Comparative Seeds Storage Transcriptome Analysis of Schott, a Threatened Tree Species from Brazil.

Schott (Anacardiaceae), also known as a 'gonçalo-alves', is a tree of the American tropics, with distribution in Mexico, part of Central America, Argentina, Bolivia, Brazil and Paraguay. In Brazil it is an endangered species that occurs in the Cerrado, Caatinga and in the Amazon biomes. In support of ex situ conservation, this work aimed to study two accessions with different longevity (p50) of collected from two different geographic regions, and to evaluate the transcriptome during aging of the seeds in order to identify genes related to seed longevity.

Global DNA methylation and cellular 5-methylcytosine and H4 acetylated patterns in primary and secondary dormant seeds of Capsella bursa-pastoris (L.) Medik. (shepherd's purse).

Despite the importance of dormancy and dormancy cycling for plants' fitness and life cycle phenology, a comprehensive characterization of the global and cellular epigenetic patterns across space and time in different seed dormancy states is lacking. Using Capsella bursa-pastoris (L.) Medik.

Differential Interspecific Adaptation to Abiotic Stress by Species.

The success of seed-based conservation and restoration efforts using native plant species is largely determined by ensuring two key life history transitions are accommodated. These are from "seed to germinated seed" and "germinated seed to established seedling." In turn, optimization of these life history transitions is determined by a "genetic × environmental" interaction and later largely characterized by localized climatic (abiotic) conditions.

On the origin of giant seeds: the macroevolution of the double coconut (Lodoicea maldivica) and its relatives (Borasseae, Arecaceae).

Seed size shapes plant evolution and ecosystems, and may be driven by plant size and architecture, dispersers, habitat and insularity. How these factors influence the evolution of giant seeds is unclear, as are the rate of evolution and the biogeographical consequences of giant seeds. We generated DNA and seed size data for the palm tribe Borasseae (Arecaceae) and its relatives, which show a wide diversity in seed size and include the double coconut (Lodoicea maldivica), the largest seed in the world.

A Spectrophotometric Assay for Robust Viability Testing of Seed Batches Using 2,3,5-Triphenyl Tetrazolium Chloride: Using L. as a Model.

A comparative analysis was carried out of published methods to assess seed viability using 2,3,5-triphenyltetrazolium chloride (TTC) based assays of seed batches. The tests were carried out on seeds of barley ( cv. Optic) as a model.

Epigenetic and hormonal profile during maturation of Quercus Suber L. somatic embryos.

Somatic embryogenesis is a powerful alternative to conventional mass propagation of Quercus suber L. However, poor quality and incomplete maturation of somatic embryos restrict any application. Given that epigenetic and hormonal control govern many developmental stages, including maturation of zygotic embryos, global DNA methylation and abscisic acid (ABA) were analyzed during development and maturation of cork oak somatic embryos.

The rheological properties of the seed coat mucilage of Capsella bursa-pastoris L. Medik. (shepherd's purse).

The outer surface of myxospermous seed coats contains mucilage which absorbs large amounts of water relative to its dry weight. Ecologically, the seed mucilage can affect seed germination and dormancy. Upon hydration, a large proportion of the seed mucilage is lost to the soil and the physics of soil-seed mucilage interactions has not been assessed.

Epigenetics, the role of DNA methylation in tree development.

During development of multicellular organisms, cells become differentiated by modulating different programs of gene expression. Cells have their own epigenetic signature which reflects genotype, developmental history, and environmental influences, and it is ultimately reflected in the phenotype of the cells and the organism. However, in normal development or disease situations, such as adaptation to climate change or during in vitro culture, some cells undergo major epigenetic reprogramming involving the removal of epigenetic marks in the nuclei followed by the establishment of a different new set of marks.

Co-adaptation of seed dormancy and flowering time in the arable weed Capsella bursa-pastoris (shepherd's purse).

Background And Aims: The duration of the plant life cycle is an important attribute that determines fitness and coexistence of weeds in arable fields. It depends on the timing of two key life-history traits: time from seed dispersal to germination and time from germination to flowering. These traits are components of the time to reproduction.

A mathematical model of mucilage expansion in myxospermous seeds of Capsella bursa-pastoris (shepherd's purse).

Background And Aims: Myxospermy is a term which describes the ability of a seed to produce mucilage upon hydration. The mucilage is mainly comprised of plant cell-wall polysaccharides which are deposited during development of those cells that comprise the seed coat (testa). Myxospermy is more prevalent among those plant species adapted to surviving on arid sandy soils, though its significance in determining the ecological fitness of plants is unclear.

Challenges facing seed banks and agriculture in relation to seed quality.

Seeds form a convenient vehicle for storage of germplasm, both for agricultural purposes and conservation of wild species. When required, seeds can be taken from storage and germinated, and plants can be propagated for the desired purpose, e.g.

Dark-mediated dormancy release in stratified Lolium rigidum seeds is associated with higher activities of cell wall-modifying enzymes and an apparent increase in gibberellin sensitivity.

Dormancy release in freshly matured, imbibed annual ryegrass (Lolium rigidum) seeds is inhibited by light and involves a decrease in seed sensitivity to abscisic acid. Other processes involved in dormancy release in the dark were investigated by measuring seed storage compound mobilisation and the activity of cell wall-degrading enzymes. Activities of endo-β-mannanase and total peroxidase were higher in dark-stratified compared to light-stratified seeds, indicating that weakening of the structures constraining the embryo was accelerated in the dark.

Acetylated H4 histone and genomic DNA methylation patterns during bud set and bud burst in Castanea sativa.

The relationships between genomic DNA cytosine methylation, histone H4 acetylation and bud dormancy in Castanea sativa are described. Acetylated H4 histone and genomic DNA methylation patterns showed opposite abundance patterns during bud set and bud burst. Increased and decreased methylation levels in the apical buds coincided with bud set and bud burst, respectively.

ABA inhibits embryo cell expansion and early cell division events during coffee (Coffea arabica 'Rubi') seed germination.

Background And Aims: Coffee seed germination represents an interplay between the embryo and the surrounding endosperm. A sequence of events in both parts of the seed determines whether germination will be successful or not. Following previous studies, the aim here was to further characterize the morphology of endosperm degradation and embryo growth with respect to morphology and cell cycle, and the influence of abscisic acid on these processes.

Mechanism and control of Solanum lycocarpum seed germination.

Background And Aims: Solanaceae seed morphology and physiology have been widely studied but mainly in domesticated crops. The present study aimed to compare the seed morphology and the physiology of germination of Solanum lycocarpum, an important species native to the Brazilian Cerrado, with two species with endospermic seeds, tomato and coffee.

Methods: Morphological parameters of fruits and seeds were determined by microscopy.

Seed dormancy release in Arabidopsis Cvi by dry after-ripening, low temperature, nitrate and light shows common quantitative patterns of gene expression directed by environmentally specific sensing.

The depth of seed dormancy can be influenced by a number of different environmental signals, but whether a common mechanism underlies this apparently similar response has yet to be investigated. Full-genome microarrays were used for a global transcript analysis of Arabidopsis thaliana Cape Verde Island accession seeds exposed to dry after-ripening (AR), or low temperature, nitrate and light when imbibed. Germination studies showed that the sensitivity of imbibed seeds to low temperature, nitrate and light was dependent upon the length of time spent AR following harvest.

Gene expression profiles of Arabidopsis Cvi seeds during dormancy cycling indicate a common underlying dormancy control mechanism.

Physiologically dormant seeds, like those of Arabidopsis, will cycle through dormant states as seasons change until the environment is favourable for seedling establishment. This phenomenon is widespread in the plant kingdom, but has not been studied at the molecular level. Full-genome microarrays were used for a global transcript analysis of Arabidopsis thaliana (accession Cvi) seeds in a range of dormant and dry after-ripened states during cycling.

Exogenous gibberellins inhibit coffee (Coffea arabica cv. Rubi) seed germination and cause cell death in the embryo.

The mechanism of inhibition of coffee (Coffea arabica cv. Rubi) seed germination by exogenous gibberellins (GAs) and the requirement of germination for endogenous GA were studied. Exogenous GA(4+7) inhibited coffee seed germination.

Differentially expressed genes associated with dormancy or germination of Arabidopsis thaliana seeds.

Differential display analysis using dormant and non-dormant Arabidopsis thaliana (L.) Heynh seeds resulted in a set of genes that were associated with either dormancy or germination. Expression of the germination-associated genes AtRPL36B and AtRPL27B, encoding two ribosomal proteins, was undetectable in the dry seed, low in dormant seed, and high under conditions that allowed completion of germination.

Abscisic acid controls embryo growth potential and endosperm cap weakening during coffee (Coffea arabica cv. Rubi) seed germination.

The mechanism and regulation of coffee seed germination were studied in Coffea arabica L. cv. Rubi.