Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Plant Cell Environ ; 42(2): 591-605, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30193400

RESUMEN

Seedling emergence is a critical stage in the establishment of desert plants. Soil microbes participate in plant growth and development, but information is lacking with regard to the role of microbes on seedling emergence. We applied the biocides (captan and streptomycin) to assess how seed mucilage interacts with soil microbial community and physiochemical processes to affect seedling emergence of Artemisia sphaerocephala on the desert sand dune. Fungal and bacterial community composition and diversity and fungal-bacterial interactions were changed by both captan and streptomycin. Mucilage increased soil enzyme activities and fungal-bacterial interactions. Highest seedling emergence occurred under streptomycin and mucilage treatment. Members of the phyla Firmicutes and Glomeromycota were the keystone species that improved A. sphaerocephala seedling emergence, by increasing resistance of young seedlings to drought and pathogen. Seed mucilage directly improved seedling emergence and indirectly interacted with the soil microbial community through strengthening fungal-bacterial interactions and providing favourable environment for soil enzymes to affect seedling emergence. Our study provides a comprehensive understanding of the regulatory mechanisms by which soil microbial community and seed mucilage interactively promote successful establishment of populations of desert plants on the barren and stressful sand dune.


Asunto(s)
Interacciones Microbiota-Huesped , Mucílago de Planta/fisiología , Plantones/crecimiento & desarrollo , Semillas/fisiología , Microbiología del Suelo , Antiinfecciosos/farmacología , Artemisia/crecimiento & desarrollo , Artemisia/metabolismo , Artemisia/microbiología , Captano/farmacología , Clima Desértico , Secuenciación de Nucleótidos de Alto Rendimiento , Interacciones Microbiota-Huesped/fisiología , Mucílago de Planta/metabolismo , ARN Ribosómico 16S/genética , Plantones/metabolismo , Plantones/microbiología , Semillas/metabolismo , Semillas/microbiología , Estreptomicina/farmacología
2.
J Plant Physiol ; 232: 1-11, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30530198

RESUMEN

Arbuscular mycorrhizal (AM) symbiosis can play a role in improving seedling establishment in deserts, and it has been suggested that achene mucilage facilitates seedling establishment in sandy deserts and that mucilage biodegradation products may improve seedling growth. We aimed to determine if AM symbiosis interacts with achene mucilage in regulating seedling growth in sand dunes. Up to 20 A M fungal taxa colonized Artemisia sphaerocephala roots in the field, and mycorrhizal frequency and colonization intensity exhibited seasonal dynamics. In the greenhouse, total biomass of AM fungal-colonized plants decreased, whereas the root/shoot ratio increased. AM symbiosis resulted in increased concentrations of nutrients and chlorophyll and decreased concentrations of salicylic acid (SA) and abscisic acid (ABA). Achene mucilage had a weaker effect on biomass and on nutrient, chlorophyll, and phytohormone concentration than did AM symbiosis. We suggest that AM symbiosis and achene mucilage act independently in enhancing seedling establishment in sandy deserts.


Asunto(s)
Artemisia/crecimiento & desarrollo , Frutas/fisiología , Micorrizas/fisiología , Mucílago de Planta/fisiología , Simbiosis/fisiología , Artemisia/genética , Artemisia/microbiología , Artemisia/fisiología , Aspergillus niger/genética , Aspergillus niger/fisiología , Clorofila/metabolismo , ADN de Hongos/genética , ADN de Plantas/genética , Clima Desértico , Frutas/metabolismo , Micorrizas/genética , Filogenia , Reguladores del Crecimiento de las Plantas/fisiología , Raíces de Plantas/microbiología , Raíces de Plantas/fisiología , Reacción en Cadena de la Polimerasa , Ácido Salicílico/metabolismo , Plantones/crecimiento & desarrollo , Plantones/microbiología , Análisis de Secuencia de ADN
3.
Oecologia ; 173(4): 1451-8, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23872709

RESUMEN

Post-dispersal seed removal by animals can lead to extensive seed loss and thus is an important factor in structuring plant communities. However, we know much less about post-dispersal seed predation than about other forms of herbivory. Mucilage plays many ecological roles in adaptation of plants to diverse environments; nevertheless, until now the role of mucilage in ant-mediated seed movement remains largely hypothetical. We studied the role of mucilage in seed removal of Artemisia sphaerocephala by ants in Mu Us Sandland in Inner Mongolia, China. Messor aciculatus was the most active seed predator of Artemisia sphaerocephala. Time to first ant collecting (T 1st) of wet intact seeds was longest and significantly different from that for dry intact seeds, wet demucilaged seeds, and dry demucilaged seeds; number of seeds removed to ant nests was lowest for wet intact seeds. After they were collected by ants, 5 % of wet intact seeds were dropped during transport. Our results indicate that seed mucilage of Artemisia sphaerocephala may play a significant role in post-dispersal seed removal by (1) making seeds less attractive to ants, thus resulting in a delay of collection time; (2) forming a strong bond to soil particles, making it difficult for ants to remove seeds; and (3) making seeds more likely to be dropped during transport, thereby allowing them to escape from predation even after collection by ants. This study demonstrates the importance of mucilage in reducing seed removal by ants and thus in anchoring seeds of desert plants in the vicinity of mother plants.


Asunto(s)
Hormigas , Artemisia , Mucílago de Planta/fisiología , Dispersión de Semillas , Adaptación Fisiológica , Animales , China , Desecación , Ecosistema , Plantas , Semillas/fisiología , Suelo , Agua/fisiología
4.
BMC Plant Biol ; 12: 170, 2012 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-23006315

RESUMEN

BACKGROUND: Maternal effects may influence a range of seed traits simultaneously and are likely to be context-dependent. Disentangling the interactions of plant phenotype and growth environment on various seed traits is important for understanding regeneration and establishment of species in natural environments. Here, we used the seed-dimorphic plant Suaeda aralocaspica to test the hypothesis that seed traits are regulated by multiple maternal effects. RESULTS: Plants grown from brown seeds had a higher brown:black seed ratio than plants from black seeds, and germination percentage of brown seeds was higher than that of black seeds under all conditions tested. However, the coefficient of variation (CV) for size of black seeds was higher than that of brown seeds. Seeds had the smallest CV at low nutrient and high salinity for plants from brown seeds and at low nutrient and low salinity for plants from black seeds. Low levels of nutrients increased size and germinability of black seeds but did not change the seed morph ratio or size and germinability of brown seeds. High levels of salinity decreased seed size but did not change the seed morph ratio. Seeds from high-salinity maternal plants had a higher germination percentage regardless of level of germination salinity. CONCLUSIONS: Our study supports the multiple maternal effects hypothesis. Seed dimorphism, nutrient and salinity interacted in determining a range of seed traits of S. aralocaspica via bet-hedging and anticipatory maternal effects. This study highlights the importance of examining different maternal factors and various offspring traits in studies that estimate maternal effects on regeneration.


Asunto(s)
Chenopodiaceae/fisiología , Nitrógeno/metabolismo , Fósforo/metabolismo , Carácter Cuantitativo Heredable , Salinidad , Plantas Tolerantes a la Sal/fisiología , Semillas/fisiología , Chenopodiaceae/crecimiento & desarrollo , Clima Desértico , Germinación , Tamaño de los Órganos , Plantas Tolerantes a la Sal/crecimiento & desarrollo , Semillas/anatomía & histología , Semillas/crecimiento & desarrollo
5.
PLoS One ; 7(4): e34597, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22511952

RESUMEN

The success of seedling establishment of desert plants is determined by seedling emergence response to an unpredictable precipitation regime. Sand burial is a crucial and frequent environmental stress that impacts seedling establishment on sand dunes. However, little is known about the ecological role of seed mucilage in seedling emergence in arid sandy environments. We hypothesized that seed mucilage enhances seedling emergence in a low precipitation regime and under conditions of sand burial. In a greenhouse experiment, two types of Artemisia sphaerocephala achenes (intact and demucilaged) were exposed to different combinations of burial depth (0, 5, 10, 20, 40 and 60 mm) and irrigation regimes (low, medium and high, which simulated the precipitation amount and frequency in May, June and July in the natural habitat, respectively). Seedling emergence increased with increasing irrigation. It was highest at 5 mm sand burial depth and ceased at burial depths greater than 20 mm in all irrigation regimes. Mucilage significantly enhanced seedling emergence at 0, 5 and 10 mm burial depths in low irrigation, at 0 and 5 mm burial depths in medium irrigation and at 0 and 10 mm burial depths in high irrigation. Seed mucilage also reduced seedling mortality at the shallow sand burial depths. Moreover, mucilage significantly affected seedling emergence time and quiescence and dormancy percentages. Our findings suggest that seed mucilage plays an ecologically important role in successful seedling establishment of A. sphaerocephala by improving seedling emergence and reducing seedling mortality in stressful habitats of the sandy desert environment.


Asunto(s)
Artemisia/crecimiento & desarrollo , Mucílago de Planta/fisiología , Semillas/crecimiento & desarrollo , Adaptación Fisiológica , Riego Agrícola , Desecación , Dióxido de Silicio
6.
Plant Cell Environ ; 35(5): 872-83, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22070663

RESUMEN

In contrast to the extensive understanding of seed mucilage biosynthesis, much less is known about how mucilage is biodegraded and what role it plays in the soil where seeds germinate. We studied seed mucilage biodegradation by a natural microbial community. High-performance anion-exchange chromatography (HPAEC) was used to determine monosaccharide composition in achene mucilage of Artemisia sphaerocephala. Mucilage degradation by the soil microbial community from natural habitats was examined by monosaccharide utilization tests using Biolog plates, chemical assays and phospholipid fatty acid (PLFA) analysis. Glucose (29.4%), mannose (20.3%) and arabinose (19.5%) were found to be the main components of achene mucilage. The mucilage was biodegraded to CO(2) and soluble sugars, and an increase in soil microbial biomass was observed during biodegradation. Fluorescence microscopy showed the presence of mucilage (or its derivatives) in seedling tissues after growth with fluorescein isothiocyanate (FITC)-labelled mucilage. The biodegradation also promoted early seedling growth in barren sand dunes, which was associated with a large soil microbial community that supplies substances promoting seedling establishment. We conclude that biodegradation of seed mucilage can play an ecologically important role in the life cycles of plants especially in harsh desert environments to which A. sphaerocephala is well-adapted.


Asunto(s)
Adhesivos/metabolismo , Artemisia/fisiología , Polisacáridos/metabolismo , Microbiología del Suelo , Adaptación Fisiológica/fisiología , Adhesivos/química , Artemisia/química , Artemisia/crecimiento & desarrollo , Artemisia/microbiología , Biodegradación Ambiental , Biomasa , Dióxido de Carbono/metabolismo , Clima Desértico , Ecosistema , Germinación , Modelos Teóricos , Polisacáridos/química , Dispersión de Semillas , Plantones/crecimiento & desarrollo , Semillas/química , Semillas/crecimiento & desarrollo , Semillas/fisiología , Suelo
7.
PLoS One ; 6(9): e24346, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21912689

RESUMEN

Despite proposed ecological importance of mucilage in seed dispersal, germination and seedling establishment, little is known about the role of mucilage in seed pre-germination processes. Here we investigated the role of mucilage in assisting achene cells to repair DNA damage during dew deposition in the desert. Artemisia sphaerocephala achenes were first treated γ-irradiation to induce DNA damage, and then they were repaired in situ in the desert dew. Dew deposition duration can be as long as 421 min in early mornings. Intact achenes absorbed more water than demucilaged achenes during dew deposition and also carried water for longer time following sunrise. After 4-d dew treatment, DNA damage of irradiated intact and demucilaged achenes was reduced to 24.38% and 46.84%, respectively. The irradiated intact achenes exhibited much higher DNA repair ratio than irradiated demucilaged achenes. Irradiated intact achenes showed an improved germination and decreased nonviable achenes after dew treatment, and significant differences in viability between the two types of achenes were detected after 1020 min of dew treatment. Achene mucilage presumably plays an ecologically important role in the life cycle of A. sphaerocephala by aiding DNA repair of achene cells in genomic-stressful habitats.


Asunto(s)
Adaptación Fisiológica , Adhesivos/metabolismo , Artemisia/fisiología , ADN de Plantas/genética , Clima Desértico , Frutas/metabolismo , Agua/metabolismo , Adaptación Fisiológica/efectos de los fármacos , Adaptación Fisiológica/genética , Adaptación Fisiológica/efectos de la radiación , Artemisia/efectos de los fármacos , Artemisia/metabolismo , Artemisia/efectos de la radiación , Daño del ADN/genética , Reparación del ADN/efectos de los fármacos , Reparación del ADN/genética , Reparación del ADN/efectos de la radiación , Frutas/efectos de los fármacos , Frutas/fisiología , Frutas/efectos de la radiación , Genoma de Planta/genética , Germinación/efectos de los fármacos , Germinación/genética , Germinación/efectos de la radiación , Agua/farmacología
8.
Plant Physiol Biochem ; 48(2-3): 131-5, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20093038

RESUMEN

Artemisia sphaerocephala (Asteraceae) is one of the pioneer species in moving and semi-stable sand dunes in the deserts of northwest China. The outer surface of A. sphaerocephala achenes contains a pectinaceous mucilage layer that can imbibe a large amount of water when wetted. We hypothesized that the mucilage can aid achene germination in heterogeneous environments. Germination of both intact achenes and those from which the mucilage had been removed (demucilaged) declined with increasing osmotic potential and NaCl concentration. However, the germination percentage of intact achenes was significantly higher than that of demucilaged achenes. The early seedling growth of intact achenes did not differ significantly from that of demucilaged achenes in either osmotic potential or NaCl solutions. Achene mucilage presumably plays an ecologically important role in the life cycle of A. sphaerocephala by aiding germination in osmotically- and saline-stressful habitats of the cold desert environment.


Asunto(s)
Artemisia/crecimiento & desarrollo , Germinación , Ósmosis , Proteínas de Plantas/fisiología , Tolerancia a la Sal , Semillas/crecimiento & desarrollo , Estrés Fisiológico , Adaptación Fisiológica , Artemisia/fisiología , China , Clima Desértico , Ecosistema , Glicoproteínas/fisiología , Polisacáridos/fisiología , Plantones/crecimiento & desarrollo , Semillas/fisiología , Cloruro de Sodio , Agua/fisiología
9.
Ann Bot ; 101(2): 277-83, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17495979

RESUMEN

BACKGROUND AND AIMS: Repair of damage to DNA of seed embryos sustained during long periods of quiescence under dry desert conditions is important for subsequent germination. The possibility that repair of embryo DNA can be facilitated by small amounts of water derived from dew temporarily captured at night by pectinaceous surface pellicles was tested. These pellicles are secreted during early seed development and form mucilage when hydrated. METHODS: Seeds of Artemisia sphaerocephala and Artemisia ordosica were collected from a sandy desert. Their embryos were damaged by gamma radiation to induce a standard level of DNA damage. The treated seeds were then exposed to nocturnal dew deposition on the surface of soil in the Negev desert highlands. The pellicles were removed from some seeds and left intact on others to test the ability of mucilage to support repair of the damaged DNA when night-time humidity and temperature favoured dew formation. Repair was assessed from fragmentation patterns of extracted DNA on agarose gels. KEY RESULTS: For A. sphaerocephala, which has thick seed pellicles, DNA repair occurred in seeds with intact pellicles after 50 min of cumulative night dew formation, but not in seeds from which the pellicles had been removed. For A. ordosica, which has thin seed pellicles, DNA repair took at least 510 min of cumulative night dewing to achieve partial recovery of DNA integrity. The mucilage has the ability to rehydrate after daytime dehydration. CONCLUSIONS: The ability of seeds to develop a mucilaginous layer when wetted by night-time dew, and to repair their DNA under these conditions, appear to be mechanisms that help maintain seed viability under harsh desert conditions.


Asunto(s)
Adaptación Fisiológica , Adhesivos/metabolismo , Reparación del ADN , ADN de Plantas/metabolismo , Pectinas/metabolismo , Semillas/metabolismo , Agua/metabolismo , Adaptación Fisiológica/efectos de la radiación , Artemisia/efectos de la radiación , Artemisia/ultraestructura , Ritmo Circadiano/efectos de la radiación , Reparación del ADN/efectos de la radiación , Clima Desértico , Rayos gamma , Humedad , Semillas/genética , Semillas/efectos de la radiación , Semillas/ultraestructura , Factores de Tiempo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA