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1.
PLoS One ; 9(9): e105500, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25184224

RESUMO

Plant species show different responses to the elevated temperatures that are resulting from global climate change, depending on their ecological and physiological characteristics. The highly invasive shrub Lantana camara occurs between the latitudes of 35 °N and 35 °S. According to current and future climate scenarios predicted by the CLIMEX model, climatically suitable areas for L. camara are projected to contract globally, despite expansions in some areas. The objective of this study was to test those predictions, using a pot experiment in which branch cuttings were grown at three different temperatures (22 °C, 26 °C and 30 °C). We hypothesized that warming would facilitate the invasiveness of L. camara. In response to rising temperatures, the total biomass of L. camara did increase. Plants allocated more biomass to stems and enlarged their leaves more at 26 °C and 30 °C, which promoted light capture and assimilation. They did not appear to be stressed by higher temperatures, in fact photosynthesis and assimilation were enhanced. Using lettuce (Lactuca sativa) as a receptor plant in a bioassay experiment, we also tested the phytotoxicity of L. camara leachate at different temperatures. All aqueous extracts from fresh leaves significantly inhibited the germination and seedling growth of lettuce, and the allelopathic effects became stronger with increasing temperature. Our results provide key evidence that elevated temperature led to significant increases in growth along with physiological and allelopathic effects, which together indicate that global warming facilitates the invasion of L. camara.


Assuntos
Espécies Introduzidas , Lantana/crescimento & desenvolvimento , Extratos Vegetais/toxicidade , Caules de Planta/crescimento & desenvolvimento , Biomassa , Clorofila/biossíntese , Metabolismo Energético/fisiologia , Germinação/efeitos dos fármacos , Aquecimento Global , Lantana/metabolismo , Alface/efeitos dos fármacos , Alface/crescimento & desenvolvimento , Modelos Biológicos , Fotossíntese/fisiologia , Dispersão Vegetal , Folhas de Planta/química , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Caules de Planta/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Temperatura
2.
PLoS One ; 8(11): e80623, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24265832

RESUMO

Clonal growth allows plants to spread horizontally and to experience different levels of resources. If ramets remain physiologically integrated, clonal plants can reciprocally translocate resources between ramets in heterogeneous environments. But little is known about the interaction between benefits of clonal integration and patterns of resource heterogeneity in different patches, i.e., coincident patchiness or reciprocal patchiness. We hypothesized that clonal integration will show different effects on ramets in different patches and more benefit to ramets under reciprocal patchiness than to those under coincident patchiness, as well as that the benefit from clonal integration is affected by the position of proximal and distal ramets under reciprocal or coincident patchiness. A pot experiment was conducted with clonal fragments consisting of two interconnected ramets (proximal and distal ramet) of Fragaria orientalis. In the experiment, proximal and distal ramets were grown in high or low availability of resources, i.e., light and water. Resource limitation was applied either simultaneously to both ramets of a clonal fragment (coincident resource limitation) or separately to different ramets of the same clonal fragment (reciprocal resource limitation). Half of the clonal fragments were connected while the other half were severed. From the experiment, clonal fragments growing under coincident resource limitation accumulated more biomass than those under reciprocal resource limitation. Based on a cost-benefit analysis, the support from proximal ramets to distal ramets was stronger than that from distal ramets to proximal ramets. Through division of labour, clonal fragments of F. orientalis benefited more in reciprocal patchiness than in coincident patchiness. While considering biomass accumulation and ramets production, coincident patchiness were more favourable to clonal plant F. orientalis.


Assuntos
Meio Ambiente , Fragaria/crescimento & desenvolvimento , Análise de Variância , Biomassa , Ecossistema
3.
PLoS One ; 7(9): e44221, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22957054

RESUMO

Clonal growth allows plants to spread horizontally and to establish ramets in sites of contrasting resource status. If ramets remain physiologically integrated, clones in heterogeneous environments can act as cooperative systems--effects of stress on one ramet can be ameliorated by another connected ramet inhabiting benign conditions. But little is known about the effects of patch contrast on physiological integration of clonal plants and no study has addressed its effects on physiological traits like osmolytes, reactive oxygen intermediates and antioxidant enzymes. We examined the effect of physiological integration on survival, growth and stress indicators such as osmolytes, reactive oxygen intermediates (ROIs) and antioxidant enzymes in a clonal plant, Fragaria orientalis, growing in homogenous and heterogeneous environments differing in patch contrast of water availability (1 homogeneous (no contrast) group; 2 low contrast group; 3 high contrast group). Drought stress markedly reduced the survival and growth of the severed ramets of F. orientalis, especially in high contrast treatments. Support from a ramet growing in benign patch considerably reduced drought stress and enhanced growth of ramets in dry patches. The larger the contrast between water availability, the larger the amount of support the depending ramet received from the supporting one. This support strongly affected the growth of the supporting ramet, but not to an extent to cause increase in stress indicators. We also found indication of costs related to maintenance of physiological connection between ramets. Thus, the net benefit of physiological integration depends on the environment and integration between ramets of F. orientalis could be advantageous only in heterogeneous conditions with a high contrast.


Assuntos
Secas , Fragaria/metabolismo , Antioxidantes/química , Biomassa , Meio Ambiente , Fragaria/crescimento & desenvolvimento , Peróxido de Hidrogênio/química , Luz , Fotossíntese , Folhas de Planta/metabolismo , Fenômenos Fisiológicos Vegetais , Espécies Reativas de Oxigênio , Solo , Água/química
4.
Ying Yong Sheng Tai Xue Bao ; 16(9): 1687-92, 2005 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-16355784

RESUMO

There are two ways in Symplocos laurina propagation, clonal and sexual reproduction. The study showed that under different habitat conditions, Symplocos laurina could adopt different ways to propagate and occupy space. In conditions with abundant water and nutrient resources, such as in evergreen broad-leaved forests or bamboo forests, the survival rate and space-occupying ability of both ramets and sexual seedlings were relatively high, with clonal ramets took advantage in terms of number and space, suggesting that clonal propagation was the dominant way in such environments. Oppositely, in habitats lack of sufficient nutrition, the survival rate and space-occupying ability of seedlings were low, and grown-up plantlets would preempt in number and space occupation. Bottleneck in sexual propagation appeared in the stage from seed to seedling, while clonal propagation appeared during the period from seedling to ramet. The way of Symplocos laurina invasion was to settle a plantlet, and then occupied the space rapidly by clonal growth, with clonal seedlings dominated in initial stage and lost the advantage after 15 ages.


Assuntos
Ecossistema , Reprodução Assexuada/fisiologia , Reprodução/fisiologia , Árvores/fisiologia , Adaptação Biológica , Meio Ambiente , Densidade Demográfica , Plântula/fisiologia
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