Structure, ultrastructure and cation accumulation in quinoa epidermal bladder cell complex under high saline stress.

Quinoa is a facultative halophyte with excellent tolerance to salinity. In this study, the epidermal bladder cell complex (EBCc) of quinoa leaves was studied to determine their cellular characteristics and involvement in salt tolerance. We used light microscopy, confocal RAMAN microscopy, confocal fluorescence microscopy, transmission electron microscopy, and environmental scanning electron microscopy complemented by energy dispersive X-ray analysis.

Red light delays programmed cell death in non-host interaction between Pseudomonas syringae pv tomato DC3000 and tobacco plants.

Light modulates almost every aspect of plant physiology, including plant-pathogen interactions. Among these, the hypersensitive response (HR) of plants to pathogens is characterized by a rapid and localized programmed cell death (PCD), which is critical to restrict the spread of pathogens from the infection site. The aim of this work was to study the role of light in the interaction between Pseudomonas syringae pv.

Shotgun proteomic analysis of quinoa seeds reveals novel lysine-rich seed storage globulins.

Quinoa seeds have high protein content and an exceptional balance of amino acids, with higher contents of lysine, methionine and cysteine than common cereals. To date, only three globulins, all of which have a content of lysine mass that does not exceed 3.8%, have been identified in quinoa.

Deterioration of willow seeds during storage.

Willow (Salix spp.) seeds are able to tolerate desiccation, but differ from typical orthodox seeds in that they lose viability in a few days at room temperature, and in that the chloroplasts in embryo tissues do not dedifferentiate during maturation drying, thus retaining chlorophyll and maintaining intact their thylakoid membranes. In the present study, we investigated the damage generated in willow seeds during storage under appropriate conditions to exclude the eventual generation of reactive oxygen species by photooxidation.

Activation of Nucleases, PCD, and Mobilization of Reserves in the Megagametophyte During Germination.

The megagametophyte of mature seeds of consists of cells with thin walls, one or more nuclei, a central vacuole storing proteins, and a cytoplasm rich in amyloplasts, mitochondria and lipid bodies. In this study, we describe the process of mobilization of reserves and analyzed the dismantling of the tissue during germination, using a range of well-established markers of programmed cell death (PCD), including: morphological changes in nuclei and amyloplasts, DNA degradation, and changes in nuclease profiles. TUNEL reaction and DNA electrophoresis demonstrate that DNA fragmentation in nuclei occurs at early stages of germination, which correlates with induction of specific nucleases.

Death of embryos from 2300-year-old quinoa seeds found in an archaeological site.

In the 1970s, during excavations at Los Morrillos, San Juan, Argentina, quinoa seeds were found within ancient pumpkin crocks protected from the light and high temperatures, and preserved in the very dry conditions of the region. The radiocarbon dates confirmed the age of these seeds at around 2300 years. Sectioning of some of these seeds showed reddish-brown embryos, different from the white embryos of recently harvested quinoa seeds.

Somatic Embryogenesis in Araucaria angustifolia (Bertol.) Kuntze (Araucariaceae).

This chapter deals with the features of somatic embryogenesis (SE) in Araucaria angustifolia, an endangered and native conifer from south Brazil. In this species SE includes the induction and proliferation of embryogenic cultures composed of pro-embryogenic masses (PEMs), which precede somatic embryos development. A.

Cellular and molecular aspects of quinoa leaf senescence.

During leaf senescence, degradation of chloroplasts precede to changes in nuclei and other cytoplasmic organelles, RuBisCO stability is progressively lost, grana lose their structure, plastidial DNA becomes distorted and degraded, the number of plastoglobuli increases and abundant senescence-associated vesicles containing electronically dense particles emerge from chloroplasts pouring their content into the central vacuole. This study examines quinoa leaf tissues during development and senescence using a range of well-established markers of programmed cell death (PCD), including: morphological changes in nuclei and chloroplasts, degradation of RuBisCO, changes in chlorophyll content, DNA degradation, variations in ploidy levels, and changes in nuclease profiles. TUNEL reaction and DNA electrophoresis demonstrated that DNA fragmentation in nuclei occurs at early senescence, which correlates with induction of specific nucleases.

Toward establishing a morphological and ultrastructural characterization of proembryogenic masses and early somatic embryos of Araucaria angustifolia (Bert.) O. Kuntze.

Somatic embryogenesis is a morphogenetic route useful for the study of embryonic development, as well as the large-scale propagation of endangered species, such as the Brazilian pine (Araucaria angustifolia). In the present study, we investigated the morphological and ultrastructural organization of A. angustifolia somatic embryo development by means of optical and electron microscopy.

Programmed cell death in seeds of angiosperms.

During the diversification of angiosperms, seeds have evolved structural, chemical, molecular and physiologically developing changes that specially affect the nucellus and endosperm. All through seed evolution, programmed cell death (PCD) has played a fundamental role. However, examples of PCD during seed development are limited.

Analogous reserve distribution and tissue characteristics in quinoa and grass seeds suggest convergent evolution.

Quinoa seeds are highly nutritious due to the quality of their proteins and lipids and the wide range of minerals and vitamins they store. Three compartments can be distinguished within the mature seed: embryo, endosperm, and perisperm. The distribution of main storage reserves is clearly different in those areas: the embryo and endosperm store proteins, lipids, and minerals, and the perisperm stores starch.

The effect of morphological and functional variables on ranking position of professional junior Basque surfers.

The aim of this study was to analyse the association of morphology as well as functional outcomes during a paddling test with ranking position (RP) of competitive junior surfers. Ten male surfers (age, mean 17.60, s=2.

Programmed cell death during quinoa perisperm development.

At seed maturity, quinoa (Chenopodium quinoa Willd.) perisperm consists of uniform, non-living, thin-walled cells full of starch grains. The objective of the present study was to study quinoa perisperm development and describe the programme of cell death that affects the entire tissue.

Willow seedlings from photooxidized seeds accelerate cotyledon death and anticipate first leaf emergence: a histological and biochemical study following germination.

In willow seeds, photooxidative damage is mainly restricted to the outer cotyledonary tissues, significantly reducing normal germination. Here we analyzed the damage generated in cotyledonary tissues and investigated whether the increase in reactive oxygen species (ROS) generation in seedlings from photooxidized seeds can affect the morphogenetic capacity of the shoot apical meristem. Seeds were photooxidized under different light intensities and the evolution of the damage during seedling growth was studied by light and transmission electron microscopies.

Immunoanalysis of dehydrins in Araucaria angustifolia embryos.

The aim of this study was to describe the dehydrin content of mature Araucaria angustifolia embryos, a species of endangered and economically important conifers, native to southern Brazil, northeastern Argentina, and eastern Paraguay. The A. angustifolia seeds have been categorized as recalcitrant.

Floral features, pollination biology and breeding system of Chloraea membranacea Lindl. (Orchidaceae: Chloraeinae).

Background And Aims: The pollination biology of very few Chloraeinae orchids has been studied to date, and most of these studies have focused on breeding systems and fruiting success. Chloraea membranacea Lindl. is one of the few non-Andean species in this group, and the aim of the present contribution is to elucidate the pollination biology, functional floral morphology and breeding system in native populations of this species from Argentina (Buenos Aires) and Brazil (Rio Grande do Sul State).

Accumulation pattern of dehydrins during sugarcane (var. SP80.3280) somatic embryogenesis.

Unlabelled: The objective of the present study was to determine dehydrin protein levels in sugarcane var. SP80-3280 during somatic embryogenesis. Dehydrins from embryogenic and non-embryogenic cell cultures were analyzed using western blot and in situ immunolocalization microscopy.

Fluctuation of oxidative stress indicators in Salix nigra seeds during priming.

Salix nigra seeds subjected to increased humidification show a decrease in normal germination (NG) during early imbibition followed by a recovery in that parameter at increasing imbibition times. Since photo-oxidized seeds contain high levels of reactive oxygen species (ROS), it is possible to infer that the atypical decrease in NG is a consequence of a higher ROS mobilization at early imbibition and the subsequent recovery from an increase in antioxidant activity. In this study, several oxidative stress indicators were evaluated in photo-oxidized seeds subjected to priming.

The control of root growth by reactive oxygen species in Salix nigra Marsh. seedlings.

The production of reactive oxygen species (ROS) in specific regions of Salix seedlings roots seems essential for the normal growth of this organ. We examined the role of different ROS in the control of root development in Salix nigra seedlings, and explored possible mechanisms involved in the regulation of ROS generation and action. Root growth was not significantly affected by OH quenchers, while it was either partially or completely inhibited in the presence of H₂O₂ or O₂·⁻ scavengers, respectively.

On the nature and origin of the oxalate package in Solanum sisymbriifolium anthers.

This is a detailed study carried out in Solanum sisymbriifolium Lam. on the development of the circular cell cluster (CCC) during crystal deposition, as well as the composition of the crystals. Light microscopy and scanning and transmission electron microscopy (TEM) were used to characterize tissue throughout anther development.

Effects of photooxidation on membrane integrity in Salix nigra seeds.

Background And Aims: Salix nigra seeds are desiccation-tolerant, as are orthodox seeds, although in contrast to other orthodox seeds they lose viability in a few weeks at room temperature. They also differ in that the chloroplasts of the embryo tissues conserve their chlorophyll and endomembranes. The aim of this paper was to investigate the role of chlorophyll in seed deterioration.

Storage lipids and proteins of Euterpe edulis seeds.

Comparative studies on fatty acid and protein composition of the endosperm and embryo of palmito (Euterpe edulis Martius) were conducted using gas-liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. On a dry weight basis, the embryo contained extremely lower amounts of lipids and proteins than did the endosperm, which was associated with the scarce lipid and protein bodies previously reported in axis and cotyledon. The fatty acid composition also exhibited differences between both tissues: (I) the fatty acid diversity was greater in embryo than in endosperm; (II) embryo and endosperm contained predominantly linoleic, palmitic, oleic and stearic acids even though the relative values were different for each tissue.

A cytoplasmically inherited barley mutant is defective in photosystem I assembly due to a temperature-sensitive defect in ycf3 splicing.

A cytoplasmically inherited chlorophyll-deficient mutant of barley (Hordeum vulgare) termed cytoplasmic line 3 (CL3), displaying a viridis (homogeneously light-green colored) phenotype, has been previously shown to be affected by elevated temperatures. In this article, biochemical, biophysical, and molecular approaches were used to study the CL3 mutant under different temperature and light conditions. The results lead to the conclusion that an impaired assembly of photosystem I (PSI) under higher temperatures and certain light conditions is the primary cause of the CL3 phenotype.

Mal de Río Cuarto virus (MRCV) genomic segment S3 codes for the major core capsid protein.

Mal de Río Cuarto virus (MRCV) is a newly described species of the genus Fijivirus, family Reoviridae. Compared with other plant-infecting genus of the family, the function and localization of MRCV and other Fijivirus proteins are poorly understood. Through analysis of viral particle purifications, we positively identified five structural proteins of approximately 170, 140, 130, 66, and 62 kDa.