Search results for "stomate"
showing 4 items of 4 documents
Impact of Plasmopara viticola on starch metabolism and stomachal functions in grapevine leaves
2011
The grapevine downy mildew affects leaves and young berries and can affect the harvest quality and quantity. The causal agent is the obligate biotroph oomycete Plasmopara viticola that induces severe physiological alterations in infected leaves. One is the abnormal accumulation of starch in oil spots, the characteristic symptoms of the disease. Another is a deregulation of stomatal movements. Stomata, natural openings on the leaf surface allowing gas exchanges between the plant and the atmosphere, stay abnormally open during the night and do no longer close upon water stress or ABA treatment in infected leaves. This thesis is divided into two chapters that aim to i) explain the origin and m…
Genesis of amorphous calcium carbonate containing alveolar plates in the ciliate Coleps hirtus (Ciliophora, Prostomatea).
2013
7 pages; International audience; In the protist world, the ciliate Coleps hirtus (phylum Ciliophora, class Prostomatea) synthesizes a peculiar biomineralized test made of alveolar plates, structures located within alveolar vesicles at the cell cortex. Alveolar plates are arranged by overlapping like an armor and they are thought to protect and/or stiffen the cell. Although their morphology is species-specific and of complex architecture, so far almost nothing is known about their genesis, their structure and their elemental and mineral composition. We investigated the genesis of new alveolar plates after cell division and examined cells and isolated alveolar plates by electron microscopy, e…
Are grapevine stomata involved in the elicitor-induced protection against downy mildew?
2009
Stomata, natural pores bordered by guard cells, regulate transpiration and gas exchanges between plant leaves and the atmosphere. These natural openings also constitute a way of penetration for microorganisms. In plants, the perception of potentially pathogenic microorganisms or elicitors of defense reactions induces a cascade of events, including H2O2 production, that allows the activation of defense genes, leading to defense reactions. Similar signaling events occur in guard cells in response to the perception of abscisic acid (ABA), leading to stomatal closure. Moreover, few elicitors were reported to induce stomatal closure in Arabidopsis and Vicia faba leaves. Because responses to ABA…
Data from: New Trepostomate bryozoans from the upper Ordovician of Morocco and the temperature influence on zooid size
2015
New Upper Ordovician trepostomate bryozoans from the eastern Anti-Atlas of Morocco have been identified. They have been collected from the lower and intermediate units of the Khabt-el-Hajar Formation, late Katian in age, representing, respectively, bryozoan-pelmatozoan meadows with siliciclastic input, degraded by wave activity in a mid-ramp setting, and outer-ramp environments with marly substrates. Ten species of the genera Cyphotrypa, Calloporella, Diplotrypa, Parvohallopora, Dekayia, and Aostipora are described. Of them, three species are new: Cyphotrypa regularis Jiménez-Sánchez, Parvohallopora cystata Jiménez-Sánchez, and Aostipora elongata Jiménez-Sánchez. Univariate statistical anal…