Alteration of element contents in guard cells of Norway spruce (Picea abies) subjected to ozone fumigation and (or) water stress: X-ray microanalysis study

Abstract

L~, P. 1994. Alteration of element contents in guard cells of Norway spruce (Picea abies) subjected to ozone fumigation and (or) water stress: X-ray microanalysis study. Can. J. Bot. 72: [86][87][88][89][90][91][92]. Two clones of Norway spruce Picea abies (L.) Karst. (Gerardmer clone and Istebna clone) were subjected to an ozoneenriched atmosphere. The X-ray microanalysis of elements present in the guard cells showed a decrease in potassium for the Gerardmer clone along with a larger closing of guard cells and an increase in calcium contents; for the Istebna clone, ozone did not affect these contents. When a drought stress was applied, an increase in calcium content of guard cells of the Istebna clone was also found. However, the potassium content was smaller in this case for the two clones and could well be due to stomata1 closure. When ozone and drought stress were applied together, the potassium content in the Istebna clone was not affected, but for the Gerardmer clone, ozone reduced the decrease in potassium content that occurred as drought stress developed. However, calcium (and manganese) content increased significantly when the Gerardmer clone was exposed to ozone. It seems likely that the Gerardmer clone is sensitive to ozone and when subjected to a drought stress this sensitivity is increased. For the Istebna clone, the resistance to ozone is unaffected by the drought stress treatment. The Istebna clone, however, seems sensitive to drought. These characteristic responses in the two different Norway spruce clones are probably due to genetic differences and may explain the contradictory observations in the response of the stomata during the simultaneous implementation of the complex stresses. et L O O S V E L~, P. 1994. Alteration of element contents in guard cells of Norway spruce (Picea abies) subjected to ozone fumigation and (or) water stress: X-ray microanalysis study. Can. J. Bot. 72: 86-92. Deux clones de Picea abies (L.) Karst. (GCrardmer et Istebna) ont Ct C soumis i une atmosphkre enrichie en ozone. Lamicroanalyse X des ClCments presents dans les stomates a montrC une baisse des teneurs en potassium en relation avec une fermeture plus importante des stomates et une augmentation en calcium, ceci pour le clone GCrardmer; pour le clone Istebna, I'ozone n'affecte pas les teneurs de ces deux ClCments. Lorsqu'un stress hydrique est appliquC, une augmentation des teneurs en calcium dans les stomates du clone Istebna est enregistrke mais les teneurs en potassium sont plus faibles pour les deux clones dans ces conditions en relation avec une fermeture des stomates. Lorsque les deux traitements, ozone et stress hydrique sont appliquCs simultantment, les teneurs en potassium n'holuent pas par rapport au traitement stress hydrique pour le clone Istebna, mais pour le clone Gerardmer, I'ozone rtduit la baisse en potassium qui se produit lors du stress hydrique. Par contre les teneurs en calcium (et manganbse) augmentent considCrablement pour le clone GCrardmer par rapport au traitement ozone.Le clone GCrard...

Changes in stomatal behaviour in the calcicole Leontodon hispidus due to the disruption by ozone of the regulation of apoplastic Ca2+ by trichomes

“…This was approximately 25% in plants grown with 15 mM Ca 2+ in the rhizosphere. Ozone and H 2 O 2 are known to have a marked eect on the Ca 2+ homeostasis and stomatal behaviour of plants (Castillo and Heath 1990;Fink 1991;Le Thiec et al 1994;Price et al 1994;McAinsh et al 1996;Clayton et al 1999;Pei et al 2000). Therefore, the reduction in stomatal conductance observed in L. hispidus in response to ozone may be due to the disruption of guard-cell Ca 2+ homeostasis, and hence Ca 2+ -mediated signal transduction, resulting from the potentially deleterious eects of ozone on the mechanism by which apoplastic Ca 2+ is regulated in this species.…”

“…Furthermore, exposure of Norway spruce to ozone has been found to induce a marked redistribution of calcium oxalate crystals from the apoplast into the vacuoles of epidermal cells and those of the stomatal complex (Fink 1991). In addition, the Ca 2+ content of guard cells has been shown to be higher in Norway spruce grown in an ozone-enriched atmosphere compared to those grown under ambient conditions and has been associated with a decrease in stomatal aperture (Le Thiec et al 1994). Ozone-induced changes in plant Ca 2+ homeostasis have important implications for Ca 2+ -mediated signal transduction in guard cells and the control of stomatal aperture, particularly in plants growing on Ca 2+ -rich soils.…”

Ozone and water deficit reduced growth of Aleppo pine seedlings

“…Five c and five c + 1 needles were sampled from each seedling, and each needle was analyzed five times. The material to be analyzed was prepared according to the method used in Le Thiec et al [25]. Sections of plant material were examined under a scanning electron microscope (Stereoscan 90B, Cambridge) at 15 kV, equipped with a energy dispersive microanalysis system (EDX, diode Si-Li; Analyzer AN10000 10/25).…”

Changes in Stomatal Behavior and Guard Cell Cytosolic Free Calcium in Response to Oxidative Stress

“…Oxidative stresses have been shown indirectly to have the potential to influente Caz+ transport in plants (Castillo and Heath, 1990;Price, 1990;Fink, 1991;Le Thiec et al, 1994b). However, there is little direct evidence regarding their effect on the regulation of Ca2+ homeostasis (Price et al, 1994).…”

“…This implies a substantial movement of Ca2+ through the cytoplasm of these cells. The total Ca2+ content of stomatal guard cells, determined by x-ray microanalysis, has also been shown to be higher in Norway spruce grown in an O,-enriched atmosphere than those grown under ambient conditions (Le Thiec et al, 1994b). This is associated with a decrease in stomatal aperture.…”