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1.
Medicine (Baltimore) ; 99(7): e19065, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32049806

RESUMO

The objective of this paper is to demonstrate, considering the experiences from Chinese people, if slow transit constipation (STC) can be accurately diagnosed, choosing patients qualifying for surgery, subtotal colectomy with antiperistaltic cecosigmoidal anastomosis (STC-Anti-CSA) may come with more acceptable short and long-term outcomes.A retrospective study was performed at a department of colorectal and anal surgery. A cohort of 29 patients were coming with up to 5 years' follow-up care, who were in a diverse range of age, BMI, laxative medicine histories, including both males and females. Pre-surgery work-up strictly followed a protocol designed to rule out the patients who were not suitable for surgery treatments. Classification of STC was followed after diagnosis. STC-Anti-CSA was performed in all cases. The operative time, blood loss, average post-operative length of stay (LOS), frequency of BMs, stool consistency and patients satisfaction, by using Wexner constipation score (WCS), numerical rating scale (NRS), and abdominal bloating score (ABS), over the study period were recorded.In this study, there were 14 males and 15 females, with mean age 51, and BMI from 20.14 to 31.62 kg/m. The period of laxative medicine history was 4.8 years (2-13 years). The mean operative time was 152 ±â€Š34 min, and the mean perioperative blood loss was 123 ±â€Š51 mL. Average post-operative LOS (LOS) was 8 days. There were no severe post-operative complications, peri-operative mortality, anastomotic leaks, or revisions of the original surgery. Initial post-operative BMs averaged 6 times/day. During the period of 1 month to 12 months follow-up care, BMs fell down to 2 or 3 times/day. By the 1st to 3rd year follow-up care, BMs averaged 5 to 7 times/week. However, from the 4th year to 5th year, constipations recurred somehow. However, most patients were satisfied with their bowel patterns.STC-Anti-CSA can receive acceptable postoperative outcomes as long as the patients can be accurately diagnosed and classified as severe STC. Among the surgical procedures for STC, this procedure may be another suitable option, especially for Chinese people.


Assuntos
Ceco/cirurgia , Constipação Intestinal/cirurgia , Reto/cirurgia , Adulto , Idoso , Anastomose Cirúrgica , China , Colectomia , Feminino , Trânsito Gastrointestinal , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Qualidade de Vida , Estudos Retrospectivos , Resultado do Tratamento
2.
Int Wound J ; 17(3): 555-561, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31975537

RESUMO

Sacrococcygeal pilonidal sinus is one of common diseases in general department. However, it is characterised, for surgeons, by high post-surgical recurrence and high incidence of post-surgical wound complications. Due to that fact, this retrospective randomised clinical study was designed to evaluate the surgical procedure effect of Z-plasty (ZP), compared with convention simple excision (SE). A total of 67 patients from May 2015 to May 2019 in our department were studied into two groups randomly, the group of ZP and the group of SE. The patients' characteristics, surgical data, hospital length of stay (LOS), and post-surgery complications were recorded. Statistical approaches were proceed with P-value analysis. The results are as follows. No significant differences were found between these two groups of the ages, gender distribution, Body Mass Index (BMI), smoking history, diabetes mellitus, and blood hypertension. The estimated blood loss, specimen volume, distance to anus, and drain output on the first day of post-surgery between the two groups were not statistically significant, either. However, surgical time in the ZP group was longer than that in the SE group (P < .0001). LOS in the ZP group was obviously shorter than that in the SE group (P = .0051). Furthermore, the patients of the ZP group were tending to suffer from fewer post-surgical complications than the ones of the SE group. In a conclusion, we hold the point view that the surgical procedure of ZP can lead a better outcome than SE because it demonstrated shortened LOS and fewer post-surgical complications.

3.
Nat Commun ; 10(1): 5230, 2019 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-31745089

RESUMO

The Hengduan Mountains (HDM) biodiversity hotspot exhibits exceptional alpine plant diversity. Here, we investigate factors driving intraspecific divergence within a HDM alpine species Salix brachista (Cushion willow), a common component of subnival assemblages. We produce a high-quality genome assembly for this species and characterize its genetic diversity, population structure and pattern of evolution by resequencing individuals collected across its distribution. We detect population divergence that has been shaped by a landscape of isolated sky island-like habitats displaying strong environmental heterogeneity across elevational gradients, combined with population size fluctuations that have occurred since approximately the late Miocene. These factors are likely important drivers of intraspecific divergence within Cushion willow and possibly other alpine plants with a similar distribution. Since intraspecific divergence is often the first step toward speciation, the same factors can be important contributors to the high alpine species diversity in the HDM.

4.
World J Gastroenterol ; 25(32): 4764-4778, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31528100

RESUMO

BACKGROUND: Non-invasive evaluation for liver fibrosis is clinically important, especially in patients with undetectable hepatitis B virus (HBV) DNA treated with nucleoside analogs. AIM: To clarify the monitoring power of hepatitis B core-related antigen (HBcrAg) for hepatic histologic changes in patients with chronic hepatitis B (CHB) treated with entecavir. METHODS: This prospective multicenter study used multiple ordinal and multivariate logistics regression analysis to assess variables associated with Ishak fibrosis score and regression for fibrosis regression, respectively, in 403 CHB patients, including 374 with entecavir for 72 weeks (291 underwent paired liver biopsy) and 29 as controls. RESULTS: Level of HBcrAg correlated negatively with liver fibrosis staging (γ = -0.357, P < 0.001) in hepatitis B e antigen (HBeAg)-positive patients, and positively with liver fibrosis staging in HBeAg-negative patients. Higher HBcrAg concentration was associated with younger age, HBeAg positive status, high HBV DNA loads, high level of hepatitis B surface antigen (HBsAg) and higher necroinflammation, but not with HBV genotype. Serum concentration of HBcrAg, basal core promoter/precore (BCP/PC) mutant, quantitation of HBsAg (qHBsAg) and platelet counts were independently associated with Ishak fibrosis score on multiple ordinal regression. HBV DNA was undetectable in 88.37% of patients treated with entecavir at week 72, while their level of HBcrAg was still detectable. A greater reduction in post-treatment HBcrAg concentration was associated with the regression of hepatic fibrosis and histological improvement. HBcrAg concentration > 6.33 log IU/mL at baseline and logarithmic reduction > 1.03 log IU/mL at week 72 were associated with a higher chance of regression of liver fibrosis and histological improvement, respectively. CONCLUSION: HBcrAg level is associated with liver fibrosis progression. HBcrAg is an excellent monitor of hepatic histological changes, especially in CHB patients treated with nucleoside analogs.


Assuntos
Antivirais/uso terapêutico , Antígenos do Núcleo do Vírus da Hepatite B/sangue , Vírus da Hepatite B/isolamento & purificação , Hepatite B Crônica/tratamento farmacológico , Cirrose Hepática/diagnóstico , Adulto , Biomarcadores/sangue , DNA Viral/sangue , DNA Viral/isolamento & purificação , Progressão da Doença , Feminino , Guanina/análogos & derivados , Guanina/uso terapêutico , Antígenos do Núcleo do Vírus da Hepatite B/imunologia , Antígenos do Núcleo do Vírus da Hepatite B/isolamento & purificação , Vírus da Hepatite B/imunologia , Hepatite B Crônica/sangue , Hepatite B Crônica/patologia , Humanos , Fígado/patologia , Fígado/virologia , Cirrose Hepática/sangue , Cirrose Hepática/patologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento
5.
New Phytol ; 224(4): 1512-1517, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31418867

RESUMO

A widely observed pollinator decline around the world has led to the prediction that terrestrial ecosystems could be disrupted as plant pollination suffers, but declining pollination success has not been tested rigorously in wild plants, and it still remains unclear how pollination success of plant species responds differently in the context of pollinator decline. By viewing the number of seeds per pod as a quantitative measure of successful pollination, we examined seed pods in 4637 herbarium specimens of 109 obligately outcrossing legumes collected over the past century. We found that only 13 species showed significant temporal change with nine of those as an increase. None of the three subfamilies of legumes showed a consistent trend, and the subfamily Papilionoideae with the most specialized flowers, had increasing seed number per pod more often than decreasing. We conclude that legume pollination in China shows no sign of disruption and the effects of plant-pollinator disruption may be more complicated than simplistic predictions have allowed.

6.
Bioresour Technol ; 292: 121994, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31437799

RESUMO

Bio-char samples were prepared from gasification of corn straw under N2, CO2 and H2O conditions, and systematically characterized to reveal the effects of gaseous agents on the evolution of char structural features during the gasification process. The results showed that the increase of reacting temperature had positive effects on the gasification of char in both H2O and CO2 atmospheres. The evolution of char pore structures under H2O and CO2 was quite different. The formation of micropores was facilitated by CO2, while mesopores and macropores were developed more in H2O condition. Besides, char structures obtained at 800 °C were more ordered than those obtained at 600 °C. Compared with the longitudinal merging, the aromatic layers preferred to grow laterally. Moreover, the mechanisms of gasification between char and gaseous agents were different. CO2 preferred to react with amorphous carbon, while the cross-linked carbon was more likely to be consumed during char gasification with H2O.


Assuntos
Carvão Vegetal , Gases , Biomassa , Dióxido de Carbono , Cinética
7.
J Food Sci ; 84(1): 19-30, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30561035

RESUMO

Despite the advancement of medical science, diseases are part-and-parcel of human life. Plants have provided humans with medicines since time immemorial, and are still one of the primary sources for drug discovery. Brassica rapa L., commonly known as turnip, is one of the world's oldest cultivated vegetables. Besides being an important vegetable and source of oil, turnip is also used as a traditional medicine for the treatment of headaches, chest complaints, rheumatisms, oedemas, gonorrhoea, syphilis, and rabies. Glucosinolates and isothiocyanates (mainly 2-phenylethyl, 4-pentenyl, and 3-butenyl derivatives) are the main constituents of turnip with diverse bioactivities, especially for the protective effect against cancers. Besides, flavonoids, phenolics, indoles and volatiles are also concomitant in this plant. Pharmacological investigation on turnip revealed the antitumor, antihypertensive, antidiabetic, antioxidant, antiinflammatory, hepatoprotective, and nephroprotective effects. The anticancer property was found to be the most promising biological activity of turnip with 2-phenylethyl isothiocyanate, phenylpropionitrile, brassicaphenanthrene A, 6-paradol, and trans-6-shogaol as the major active constituents. Flavonoids and phenolics with high free radical scavenging activity should be corresponding to the antioxidant effects. Arvelexin, an indole derivative in turnip, was reported with various effects involving antiinflamatory, antihypertensive and hypolipidemic potency. In spite of many studies concerning either the chemical constituents or the biological activities of turnip, only a few cases disclosed the active ingredients responsible for diverse bioactivities. This review summarizes the research progress on the chemistry and health-benefits of turnip over the past 20 years to provide a reference for the further investigation.


Assuntos
Brassica rapa/química , Compostos Fitoquímicos/farmacologia , Analgésicos/farmacologia , Animais , Anti-Infecciosos/farmacologia , Anti-Inflamatórios/farmacologia , Fármacos Antiobesidade/farmacologia , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Flavonoides/análise , Flavonoides/farmacologia , Glucosinolatos/análise , Glucosinolatos/farmacologia , Humanos , Hipoglicemiantes/farmacologia , Hipolipemiantes/farmacologia , Isotiocianatos/análise , Isotiocianatos/farmacologia , Rim/efeitos dos fármacos , Rim/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Compostos Fitoquímicos/análise , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/farmacologia
8.
J Phys Chem A ; 123(3): 674-681, 2019 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-30586305

RESUMO

During pyrolysis of holocellulose, secondary reactions of the primary pyrolytic products inevitably occur, affecting the final pyrolytic product distribution. Carboxylic acids from primary pyrolysis process have significant interaction effects on both holocellulose and its pyrolytic products, whereas, the interaction mechanisms are still unclear. In the present study, acetic acid is selected as the typical carboxylic acid product, and glycerol is selected to represent the various hydroxyl-based compounds (both holocellulose and pyrolytic products such as anhydrosugars, etc.). The density functional theory (DFT) method is adopted to investigate the interaction mechanisms between them. Calculation results indicate that acetic acid and glycerol have strong interactions, with acetic acid acting as a catalyst for these interactions in two patterns. (I) Acetic acid enhances the dehydration reactions of glycerol with low energy barriers. (II) Acetic acid and glycerol undergo esterification to form an ester intermediate which then decomposes via various reactions. In addition, the decomposition of acetic acid can also be promoted by the catalysis of glycerol in a certain degree. This study reveals the basic interaction mechanisms between carboxylic acids and hydroxyl-based compounds, providing fundamental information to understand the secondary reactions during pyrolysis of holocellulose.

9.
Front Genet ; 9: 223, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29988524

RESUMO

Halenia (Gentianaceae) originated from the mountain regions of East Asia, and diversified in America following long migrations via Beringia. While Halenia elliptica, one species of the genus in China, migrated toward high latitudes in China. Spur length of H. elliptica is highly variable. We examined the relationship between spur length and mating pattern along a latitude gradient. Field experiments were performed in two populations of H. elliptica, and we found that this species could produce seeds via both autonomous selfing and the aid of pollinators, suggesting a mixed mating system. In seven populations of H. elliptica along a latitudinal gradient, we found a trend of decrease in spur length with the increase of latitude. Based on molecular data from 11 microsatellite loci, we found that multilocus outcrossing rate decreased with the increase of latitude while the estimated inbreeding depression increased significantly, indicating that a high degree of inbreeding depression might have prevented evolution toward complete selfing in the high latitude populations with short spur length, and thus maintained mixed mating system of H. elliptica. Our results suggest that the mixed mating system of this species might be helpful in overcoming pollinator scarcity in newly colonized populations toward high latitudes after its origination in the mountain regions of China, and the decrease of spur length in the high latitude populations could result from reduced resource allocation to pollinator associated traits.

10.
Sci Total Environ ; 634: 141-149, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29627536

RESUMO

A series of Mo2N/HZSM-5 and transition metal modified Mo2N/HZSM-5 catalysts were prepared for the catalytic upgrading of pine wood-derived pyrolytic vapors for the selective production of monocyclic aromatic hydrocarbons (MAHs), while restraining the formation of polycyclic aromatic hydrocarbons (PAHs). Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to determine the effects of several factors on selective MAHs production, including Mo2N loading on HZSM-5, transition metal (Fe, Ce, La, Cu, Cr) modification of Mo2N/HZSM-5, pyrolysis temperature, and catalyst-to-biomass ratio. In addition, quantitative experiments were conducted to determine the actual yields of major aromatic hydrocarbons and the source of aromatic hydrocarbons from basic biomass components. Results indicated that among the various catalysts, the Ce-10%Mo2N/HZSM-5 exhibited the best performance on promoting the formation of MAHs and restraining the generation of PAHs. Under the optimal conditions, the actual yields of MAHs and PAHs from Ce-10%Mo2N/HZSM-5 catalytic process were 99.8mg/g and 7.5mg/g, while those from HZSM catalyst were only 77.2mg/g and 23.7mg/g respectively. Furthermore, the possible catalytic mechanism of the Ce-Mo2N/HZSM-5 catalyst was proposed based on the catalyst characterization.

11.
Molecules ; 23(4)2018 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-29561787

RESUMO

Coal is a major contributor to the global emission of nitrogen oxides (NOx). The NOx formation during coal utilization typically derives from the thermal decomposition of N-containing compounds (e.g., pyrrolic groups). NH3 and HCN are common precursors of NOx from the decomposition of N-containing compounds. The existence of H2O has significant influences on the pyrrole decomposition and NOx formation. In this study, the effects of H2O on pyrrole pyrolysis to form NOx precursors HCN and NH3 are investigated using the density functional theory (DFT) method. The calculation results indicate that the presence of H2O can lead to the formation of both NH3 and HCN during pyrrole pyrolysis, while only HCN is formed in the absence of H2O. The initial interaction between pyrrole and H2O determines the N products. NH3 will be formed when H2O attacks the C2 position of pyrrole with its hydroxyl group. On the contrary, HCN will be generated instead of NH3 when H2O attacks the C3 position of pyrrole with its hydroxyl group. In addition, the DFT calculations clearly indicate that the formation of NH3 will be promoted by H2O, whereas the formation of HCN is inhibited.


Assuntos
Amônia/química , Temperatura Alta , Cianeto de Hidrogênio/química , Modelos Moleculares , Pirróis/química , Água/química , Conformação Molecular
12.
Front Chem ; 6: 32, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29515994

RESUMO

A new technique was proposed to co-produce phenol and activated carbon (AC) from catalytic fast pyrolysis of biomass impregnated with K3PO4 in a hydrogen atmosphere, followed by activation of the pyrolytic solid residues. Lab-scale catalytic fast pyrolysis experiments were performed to quantitatively determine the pyrolytic product distribution, as well as to investigate the effects of several factors on the phenol production, including pyrolysis atmosphere, catalyst type, biomass type, catalytic pyrolysis temperature, and catalyst impregnation content. In addition, the pyrolytic solid residues were activated to prepare ACs with high specific surface areas. The results indicated that phenol could be obtained due to the synergistic effects of K3PO4 and hydrogen atmosphere, with the yield and selectivity reaching 5.3 wt% and 17.8% from catalytic fast pyrolysis of poplar wood with 8 wt% K3PO4 at 550°C in a hydrogen atmosphere. This technique was adaptable to different woody materials for phenol production. Moreover, gas product generated from the pyrolysis process was feasible to be recycled to provide the hydrogen atmosphere, instead of extra hydrogen supply. In addition, the pyrolytic solid residue was suitable for AC preparation, using CO2 activation method, the specific surface area was as high as 1,605 m2/g.

13.
J Dig Dis ; 19(3): 144-154, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29389068

RESUMO

OBJECTIVE: To evaluate tolvaptan as a novel therapeutic option for Chinese patients with liver cirrhosis-associated ascites in a phase 2 clinical trial. METHODS: This randomized, double-blind, placebo-controlled, multicenter trial was conducted in patients with insufficient responses to combination therapies of an oral loop diuretic and an aldosterone antagonist. Reduction in body weight and abdominal circumference, increase in 24-h cumulative urine volume and improvement in serum sodium level from baseline to the end of treatment in the tolvaptan groups (15 mg/day or 30 mg/day orally) were compared with those in the placebo group. Drug safety was also assessed. RESULTS: Sixty-two patients were allocated to the placebo group, 56 to the tolvaptan 15-mg group and 63 to the tolvaptan 30-mg group. Their mean changes in body weight were -0.5 ± 1.6 kg, -2.1 ± 2.0 kg and -1.9 ± 2.0 kg, respectively. Body weight reductions in both tolvaptan groups were significantly greater than that in the placebo group (difference -1.6, 95% confidence interval [CI] -2.5 to -0.8, and difference -1.4, 95% CI, -2.2 to -0.7, both P < 0.0001). The administration of tolvaptan also significantly reduced the abdominal circumference, increased 24-h cumulative urine volume and serum sodium level compared with placebo. The most common adverse events in the tolvaptan groups were constipation, diarrhea, dry mouth and thirst, with no severe adverse events observed. CONCLUSION: Tolvaptan at 15 mg/day significantly reduced the body weight and abdominal circumference in patients with liver cirrhosis-associated ascites, which needs to be confirmed in a phase 3 trial.


Assuntos
Antagonistas dos Receptores de Hormônios Antidiuréticos/administração & dosagem , Ascite/tratamento farmacológico , Benzazepinas/administração & dosagem , Cirrose Hepática/tratamento farmacológico , Abdome/patologia , Adolescente , Adulto , Idoso , Antagonistas dos Receptores de Hormônios Antidiuréticos/efeitos adversos , Antagonistas dos Receptores de Hormônios Antidiuréticos/farmacologia , Ascite/patologia , Ascite/fisiopatologia , Benzazepinas/efeitos adversos , Benzazepinas/farmacologia , Peso Corporal/efeitos dos fármacos , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Cirrose Hepática/patologia , Cirrose Hepática/fisiopatologia , Masculino , Pessoa de Meia-Idade , Sódio/sangue , Tolvaptan , Urina , Adulto Jovem
14.
Ecol Evol ; 7(20): 8156-8160, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-29075439

RESUMO

Examining variations in pollinator effectiveness can enhance our understanding of how pollinators and plants interact. Pollen deposition and seed production after a single visit by a pollinator are often used to estimate pollinator effectiveness. However, seed production is not always directly related to pollen deposition because not all pollen grains that are deposited on a stigma are compatible or conspecific. In the field, we tested pollinator effectiveness based on pollen deposition and the resulting seed production after single visits by different pollinator groups in a gynodieocious alpine plant Cyananthus delavayi (Campanulaceae). Our results showed that mean pollen deposition was generally inconsistent with mean seed production when comparisons were performed among different pollinator groups and sexes. In general, the correlations were not significant between pollen deposition and seed production in both perfect and female flowers after single visits by halictid bees, bumble bees, and hoverflies. We suggest seed set of virgin flowers after single visits is a more reliable indicator of pollinator effectiveness than pollen deposition and would be a better indicator of pollinator effectiveness for future studies.

15.
J Plant Res ; 130(6): 989-997, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28642987

RESUMO

Chromosome number and genome size are important cytological characters that significantly influence various organismal traits. We investigated chromosome number and genome size variation in 73 accessions belonging to four Colocasia species from China. Five different chromosome counts (2n = 26, 28, 38, 42, and 56) were found, the largest one representing a new record in Colocasia. The basic chromosome numbers are x = 13, 14, and 19, corresponding to 2x, 3x, and 4x cytotypes. Yunnan Province, China is considered the center of Colocasia polyploid origin. The 2C values in our accessions ranged from 3.29 pg in C. gigantea to 12.51 pg in C. esculenta. All species exhibit inter- and intraspecific chromosomal variation. Differences in DNA content among the Colocasia species seem to have occurred by chromosomal gain under similar habitats. Polyploidization also obviously contributes to 2C value variation.


Assuntos
Cromossomos de Plantas/genética , Colocasia/genética , Variação Genética , Tamanho do Genoma , Genoma de Planta/genética , China , Geografia , Cariótipo , Fenótipo , Folhas de Planta/genética , Raízes de Plantas/genética , Poliploidia
16.
Sci Rep ; 7: 42466, 2017 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-28195162

RESUMO

Climatic tolerance, especially drought tolerance, is one of the major factors shaping the geographic distributions of plant species. Thus, the general decline in rainfall from the Himalaya-Hengduan Mountains (HHM) to the inner Qinghai-Tibet Plateau (QTP) might account for the significant differences in species distributions and richness between the two regions. To test this hypothesis, we conducted a water stress experiment using four Anisodus species (A. tanguticus, A. luridus, A. carniolicoides and A. acutangulus), which were treated with different levels of water stress in a glasshouse, and examined their differences in physiological responses. The results suggest that A. tanguticus, which inhabits the inner QTP, generally has higher fitness under severe water stress than the other species based on its high root:shoot ratio, long-term water use efficiency and photosynthetic rate, indicating that it possesses a genetically based drought tolerance mechanism. Our results suggest that plant species inhabiting the inner QTP may be more drought tolerant than those inhabiting the HHM regions. This provides a new example supporting the hypothesis that climatic tolerance plays a major role in shaping plant distributions on the QTP and its adjacent highlands and presents new insights into the patterns of geographic distribution and diversity of the plants inhabiting these areas.


Assuntos
Adaptação Biológica , Secas , Meio Ambiente , Solanaceae/fisiologia , Estresse Fisiológico , Biomassa , Clorofila/metabolismo , Nitrogênio/metabolismo , Característica Quantitativa Herdável , Solo/química , Tibet , Água
17.
Ecol Evol ; 7(2): 541-549, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28116051

RESUMO

Pollination systems and associated floral traits generally differ between core and marginal populations of a species. However, such differences are rarely examined in plants with a mixed wind- and bumblebee-pollination system, and the role of wind pollination during range expansion in ambophilous plants remains unclear. We compared floral traits and the contributions of bumblebee and wind pollination in refugium and marginal populations of the ambophilous plant Aconitum gymnandrum. We found that most floral traits differed between the two populations, and those traits associated with the shift to wind pollination were pronounced in the marginal population. Bumblebee visitation rates varied significantly, but were generally low in the marginal population. Wind pollination occurred in both populations, and the efficiency was lower than that of bumblebee pollination. Two types of pollen grains, namely round and fusiform pollen, were transported to a stigma by bumblebees and wind, but fusiform pollen contributed to wind pollination to a larger degree, especially in the marginal population. Our results suggest that wind pollination was enhanced by pollen dimorphism in the marginal population of A. gymnandrum, and wind pollination may provide reproductive assurance when bumblebee activity is unpredictable during range expansion, indicating that ambophily is stable in this species and shift in pollination system could be common when plants colonize new habitats.

18.
PLoS One ; 11(11): e0166134, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27812188

RESUMO

Eastern Asia (EA) is a key region for the diversification of flowering plants in the Northern Hemisphere, but few studies have focused on the biogeographic history within EA in the context of the other northern continents. Polygonatum is an important medicinal genus widely distributed in the Northern Hemisphere with its highest species richness in EA, and it represents an excellent model for studying the evolution of biogeographic patterns in this region. Divergence time estimation was used to examine the biogeographic history of Polygonatum based on nuclear ITS and four plastid sequences (rbcL, matK, psbA-trnH and trnC-petN) from 30 Polygonatum species and 35 outgroup taxa. The ancestral area of Polygonatum and subsequent dispersal routes were inferred using Bayes-Lagrange. Polygonatum was estimated to have originated in southern EA during the middle Miocene (14.34-13.57 Ma) with subsequent south-to-north expansion in the late Miocene. Multiple intercontinental dispersal events were inferred between EA and Europe or North America, and all of them have occurred recently in the late Miocene to Pliocene. The separation of Polygonatum into the south and north lineages and their subsequent diversifications in the late Miocene supports the existence of a biogeographic divide between the northern and southern parts of EA that also coincides with the retreat and redevelopment of the arid zone in EA in the Neogene. Our results demonstrate the complexity of biogeographic history of Polygonatum in the Northern Hemisphere including early vicariance followed by frequent and recent dispersals in the Neogene.


Assuntos
Geografia , Dispersão Vegetal , Polygonatum/classificação , Polygonatum/fisiologia , Teorema de Bayes , Biodiversidade , Extremo Oriente
19.
Front Plant Sci ; 7: 1329, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27630654

RESUMO

Polyploid species generally occupy harsher habitats (characterized by cold, drought and/or high altitude) than diploids, but the converse was observed for Chamerion angustifolium, in which diploid plants generally inhabit higher altitudes than their polyploid derivatives. Plants at high altitudes may experience cold-induced water stress, and we therefore examined the physiological responses of diploid and hexaploid C. angustifolium to water stress to better understand the ecological differentiation of plants with different ploidy levels. We conducted a common garden experiment by subjecting seedlings of different ploidy levels to low, moderate, and severe water stress. Fourteen indicators of physiological fitness were measured, and the anatomical characteristics of the leaves of each cytotype were determined. Both cytotypes were influenced by drought, and diploids exhibited higher fitness in terms of constant root:shoot ratio (R:S ratio) and maximum quantum yield of PS II (Fv/Fm ), less reduced maximal photosynthetic rate (A max), transpiration rate (E), intercellular CO2 concentration (C i) and stomatal conductance (g s), and higher long-term water use efficiency (WUEL) under severe water stress than did hexaploids. Analysis of leaf anatomy revealed morphological adjustments for tolerating water deficiency in diploids, in the form of closely packed mesophyll cells and small conduits in the midvein. Our results indicate that diploid C. angustifolium is more tolerant of drought than hexaploid plants, ensuring the successful survival of the diploid at high altitudes. This eco-physiological divergence may facilitate the species with different cytotypes to colonize new and large geographic ranges with heterogeneous environmental conditions.

20.
Sci Rep ; 6: 28302, 2016 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-27312838

RESUMO

Responses of plant traits to climate changes are complex, which could be mirrored by the investigations of herbarium specimens. By examining specimens of Rosa and Cotoneaster species collected since 1920s in Hengduan Mountains, we analyzed the changes of flowering phenology and flower size in the past century when climate changes were considered to be intensified. We found that flowering phenology of Rosa showed no significant change, but flowering phenology of Cotoneaster was delayed in recent years. Flower size of Rosa species showed a marginally significant decrease over the past century. The results suggested that responses of flowering time to global changes and pollinator mediated selection on floral traits might be more complex than what were expected. Our results indicated that future researches based on investigations of herbarium specimens should be carried out on multiple plant species with different flower structures and life histories to better understand the effects of climate changes on plant traits.


Assuntos
Mudança Climática/história , Flores/crescimento & desenvolvimento , Rosa/crescimento & desenvolvimento , Rosaceae/crescimento & desenvolvimento , China , História do Século XX
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