Freshly harvested seeds of Arabidopsis thaliana, Columbia (Col) accession were dormant when imbibed at 25°C in the dark. Their dormancy was alleviated by continuous light during imbibition or 5 weeks storage 20°C (after-ripening). We investigated possible role reactive oxygen species (ROS) regulation Col seed dormancy. After 24 h 25°C, non-dormant produced more ROS than seeds, and their catalase activity lower. In situ localization revealed that germination associated with an accumulation...

ABSTRACT Seed dormancy, defined as the inability to germinate under favourable conditions, is controlled by abscisic acid (ABA) and gibberellins (GAs). Phytohormone signalling interacts with reactive oxygen species (ROS) regarding diverse aspects of plant physiology assumed be important in dormancy alleviation. Using dormant barley grains that do not at 30 °C darkness, we analysed ROS content ROS‐processing systems, ABA metabolism, GA‐responsive genes involved GA metabolism response hydrogen...

Changes in catalase (CAT) activity and CAT isoform pattern expression were investigated developing sunflower (Helianthus annuus L.) seeds during desiccation on the mother plant after artificial drying flowerheads. Seeds regularly desiccated their development reached mass maturity at c. 42 d flowering (DAF). Freshly harvested did not germinate any stage of because they dormant, but dormancy was broken 5-6 months dry storage. Immature desiccation-tolerant 24 DAF since able to fully flowerheads...

Two mechanisms have been suggested as being responsible for dormancy in barley grain: (i) ABA the embryo, and (ii) limitation of oxygen supply to embryo by fixation a result oxidation phenolic compounds glumellae. The aim present work was investigate whether hypoxia imposed glumellae interferes with metabolism thus resulting dormancy. In dormant non-dormant grains incubated at 20 °C 30 (i.e. when is not expressed), content decreased dramatically during first 5 h incubation before germination...

We have investigated the stomatal and phototropic responses to blue light of a number single double mutants at various loci that encode proteins involved in blue-light Arabidopsis. The light-grown mutant plants (cry1, cry2, nph1, nph3, nph4, cry1cry2, nph1cry1) did not differ significantly from those their wild-type counterparts. Second positive etiolated seedlings, cry1, npq1-2, were also similar Although npq1 cry1cry2 showed somewhat reduced amplitude for first phototropism, threshold,...

Lipocalins are a group of multifunctional proteins, recognized as carriers small lipophilic molecules, which have been characterized in bacteria and animals. Two true lipocalins recently identified plants, the temperature-induced lipocalin (TIL) chloroplastic (CHL), expression is induced by various abiotic stresses. Each appeared to be specialized responses specific stress conditions Arabidopsis thaliana, with AtTIL AtCHL playing protective role against heat high light, respectively. The...

Germination of primary dormant barley grains is promoted by darkness and temperatures below 20 °C, but strongly inhibited blue light. Exposure under light at 10 °C for periods longer than five days, results in a progressive inability to germinate the dark, considered as secondary dormancy. We demonstrate that inhibitory effect reinforced hypoxia. The associated with an increase embryo abscisic acid (ABA) content (by 3.5- 3.8-fold) sensitivity both ABA Analysis expression metabolism genes...

The changes in germination potential of freshly harvested seeds Arabidopsis thaliana stored various combinations temperature and relative humidity were investigated over 63 weeks storage. Seeds the wild type Col-0 two mutants displaying low high levels dormancy, cat2-1 mtr4-1, respectively, at harvest 24 different environments including a combination eight humidities, from 1 to 85%, four temperatures (10, 15, 20, 25 °C). These mutations did not influence behaviour during Primary dormant...

Dormancy is a complex evolutionary trait that temporally prevents seed germination, thus allowing seedling growth at favorable season. High-throughput analyses of transcriptomes have led to significant progress in understanding the molecular regulation this process, but role posttranscriptional mechanisms has received little attention. In work, we studied dynamics messenger RNA association with polysomes and compared transcriptome translatome dormant nondormant seeds Arabidopsis (Arabidopsis...

Urban trees are often not considered in air-quality models although they can significantly impact the concentrations of pollutants. Gas and particles deposit on leaf surfaces, lowering their concentrations, but tree crown aerodynamic effect is antagonist, limiting dispersion pollutants streets. Furthermore, emit Biogenic Volatile Organic Compounds (BVOCs) that react with other compounds to form ozone secondary organic aerosols. This study aims quantify impacts these three effects (dry...

ABSTRACT Stomatal responses to light of Arabidopsis thaliana wild‐type plants and mutant deficient in starch (phosphoglucomutase deficient) were compared gas exchange experiments. density, size ultrastructure identical for the two phenotypes, but no was observed guard cells whatever time day. The overall extent changes stomatal conductance during 14 h light–10 dark cycles similar phenotypes. However, slow endogenous opening occurring darkness wild type not plants. Stomata responded much more...

At harvest, barley seeds are dormant because their germination is difficult above 20°C. Incubation of primary at 30°C, a temperature which they do not germinate, results in loss ability to germinate This phenomenon corresponds an induction secondary dormancy already observed after pre-treatment 30°C as short 4–6 h, and optimal 24–48 h. It associated with maintenance high level embryo ABA content during seed incubation transfer 20°C, while decreases rapidly embryos placed directly Induction...

The regulation of plant gene expression, necessary for development and adaptive responses, relies not only on RNA transcription but also messenger (mRNA) fate. To understand whether seed germination the degradation specific subsets mRNA, we investigated 5′ to 3′ decay machinery participated in this process. Arabidopsis (Arabidopsis thaliana) seeds exoribonuclease4 (xrn4) varicose (vcs) mutants displayed distinct dormancy phenotypes. Transcriptome analysis xrn4-5 vcs-8 mutant allowed us...

The coleoptiles of wheat ( Triticum aestivum L.) seedlings cultivar Trémie are desiccation tolerant when 3 days old, although the roots not. Cutting some open prior to dehydration rapidly increased drying rate. This rendered sensitive desiccation, providing a useful model with which study tolerance. Both and were dehydrated 0.3 g H 2 O −1 dry mass (g.g) thereafter rehydrated. Sensitive tissues accr‐ ued lipid peroxidation products MDA, substantial subcellular damage was evident in tissues....

Freshly harvested barley seeds are considered as dormant since they do not germinate at temperatures above 20 degrees C. This dormancy is broken during dry storage. Molecular regulation of was investigated using cDNA-AFLP to identify transcripts differentially expressed in and non-dormant embryos. Transcript patterns embryos from both imbibed for 5 h 30 C, a temperature which expressed, were compared. Thirty-nine Transcript-Derived Fragments (TDF) that reproducibly among treatments...

Abstract Global warming is a major agricultural issue in the Northern hemisphere where higher temperatures are expected to be associated with restricted water availability. In Europe, for maize, earlier and further northward sowings forecasted order avoid deficit periods crop life cycle. However these conditions may compromise seed germination stand establishment since they will take place at cold temperatures. It urgent better understand molecular bases of response germinating maize seeds...

In barley, primary dormant grains did not germinate at 30 °C in air and 15 an atmosphere containing less than 10% O2, while they germinated easily air. O2 tension embryos measured with microsensors was 15.8% but only 0.3% °C. Incubation of is known to induce secondary dormancy it shown here that also induced by a 3 d treatment tensions lower After such treatments, the lost their ability subsequently During seed 5% embryo abscisic acid (ABA) content decreased more slowly altered after...

Summary Seed dormancy, which blocks germination in apparently favourable conditions, is a key regulatory control point of plant population establishment. As requires de novo translation, its regulation by dormancy likely to be related the association individual transcripts polysomes. Here, polysome‐associated mRNA s, that is, translatome, were fractionated and characterized with microarrays dormant nondormant sunflower ( H elianthus annuus ) embryos during their imbibition at 10°C,...

Stomatal responses to ABA and CO2 were investigated in Arabidopsis thaliana (L.) Heynh. wild-type insensitive mutants (abi1-1, abi2-1, abi1-1abi2-1) at the whole plant isolated epidermis levels. In plants, feeding roots with (1–50 µM) triggered a rapid drop leaf conductance which levelled off during following photoperiods, strongly inhibited increase induced by light. The response was abi1-1, abi2-1 abi1-1abi2-1 double mutants, but residual long-term decrease still observed. exogenous...

Various studies indicate that cell division is a post-germination phenomenon, with radicle protrusion occurring by elongation, while others demonstrate induction of the cycle occurs in osmo-conditioned seeds prior to growth. The aim present work was investigate occurrence during germination as related grain hydration, using: (i) flow cytometry technique estimate percentage nuclei G(1) and G(2) phases cycle; (ii) reverse transcription-PCR (RT-PCR) order characterize expression genes encoding...

In order to detect gene products involved in Arabidopsis drought adaptive strategy, 2D-PAGE protein patterns of two auxin-insensitive mutants, axr1, axr2, differentially affected specific responses, were compared the wild-type Columbia ecotype, well-watered and drought-stressed conditions. Coupled computer analysis polypeptide amounts, 2D-electrophoresis revealed subtle changes expression induced by progressive stress and/or mutations affecting auxin response pathway. The differential axr1...

Abstract Dormant barley grains cannot germinate at 30°C and this inability to is imposed mostly by the glumellae which have been suggested limit oxygen supply embryo. Hypoxia either artificially or embryos from dormant grains, increases embryo sensitivity abscisic acid (ABA) promotes accumulation of ABA during first hours after imbibition. Expression candidate genes involved in synthesis ( HvNCED ), catabolism HvABA8OH1 ) signalling HvABI5 , HvVP1 HvPKABA was analysed isolated whole...

A , carbon assimilation rate ABA, abscisic acid Ci intercellular space CO 2 concentration g leaf conductance WUE, water use efficiency Carbon dioxide and (ABA) are two major signals triggering stomatal closure. Their putative interaction in regulation was investigated well‐watered air‐grown or double ‐grown Arabidopsis thaliana plants, using gas exchange epidermal strip experiments. With plants grown normal air, a doubling of the resulted rapid transient drop followed by recovery to...