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111.
THÉOPHILE KAZMIERCZAK VÉRONIQUE GRUBER FLORIAN FRUGIER MATHILDE CLEMENT PIERRE FRENDO DIDIER HEROUART ERIC BONCOMPAGNI 《Plant, cell & environment》2014,37(3):658-669
PRAF proteins are present in all plants, but their functions remain unclear. We investigated the role of one member of the PRAF family, MtZR1, on the development of roots and nitrogen‐fixing nodules in Medicago truncatula. We found that MtZR1 was expressed in all M. truncatula organs. Spatiotemporal analysis showed that MtZR1 expression in M. truncatula roots was mostly limited to the root meristem and the vascular bundles of mature nodules. MtZR1 expression in root nodules was down‐regulated in response to various abiotic stresses known to affect nitrogen fixation efficiency. The down‐regulation of MtZR1 expression by RNA interference in transgenic roots decreased root growth and impaired nodule development and function. MtZR1 overexpression resulted in longer roots and significant changes to nodule development. Our data thus indicate that MtZR1 is involved in the development of roots and nodules. To our knowledge, this work provides the first in vivo experimental evidence of a biological role for a typical PRAF protein in plants. 相似文献
112.
VIOLAINE JOURDIE NADIR ALVAREZ JAIME MOLINA‐OCHOA TREVOR WILLIAMS DAVID BERGVINSON BETTY BENREY TED C. J. TURLINGS PIERRE FRANCK 《Molecular ecology》2010,19(10):2168-2179
Plant chemistry can strongly influence interactions between herbivores and their natural enemies, either by providing volatile compounds that serve as foraging cues for parasitoids or predators, or by affecting the quality of herbivores as hosts or prey. Through these effects plants may influence parasitoid population genetic structure. We tested for a possible specialization on specific crop plants in Chelonus insularis and Campoletis sonorensis, two primary parasitoids of the fall armyworm, Spodoptera frugiperda. Throughout Mexico, S. frugiperda larvae were collected from their main host plants, maize and sorghum and parasitoids that emerged from the larvae were used for subsequent comparison by molecular analysis. Genetic variation at eight and 11 microsatellites were respectively assayed for C. insularis and C. sonorensis to examine isolation by distance, host plant and regional effects. Kinship analyses were also performed to assess female migration among host‐plants. The analyses showed considerable within population variation and revealed a significant regional effect. No effect of host plant on population structure of either of the two parasitoid species was found. Isolation by distance was observed at the individual level, but not at the population level. Kinship analyses revealed significantly more genetically related—or kin—individuals on the same plant species than on different plant species, suggesting that locally, mothers preferentially stay on the same plant species. Although the standard population genetics parameters showed no effect of plant species on population structure, the kinship analyses revealed that mothers exhibit plant species fidelity, which may speed up divergence if adaptation were to occur. 相似文献
113.
114.
The evolution of acoustic signals is influenced by environmental constraints. We studied two sympatric but unrelated seabirds: the Little Penguin Eudyptula minor and Short-tailed Shearwater Puffinus tenuirostris , to examine the degree to which similarities in their ecology had led to convergence in their calls. Both species nest in burrows in Southern Australia and, at night, are highly vocal and territorial. First, we analysed the physical characteristics of the territorial call. Secondly, we studied the transmission of calls through burrows and varying distances through vegetation. Thirdly, we used playback experiments of natural signals to demonstrate that the response disappears between 4–8 m, and of modified signals to understand the coding-decoding process linked to the territorial function of the call. The structure of the territorial calls of the two species clearly differs, but both species produce a succession of gaps in amplitude and frequency, and a high degree of redundancy. Our experiments show that, to decode the territorial message, birds pay attention only to parameters that are less degraded during propagation and ignore fine details of structure that are quickly degraded, even at relatively short distances (< 8 m). In both species, territorial information is mainly conveyed by the rhythmic succession of two sounds (syllables or subsyllables), birds paying attention to the FM structure of these successive sounds but not to the AM. This convergent coding is adaptive in that it reduces the possibility that the meaning may be distorted by interference from noise and acoustic screening. 相似文献
115.
FAHAD RASHEED ERWIN DREYER BÉATRICE RICHARD FRANCK BRIGNOLAS PIERRE MONTPIED DIDIER LE THIEC 《Plant, cell & environment》2013,36(1):87-102
13C discrimination between atmosphere and bulk leaf matter (Δ13Clb) is frequently used as a proxy for transpiration efficiency (TE). Nevertheless, its relevance is challenged due to: (1) potential deviations from the theoretical discrimination model, and (2) complex time integration and upscaling from leaf to whole plant. Six hybrid genotypes of Populus deltoides×nigra genotypes were grown in climate chambers and tested for whole‐plant TE (i.e. accumulated biomass/water transpired). Net CO2 assimilation rates (A) and stomatal conductance (gs) were recorded in parallel to: (1) 13C in leaf bulk material (δ13Clb) and in soluble sugars (δ13Css) and (2) 18O in leaf water and bulk leaf material. Genotypic means of δ13Clb and δ13Css were tightly correlated. Discrimination between atmosphere and soluble sugars was correlated with daily intrinsic TE at leaf level (daily mean A/gs), and with whole‐plant TE. Finally, gs was positively correlated to 18O enrichment of bulk matter or water of leaves at individual level, but not at genotype level. We conclude that Δ13Clb captures efficiently the genetic variability of whole‐plant TE in poplar. Nevertheless, scaling from leaf level to whole‐plant TE requires to take into account water losses and respiration independent of photosynthesis, which remain poorly documented. 相似文献
116.
MOHANNAD ISMAIL JOAN VAN BAAREN THIERRY HANCE JEAN‐SEBASTIEN PIERRE PHILIPPE VERNON 《Ecological Entomology》2013,38(4):355-363
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117.
DORIS GOMEZ CHRISTINA RICHARDSON MARC THÉRY THIERRY LENGAGNE JEAN‐PAUL LÉNA SANDRINE PLÉNET PIERRE JOLY 《Biological journal of the Linnean Society. Linnean Society of London》2011,103(3):633-647
In nocturnal treefrogs, mate choice implies the use of acoustic and visual signals. Multimodality is suspected to have evolved for either information redundancy or information complementariness. It is essential to explore multimodality in a natural context to understand the selection pressures operating on the signals. In the present study, we investigated calling and coloration in relation to male biometry and condition in four populations of European treefrog (Hyla arborea) varying in size and genetic isolation. We compared the signal intensity between core and satellite populations to estimate the impact of genetic diversity on male secondary sexual traits. The results obtained show important regional variations in both traits, likely as a result of local adaptations. Call and coloration are weakly correlated within an individual, implying that these traits likely convey different information about the signaller's identity or quality, thus supporting the hypothesis of complementariness of multiple messages. By contrast to the experimental evidence, we find that call and coloration are not related to male condition (as estimated by the residual of mass over size), suggesting that the condition‐dependence of these traits may be mediated by complex mechanisms not accurately reflected by the chosen estimator. Finally, male call and colour phenotypes present no robust pattern of variation with isolation status, probably because of variation in local selective pressures and in history of population dynamics. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 633–647. 相似文献
118.
The impact of heat stress on the functioning of the photosynthetic apparatus was examined in pea (Pisum sativum L.) plants grown at control (25 °C; 25 °C-plants) or moderately elevated temperature (35 °C; 35 °C-plants). In both types of plants net photosynthesis (Pn) decreased with increasing leaf temperature (LT) and was more than 80% reduced at 45 °C as compared to 25 °C. In the 25 °C-plants, LTs higher than 40 °C could result in a complete suppression of Pn. Short-term acclimation to heat stress did not alter the temperature response of Pn. Chlorophyll a fluorescence measurements revealed that photosynthetic electron transport (PET) started to decrease when LT increased above 35 °C and that growth at 35 °C improved the thermal stability of the thylakoid membranes. In the 25 °C-plants, but not in the 35 °C-plants, the maximum quantum yield of the photosystem II primary photochemistry, as judged by measuring the Fv/Fm ratio, decreased significantly at LTs higher than 38 °C. A post-illumination heat-induced reduction of the plastoquinone pool was observed in the 25 °C-plants, but not in the 35 °C-plants. Inhibition of Pn by heat stress correlated with a reduction of the activation state of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Western-blot analysis of Rubisco activase showed that heat stress resulted in a redistribution of activase polypeptides from the soluble to the insoluble fraction of extracts. Heat-dependent inhibition of Pn and PET could be reduced by increasing the intercellular CO2 concentration, but much more effectively so in the 35 °C-plants than in the 25 °C-plants. The 35 °C-plants recovered more efficiently from heat-dependent inhibition of Pn than the 25 °C-plants. The results show that growth at moderately high temperature hardly diminished inhibition of Pn by heat stress that originated from a reversible heat-dependent reduction of the Rubisco activation state. However, by improving the thermal stability of the thylakoid membranes it allowed the photosynthetic apparatus to preserve its functional potential at high LTs, thus minimizing the after-effects of heat stress. 相似文献
119.
Assessment of Enzyme Induction and Aerenchyma Formation as Mechanisms for Flooding Tolerance in Trifolium subterraneum 'Park' 总被引:6,自引:0,他引:6
ASCHI-SMITI Samira; ChAIBI WIDED; BROUQUISSE RENAUD; RICARD BERENICE; SAGLIO PIERRE 《Annals of botany》2003,91(2):195-204
The objective of this study was to evaluate the role of enzymeinduction and aerenchyma formation in prolonged tolerance tosoil flooding in a variety of underground clover (Trifoliumsubterraneum Park) previously selected for resistance.Seedlings were grown in hydroponic tanks, initially with aerationfor 3 weeks and subsequently in the absence of aeration forup to 3 weeks. After 1 h in the absence of aeration, theoxygen concentration in the hydroponic medium had decreasedto 1·5 %. During the 3 weeks of extreme oxygen deficiency,primary roots died and were replaced by considerable numbersof adventitious roots. Activities of many glycolytic and fermentativeenzymes increased in adventitious roots. Excised adventitiousroots were capable of immediate induction of ethanol in theabsence of lactate production, in association with energy chargehigher than that in excised roots of aerobically maintainedcontrols. Energy charge was even higher when measured in adventitiousroots in planta. Interestingly, haemoglobin protein could becorrelated with energy charge. Aerenchyma was readily visualizedin adventitious roots by optical microscopy of longitudinaland transverse sections. We conclude that avoidance of rootanoxia via aerenchyma is the major mechanism for prolonged roottolerance in Trifolium subterraneum Park. 相似文献
120.
perm is a permutation program designed to detect statistical connections between grouping structures and grouping factors or correlates. Groups may be of various kinds such as herds, flocks, schools and mating couples provided they make up meaningful social units. Relatedness, population membership and genotypic contents are among several aggregating variables which may be processed. Typically, perm takes in a collection of grouped data and outputs a P value. The latter is computed on the basis of random membership among groups (HO). All files, including input, output and program, are of Excel type (.xls). perm can be downloaded free of charge at: http://www.bio.ulaval.ca/louisbernatchez/downloads.htm . 相似文献