A new cycad species,Cycas annaikalensis, has been discovered from the Malabar Coast of the southern Western Ghats of India. Although geographically distributed in
a small population within the range ofC. circinalis, it can be distinguished from the other described IndianCycas species by its distinct habitat, habit, morphology of vegetative and reproductive parts, and anatomy of leaflets. 相似文献
Abstract A scanning electron microscopy (SEM) study of Cycas cuticle characteristics was undertaken in order to expand our knowledge of microscopic characters not observable under light microscopy and to clarify unresolved affinitites among some species within the genus. Whole leaf and isolated cuticle specimens from the middle region of leaflets of greenhouse-grown plants of Cycas revoluta, Cycas rumphii, Cycas circinalis, Cycas media, and Cycas normanbyana were examined using SEM for interior and exterior features. Characteristics in common include hypostomy, hair bases on abaxial and adaxial surfaces, adaxial cells randomly arranged, adaxial exterior cuticle smooth, and stomata sunken to various degrees but stomatal pit always formed by two layers of epidermal cells. Stomatal complex is of the polyperigenous type. Stomata randomly dispersed and oriented, and except C. revoluta, are not contiguous. Stomata deeply sunken in C. revoluta, intermediate in C. rumphii and C. normanbyana, and less sunken in C. circinalis and C. media. Aperture between guard cells extends the entire stomatal length in C. rumphii and C. normanbyana, ~80% in C. circinalis and C. media, and ~50% in C. revoluta. Cuticular features of C. revoluta show the greatest difference from the other species in complex relief of exterior cuticle and interior cuticular structure of subsidiary cells; C. media and C. circinalis show close similarity to each other and their stomatal complex dimensions fall within the same unique cluster using principal component analysis under normalized variables. C. normanbyana and C. rumphii show the most similarity to each other in cuticular micromorphology. Stomatal complex dimensions of these two species fall into a second cluster that also includes C. revoluta. These data contrast with current taxonomy placing C. normanbyana synonymous to C. media. 相似文献
A new species of cycad allied to theC. circinalis group,Cycas pranburiensis, is described from the southeast karst area of Thailand near Pranburi, Prachuap Khiri Khan province. It is distinguished
by its short leaves with broad, coriaceous leaflets and mostly unarmed petioles, and the extended, gently curved sterile apices
of the microsporophylls. The cone beetle fauna of the new species, believed to be involved in pollination, is distinct from
that of other southeast Asian species ofCycas. 相似文献
Ailanthusaltissima or Ailanthusglandulosa (Simaroubaceae) is known as tree of heaven. It is a dioecious plant with staminate and pistillate flowers that grow on separate trees. In recent years, A.altissima has been frequently planted in numerous areas, especially in arid and semiarid lands of Iran and also used as an ornamental tree in several Iran cities including Kerman. The aim of this research was to identify IgE-binding proteins responsible for type I hypersensitivities of A. altissima pollen extract. In this study, pollen’s proteins were extracted and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Total protein content of pollen extracts was measured by Bradford assay. Allergenicity of pollen extract was evaluated by skin test and immunoblotting. Results showed that total protein concentration of A.altissima pollen was found to be 1.34 μg μl?1. In A. altissima pollen extract, different protein fractions were identified by SDS-PAGE mostly at 42, 53.7, 63, 87.7, 100 and 120 kDa. Skin tests showed a delayed hypersensitivity. Immunoblotting of A. altissima pollen extract with pooled subject’s sera detected a major IgE-binding component of 42 kDa. Moreover, these results will provide a platform for cloning cDNA encoding allergenic protein from A.altissima pollen. 相似文献
As ancient gymnosperm and woody plants, cycads have survived through dramatic tectonic activities, climate fluctuation, and environmental variations making them of great significance in studying the origin and evolution of flora biodiversity. However, they are among the most threatened plant groups in the world. The principal aim of this review is to outline the distribution, diversity, and conservation status of Cycas in China and provide suggestions for conservation practices. In this review, we describe the taxonomy, distribution, and conservation status of Cycas in China. By comparing Chinese Cycas species with its relatives worldwide, we then discuss the current genetic diversity, genetic differentiation of Cycas, and try to disentangle the potential effects of Quaternary climate changes and topographical events on Cycas. We review conservation practices from both researchers and practitioners for these rare and endangered species. High genetic diversity at the species level and strong genetic differentiation within Cycas have been observed. Most Cycas species in southwest China have experienced population retreats in contrast to the coastal Cycas's expansion during the Quaternary glaciation. Additionally, human activities and habitat fragmentation have pushed these endangered taxa to the brink of extinction. Although numerous efforts have been made to mitigate threats to Cycas survival, implementation and compliance monitoring in protection zones are currently inadequate. We outline six proposals to strengthen conservation measures for Cycas in China and anticipate that these measures will provide guidelines for further research on population genetics as well as conservation biology of not only cycads but also other endangered species worldwide. 相似文献
Cycas dharmrajii L.J.Singh (Cycadaceae), a new species from the Andaman Islands, India is described and illustrated, and its conservation status is assessed. An abnormal branching habit of the giant trunk, its swollen base, often branched, polymorphic aerial roots, medium‐sized leaves, megasporophylls with well‐defined 10–28 paired lateral hook‐like structures and 1–3 pairs of ovules, 2‐schizo‐lysigenous mucilage canals in leaflet, and characteristic pitting on the periclinal walls of the epidermal cells of the leaflets distinguishes it from all previously known species. A key to the species of Cycas from the Andaman and Nicobar Islands is also provided. 相似文献
This study addresses the apportionment of genetic diversity between Cycas revoluta and C. taitungensis, species that constitute the section Asiorientales and represent a unique, basal lineage of the Laurasian genus Cycas. Fossil evidence indicates divergence of the section from the rest of Cycas at least 30 million years ago. Geographically, C. taitungensis is limited to Taiwan whereas C. revoluta is found in the Ryukyu Archipelago and on mainland China. 相似文献
We developed a set of 12 EST-microsatellite markers (EST-STRs) from Cycas rumphii Miq. and tested them on an ex situ collection of the endangered Cycas micronesica K.D. Hill. The number of alleles per locus in both species ranged from 1 to 15. Observed and expected heterozygosities ranged
from 0.000 to 0.842, and 0.000 to 0.883, respectively. All primers amplified in four additional Cycas species. These markers are the first genome-enabled tools for cycad population level studies, and are now available to inform
conservation efforts and disentangle the biogeographic history of the genus. 相似文献
The chromosomes of Cycas pectinata are studied from root tipand pollen mitoses. The male and female plants showed the samenumber of chromosomes (2n = 22) with almost identical chromosomemorphology. The only difference is that in the female planttwo chromosomes of the somatic complement (pair III) bear satellites,while in the male the same pair is heteromorphic with only oneof its members bearing a satellite. This becomes further clearwhen two types of haplid complements are noticed in pollen mitosis,one type possessing a satellited chromosome, and the other showingnone bearing a satellite. The pair of chromosomes which is heteromorphic in the male isassumed to be associated with sex determination in Cycas, themale being the heterogametic sex with XY type of sex chromosomes. 相似文献
An aerobiological survey was performed in Berhampore town of West Bengal, India, to know the frequency of three common airborne
pollen, namely Acacia auriculiformis, Eucalyptus citriodora and Madhuca indica using an ASTIR one day volumetric sampler. Acacia pollen showed its peak concentration in September, followed by Madhuca in April, while Eucalyptus showed its two peaks between September–October and January–April. Meteorological factors like temperature, RH, rainfall played
an important role in release and dispersal of pollen. Skin prick tests with the antigenic extracts of the three pollen types,
showed their allergenic potentialities. The highest markedly positive reactions were exhibited by Eucalyptus (34.04%), followed by Madhuca (22.93%) and Acacia (21.87%). 30–60% (NH4)2 SO4 cut fraction (Fraction II) of each pollen type showed maximum positivity in skin prick test. Biochemical analysis showed
that Acacia pollen was richer in protein and carbohydrate, than the other two types. The total protein component of the above
types were studied by SDS-PAGE showing different protein bands with a range of molecular weight 29–110 KD. In isolated fraction
II (allergenically most potent) of Eucalyptus and Madhuca different protein band of 43–200 KD were obtained, while a single protein band of 57 KD was obtained for Acacia. The IgE specific allergenic reactivity was confirmed by Dot-blotting technique.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
Two new species of the family Myrmecolacidae, Myrmecolax comparilisn. sp. and Stichotrema sagaxn. sp., are described from West Bengal, India. Myrmecolax comparilis is the third species of that genus described from India while Stichotrema sagax is the first record of that genus for this country. 相似文献
The H2 uptake activity of three cyanobionts isolated fromCycas revoluta, C. circinalis andazolla filiculoides was shown to be related primarily to the growth rate and independent of the main mode of carbon nutrition. Significant H2 uptake was found in the coralloid roots ofCycas revoluta andZamia furfuracea (3 and 22 times higher than the respective C2H2 reduction activities). The results attained allow us to conclude that in cyanobacteria, in contrast to most nitrogen-fixing heterotrophs, uptake hydrogenase activity is not repressed by carbon substrates and that cyanobacteria in association seem to be endowed with sufficient H2 uptake capacity to recover all of the H2 released during the process of N2-fixation. 相似文献
Photosynthetic carboxylating enzymes and the effects of light and temperature on 14CO2 efflux in two species of gymnosperm leaves were studied. The activity of RuBP carboxylase was high and that of PEP carboxylase was very low when compared to C4 plants. The CO2 compensation point was high. 14CO2 efflux was greater in light than in darkness and the ratio (L/D) increased with increase in temperature and light intensity. The inhibitors of glycolate metabolism showed decreased 14CO2 evolution in light while dark respiration was unaffected. It is concluded that both Cycas circinalis, L. and Cycas beddomei Dyer are C3 plants. 相似文献
The genusCycas is revised for Thailand. Ten species are enumerated, five of them described as new (C. chamaoensis, C. clivicola, C. litoralis, C. nongnoochiae, C. tansachana), with one new subspecies (C. clivicola subsp.lutea). The species are placed within an infrageneric classification previously outlined. Distributions of the taxa are mapped, eight of the species are illustrated, and a key to species is provided. Previous records ofC. circinalis andC. rumphii from Thailand (here not regarded as indigenous in Thailand) are discussed. 相似文献
During production of sugar beet (Beta vulgaris) seeds in greenhouses, workers frequently develop allergic symptoms. The aim of this study was to identify and characterize possible allergens in sugar beet pollen.
Methods
Sera from individuals at a local sugar beet seed producing company, having positive SPT and specific IgE to sugar beet pollen extract, were used for immunoblotting. Proteins in sugar beet pollen extracts were separated by 1- and 2-dimensional electrophoresis, and IgE-reactive proteins analyzed by liquid chromatography tandem mass spectrometry.
Results
A 14 kDa protein was identified as an allergen, since IgE-binding was inhibited by the well-characterized allergen Che a 2, profilin, from the related species Chenopodium album. The presence of 17 kDa and 14 kDa protein homologues to both the allergens Che a 1 and Che a 2 were detected in an extract from sugar beet pollen, and partial amino acid sequences were determined, using inclusion lists for tandem mass spectrometry based on homologous sequences.
Conclusion
Two occupational allergens were identified in sugar beet pollen showing sequence similarity with Chenopodium allergens. Sequence data were obtained by mass spectrometry (70 and 25%, respectively for Beta v 1 and Beta v 2), and can be used for cloning and recombinant expression of the allergens. As for treatment of Chenopodium pollinosis, immunotherapy with sugar beet pollen extracts may be feasible. 相似文献
Three new species of the genus Zygnemopsis (Skuja) Trans. 1934 (Z. benghalensis sp. nov.; Z. pseudolahaulensis sp. nov., and Z. scrobiculata sp. nov.) are described from West Bengal, India. 相似文献
Left: Justicia betonica inflorescence showing completely opened bilabiate flowers. Photo by Prakash Karmakar Top-right: Potter wasp (Anterhynchium abdominale) collecting nectar. By Mrinmoy Midday Bottom-center: Black and White Cuckoo bee (Thyreus) searching for nectar. By P. Karmakar Bottom-right: Sweet bee (Halictus acrocephalus) gathering pollen. By M. Midday The photographs are taken adjacent to the Vidyasagar University Campus, West Bengal, India. Karmakar P et al. (2022) Floral biology, breeding system and pollination ecology of Justicia betonica L. (Acanthaceae): an assessment of its low reproductive success in West Bengal, India. Plant Species Biology, 278–293. https://doi.org/10.1111/1442-1984.12380