Search results for "auxin"
showing 10 items of 81 documents
Aspects fonctionnels, structuraux et évolutifs de la réponse transcriptionnelle à l’auxine
2017
Auxin is a plant hormone implicated in almost all plant developmental stages, since the embryo formation till flowering, determining the position of the organs in the plant and thus, its whole structure. As for any other hormone, auxin perception is followed by a signal transduction that finishes in a series of changes in a plant cell, including transcriptional changes. This thesis is divided in 3 chapters, each with a focus on the structural, molecular and evolutionary aspects of different proteins involved in the regulation of auxin genes response.First, we focused our studies on TOPLESS (TPL), a co-repressor implicated, not only in auxin responsive genes repression, but also in many othe…
What do we know about growth of vessel elements of secondary xylem in woody plants?
2021
Despite extensive knowledge about vessel element growth and the determination of the axial course of vessels, these processes are still not fully understood. They are usually explained as resulting primarily from hormonal regulation in stems. This review focuses on an increasingly discussed aspect - mechanical conditions in the vascular cambium. Mechanical conditions in cambial tissue are important for the growth of vessel elements, as well as other cambial derivatives. In relation to the type of stress acting on cambial cells (compressive versus tensile stress) we: (i) discuss the shape of the enlarging vessel elements observed in anatomical sections; (ii) present hypotheses regarding the …
Expression Patterns of Key Hormones Related to Pea (Pisum sativum L.) Embryo Physiological Maturity Shift in Response to Accelerated Growth Conditions
2019
Protocols have been proposed for rapid generation turnover of temperate legumes under conditions optimized for day-length, temperature, and light spectra. These conditions act to compress time to flowering and seed development across genotypes. In pea, we have previously demonstrated that embryos do not efficiently germinate without exogenous hormones until physiological maturity is reached at 18 days after pollination (DAP). Sugar metabolism and moisture content have been implicated in the modulation of embryo maturity. However, the role of hormones in regulating seed development is poorly described in legumes. To address this gap, we characterized hormonal profiles (IAA, chlorinated auxin…
An “omic” approach towards molecular diagnosis of resistance to auxinic herbicides in Corn poppy (Papaver rhoeas)
2021
National audience; Papaver rhoeas (corn poppy) is a major, troublesome weed in winter crops. In conventionalagriculture, poppy control is essentially achieved through herbicide application. Followingintensive use of these substances, resistance has evolved in many poppy populations across itsrange in Europe. Among the herbicide modes of action concerned by resistance are auxinmimeticherbicides (HRAC group 4/O). Resistance to this mode of action has little beeninvestigated, and its determinants remain largely unknown. Literature data suggests that, whiletarget-site-based resistance exist, non-target-site-based resistance mechanisms may bepredominant. Target-site-based resistance to auxinic h…
Regulation of legume seed size by an endosperm-expressed transcription factor
2015
BAP Pôle GEAPSI; International audience; There are numerous reports of transcription factors (TFs) which are implicated in the control of seed size and seed composition. We have identified, using a platform of TF sequences derived from the Medicago truncatula genome sequence, a class of TFs specifically expressed during the seed filling stage. One such TF, DASH, was shown to be confined to the developing endosperm. We investigated the role played by DASH through analysis of mutant alleles. These give rise to seed-lethal or near-lethal phenotypes, with degeneration of the endosperm and arrested embryo development. The relation of this phenotype to seed auxin action was investigated.
Influence de l'auxine sur le developpement in vitro de la graine de Medicago truncatula, genotype sauvage et transformants
2012
Rapport de stage Master 1 Sciences, Technologies, Vie, Terre et Santé. Spécialité Biologie Cellulaire et Physiologie BAP GEAPSI CT2
Wykorzystanie antagonistycznych właściwości Bacillus subtilis wobec Rhizoctonia solani
2017
Production of indole acetic acid by endophytic Bacillus strains
2018
Celem pracy by³o wyizolowanie i scharakteryzowanie bakterii endofitycznych korzeni buraka cukrowego pod k¹tem ich zdolnooeci do produkcji kwasu indolilooctowego (IAA). Materia³ dooewiadczalny do izolacji bakterii endofitycznych stanowi³y korzenie burak cukrowego. Ilooeæ wytworzonego IAA przez endofityczne szczepy Bacillus (B. amyloliquefaciens, B. megaterium, B. subtilis) oznaczono metod¹ kolorymetryczn ¹ z odczynnikiem Salkowskiego. Szczepy hodowano w po¿ywce LB (Laurin Broth) suplementowanej L-tryptofanem w stê¿eniach 100–10000 g/cm3 i inkubowano w 30 oC przez 7 dni. Najwy¿sze stê¿enie IAA odnotowano po 4 dniach w hodowlach zawieraj¹cych 10000 g/cm3 L-tryptofanu. Dla szczepu B. subtilis i…
Factors controlling adventitious bud induction and plant regeneration in matureJuniperus oxycedrus leaves cultured in vitro
1994
The morphogenetic capacity of matureJuniperus oxycedrus L. leaves cultured in vitro has been studied, noting nutritive, hormonal, and environmental factors inducing differentiation and development of adventitious shoots. Bud primordia formed directly from the leaves. Highest bud differentiation rates were obtained when the explants were cultured for at least 21 days on a modified Schenk and Hildebrandt solidified medium containing 0.5 μM benzyladenine under a 16-h photoperiod. Maximum bud development and elongation was achieved on cytokinin-free medium containing 4% (wt/vol) sucrose and 0.05% (wt/vol) activated charcoal. Regenerated shoots were excised and induced to root on media with auxi…
Effect of growth regulators onin vitro propagation ofFicus benjamina cv. Exotica
1994
Stem internodes with axillary buds were excised from 5-year old trees ofFicus benjamina cv. Exotica. The effect of 6-benzylaminopurine (BAP), gibberellic acid (GA3), indole-3-acetic acid (IAA), naphthaleneacetic acid (NAA), and 2,4-dichlorophenoxyacetic acid (2,4-D) on shoot growth and proliferationin vitro was investigated. Multiple shoots were developed after 3–4 weeks from stem internodes with axillary buds incubated in Murashige and Skoog (MS) medium supplemented with phloroglucinol (PG) and BAP. Optimum shoot proliferation took place in the presence of 1.0 mg l−1 BAP. Shoots obtained could be elongated in a medium with 0.5 mg l−1 GA3 prior to their rooting. The root initiation was succ…