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Dive into the research topics where Laurent Leport is active.

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Featured researches published by Laurent Leport.


European Journal of Agronomy | 1999

Physiological responses of chickpea genotypes to terminal drought in a mediterranean-type environment

Laurent Leport; Neil C. Turner; Robert J. French; M.D. Barr; R. Duda; S.L. Davies; D. Tennant; Kadambot H. M. Siddique

Two field experiments were carried out to investigate the eVects of terminal drought on chickpea grown under water-limited conditions in the Mediterranean-climatic region of Western Australia. In the first experiment, five desi (small angular seeds) chickpeas and one kabuli ( large round seeds) chickpea were grown in the field with and without irrigation after flowering. In the second experiment, two desi and two kabuli cultivars were grown in the field with either irrigation or under a rainout shelter during pod filling. Leaf water potential (Y l ), dry matter partitioning after pod set and yield components were measured in both experiments while growth before pod set, photosynthesis, pod water potential and leaf osmotic adjustment were measured in the first experiment only. In the first experiment, total dry matter accumulation, water use, both in the pre- and post-podding phases, Y l and photosynthesis did not vary among genotypes. In the rainfed plants, Y l decreased below ’3 MPa while photosynthesis decreased to about a tenth of its maximum at the start of seed filling. Osmotic adjustment varied significantly among genotypes. Although flowering commenced from about 100 days after sowing (DAS) in both experiments, pod set was delayed until 130‐135 DAS in the first experiment, but started at 107 DAS in the second experiment. Water shortage reduced seed yield by 50 to 80%, due to a reduction in seed number and seed size. Apparent redistribution of stem and leaf dry matter during pod filling varied from 0 to 60% among genotypes, and suggests that this characteristic may be important for a high harvest index and seed yield in chickpea.


Plant and Soil | 2002

Abscisic acid concentration, root pH and anatomy do not explain growth differences of chickpea (Cicer arietinum L.) and lupin (Lupinus angustifolius L.) on acid and alkaline soils

Wolfram Hartung; Laurent Leport; R. George Ratcliffe; Angela Sauter; Regina Duda; Neil C. Turner

The ABA concentrations of leaves, roots, soils and transport fluids of chickpea and lupin plants growing in acid (pH=4.8) and alkaline (pH=8.0) soils and an acid soil with an alkaline subsoil and an alkaline soil with an acid subsoil were measured with the aim of explaining the poor growth of narrow-leafed lupins in alkaline soil. The ABA concentration in the leaves was higher in lupin than chickpea, but did not differ when the plants were grown in alkaline compared to acid soil. The ABA concentration of the roots and xylem sap of lupin did not differ significantly when grown in acid or alkaline soil. Chickpea roots and xylem sap had, however, lower ABA concentrations in acid soil. The ABA concentration in the soil solution was higher in the acid than in the alkaline soil. Roots of lupin and chickpea showed no suberization of the hypodermis or exodermis whether grown aeroponically or hydroponically and the pH of the cytoplasm did not change significantly when root cells of lupin and chickpea were exposed to external pHs of 4.8 or 8.0. The chickpea roots had greater suberization of the endodermal cells adjacent to radial xylem rays and maintained a slightly higher vacuolar pH than lupin in both acid and alkaline external media, but these small differences are insufficient to explain the reductions in lupin growth in alkaline soil.


Planta | 1996

Diurnal modulation of phosphoenolpyruvate carboxylation in pea leaves and roots as related to tissue malate concentrations and to the nitrogen source

Laurent Leport; Andrea Kandlbinder; Bernhard Baur; Werner M. Kaiser

Phosphoenolpyruvate (PEP) carboxylation was measured as dark 14CO2 fixation in leaves and roots (in vivo) or as PEP carboxylase (PEPCase) activity in desalted leaf and roof extracts (in vitro) from Pisum sativum L. cv. Kleine Rheinländerin. Its relation to the malate content and to the nitrogen source (nitrate or ammonium) was investigated. In tissue from nitrate-grown plants, PEP carboxylation varied diurnally, showing an increase upon illumination and a decrease upon darkening. Diurnal variations in roots were much lower than in leaves. Fixation rates in leaves remained constantly low in continuous darkness or high in continuous light. Dark CO2 fixation of leaf slices also decreased when leaves were preilluminated for 1 h in CO2-free air, suggesting that the modulation of dark CO2 fixation was related to assimilate availability in leaves and roots. Phosphoenolpyruvate carboxylase activity was also measured in vitro. However, no difference in maximum enzyme activity was found in extracts from illuminated or darkened leaves, and the response to substrate and effectors (PEP, malate, glucose-6-phosphate, pH) was also identical. The serine/threonine protein kinase inhibitors K252b, H7 and staurosporine, and the protein phosphatase 2A inhibitors okadaic acid and cantharidin, fed through the leaf petiole, did not have the effects on dark CO2 fixation predicted by a regulatory system in which PEPCase is modulated via reversible protein phosphorylation. Therefore, it is suggested that the diurnal modulation of PEP carboxylation in vivo in leaves and roots of pea is not caused by protein phosphorylation, but rather by direct allosteric effects. Upon transfer of plants to ammonium-N or to an N-free nutrient solution, mean daily malate levels in leaves decreased drastically within 4–5 d. At that time, the diurnal oscillations of PEP carboxylation in vivo disappeared and rates remained at the high light-level. The coincidence of the two events suggests that PEPCase was de-regulated because malate levels became very low. The drastic decrease of leaf malate contents upon transfer of plants from nitrate to ammonium nutrition was apparently not caused by increased amino acid or protein synthesis, but probably by higher decarboxylation rates.


Planta | 2015

Assessment of nutrient remobilization through structural changes of palisade and spongy parenchyma in oilseed rape leaves during senescence

Clément Sorin; Maja Musse; François Mariette; Alain Bouchereau; Laurent Leport

Main conclusionDifferential palisade and spongy parenchyma structural changes in oilseed rape leaf were demonstrated. These dismantling processes were linked to early senescence events and associated to remobilization processes.AbstractDuring leaf senescence, an ordered cell dismantling process allows efficient nutrient remobilization. However, in Brassica napus plants, an important amount of nitrogen (N) in fallen leaves is associated with low N remobilization efficiency (NRE). The leaf is a complex organ mainly constituted of palisade and spongy parenchyma characterized by different structures and functions concerning water relations and carbon fixation. The aim of the present study was to demonstrate a specific structural evolution of these parenchyma throughout natural senescence in B. napus, probably linked to differential nutrient remobilization processes. The study was performed on 340 leaves from 32 plants during an 8-week development period under controlled growing conditions. Water distribution and status at the cellular level were investigated by low-field proton nuclear magnetic resonance (NMR), while light and electron microscopy were used to observe cell and plast structure. Physiological parameters were determined on all leaves studied and used as indicators of leaf development and remobilization progress. The results revealed a process of hydration and cell enlargement of leaf tissues associated with senescence. Wide variations were observed in the palisade parenchyma while spongy cells changed only very slightly. The major new functional information revealed was the link between the early senescence events and specific tissue dismantling processes.


Plants (Basel, Switzerland) | 2015

A Comparative Study of Proteolytic Mechanisms during Leaf Senescence of Four Genotypes of Winter Oilseed Rape Highlighted Relevant Physiological and Molecular Traits for NRE Improvement

Alexandra Girondé; Marine Poret; Philippe Etienne; Jacques Trouverie; Alain Bouchereau; Françoise Le Cahérec; Laurent Leport; Marie-Françoise Niogret; Jean-Christophe Avice

Winter oilseed rape is characterized by a low N use efficiency related to a weak leaf N remobilization efficiency (NRE) at vegetative stages. By investigating the natural genotypic variability of leaf NRE, our goal was to characterize the relevant physiological traits and the main protease classes associated with an efficient proteolysis and high leaf NRE in response to ample or restricted nitrate supply. The degradation rate of soluble proteins and D1 protein (a thylakoid-bound protein) were correlated to N remobilization, except for the genotype Samouraï which showed a low NRE despite high levels of proteolysis. Under restricted nitrate conditions, high levels of soluble protein degradation were associated with serine, cysteine and aspartic proteases at acidic pH. Low leaf NRE was related to a weak proteolysis of both soluble and thylakoid-bound proteins. The results obtained on the genotype Samouraï suggest that the timing between the onset of proteolysis and abscission could be a determinant. The specific involvement of acidic proteases suggests that autophagy and/or senescence-associated vacuoles are implicated in N remobilization under low N conditions. The data revealed that the rate of D1 degradation could be a relevant indicator of leaf NRE and might be used as a tool for plant breeding.


European Journal of Agronomy | 2006

Variation in pod production and abortion among chickpea cultivars under terminal drought

Laurent Leport; Neil C. Turner; S.L. Davies; Kadambot H. M. Siddique


Plant Physiology | 1998

cis-Isomers of Cytokinins Predominate in Chickpea Seeds throughout Their Development

Robert Joseph Neil Emery; Laurent Leport; Joanne Edith Barton; Neil C. Turner; Craig A. Atkins


Crop Science | 2009

Seed Size Is Associated with Sucrose Synthase Activity in Developing Cotyledons of Chickpea

Neil C. Turner; Robert T. Furbank; Jens Berger; Patrizia Gremigni; Shahal Abbo; Laurent Leport


Applied Sciences | 2018

Leaf Development Monitoring and Early Detection of Water Deficiency by Low Field Nuclear Magnetic Resonance Relaxation in Nicotiana tabacum Plants

Clément Sorin; François Mariette; Maja Musse; Laurent Leport; Florence Cruz; Jean-Claude Yvin


Archive | 2016

Agricultural composition for stimulating the nitrogen metabolism of plants, comprising a seaweed extract of the laminaria genus and glutamic acid, corresponding methods and uses

Marc Guillermou; Sylvie Levivier; Olivier Klarzynski; Laurent Leport; Alain Bouchereau

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Neil C. Turner

Commonwealth Scientific and Industrial Research Organisation

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Kadambot H. M. Siddique

University of Western Australia

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S.L. Davies

University of Western Australia

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