Roles of Calcium Signaling in Gene Expression and Photosynthetic Acclimatization of Micro-Tom (MT) after Mechanical Damage.

A momentary increase in cytoplasmic Ca generates an oscillation responsible for the activation of proteins, such as calmodulin and kinases, which interact with reactive oxygen species (ROS) for the transmission of a stress signal. This study investigated the influence of variations in calcium concentrations on plant defense signaling and photosynthetic acclimatization after mechanical damage. Micro-Tom was grown with 0, 2 and 4 mM Ca, with and without mechanical damage.

Cell wall thickenings and tylosoid: developmental morphology reveals novelties for secretory canals in Protium ovatum (Burseraceae).

We investigated the structure, histochemistry, and ultrastructure of the secretory canals in the vegetative axis of Protium ovatum from a developmental perspective. Samples of roots, stems, and leaves were analyzed using light and transmission electron microscopy. Secretory canals composed of a uniseriate epithelium and a wide lumen occurred in the phloem of all analyzed organs.

Apoplasmic barrier in the extrafloral nectary of Citharexylum myrianthum (Verbenaceae).

The cytological changes underlying the formation of an apoplasmic barrier in the multi-layered extrafloral nectaries of Citharexylum myrianthum are compatible with the synthesis, transport and deposition of suberin. In terms of ontogenesis and function, the intermediate layers of these nectaries are homologous with the stalks of nectar-secreting trichomes. Anticlinal cell wall impregnations are common in trichomatic nectaries and their functions as endodermis-like barriers have been discussed because of possible direct effects on the nectary physiology, mainly in the nectar secretion and resorption.

Potential Plant-Plant Communication Induced by Infochemical Methyl Jasmonate in Sorghum ().

Despite the fact that they are sessile organisms, plants actively move their organs and also use these movements to manipulate the surrounding biotic and abiotic environments. Plants maintain communication with neighboring plants, herbivores, and predators through the emission of diverse chemical compounds by their shoots and roots. These infochemicals modify the environment occupied by plants.

Anatomical and ultrastructural studies reveal temporal and spatial variation in the oil production in leaves of the diesel tree (Copaifera langsdorffii, Leguminosae).

The oily resin produced by Copaifera langsdorffii, commonly called oil of copaiba, is widely exploited by the drug, cosmetic, and biodiesel industries. The distribution of oily secretory cavities and canals (secretory spaces) over the vegetative body characterizes this species. Oil is stored inside the lumen of the secretory spaces and only reaches the organ surface after injuries.

Autophagy and vacuolar biogenesis during the nectary development.

Different autophagy pathways are a driver of vacuolar biogenesis and are development stage specific during the extrafloral nectary development in Citharexylum myrianthum. Plant autophagy plays an important role in various developmental processes such as seed germination, pollen maturation and leaf senescence. However, studies that address the evidence of autophagy and its role in the development of plant glands are scarce and largely restricted to laticifers.

Fusoid cells in the grass family Poaceae (Poales): a developmental study reveals homologies and suggests new insights into their functional role in young leaves.

Background And Aims: In mature grass leaf blades as seen in cross-section, oblong cell-like structures have been interpreted most recently as intercellular gas spaces delimited by successive collapsed fusoid cells. These cells have been reported in at least seven of 12 subfamilies of Poaceae and are considered a synapomorphy for the family; however, no developmental work has been performed to verify their meristematic origin or to assess possible homologies within the graminid clade (= Flagellariaceae + [(Joinvilleaceae + Ecdeiocoleaceae) + Poaceae]) or among subfamilies of Poaceae. A developmental study was therefore carried out, including 20 species in three families (Flagellariaceae, Joinvilleaceae and Poaceae), representing the earlier-diverging and derived branches within the graminid clade and Poaceae.

Structural associations between organelle membranes in nectary parenchyma cells.

The close association between membranes and organelles, and the intense chloroplast remodeling in parenchyma cells of extrafloral nectaries occurred only at the secretion time and suggest a relationship with the nectar secretion. Associations between membranes and organelles have been well documented in different tissues and cells of plants, but poorly explored in secretory cells. Here, we described the close physical juxtaposition between membranes and organelles, mainly with chloroplasts, in parenchyma cells of Citharexylum myrianthum (Verbenaeceae) extrafloral nectaries under transmission electron microscopy, using conventional and microwave fixation.

Resin secretory canals in Protium heptaphyllum (Aubl.) Marchand. (Burseraceae): a tridimensional branched and anastomosed system.

Protium heptaphyllum is a Burseraceae species known by the production of aromatic resin with medicinal, economic, and ecological values. Information on the development, architecture, and lifetime of the secretory system are crucial to understand the resin production and contribute to a more sustainable tapping regime. We investigated the histology and ultrastructure of the secretory canals under a developmental point of view.

Structure and functioning of oil cavities in the shoot apex of Metrodorea nigra A. St.-Hil. (Rutaceae).

This study investigates the histology and subcellular features of secretory cavities during the development of the shoot apex of Metrodorea nigra A. St.-Hil.

PEG-induced osmotic stress in Mentha x piperita L.: Structural features and metabolic responses.

The present study investigated whether osmotic stress induced by the exposure of peppermint (Mentha x piperita L.) to moderate and severe stress for short periods of time changes the plant's physiological parameters, leaf anatomy and ultrastructure and essential oil. Plants were exposed to two levels of polyethyleneglycol (50 g L(-1) and 100 g L(-1) of PEG) in a hydroponic experiment.

Flavonoids modify root growth and modulate expression of SHORT-ROOT and HD-ZIP III.

Flavonoids are a class of distinct compounds produced by plant secondary metabolism that inhibit or promote plant development and have a relationship with auxin transport. We showed that, in terms of root development, Copaifera langsdorffii leaf extracts has an inhibitory effect on most flavonoid components compared with the application of exogenous flavonoids (glycosides and aglycones). These compounds alter the pattern of expression of the SHORT-ROOT and HD-ZIP III transcription factor gene family and cause morpho-physiological alterations in sorghum roots.

Glandular trichome density and essential oil composition in leaves and inflorescences of Lippia origanoides Kunth (Verbenaceae) in the Brazilian Cerrado.

The essential oils from leaves and inflorescences of Lippia origanoides Kunth present aromatic and medicinal potential and have been used to treat several diseases, including melanoma. In Brazil, L. origanoides is commonly found in campo cerrado and cerrado stricto sensu, physiognomies featured mainly by the differential light conditions to which short and medium-sized plants are subjected.

The role of the parenchyma sheath and PCD during the development of oil cavities in Pterodon pubescens (Leguminosae-Papilionoideae).

Pterodon pubescens cavities are constituted by lumen and uniseriated epithelium surrounded by multiseriate parenchyma sheath. We studied the development of secretory cavities, including the role of parenchyma sheath, using light and transmission electron microscopy. A Tunel assay was performed to verify whether programmed cell death (PCD) occurs during the process.

Pulvinus functional traits in relation to leaf movements: a light and transmission electron microscopy study of the vascular system.

Previous studies on legume pulvini suggest that the vascular system plays an important role in the redistribution of ions and transmission of stimuli during leaf's movements. However, the number of anatomical and ultrastructural studies is limited to few species. The aim of this paper is to investigate the structure and cellular features of the pulvinus vascular system of nine legume species from Brazilian cerrado, looking for structural traits pointing to its participation in the leaf's movements.