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1.
Recent studies have established the controlling influence of rhizospheric biota, especially arbuscular mycorrhizal fungi (AMF), on colonization and spread of some alien plants in their introduced range. But how AMF from different geographical sources influence traits that contribute to invasiveness, particularly in presence of neighbouring plants of other species, has been rarely investigated. Thus, we compared the influence of some local (Kashmir Himalayan isolates) and non-local (isolates from Rajasthan, India) AMF isolates of Glomus moseae, G. fasciculatum and Gigaspora margarita on vegetative and reproductive attributes of Mayweed Chamomile (Anthemis cotula L.), a highly invasive species in the Kashmir Himalaya, India. We also examined whether or not the neighbouring plant species, namely Daucus carota L. (Apiaceae) alters the mutualistic interaction between the AMF and A. cotula. Pot experiments revealed greater positive impact of the local than the non-local AMF on vegetative as well as reproductive attributes of A. cotula. Experimental field studies showed that the incidence of highly prevalent Arum-type mycorrhizal colonization in natural populations of A. cotula was reduced in presence of D. carota. Besides, the local AMF significantly promoted growth of A. cotula more than D. carota under mixed-culture conditions. These results suggest that the facilitation of some alien plant invasions by AMF needs to be considered together with plant–plant interactions and invasion-induced changes in the soil microbial community. 相似文献
2.
Syed Mudassir Jeelani Santosh Kumari Raghbir Chand Gupta Mohmmad Abubakar Ahmad Siddique 《Plant Systematics and Evolution》2014,300(5):1175-1198
Cytomorphological studies were made on 322 populations of 150 species/153 taxa belonging to 79 genera and 23 families of flowering plants. Out of these, 14 species were cytologically worked out for the first time on a worldwide basis along with B-chromosomes (0–1B) recorded for the first time in Agrimonia eupatoria. Similarly, 29 species were reported with varied chromosomal reports on a worldwide basis. The chromosome numbers ranged from 2n = 10 to 2n = 96 and posed high amount of intraspecific genetic diversity when seen in relation to other reports for the worked out species in light of previous chromosomal databases on India and world basis. The different levels of ploidy in these species/taxa vary from 2x to 12x with the overall polyploidy being 27.45 % and predominant in members belonging to the genera Ranunculus and Epilobium as well as families Ranunculaceae and Rosaceae. In the taxa showing anomalous meiotic behavior, cytomixis is found to be quite common and associated with various meiotic abnormalities in the meiocytes, which ultimately leads to pollen sterility and formation of variable sized pollen grains. 相似文献
3.
A.H. Munshi 《Aerobiologia》2000,16(3-4):449-452
Several grass pollens are important environmental bio-pollutants, causing various allergic disorders in susceptible persons.
Therefore, it is essential to study the period and duration of the flowering of the plants growing in a particular region/area.
For the area Srinagar (Kashmir Himalaya), a flowering calendar of grasses consisting of 57 species which fall under 35 genera
has been compiled in order to provide an understanding of habit, period of pollen release and their dispersal from the flowers,
pollen load in the atmosphere and the influence of meterological parameters.
The main object of this research work is to provide an information regarding the frequency of grass pollen in atmosphere to
the physicians, or medical practitioners. The maximum flowering period is recorded from July to September.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
4.
Carstem Humlum 《Ecography》1981,4(4):238-244
Age distributions and fruit production of populations of Oxyria digyna (L) Hill were studied in Norway and Greenland. The observed age distributions were described by the negative exponential function and by the power function. Three kinds of distributions were observed: steep, flat and bell-shaped with the corresponding hint production: 33–917, 8–108 and 76–303 fruits per individual. The population with the steep age distributions and high fruit productions were assumed to be increasing. They were found in sites with almost no vegetation (≤10% cover). The populations with the flat age distributions and the low fruit production were assumed to be stable. They were found in sites with a vegetational cover of 50–75%. The populations with the bell-shaped age distributions and the intermediate fruit productions were assumed to be decreasing. They were found in sites with a closed vegetation (cover ≥100%). 相似文献
5.
Anzar A. Khuroo Ewald Weber Akhtar H. Malik G. H. Dar Zafar A. Reshi 《Nordic Journal of Botany》2010,28(6):685-696
Biodiversity inventories unravel insightful taxonomic and biogeographic patterns that provide valuable inputs in guiding conservation practices and policymaking. Here we present an updated inventory of the native and alien woody flora of the Kashmir Himalaya, India, together with analyses of the patterns of taxonomic composition, geographic distribution, and invasion status of the alien species. The data was assembled from the floristic literature of the last two centuries, supplemented with herbarium records and validated by field surveys over the past decade. In total, the woody flora comprised of 520 species; out of these 322 species were native and 198 alien, yielding a proportion of 38% aliens. Amongst the natives, 16 species are on the IUCN red list 2009. While 37 genera included both native and alien species indicating a potential for hybrid formation, only 15 families were represented by alien species exclusively. Regarding the invasion status, presently 37 alien woody species are naturalized and 7 are invasive in the region. The results show that the Kashmir Himalaya harbours a diverse woody flora. It is concluded that a distinction between the native and the alien flora, as adopted in the present study, is crucial for a meaningful analysis of any biodiversity patterns. We predict that in the near future many alien woody species, presently naturalized in the region, can become serious plant invaders, and therefore need further research efforts and timely management. 相似文献
6.
The critically endangered and perennial alpine endemic angiosperms, namely, Aquilegia nivalis, Lagotis cashmeriana and Meconopsis latifolia inhabit such habitats in the Kashmir Himalaya that are characterised by short growing season and heavy snow cover for about
3–4 months during winter season. The seeds of these species under natural conditions experience a long period of pre-chilling
during winter prior to their germination in following spring season. Taking cue from such a requirement, present study investigated
the effect of chilling and exogenous application of growth hormones, NO3
− and NH4
+ on total percent germination of otherwise deep-dormant seeds of these species, under alternate light/dark and continuous
dark light regimes. Prolonged pre-chilling followed by treatment of seeds with different doses of GA3 had a pronounced stimulatory effect on the total germination percentage in all the three species. In fact, highest germination
percentage in A. nivalis was recorded only when pre-chilled seeds were treated with 1.5 mM GA3 under alternate light/dark conditions. Likewise, germination of pre-chilled seeds of L. cashmeriana with ruptured seed coats was improved when treated with various concentrations of GA3. Seed germination in M. latifolia was also favourably influenced by treatment of pre-chilled seeds with GA3 or nitrogen applied either as NO3
− or as NH4
+ under alternate light/dark conditions. Treatment of seeds with kinetin (6-furfuryl-aminopurine) had no significant influence
on germination percentage in any of the three species. Thus, prolonged chilling of seeds followed by their treatment with
GA3 under alternate light/dark conditions are the requirements necessary for seed germination in these species. 相似文献
7.
Prashant K. Pusalkar 《Nordic Journal of Botany》2014,32(3):308-313
The new species Picrorhiza tungnathii Pusalkar is described and illustrated from the western Himalaya, India. It is distinguished from the allied P. kurrooa Royle ex Benth. by being 10–25 cm tall, having a moderately dense, (10–)15–25‐flowered spike, a zygomorphic, 2‐lipped, glandular‐ciliate corolla that is equaling or slightly exceeding the calyx and partly visible or sub‐exserted between the calyx lobes, a conspicuously long (longer than the corolla lobes), curved corolla tube (1/2–4/5 the length of the calyx), unequal corolla lobes that are ovate‐lanceolate to lanceolate, acute to sub‐acuminate and moderately ciliate, a mid‐lobe of the upper lip that is obliquely erect, galeate with retuse or emarginate apex, lateral corolla lobes that are slightly smaller than the mid‐lobe of the upper lip, a lower corolla lip that is slightly shorter than the lateral lobes, obliquely erect or spreading, didynamous, long‐exserted (2–3 times the corolla) stamens, pollen of the Paederota‐type and a style that is 2–3 times as long as the corolla. 相似文献
8.
The relationship between susceptibility to photoinhibition, zeaxanthin formation and chlorophyll fluorescence quenching at suboptimal temperatures was studied in chilling-sensitive maize and in non-acclimated and cold-acclimated Oxyria digyna , a chilling-tolerant plant of arctic and alpine habitats. In maize, zeaxanthin formation was strongly suppressed by chilling. Zeaxanthin formed during preillumination at 20°C did not protect maize leaves from photoinhibition during a subsequent high-light, low-temperature treatment, as judged from the ratios of variable to maximal fluorescence, Fv /Fm . However, such preillumination significantly increased non-photochemical quenching (qN ) at low temperatures, mainly due to an enhancement of the fast-relaxing qN component (i.e., of energy-dependent quenching. qE ). In O. digyna , cold-acclimation resulted in an increased zeaxanthin formation in the temperature range of 2.5–20°C. Cold-acclimation substantially decreased the susceptibility towards photoinhibition at 4°C, but qN remained nearly unchanged between 2 and 38°C, as compared to control plants. Effects of cold acclimation on photosynthesis, photochemical quenching and quantum efficiency of photosystem II were small and indicated a slight amelioration only of the function of the photosynthetic apparatus at suboptimal temperatures (2–20°Ct. I) is concluded, that the xanthophyll cycle is strongly influenced by cold acclimation, while effects on the photosynthetic carbon assimilation only play a minor role in O. digyna. 相似文献
9.
The present study is part of our research project on cytomorphology of gamopetalous flora of Kashmir Himalaya, a zone with rich biodiversity. Out of 134 species of Gamopetalae meiotically investigated, chromosome numbers for 30 accessions belonging to 17 species and six families are new or varied reports. Euphrasia paucifolia (n = 22), Lactuca decipiens (n = 8), Saussurea albescens (n = 17), Saussurea roylei (n = 16), Saussurea taraxacifolia (n = 16) and Veronica deltigera (n = 8) are first cytological reports for these species. Anaphalis nepalensis (n = 28), Codonopsis rotundifolia (n = 16) and Hieracium vulgatum (n = 27) are new euploid chromosome reports for these species suggesting potential speciation through chromosomal evolution. Besides, Androsace mucronifolia (n = 10), A. sempervivoides (n = 10), Cicerbita lessertiana (n = 8), Dracocephalum nutans (n = 5), Erigeron patentisquama (n = 9), Galium pauciflorum (n = 11), Onopordum acanthium (n = 17) and Xanthium spinosum (n = 8) are the first chromosome reports to Indian accessions of the species. Out of the 17 species, 9 species (52.9 %) viz. A. nepalensis, C. lessertiana, C. rotundifolia, D. nutans, E. patentisquama, Euphrasia paucifolia, L. decipiens, O. acanthium and V. deltigera show abnormal meiosis/microsporogenesis of one or other type, thereby leading to pollen anomalies. 相似文献
10.
In any geographical area, surveys of the prevalence of intestinal helminths are necessary to suggest appropriate control measures. The aim of this study was to determine the prevalence of intestinal helminth infections in children of the Kashmir valley and to identify the risk factors. Stool samples were collected from 2256 children from rural as well as urban areas of the Kashmir valley. The samples were examined by simple smear and zinc sulphate concentration methods. Intensity of the infection was quantified by Stoll's egg-counting technique. Infection by at least one intestinal helminth was found in 71.18% of the sampled population. The prevalence of Ascaris lumbricoides was highest (68.30%), followed by Trichuris trichiura (27.92%), Enterobius vermicularis (12.67%) and Taenia saginata (4.60%). Light (57.1%) to moderate (42.8%) intensity of infection was observed for A. lumbricoides, while the majority of the infected children (92.3%) harboured a light intensity of infection for T. trichiura. The age group, rural or urban residence, type of water source, boiled or unboiled water, type of defecation site, level of personal hygiene and maternal education were associated with helminth infection. Adequate control measures are urgently needed to combat the high prevalence of intestinal helminths and risk factors in the children of Kashmir valley. 相似文献
11.
The ranges of arctic-alpine species have shifted extensively with Pleistocene climate changes and glaciations. Using sequence data from the trnH-psbA and trnT-trnL chloroplast DNA spacer regions, we investigated the phylogeography of the widespread, ancient (>3 million years) arctic-alpine plant Oxyria digyna (Polygonaceae). We identified 45 haplotypes and six highly divergent major lineages; estimated ages of these lineages (time to most recent common ancestor, T(MRCA)) ranged from ~0.5 to 2.5 million years. One lineage is widespread in the arctic, a second is restricted to the southern Rocky Mountains of the western United States, and a third was found only in the Himalayan and Altai regions of Asia. Three other lineages are widespread in western North America, where they overlap extensively. The high genetic diversity and the presence of divergent major cpDNA lineages within Oxyria digyna reflect its age and suggest that it was widespread during much of its history. The distributions of individual lineages indicate repeated spread of Oxyria digyna through North America over multiple glacial cycles. During the Last Glacial Maximum it persisted in multiple refugia in western North America, including Beringia, south of the continental ice, and within the northern limits of the Cordilleran ice sheet. Our data contribute to a growing body of evidence that arctic-alpine species have migrated from different source regions over multiple glacial cycles and that cryptic refugia contributed to persistence through the Last Glacial Maximum. 相似文献
12.
13.
Present paper deals with 20 species of the genusArtemisia occurring in the North-West Himalaya. Chromosome counts are given for 18 species (for 3 species for the first time). Two new species,A. banihalensis (A. roxburghiana agg.) andA. cashemirica (A. parviflora agg.), are described. 相似文献
14.
Nervilia pangteyana J. S. Jalal, Kumar & G. S. Rawat (Orchidaceae), a new species from western Himalaya (Uttarakhand), India is described, illustrated and compared with its closest relative. In addition, a key is given to distinguish between species of Nervilia in the western Himalayas. 相似文献
15.
16.
Arctodiaptomus (Rhabdodiaptomus) michaeli n.sp. is described from the material collected in Alapathar Lake and Marsar Lake of Kashmir, India. 相似文献
17.
Jean-Claude Rage Sudagar S. Gupta Guntupalli V. R. Prasad 《Pal?ontologische Zeitschrift》2001,75(2):197-205
The Neogene Siwalik deposits of Jammu Province (India) have yielded amphibians and squamates. The collection includes the
first amphibians and the first colubroid snakes from the Siwalik Group. Amphibians comprise only anurans: a possible Ranidae
and one, or perhaps two, non-ranid frogs Squamates include one lizard,Varanus sp. (Varanidae), whereas snakes are represented by three taxa:Acrochordus dehmi (Acrochordidae), an indeterminate Colubridae, and a snake that is either a Colubridae or an Elapidae.Varanus sp. andA. dehmi have been yielded by the Upper Miocene Ramnagar Member, whereas the anurans and colubroid snakes come from the Upper Pliocene
Labli Member. These taxa are indicative of aquatic palaeoenvironment. 相似文献
18.
Stalactites and moonmilk from Sahastradhara caves in Siwalik Himalayas were studied to understand the role of microbes in their genesis. Fourier spectroscopy in the moonmilk indicates a complex milieu of organic compounds that is unusual for inorganic formations. Stable C and O isotopes show trends in the moonmilk and stalactite, which suggest biogenic input; the geochemical inference is consistent with evidence from microscopy and laboratory-based microbial cultures. Light microscopy of moonmilk samples show the presence of a number of microbial forms similar to Cyanobacteria, and scanning electron microscope (SEM) images show microbial structures similar to Spirulina. The total number of microbial cells using SYBR Gold is 6.5 × 105 cells, g sed?1in moonmilk and 3.2 × 105 cells, g sed?1 in stalactites. FISH indicates approximately 3.5 × 105 cells, g sed?1 in moonmilk and 2 × 105 cells, g sed?1 in stalactites. SEM images of the moonmilk indicate a large network of microbial filaments along with minerals, which are identified as calcite based on their x-ray diffraction pattern. In vitro laboratory cultures with pure monogenic strains isolated from the moonmilk and stalactites raise pH in the medium, which facilitate calcite precipitation. The mineral precipitating isolates were identified as: Bacillus pumilis, B. cereus, B. anthracis, B. lentus, B. sphaericus, B. circulans and Actinomycetes. The Sahastradhara moonmilk and statactites are colonized by a diverse microbial community and the isolated bacterial strains induce biomineralization on different nutrient media, supporting their biogenic origin. 相似文献
19.
20.
Shiva K. Sharma Madho S. Bisht Maharaj K. Pandit 《Plant Systematics and Evolution》2010,287(1-2):29-36
In higher plants, synaptic mutation-associated gametic abnormalities are reported mostly in crop plants, but studies have rarely focused on the natural plant populations. This is particularly so in threatened herbaceous perennials, some of which are known to suffer from loss of sexual reproduction driven by the genetic mutations. Cytological investigations of Panax species, viz. P. sikkimensis, P. sokpayensis and P. bipinnatifidus, revealed that all the species were diploid with 2n = 24 chromosomes. Natural occurrence of synaptic mutation was recorded in Panax sikkimensis in the Kalep population of North Sikkim, India. We recorded that 86.03% of pollen mother cells (PMCs) lacked bivalent formation and had 24 distinct univalents at prophase I in the mutant plants of P. sikkimensis. We found a significantly lower mean number of chiasmata per cell (0.31 ± 0.91; t test = 38.24, P < 0.001) in the mutant plants as compared to the normal plants (21.04 ± 4.56). The chromosomal associations in the PMCs of the synaptic mutants ranged from 25% bivalents and 75% univalents to 100% univalents at diplotene/diakinesis. The unequal distribution of chromosomes at anaphase I and II resulted in the formation of microspores and microcytes of differing sizes. The pollen stainability test in the mutant population of P. sikkimensis revealed very low (0.12%) pollen fertility reflecting the consequences of synaptic mutation. Synaptic mutation in the herbaceous perennial P. sikkimensis was considered to be responsible for the male sterility in the species. 相似文献