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1.
PLoS One ; 19(4): e0302211, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38635726

RESUMO

Evolutionary maintenance of dioecy is a complex phenomenon and varies by species and underlying pathways. Also, different sexes may exhibit variable resource allocation (RA) patterns among the vegetative and reproductive functions. Such differences are reflected in the extent of sexual dimorphism. Though rarely pursued, investigation on plant species harbouring intermediate sexual phenotypes may reveal useful information on the strategy pertaining to sex-ratios and evolutionary pathways. We studied H. rhamnoides ssp. turkestanica, a subdioecious species with polygamomonoecious (PGM) plants, in western Himalaya. The species naturally inhabits a wide range of habitats ranging from river deltas to hill slopes. These attributes of the species are conducive to test the influence of abiotic factors on sexual dimorphism, and RA strategy among different sexes. The study demonstrates sexual dimorphism in vegetative and reproductive traits. The sexual dimorphism index, aligned the traits like height, number of branches, flower production, and dry-weight of flowers with males while others including fresh-weight of leaves, number of thorns, fruit production were significantly associated with females. The difference in RA pattern is more pronounced in reproductive traits of the male and female plants, while in the PGM plants the traits overlap. In general, habitat conditions did not influence either the extent of sexual dimorphism or RA pattern. However, it seems to influence secondary sex-ratio as females show their significant association with soil moisture. Our findings on sexual dimorphism and RA pattern supports attributes of wind-pollination in the species. The observed extent of sexual dimorphism in the species reiterates limited genomic differences among the sexes and the ongoing evolution of dioecy via monoecy in the species. The dynamics of RA in the species appears to be independent of resource availability in the habitats as the species grows in a resource-limited and extreme environment.


Assuntos
Hippophae , Caracteres Sexuais , Reprodução , Polinização , Plantas , Alocação de Recursos
2.
Front Plant Sci ; 15: 1355680, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38606073

RESUMO

Infraspecific floral trait variations may appear in response to elevational differences in alpine plant species. There is enormous information on the selection of such morphs mediated by biotic and/or abiotic variables. Whether such differences contribute to differences in reproductive strategy and mating outcomes is rarely investigated. We investigated these aspects in two distinct elevational floral morphs (Red and Pink) of Rhododendron arboreum Sm. in Western Himalaya. The red morphs occupy the lower elevations while pink morphs the higher elevations. The two morphs differ in floral traits like phenology, dimension, display, quality of floral rewards, and pollinators that happen to influence interaction with available pollinator pool at each elevation. The pink morph exhibits entomophily, while the red ones show ornithophily. Although experimental pollinations established that both the morphs are self-compatible, selfing results in significantly lower fruit-set than either cross- or open-pollinations. The outcrossing rate in the red morph, as determined by using simple sequence repeat (SSR) markers, was higher (tm=0.82) than that in the pink morph (tm=0.76), with a tendency of the latter to be shifting towards mixed-mating strategy. However, the extent of biparental inbreeding was comparable among the two morphs. It is inferred that the differences in the mating outcomes among the morphs in the tree species are linked to those emerging from floral traits and the pollination by different functional groups of floral visitors.

3.
Environ Monit Assess ; 195(6): 715, 2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37221436

RESUMO

Climate change impact on the habitat distribution of umbrella species presents a critical threat to the entire regional ecosystem. This is further perilous if the species is economically important. Sal (Shorea robusta C.F. Gaertn.), a climax forest forming Central Himalayan tree species, is one of the most valuable timber species and provides several ecological services. Sal forests are under threat due to over-exploitation, habitat destruction, and climate change. Sal's poor natural regeneration and its unimodal density-diameter distribution in the region illustrate the peril to its habitat. We, modelled the current as well as future distribution of suitable sal habitats under different climate scenarios using 179 sal occurrence points and 8 bioclimatic environmental variables (non-collinear). The CMIP5-based RCP4.5 and CMIP6-based SSP245 climate models under 2041-2060 and 2061-2080 periods were used to predict the impact of climate change on sal's future potential distribution area. The niche model results predict the mean annual temperature and precipitation seasonality as the most influential sal habitat governing variables in the region. The current high suitability region for sal was 4.36% of the total geographic area, which shows a drastic decline to 1.31% and 0.07% under SSP245 for 2041-60 and 2061-80, respectively. The RCP-based models predicted more severe impact than SSP; however, both RCP and SSP models showed complete loss of high suitability regions and overall shift of species northwards in the Uttarakhand state. We could identify the current and future suitable habitats for conserving sal population through assisted regeneration and management of other regional issues.


Assuntos
Dipterocarpaceae , Ecossistema , Modelos Climáticos , Monitoramento Ambiental , Cloreto de Sódio , Sais
4.
Indian J Nephrol ; 32(5): 480-483, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36568596

RESUMO

A 45-year-old gentleman underwent kidney transplantation in March 2010. He remained apparently healthy for the next 10 years when he developed anorexia and weight loss. Diagnostic workup revealed cytomegalovirus (CMV) pneumonia. While viremia resolved within 3 weeks of initiation of valganciclovir, he developed progressive breathlessness and hypoxia on exertion. Imaging of thorax revealed central peri-bronchovascular consolidation and fine reticulations with peripheral sparing. Computed tomography (CT)-guided percutaneous lung biopsy revealed organizing intra-alveolar exudates, suggestive of organizing pneumonia, with no evidence of active infection on biopsy as well as bronchoalveolar lavage (BAL) cytology. This atypical pattern of central distribution of opacities is not typical of organizing pneumonia where peripheral subpleural distribution is more common. Patient responded dramatically following escalation of steroids, with complete resolution of infiltrates on follow-up imaging.

5.
Front Plant Sci ; 13: 773572, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35371128

RESUMO

Nymphaea, commonly known as water lily, is the largest and most widely distributed genus in the order Nymphaeales. The importance of Nymphaea in wetland ecosystems and their increased vulnerability make them a great choice for conservation and management. In this work, we studied genetic diversity in a collection of 90 N. micrantha and 92 N. nouchali individuals from six different states of India, i.e., Assam, Manipur, Meghalaya, Maharashtra, Goa, and Kerala, using simple sequence repeat (SSR) markers developed by low throughput Illumina sequencing (10X coverage of genome) of N. micrantha. Nymphaea nouchali is native to India, whereas N. micrantha is suggested to be introduced to the country for its aesthetic and cultural values. The study revealed extensive polymorphism in N. nouchali, while in N. micrantha, no apparent genetic divergence was detected prompting us to investigate the reason(s) by studying the reproductive biology of the two species. The study revealed that N. micrantha predominantly reproduces asexually which has impacted the genetic diversity of the species to a great extent. This observation is of immense importance for a successful re-establishment of Nymphaea species during restoration programs of wetlands. The information generated on reproductive behaviors and their association with genotypic richness can help in strategizing genetic resource conservation, especially for species with limited distribution. The study has also generated 22,268 non-redundant microsatellite loci, out of which, 143 microsatellites were tested for polymorphism and polymorphic markers were tested for transferability in five other Nymphaea species, providing genomic resources for further studies on this important genus.

6.
Front Genet ; 13: 814486, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35281836

RESUMO

Seed size/weight is a multigenic trait that is governed by complex transcriptional regulatory pathways. An understanding of the genetic basis of seed size is of great interest in the improvement of seed yield and quality in oilseed crops. A global transcriptome analysis was performed at the initial stages of seed development in two lines of Brassica juncea, small-seeded EH-2 and large-seeded PJ. The anatomical analyses revealed significant differences in cell number and cell size in the outer layer of the seed coat between EH-2 and PJ. Pairwise comparisons at each developmental stage identified 5,974 differentially expressed genes (DEGs) between the two lines, of which 954 genes belong to different families of transcription factors. Two modules were found to be significantly correlated with an increased seed size using weighted gene coexpression network analysis. The DEG and coexpression datasets were integrated with the thousand seed weight (Tsw) quantitative trait loci (QTL) mapped earlier in the EPJ (EH-2 × PJ) doubled haploid (DH) population, which identified forty potential key components controlling seed size. The candidate genes included genes regulating the cell cycle, cell wall biogenesis/modification, solute/sugar transport, and hormone signaling. The results provide a valuable resource to widen the current understanding of regulatory mechanisms underlying seed size in B. juncea.

7.
Ecol Evol ; 12(3): e8697, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35342566

RESUMO

So far, oil-rewarding flowers are known to be pollinated only by oil-collecting bees, which gather and use lipids for larval feed and nest building. As honeybees do not have oil-collecting appendages on their legs, they have not been associated with pollination of such flowers. In a predominantly Apis pollinated and food deceptive clade of wild Cymbidiums, we investigated the reproductive strategy of Cymbidium aloifolium, hitherto unknown for its floral oil reward. Our study demonstrates the requisites for establishment of mutualistic interaction between the oil flower and Apis cerana indica, a corbiculate bee. Success in pollination requires learning by honeybees to access the food reward, thereby displaying cognitive ability of the pollinator to access the customized reward. Morphometric matching between orchid flowers and the pollinator, and that between pollinia and stigmatic cavity also appear to be essential in the pollination success. Absence of pollinator competition and prolonged flower-handling time are suggested to promote floral constancy. The present study highlights the need to explore the spectrum of pollination rewards pursued by honeybees, which may include unconventional composition of floral resources.

8.
Planta ; 254(3): 55, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34415427

RESUMO

MAIN CONCLUSION: In a co-evolutionary crosstalk amid plants and their pollinators, nectaries serve as a labile link between the relatively fixed structural domains of divergent flower forms and associated pollination syndromes. Floral nectary plays a crucial role in sexual plant reproduction by enabling interaction between plants and their pollinators. It is known to associate with different floral whorls, and exhibits variations in structure and location in different clades across angiosperms. To infer evolutionary patterns, it is important to map key features associated with the trait at various taxonomic ranks. In the present study, we analysed variability and distribution of floral nectaries in Solanaceae for the first time. Floral nectaries of 23 taxa representing different clades in the family were studied using bright-field and scanning electron microscopy. The study reveals that although floral nectaries share anatomical similarity, they differ in morphology, composition within cells, and locations within a flower across the clades. The analysis suggests that (i) there is a shift from symmetric, lobed type nectary in the early branching sub-families to asymmetric, annular type in the late branching ones, (ii) floral organization has shifted from asymmetry (zygomorphy) to symmetry (actinomorphy) in corolla, and (iii) the lobed nectary correlates with zygomorphic floral forms that are pollinated by birds and long-tongued vectors, while the annular nectary is predominant among species with bee-pollinated actinomorphic flowers.


Assuntos
Magnoliopsida , Solanaceae , Animais , Abelhas , Evolução Biológica , Flores , Polinização
9.
Indian J Pathol Microbiol ; 64(3): 484-489, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34341258

RESUMO

BACKGROUND AND AIMS: An early correct diagnosis of celiac disease (CD) is fundamental to reversal of symptoms and prevention of complications in pediatric patients. Our aim was to evaluate the role of duodenal bulb biopsy by studying the degree of mucosal damage in the duodenal bulb (D1) and second part of the duodenum (D2) and correlating the findings with serum IgA anti-tTG levels. SETTINGS AND DESIGN: Pediatric patients (age <18 years) with clinical suspicion of CD and positive IgA anti-tTG titers were consecutively enrolled over a period of one year. Demographic variables, anthropometry, clinical history, laboratory values and endoscopic findings were studied. Endoscopic biopsies obtained from D1 and D2 were evaluated and assigned histopathologic grades that were correlated with serology. STATISTICAL ANALYSIS USED: Descriptive statistics were employed. RESULTS: A total of 37 clinically suspected cases of pediatric CD were studied. The mean age was 6.7 years and the M:F ratio was 1:1.3. Thirty-two (32) children had varying degrees of growth impairment. Eight (8) children had only extra-intestinal symptoms. Thirty (30) children were anemic, hypoalbuminemia was seen in five (5) children while transaminitis was seen in two (2) children. IgA anti-tTG >300 U/ml was associated with Marsh-Oberhuber Grade 3 morphology at atleast one site. CONCLUSIONS: Low positive serology values should be confirmed by histopathology. Biopsies should be taken even in the absence of endoscopic abnormality. Additional D1 biopsies placed in a separate container can increase the diagnostic yield.


Assuntos
Doença Celíaca/complicações , Doença Celíaca/imunologia , Duodeno/patologia , Imunoglobulina A/sangue , Abdome/patologia , Adolescente , Biópsia , Doença Celíaca/diagnóstico , Doença Celíaca/patologia , Criança , Pré-Escolar , Duodeno/anatomia & histologia , Feminino , Humanos , Mucosa Intestinal/patologia , Masculino
10.
Front Plant Sci ; 12: 767725, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35095948

RESUMO

Consumption of pollination reward by felonious means in a plant species can influence the foraging behavior of its pollinator and eventually the reproductive success. So far, studies on this aspect are largely confined to interaction involving plant-pollinators and nectar robbers or thieves. However, a foraging guild in such interactions may also include floral herbivores or florivores. There is a paucity of information on the extent to which nectar larcenists may influence the foraging behavior of the pollinator and reproductive fitness of plants in the presence of a florivore. We investigated various forms of larceny in the natural populations of Aerides odorata, a pollinator-dependent and nectar-rewarding orchid. These populations differed in types of foraging guild, the extent of larceny (thieving/robbing), which can occur with or without florivory, and natural fruit-set pattern. The nectariferous spur of the flower serves as an organ of interest among the foraging insects. While florivory marked by excision of nectary dissuades the pollinator, nectar thieving and robbing significantly enhance visits of the pollinator and fruit-set. Experimental pollinations showed that the species is a preferential outbreeder and experiences inbreeding depression from selfing. Reproductive fitness of the orchid species varies significantly with the extent of floral larceny. Although nectar thieving or robbing is beneficial in this self-compatible species, the negative effects of florivory were stronger. Our findings suggest that net reproductive fitness in the affected plant species is determined by the overarching effect of its breeding system on the overall interacting framework of the foraging guild.

11.
Indian J Community Med ; 45(3): 256-260, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33353996

RESUMO

Community-based participatory research (CBPR) is an approach in which researchers undertake research in partnership with those affected by the issue being studied, for the purpose of taking action or effecting social change. It can also incorporate those who will use the results to change practice and inform policy. The practice of CBPR is primarily focused on "Knowledge for Change." Most research projects in such CBPR partnerships are funded through the academic partners. In many situations, academic and professional researcher institutions and researchers find it difficult to share the information and resources or to directly engage with local community and other local stakeholders. In practice, finding an intermediary partner who has good rapport with local community and local government can be very effective. While there are good initiatives in selected medical colleges for community orientation of medical undergraduates and postgraduates in community medicine, these are not immersive enough to cause an attitudinal change. It is time that we exposed our graduates and postgraduates to CBPR concepts and practice.

12.
J Plant Res ; 133(6): 783-805, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32979146

RESUMO

Justicia adhatoda L. (Acanthaceae), an Old-World species of Justicia, is found in almost all geographical regions of India. Indian botanists have persistently used two accepted synonyms of J. adhatoda, namely, Adhatoda vasica and Adhatoda zeylanica, treating them as names of separate species, but without considering or making any reference to variation of forms in the species. Here, different aspects of variation-phenotypic, genotypic, and distributional-in Indian populations of J. adhatoda were studied to determine whether the two names might have been used to designate distinguishable forms of the species. We conducted field studies in different regions of India, laboratory studies of diverse phenotypic traits in experimental plots (anatomical, biochemical, reproductive, and morphometric), and a preliminary study of genetic variation using homologous cytochrome P450 gene fragments. We assessed herbarium samples from across India and the taxonomic literature for pointers indicating the presence of distinguishable forms. Population-level phenotypic and genetic variation pointed to the presence of two distinct morphotypes of the species, which separately tend to occur in dry and wet regions. Each form retains its original phenotype, either when the two forms are transplanted and cultivated together, or when found growing in regions (presumed introduced) outside its normal distributional range. Morphological studies and metabolic profiling (leaf and seed fatty acids, wax load and wax composition in leaf) suggest functional adaptation of the two forms, one to drier and the other to wetter regions. We could distinguish these forms in herbarium specimens dating back to 1821, but neither herbarium specimens nor the taxonomic literature reveal any reference to two forms. We propose that the forms be recognized as two distinct morphotypes of Justicia adhatoda.


Assuntos
Justicia/anatomia & histologia , Fenótipo , Ecossistema , Variação Genética , Índia , Justicia/química , Folhas de Planta/química
13.
Indian J Tuberc ; 67(3): 383-385, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32825874

RESUMO

Kikuchi-Fujimoto's disease is an uncommon self limiting, benign cause of generalised lymphadenopathy with fever. It can present as a triad of fever, night sweats and lymphadenopathy which resembles more common causes like tuberculosis and lymphoma. Being an endemic country a patient may be treated on the lines of tuberculosis often. We present case of a young female who was diagnosed as Kikuchi-Fujimoto's disease after not responding to antitubercular treatment. Pathologists and Clinicians must be aware of this condition to prevent unnecessary treatment.


Assuntos
Diagnóstico Diferencial , Linfadenite Histiocítica Necrosante/diagnóstico , Tuberculose dos Linfonodos/diagnóstico , Adulto , Biópsia por Agulha Fina , Feminino , Linfadenite Histiocítica Necrosante/patologia , Humanos , Pescoço , Tomografia Computadorizada por Raios X
14.
Int J Dev Biol ; 64(1-2-3): 7-19, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32659021

RESUMO

Professor Panchanan Maheshwari served as Professor and Head of the Department of Botany, University of Delhi, from 1950 to 1966 and built an internationally reputed School of integrated plant embryology. Studies carried out during and after Maheshwari's period from this School have enormously advanced our knowledge of the structural, developmental and functional aspects of embryological processes. This review covers studies carried out at the Delhi School on the developmental biology of dispersed pollen grains which operate from pollen dispersal from the anthers until pollen tubes discharge the male gametes in the embryo sac for fertilization. These events include pollen viability and vigour, pollen germination and pollen tube growth, structural details of the pistil relevant to pollen function, pollination and pollen-pistil interaction.


Assuntos
Biologia do Desenvolvimento , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo , Tubo Polínico/crescimento & desenvolvimento , Pólen/crescimento & desenvolvimento , Flores/genética , Flores/crescimento & desenvolvimento , Flores/metabolismo , Germinação , Proteínas de Plantas/genética , Pólen/genética , Pólen/metabolismo , Tubo Polínico/genética , Tubo Polínico/metabolismo
15.
Mol Genet Genomics ; 295(3): 563-577, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31912236

RESUMO

CRABS CLAW (CRC), a member of YABBY transcription factor family, has been previously reported to be principally involved in carpel development across angiosperms, and nectary development in core eudicots. Most of the studies suggest that CRC exists as a single copy gene, except in the Solanaceae where CRC occurs as paralogous pairs-CRCa-CRCb in Solanum lycopersicum, and CRC1-CRC2 in Petunia hybrida. In spite of their crucial role in carpel and nectary development, there is no information about the evolutionary history of the CRC paralogy in Solanaceae and whether the paralogy extends beyond Solanaceae. We analyzed homologues of CRC across angiosperms including genome sequence of fourteen species of Solanaceae available at Sol Genomics Network database, Phytozome and NCBI, to address the questions. Our phylogenetic reconstruction across angiosperms combined with comparative genomic, microsynteny and genome-fractionation analyses across the Solanaceae genomes revealed that (1) the CRCa-CRCb lineage is represented by a single copy in other flowering plants; (2) putative homologues of CRCa and CRCb are present in all the Solanaceae genomes studied; (3) the CRCa-CRCb paralogy in Solanaceae is associated with a large segmental duplication within Solanaceae (perhaps in its common ancestor), and (4) the duplicated segments have undergone different degrees of retention and loss of genes. Also, the CRC gene lineage expanded in Solanaceae following Solanaceae-α hexaploidy event and that two CRC duplicate copies were subsequently retained during the course of evolution. Besides the first detailed description of CRC evolution in Solanaceae, the study identifies potential candidate genes for future functional investigations.


Assuntos
Regulação da Expressão Gênica de Plantas , Família Multigênica , Proteínas de Plantas/genética , Duplicações Segmentares Genômicas , Solanaceae/genética , Fatores de Transcrição/genética , Evolução Molecular , Filogenia
16.
Plant Signal Behav ; 14(11): 1667730, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31526102

RESUMO

Free polyamine (PA) titers in plants may be regulated through reversible conjugate formation and/or through modulation of their synthesis, transport and degradation. PA signaling involves the well-acknowledged signaling molecule, nitric oxide (NO), which functions in diverse biological processes. Present investigations demonstrate the influence of salt stress (120 mM NaCl) and exogenous NO donor (250 µM Diethylenetriamine, DETA) on PA homeostasis of 2 d old, etiolated sunflower (Helianthus annuus L.) seedling cotyledons as a long-distance signaling response. Significantly enhanced intracellular spermine (Spm) accumulation was observed in seedling cotyledons under salt stress and in response to NO donor, the increase being more pronounced in seedlings treated with NO, evidently as a result of upregulation of the PA biosynthetic enzymes - arginine decarboxylase (ADC) and S-adenosylmethionine decarboxylase (SAMDC) - as revealed by Western blot and confocal imaging (CLSM). Moreover, salt stress induced the activity of polyamine oxidase (PAO), a PA catabolic enzyme, while NO lowered its activity in salt-stressed seedling cotyledons. NO, thus, appears to assist the seedlings in adapting to salt stress by positively regulating PA homeostasis through regulation of PA distribution between free, conjugated and bound forms, increased accumulation of PA biosynthetic enzymes and lowering the rate of PA catabolism.


Assuntos
Cotilédone/metabolismo , Helianthus/metabolismo , Óxido Nítrico/metabolismo , Poliaminas/metabolismo , Plântula/metabolismo , Adenosilmetionina Descarboxilase/metabolismo , Carboxiliases/metabolismo , Cotilédone/efeitos dos fármacos , Helianthus/efeitos dos fármacos , Estresse Salino , Plântula/efeitos dos fármacos , Cloreto de Sódio/farmacologia
17.
PhytoKeys ; 124: 23-38, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31231162

RESUMO

We present the description of Zeylanidiummanasiae (Podostemaceae), a new species from Kerala, India, which is proposed based on molecular, macro- and micromorphological data. This species is characterised by its ribbon-like dichotomous thallus, floriferous shoots produced along the margins and dichotomy of the thallus, inflorescence with two bracts, unequal stigmatic lobes, ellipsoid fruits and large seeds.

18.
Heredity (Edinb) ; 122(1): 120-132, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-29725078

RESUMO

Dioecy and the dynamics of its evolution are intensely investigated aspects of plant reproduction. Seabuckthorn (Hippophae rhamnoides ssp. turkestanica) is an alpine shrub growing wild in certain parts of western Himalaya. The previous studies have reported heteromorphic sex chromosomes in the species and yet marker-based studies indicate high similarity between the male and female genomes. Lack of information on sexual system in the species has further complicated the situation. A systematic study was thus undertaken to understand the sexual system in seabuckthorn and to discern the extent of similarity/dissimilarity between the male and female genomes by generating a large number of markers using amplified fragment length polymorphism and representational difference analysis. Floral biology and regular monitoring of species revealed the presence of polygamomonoecious (PGM) plants in most populations at a low percentage (~2-4%). PGM plants showed low pollen production and overall low fertility, suggesting a monoecy-paradioecy pathway at function. The results of the marker study demonstrated that there are limited differences between male and female genomes and these differences were not uniform across the populations in the Leh-Ladakh region, especially when the geographical distance increases. Results also suggest that a dynamic partitioning of genomes is operational between the two genders of seabuckthorn and differences are not homogenized across the populations. Both reproductive biology-based and DNA marker-based studies indicate that genders have separated recently. The present study proposes seabuckthorn as a promising model system to study evolution of dioecy and sex determination.


Assuntos
Genoma de Planta/genética , Hippophae/genética , Cromossomos Sexuais/genética , Processos de Determinação Sexual/genética , Evolução Molecular , Genes de Plantas/genética , Marcadores Genéticos/genética , Hippophae/crescimento & desenvolvimento , Polimorfismo Genético
19.
AoB Plants ; 10(2): ply019, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29644028

RESUMO

Reproductive success of a plant species can be affected by the distribution pattern of its conspecifics in a small population. Besides the low mate availability, the dynamics of breeding system and pollination mechanism may also contribute to low fruit-set in such populations. We examined the relative contribution of these reproductive attributes on fruit-set across the contrasting distribution pattern (denser vs. sparser plots) in two isolated natural populations of a near-threatened tree species, Anogeissus sericea var. nummularia. Although flowers in the species are of generalist type, the narrow stigmatic surface appears to impose a requirement for a specialist pollinator. Pollination in the tree species is mediated only by the flies. The trees exhibit partial selfing and suffer from strong inbreeding depression at the early life-history stages of the selfed progeny. We recorded significant difference between the denser and sparser plots in terms of inflorescence visits per tree, and the number of trees covered in a bout by the pollinators. Moreover, tree density showed a strong positive correlation with fruit-set. Besides the requirement of having proximity among the conspecifics to facilitate pollinator movement, pollen quality also seemed to be a crucial attribute in the reproductive success of the tree species. It is inferred that the mating pattern and fecundity of plants in small and isolated populations are significantly influenced by the extent of sexual incompatibility and magnitude of their dependence on pollinators.

20.
J Plant Res ; 131(4): 599-610, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29460199

RESUMO

Numerous bladderwort (Utricularia) species are distributed worldwide, but their reproductive biology is rarely investigated. Bladderworts are known to depend on tiny organisms to meet a significant proportion of their energy requirement by trapping them in bladders. However, information on the extent of their reliance on insects for pollination success is limited. We examined the reproductive strategy of two Utricularia species viz. Utricularia praeterita and U. babui, endemic to Western Ghats, India. The main aspects of the investigation involved floral biology, breeding system, pollination mechanism, and reproductive success. Flowers of both the species are structured for outbreeding through entomophilous floral suites, herkogamy, protandrous dichogamy and sensitive lobes of the stigma. With nearly 65% natural fruit-set, both the species appeared to be sufficiently open-pollinated. However, pollinators failed to show in plants of U. praeterita while in U. babui there was an apparent mismatch between the extent of fruit-set and pollinator visits. The study demonstrated that in the absence/insufficient visits of pollinators, the two species resort to autonomous selfing. In U. babui, denser patches of plants appeared to be crucial for attracting the pollinators. Both species are self-compatible, and reproductive success is predominantly achieved by delayed autonomous selfing. The sensitive stigma in the species fails to prevent selfing due to diminished herkogamy during the late anthetic stages. It is inferred that in the pollinator-limited environment, delayed selfing contributes to absolute natural fecundity in U. praeterita, while it produces a mixed progeny in U. babui.


Assuntos
Lamiales/fisiologia , Ecologia , Flores/anatomia & histologia , Flores/fisiologia , Flores/ultraestrutura , Frutas/crescimento & desenvolvimento , Índia , Microscopia Eletrônica de Varredura , Polinização , Reprodução , Autofertilização/fisiologia
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