii was found during the growing season in field. In autumn, both plant species accumulated nitrogen and phosphorus in their tissues. We also demonstrated that neither species induced efficient chemical defences against the herbivores. The different strategies of these two Elodea species could be explained by their different resident times in the introduced area and by an adaptation of the naturalised E. canadensis to herbivores.  相似文献   

7.
The purpose of this study was to determine the concentration of some metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn, Ca and Mg) in soil of serpentine and limestone sites, their bioaccumulation and impact on some biochemical parameters in T. luanica, T. kosovarica and T. albanica plants. T. kosovarica and T. albanica grows in serpentine soil, while T. luanica grow in limestone soil. The research showed that concentrations of Cd, Co, Cr, Fe, Mn and Ni were significantly higher at serpentine soil sites in comparison with limestone sites, while concentrations of Pb, Cd, Co and Cr in bulbs, leaves and seeds were under the limit of detection. The concentration of Ni in plant samples of T. kosovarica was significantly higher in comparison with its concentration in T. albanica, but it was under the limit of detection in T. luanica. Moreover, concentrations of Al and Fe in leaves of T. kosovarica and T. albanica were higher in comparison with T. luanica. The concentration of Mg was significantly higher in T. kosovarica and T. albanica than in T. luanica. The δ-aminolevulinic acid dehydratase activity, malondialdehyde and glutathione contents in leaves of T. luanica were higher in comparison with T. kosovarica and T. albanica. In addition, the amounts of total chlorophyll and δ-aminolevulinic acid (ALA) in leaves of T. albanica were higher in comparison with T. kosovarica and T. luanica. Our findings show that target organs of metal accumulation in three Tulip species appears to be leaves?>?seeds?>?bulbs, while the biochemical parameters show that limestone sites represent a less stressful habitat for growing these plant species in comparison with serpentine sites.  相似文献   

8.
A new species of Magnolia is described for the flora of Brazil, based on material from Bahia and Minas Gerais states. This species represents the first record of Magnoliaceae in the Northeastern region of Brazil. Magnolia brasiliensis differs from all other Brazilian species of Magnolia by having adaxially glossy leaves and differs from M. ovata by having a lower number of stamens and carpels. Despite its large extent of occurrence, the conservation status attributed to the new species is Endangered, mainly based on the low number of mature individuals in each subpopulation (< 50) and an area of occupancy of less than 16 km2.  相似文献   

9.
Micromorphological features of the leaf epidermis and the inner structure of leaf tissues of eight arborescent taxa of the genus Dracaena were analysed using light and scanning electron microscopy. The plants are xeromorphic or mesomorphic. Their leaves are isobilateral and amphistomatic, and the stomata are anomocytic and tetracytic. The mesophyll in all the species is divided into an outer chlorenchyma and a central region with colourless water-storage cells, chlorophyll cells and vascular bundles. Water-storage cells have wall bands and reticulate thickenings on the walls. The article describes and illustrates several new quantitative and qualitative leaf characters of the dragon tree group. Our findings can be used to identify the dragon tree group leaves, while the shape of epidermal cells and stomata types may be useful in the identification and classification of fragments of fossil leaves. We conclude that D. ombet and D. schizantha are not two distinct species, but should be treated as subspecies of D. ombet. Leaf characters, especially stomata depth on adaxial epidermis, height of adaxial epidermal cells and the presence and thickness of hypodermal fibre bundles markedly differ between geographical groups: Macaronesian species (D. draco and D. tamaranae), the species found in East Africa and Arabian Peninsula (D. ombet subsp. ombet, D. ombet subsp. schizantha, D. serrulata and D. cinnabari) and Southeast Asian species (D. kaweesakii and D. jayniana).  相似文献   

10.
Hyperaccumulators are plants that store exceptionally high concentrations of heavy metals or metalloids in their leaves. Phytolacca americana is one of the few species known to hyperaccumulate manganese (Mn); however, it is a common weedy species and has no specific association with high-Mn soils. Neither the mechanism by which P. americana hyperaccumulates Mn nor the ecological significance of this trait are well understood. It has recently been suggested that P. americana secretes acids into the rhizosphere as a means of acquiring phosphate, which might coincidentally increase Mn uptake. To determine whether P. americana acidifies the surrounding soil, plants were grown in rhizoboxes providing access to living roots. A thin layer of agar containing bromocresol green pH indicator dye was placed on the roots to observe color changes indicating acidification. Comparative studies showed that P. americana acidifies the rhizosphere significantly more than the non-accumulating plant Acalypha rhomboidea. A second experiment studied whether adjustment of soil pH and phosphate affect foliar Mn concentrations of P. americana. Concentrations of Mn in leaves were highest when plants were grown in acidified soils but were significantly lower in soils that were alkaline and/or enriched with phosphate. These results suggest that Mn hyperaccumulation may be a side effect of rhizosphere acidification as a phosphorus-acquisition mechanism, rather than an adaptation in its own right. The findings provide fundamental information about hyperaccumulator physiology and evolution, and may be relevant to attempts to utilize P. americana for phytoremediation.  相似文献   

11.
12.
In the large caldera of Mt. Aso, Japan, artificial grasslands were converted into forests of different species due to the decline of the livestock industry in this region. These changes in species composition are thought to have changed not only the transpiration rates (E), but also the responses in E to variations in environmental conditions. For three introduced forest types, we monitored E using sap flux sensors and computed E with a multilayer model parameterized by independently obtained leaf-scale ecophysiological traits. Modeled E replicated the time series of measured E reasonably well, but did not reproduce a decrease in E lasting 20 days after a short rainless period in conifer plantation. Mean leaf-scale stomatal conductance of two deciduous broadleaved tree species was as low as that of trees under dry conditions in other studies, possibly an adaptation for the avoidance of excessive E during rainless periods. These results suggest that land use change influenced E and its response to the rainfall patterns of the region and that drought plays an important role in influencing species-specific E characteristics in this rainy region. The multilayer model in combination with sap flux measurements was found to be a useful tool not only for the extrapolation of E, but also for the detection of the unexpected events, as long as the measured parameter values capture the species-specific seasonality in leaf ecophysiological traits.  相似文献   

13.
Two new species of Arachnothryx (Guettardeae, Rubiaceae) from the cloud forest of the Sierra Norte of Oaxaca, Mexico are described and illustrated. Arachnothryx axillaris together with A. heteranthera are the only two species in the genus with axillary inflorescences, but otherwise they are not similar. The new species is more similar to A. capitellata, but it differs in pubescence and inflorescence morphology. Arachnothryx flores-olverae can be confused with A. buddleioides mainly because they share discolorous leaves with densely tomentose pubescence, but they differ in stipule and inflorescence morphology. With these two new species the Sierra Norte of Oaxaca becomes more evidently the main hotspot of species diversity for the genus.  相似文献   

14.
Species of Alternaria are serious plant pathogens, causing major losses on a wide range of crops. Leaf blight symptoms were observed on tomato leaves, and samples were collected from various regions. Isolation was done from symptomatic tomato leaves, and 15 representatives were selected from a collection of 65 isolates of Alternaria species. The virulence of Alternaria isolates was investigated on detached leaves (DL) and whole plants of tomato cv. Super strain B. A phylogenetic analysis was performed based on three partial gene regions, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the RNA polymerase second largest subunit (RPB2) and the Alternaria major allergen gene (Alt a 1). The potentiality of Alternaria isolates to produce toxins was also investigated on the basis of thin-layer chromatography (TLC). Our investigations revealed that Alternaria isolates showed different levels of virulence either on tomato plants or DL. Based on the phylogeny of three genes, Alternaria isolates encompassed two species of small-spored morphospecies: A. alternata (14 isolates) and A. arborescens (single isolate). The produced toxins varied among Alternaria isolates with tenuazonic acid (TeA) being the most abundant mycotoxin produced by most isolates. This study highlighted on other Alternaria species in Egypt that might represent a serious concern for tomato producers as causal agents of leaf blight over other species, i.e. A. solani.  相似文献   

15.
Environmental sampling yielded two yeast species belonging to Microstromatales (Exobasidiomycetes, Ustilaginomycotina). The first species was collected from a leaf phylloplane infected by the rust fungus Coleosporium plumeriae, and represents a new species in the genus Jaminaea, for which the name Jaminaea rosea sp. nov. is proposed. The second species was isolated from air on 50% glucose media and is most similar to Microstroma phylloplanum. However, our phylogenetic analyses reveal that species currently placed in Microstroma are not monophyletic, and M. phylloplanum, M. juglandis and M. albiziae are not related to the type species of this genus, M. album. Thus, Pseudomicrostroma gen. nov. is proposed to accommodate the following species: P. glucosiphilum sp. nov., P. phylloplanum comb. nov. and P. juglandis comb. nov. We also propose Parajaminaea gen. nov. to accommodate P. albizii comb. nov. and P. phylloscopi sp. nov. based on phylogenetic analyses that show these are not congeneric with Jaminaea or Microstroma. In addition, we validate the genus Jaminaea, its respective species and two species of Sympodiomycopsis and provide a new combination, Microstroma bacarum comb. nov., for the anamorphic yeast Rhodotorula bacarum. Our results illustrate non-monophyly of Quambalariaceae and Microstromataceae as currently circumscribed. Taxonomy of Microstroma and the Microstromataceae is reviewed and discussed. Finally, analyses of all available small subunit rDNA sequences for Jaminaea species show that J. angkorensis is the only known species that possess a group I intron in this locus, once considered a potential feature indicating the basal placement of this genus in Microstromatales.  相似文献   

16.
The rice EMS-derived mutant leaf adaxialized 1 (lad1) was isolated based on its upward rolling leaf phenotype. Besides the adaxially rolled leaf, many other agronomic traits were also compromised in lad1. The rolling trait was characterized by a noticeable alteration of bulliform cells in the adaxial side of the leaves. Map-based cloning showed a single nucleotide substitution in the promoter region of the KAN1 gene in lad1 mutant. Further, over-expressing and CRISPR/cas9-edited knockdown transgenic plants confirmed that KAN1 was responsible for the mutant phenotype of lad1. Yeast two-hybrid and bimolecular fluorescence complementation assay demonstrated that KAN1 can interact with the auxin response factors ARF3, ARF7 and ARF15. Physiologically, the contents of auxin (IAA), abscisic acid (ABA), jasmonic acid (JA) and gibberellin (GA) were all significantly increased in the lad1 mutant. Moreover, the GA3 content dramatically decrease in wild-type, but increased in lad1 under IAA induction. Additionally, the expression levels of several IAA and GA biosynthesis and responsive-related genes and genes involved in leaf polarity determination were altered in lad1. Therefore, we hypothesized that KAN1/ARFs protein complexes act as auxin-dependent regulatory units that play a conserved role in leaf development.  相似文献   

17.
Cortinarius is one of the most species-rich genera of mushroom-forming fungi. Based on phylogenetic and morphological evidence, Cortinarius, sect. Riederi, is introduced at sectional level (= subsect. Riederi sensu Brandrud & Melot). The taxonomy, phylogeny, ecology and distribution of not only mainly European but also including some North American taxa of this section are treated, which includes nine species and two varieties. Of these, three taxa are described as new (C. burlinghamiae, C. pallidoriederi and C. argenteolilacinus var. dovrensis). The sect. Riederi species possess morphological features similar to Phlegmacium group(s) and forms a phylogenetically isolated lineage, with no supported affinity to other phlegmacioid groups. Three taxa are known from both Europe and North America, two species are known only from North America and five only from Europe. Altogether, eight of the ten taxa are associated with conifers or northern (boreal-subalpine) deciduous trees (Betula spp.). Only two species occur in more temperate forests (Fagus forests), and no species have so far been found in thermophilous Quercus forests  相似文献   

18.
The exotic mangrove species Laguncularia racemosa (Combretaceae) is fast-growing and was used for forestation in recent years along the southeast coast of China. The breeding system of L. racemosa is variable among populations, such as hermaphroditism, gynodioecy, and androdioecy. To determine whether androdioecy is widespread in L. racemosa, 19 planted populations were surveyed along the southeast coast of China. To determine whether local environmental factors could affect the sex ratio in androdioecious populations, the observed male frequency of different populations was compared to local average annual temperature, rainfall, and salinity. The results showed that the 19 L. racemosa populations along the southeast coast of China were androdioecious. The male frequencies of these populations varied from 31.0 to ?88.9%. Partial correlation analysis showed that average annual salinity explained 74.7% of the male frequency (p?=?0.001). It is reasonable to note that the male frequency followed a general trend, presenting peak that coincided with the low salinity. The average annual rainfall explained only 30.4% of the male frequency (p?=?0.403). And the average annual temperature explained only 20.2% of the male frequency (p?=?0.206). The variable male frequency in different androdioecious L. racemosa populations may presumably be caused by ecological or genetical processes; these hypotheses will be tested in future studies.  相似文献   

19.
We combined morphological and combined ITS, TUB and TEF sequence data to infer the phylogeny of the recently introduced genus Pseudopestalotiopsis. Two new species from China, Ps. camelliae from blighted leaves of Camellia sinensis and Ps. ignota from an undetermined host in China, are introduced with illustrated accounts and compared with similar taxa. Grey blight disease of tea appears to be caused by a group of fungi that constitutes a species complex. A new combination is proposed to emend the monophyly of Pseudopestalotiopsis and a species comparison is provided for taxa in the genus.  相似文献   

20.
A new opecoelid trematode is reported from fishes of the Lethrinidae, Lutjanidae and Nemipteridae off Lizard Island on the northern Great Barrier Reef, Australia. The new species keys to Neolebouria Gibson, 1976 and shows strong similarity to several species of that genus, but is not consistent with the type-species, N. georgiensis Gibson, 1976, or others known from temperate/polar and/or deep-sea fishes. The new species is also phylogenetically distant from N. lanceolata (Price, 1934) Reimer, 1987, the only representative of the genus for which molecular data are available. A new genus, Trilobovarium n. g., is proposed for the new species, T. parvvatis n. sp. Eight morphologically similar species, previously recognised as belonging to Neolebouria, from shallow-water, mostly tropical/subtropical fishes, are transferred to Trilobovarium: T. diacopae (Nagaty & Abdel Aal, 1962) n. comb.; T. ira (Yamaguti, 1940) n. comb.; T. khalili (Ramadan, 1983) n. comb.; T. krusadaiense (Gupta, 1956) n. comb.; T. lineatum (Aken’Ova & Cribb, 2001) n. comb.; T. moretonense (Aken’Ova & Cribb, 2001) n. comb.; T. palauense (Machida, 2014) n. comb.; and T. truncatum (Linton, 1940) n. comb. Paramanteriella Li, Qiu & Zhang, 1988 is resurrected for five species of Neolebouria with a post-bifurcal genital pore: P. cantherini Li, Qiu & Zhang, 1988; P. capoori (Jaiswal, Upadhyay, Malhotra, Dronen & Malhotra, 2014) n. comb.; P. confusa (Overstreet, 1969) n. comb.; P. leiperi (Gupta, 1956) n. comb.; and P. pallenisca (Shipley & Hornell, 1905) n. comb. Neolebouria georgenascimentoi Bray, 2002, a species with an exceptionally long cirrus-sac, is transferred to Bentholebouria Andres, Pulis & Overstreet, 2004 as B. georgenascimentoi (Bray, 2002) n. comb., and N. maorum (Allison, 1966) Gibson 1976, an unusual species known from cephalopods, is designated a species incertae sedis. Eleven species are retained in a revised concept of Neolebouria.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号