排序方式: 共有16条查询结果,搜索用时 15 毫秒
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SAMIA DJENNANE LAURENCE HIBRAND‐SAINT OYANT KOJI KAWAMURA DAVID LALANNE MICHEL LAFFAIRE TATIANA THOUROUDE SÉVERINE CHALAIN SOULAIMAN SAKR RACHID BOUMAZA NATHALIE LEDUC 《Plant, cell & environment》2014,37(3):742-757
Light and temperature are two environmental factors that deeply affect bud outgrowth. However, little is known about their impact on the bud burst gradient along a stem and their interactions with the molecular mechanisms of bud burst control. We investigated this question in two acrotonic rose cultivars. We demonstrated that the darkening of distal buds or exposure to cold (5 °C) prior to transfer to mild temperatures (20 °C) both repress acrotony, allowing the burst of quiescent medial and proximal buds. We sequenced the strigolactone pathway MAX‐homologous genes in rose and studied their expression in buds and internodes along the stem. Only expressions of RwMAX1, RwMAX2 and RwMAX4 were detected. Darkening of the distal part of the shoot triggered a strong increase of RwMAX2 expression in darkened buds and bark‐phloem samples, whereas it suppressed the acropetal gradient of the expression of RwMAX1 observed in stems fully exposed to light. Cold treatment induced an acropetal gradient of expression of RwMAX1 in internodes and of RwMAX2 in buds along the stem. Our results suggest that the bud burst gradient along the stem cannot be explained by a gradient of expression of RwMAX genes but rather by their local level of expression at each individual position. 相似文献
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Semiempirical modeling of abiotic and biotic factors controlling ecosystem respiration across eddy covariance sites 总被引:1,自引:0,他引:1
MIRCO MIGLIAVACCA MARKUS REICHSTEIN ANDREW D. RICHARDSON ROBERTO COLOMBO MARK A. SUTTON GITTA LASSLOP ENRICO TOMELLERI GEORG WOHLFAHRT NUNO CARVALHAIS ALESSANDRO CESCATTI MIGUEL D. MAHECHA LEONARDO MONTAGNANI DARIO PAPALE SÖNKE ZAEHLE ALTAF ARAIN ALMUT ARNETH T. ANDREW BLACK ARNAUD CARRARA SABINA DORE DAMIANO GIANELLE CAROLE HELFTER DAVID HOLLINGER WERNER L. KUTSCH PETER M. LAFLEUR YANN NOUVELLON CORINNA REBMANN HUMBERTO R.
Da ROCHA MIRCO RODEGHIERO OLIVIER ROUPSARD MARIA‐TERESA SEBASTIÀ GUENTHER SEUFERT JEAN‐FRANCOISE SOUSSANA MICHIEL K.
Van Der MOLEN 《Global Change Biology》2011,17(1):390-409
In this study we examined ecosystem respiration (RECO) data from 104 sites belonging to FLUXNET, the global network of eddy covariance flux measurements. The goal was to identify the main factors involved in the variability of RECO: temporally and between sites as affected by climate, vegetation structure and plant functional type (PFT) (evergreen needleleaf, grasslands, etc.). We demonstrated that a model using only climate drivers as predictors of RECO failed to describe part of the temporal variability in the data and that the dependency on gross primary production (GPP) needed to be included as an additional driver of RECO. The maximum seasonal leaf area index (LAIMAX) had an additional effect that explained the spatial variability of reference respiration (the respiration at reference temperature Tref=15 °C, without stimulation introduced by photosynthetic activity and without water limitations), with a statistically significant linear relationship (r2=0.52, P<0.001, n=104) even within each PFT. Besides LAIMAX, we found that reference respiration may be explained partially by total soil carbon content (SoilC). For undisturbed temperate and boreal forests a negative control of total nitrogen deposition (Ndepo) on reference respiration was also identified. We developed a new semiempirical model incorporating abiotic factors (climate), recent productivity (daily GPP), general site productivity and canopy structure (LAIMAX) which performed well in predicting the spatio‐temporal variability of RECO, explaining >70% of the variance for most vegetation types. Exceptions include tropical and Mediterranean broadleaf forests and deciduous broadleaf forests. Part of the variability in respiration that could not be described by our model may be attributed to a series of factors, including phenology in deciduous broadleaf forests and management practices in grasslands and croplands. 相似文献
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LUITGARD SCHWENDENMANN EDZO VELDKAMP GERALD MOSER DIRK HÖLSCHER MICHAEL KÖHLER YANN CLOUGH ISWANDI ANAS GUNAWAN DJAJAKIRANA STEFAN ERASMI DIETRICH HERTEL DANIELA LEITNER CHRISTOPH LEUSCHNER BEATE MICHALZIK PAVEL PROPASTIN AIYEN TJOA TEJA TSCHARNTKE OLIVER Van STRAATEN 《Global Change Biology》2010,16(5):1515-1530
Agroforestry systems may play a critical role in reducing the vulnerability of farmers' livelihood to droughts as tree‐based systems provide several mechanisms that can mitigate the impacts from extreme weather events. Here, we use a replicated throughfall reduction experiment to study the drought response of a cacao/Gliricidia stand over a 13‐month period. Soil water content was successfully reduced down to a soil depth of at least 2.5 m. Contrary to our expectations we measured only relatively small nonsignificant changes in cacao (?11%) and Gliricidia (?12%) sap flux densities, cacao leaf litterfall (+8%), Gliricidia leaf litterfall (?2%), soil carbon dioxide efflux (?14%), and cacao yield (?10%) during roof closure. However, cacao bean yield in roof plots was substantially lower (?45%) compared with control plots during the main harvest following the period when soil water content was lowest. This indicates that cacao bean yield was more sensitive to drought than other ecosystem functions. We found evidence in this agroforest that there is complementary use of soil water resources through vertical partitioning of water uptake between cacao and Gliricidia. This, in combination with acclimation may have helped cacao trees to cope with the induced drought. Cacao agroforests may thus play an important role as a drought‐tolerant land use in those (sub‐) tropical regions where the frequency and severity of droughts is projected to increase. 相似文献
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RENAUD RIFFLART GEORGES CARREL YANN LE COARER BENEDICTE NGUYEN THE FONTEZ 《Freshwater Biology》2009,54(7):1544-1559
1. The River Durance, the last alpine tributary of the River Rhône, is a large, braided alluvial hydrosystem. Following large-scale regulation, flow downstream of the Serre-Ponçon dam has been maintained at 1/40th of previous annual mean discharge. To assess the effects of historical disturbances, fish assemblages and habitat use were analysed during five summers in a representative reach of the middle Durance.
2. Habitat availability and use were assessed with a multi-scale approach including the variables water depth, current velocity, roughness height of substratum, amount of woody debris and lateral/longitudinal location. Eighteen fish species were sampled by electrofishing in 289 habitat sample units.
3. Partial least square (PLS) regression showed that taxa were mainly distributed according to relationships between their total length and water depth/velocity variables. Fish assemblage composition was also related to roughness height as well as distance from the bank or to the nearest large woody debris. However, PLS regression revealed no significant differences in habitat selection between two periods of varying hydromorphological stability.
4. Fish distribution patterns and density were related to proximity to the bank and cover, indicating that local scale variables need to be considered in conservation and restoration programmes. 相似文献
2. Habitat availability and use were assessed with a multi-scale approach including the variables water depth, current velocity, roughness height of substratum, amount of woody debris and lateral/longitudinal location. Eighteen fish species were sampled by electrofishing in 289 habitat sample units.
3. Partial least square (PLS) regression showed that taxa were mainly distributed according to relationships between their total length and water depth/velocity variables. Fish assemblage composition was also related to roughness height as well as distance from the bank or to the nearest large woody debris. However, PLS regression revealed no significant differences in habitat selection between two periods of varying hydromorphological stability.
4. Fish distribution patterns and density were related to proximity to the bank and cover, indicating that local scale variables need to be considered in conservation and restoration programmes. 相似文献
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YANN SURGET-GROBA BENOIT HEULIN CLAUDE-PIERRE GUILLAUME MIKLOS PUKY DMITRY SEMENOV VALENTINA ORLOVA LARISSA KUPRIYANOVA IOAN GHIRA BENEDIK SMAJDA 《Biological journal of the Linnean Society. Linnean Society of London》2006,87(1):1-11
The evolution of viviparity in squamates has been the focus of much scientific attention in previous years. In particular, the possibility of the transition from viviparity back to oviparity has been the subject of a vigorous debate. Some studies have suggested this reversal is more frequent than previously thought. However, none of them provide conclusive evidence. We investigated this problem by studying the phylogenetic relationships between oviparous and viviparous lineages of the reproductively bimodal lizard species Zootoca vivipara . Our results show that viviparous populations are not monophyletic, and that several evolutionary transitions in parity mode have occurred. The most parsimonious scenario involves a single origin of viviparity followed by a reversal back to oviparity. This is the first study with a strongly supported phylogenetic framework supporting a transition from viviparity to oviparity. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 1–11. 相似文献
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DANIEL EPRON YANN NOUVELLON†‡ PHILIPPE DELEPORTE†‡ SUSPENS IFO† GUY KAZOTTI† ARMEL THONGO M'BOU† WELCOME MOUVONDY† LAURENT SAINT ANDRE‡ OLIVIER ROUPSARD‡ CHRISTOPHE JOURDAN‡ OLIVIER HAMEL‡ 《Global Change Biology》2006,12(6):1021-1031
Soil CO2 efflux was measured in clear‐cut and intact plots in order to quantify the impact of harvest on soil respiration in an intensively managed Eucalyptus plantation, and to evaluate the increase in heterotrophic component of soil respiration because of the decomposition of harvest residues. Soil CO2 effluxes showed a pronounced seasonal trend, which was well related to the pattern of precipitation and soil water content and were always significantly lower in the clear‐cut plots than in the intact plots. On an annual basis, soil respiration represented 1.57 and 0.91 kgC m?2 yr?1 in intact and clear‐cut plots, respectively. During the first year following harvest, residues have lost 0.79 kgC m?2 yr?1. Our estimate of heterotrophic respiration was calculated assuming that it was similar to soil respiration in the clear‐cut area except that the decomposition of residues did not occur, and it was further corrected for differences in soil water content between intact and clear‐cut plots and for the cessation of leaf and fine root turnover in clear cut. Heterotrophic respiration in clear‐cut plots was estimated at 1.18 kgC m?2 yr?1 whereas it was only 0.65 kgC m?2 yr?1 in intact plots (41% of soil respiration). Assumptions and uncertainties with these calculations are discussed. 相似文献
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Variability within a pea core collection of LEAM and HSP22, two mitochondrial seed proteins involved in stress tolerance 下载免费PDF全文
MARIE‐HÉLÈNE AVELANGE‐MACHEREL NICOLE PAYET DAVID LALANNE MARTINE NEVEU DIMITRI TOLLETER JUDITH BURSTIN DAVID MACHEREL 《Plant, cell & environment》2015,38(7):1299-1311
LEAM, a late embryogenesis abundant protein, and HSP22, a small heat shock protein, were shown to accumulate in the mitochondria during pea (Pisum sativum L.) seed development, where they are expected to contribute to desiccation tolerance. Here, their expression was examined in seeds of 89 pea genotypes by Western blot analysis. All genotypes expressed LEAM and HSP22 in similar amounts. In contrast with HSP22, LEAM displayed different isoforms according to apparent molecular mass. Each of the 89 genotypes harboured a single LEAM isoform. Genomic and RT‐PCR analysis revealed four LEAM genes differing by a small variable indel in the coding region. These variations were consistent with the apparent molecular mass of each isoform. Indels, which occurred in repeated domains, did not alter the main properties of LEAM. Structural modelling indicated that the class A α‐helix structure, which allows interactions with the mitochondrial inner membrane in the dry state, was preserved in all isoforms, suggesting functionality is maintained. The overall results point out the essential character of LEAM and HSP22 in pea seeds. LEAM variability is discussed in terms of pea breeding history as well as LEA gene evolution mechanisms. 相似文献
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Photosynthetic and anatomical responses of Eucalyptus grandis leaves to potassium and sodium supply in a field experiment 总被引:4,自引:0,他引:4
PATRICIA BATTIE‐LACLAU JEAN‐PAUL LACLAU CONSTANCE BERI LAURIANE MIETTON MARTA R.ALMEIDA MUNIZ BRUNA CERSÓZIMO ARENQUE MARISA DE CASSIA PICCOLO LIONEL JORDAN‐MEILLE JEAN‐PIERRE BOUILLET YANN NOUVELLON 《Plant, cell & environment》2014,37(1):70-81
Although vast areas in tropical regions have weathered soils with low potassium (K) levels, little is known about the effects of K supply on the photosynthetic physiology of trees. This study assessed the effects of K and sodium (Na) supply on the diffusional and biochemical limitations to photosynthesis in Eucalyptus grandis leaves. A field experiment comparing treatments receiving K (+K) or Na (+Na) with a control treatment (C) was set up in a K‐deficient soil. The net CO2 assimilation rates were twice as high in +K and 1.6 times higher in +Na than in the C as a result of lower stomatal and mesophyll resistance to CO2 diffusion and higher photosynthetic capacity. The starch content was higher and soluble sugar was lower in +K than in C and +Na, suggesting that K starvation disturbed carbon storage and transport. The specific leaf area, leaf thickness, parenchyma thickness, stomatal size and intercellular air spaces increased in +K and +Na compared to C. Nitrogen and chlorophyll concentrations were also higher in +K and +Na than in C. These results suggest a strong relationship between the K and Na supply to E. grandis trees and the functional and structural limitations to CO2 assimilation rates. 相似文献
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Populations of the Caribbean lizard, Anolis roquet, are thought to have experienced long periods of allopatry before recent secondary contact. To elucidate the effects of past allopatry on population divergence in A. roquet, we surveyed parallel transects across a secondary contact zone in northeastern Martinique. We used diagnostic molecular mitochondrial DNA markers to test fine‐scale association of mitochondrial DNA lineage and geological region, multivariate statistical techniques to explore quantitative trait pattern, and cline fitting techniques to model trait variation across the zone of secondary contact. We found that lineages were strongly associated with geological regions along both transects, but quantitative trait patterns were remarkably different. Patterns of morphological and mitochondrial DNA variation were consistent with a strong barrier to gene flow on the coast, whereas there were no indications of barriers to gene flow in the transitional forest. Hence, the coastal populations behaved as would be predicted by an allopatric model of divergence in this complex, while those in the transitional forest did not, despite the close proximity of the transects and their shared geological history. Patterns of geographical variation in this species complex, together with environmental data, suggest that on balance, selection regimes on either side of the secondary contact zone in the transitional forest may be more convergent, while those either side of the secondary contact zone on the coast are more divergent. Hence, the evolutionary consequences of allopatry may be strongly influenced by local natural selection regimes. 相似文献