Specificity of cell type and timing of events associated with papilla formation and the hypersensitive reaction in leaves of Hordeum vulgare attacked by Erysiphe graminis f.sp. hordei

1990 ◽  
Vol 68 (11) ◽  
pp. 2344-2352 ◽  
Author(s):  
H. Koga ◽  
W. R. Bushnell ◽  
R. J. Zeyen
Keyword(s):  
Hordeum Vulgare ◽  
Hypersensitive Reaction ◽  
Erysiphe Graminis ◽  
Vascular Bundles ◽  
Cell Type ◽  
Abaxial Surface ◽  
Hypersensitive Cell Death ◽  
Adaxial Surface ◽  
Papilla Formation ◽  
Mla Locus

Rates of haustorium formation by Erysiphe graminis f.sp. hordei were determined for epidermal tissues of primary leaves of a near-isogenic pair of barley (Hordeum vulgare) lines, AlgR and AlgS, which differed at the Mla locus for compatibility with the fungus. Epidermal cells were divided into two classes, namely shorter or longer than 450 μm. Cells near stomatal files were always short, whereas cells more distant from stomata were long on the abaxial surface, long on the adaxial surface over vascular bundles, but short on the adaxial surface when not over vascular bundles. At 24 h after inoculation, haustoria were formed in 70–80% of attacked short cells but in only 15–20% of attacked long cells. When haustoria were absent, papillae were present, so papilla-associated resistance was more frequent in long than in short cells. However, the percentage of attacked sites with papillae was the same in AlgR and AlgS, indicating that papilla-associated resistance was not related to Mla incompatibility. In AlgR, patterns of development showed that haustoria were produced before Mla incompatibility was expressed by hypersensitive cell death. Key words: papilla, hypersensitive, barley, epidermis, resistance, powdery mildew.

scholarly journals Butia capitata (Mart.) Becc. lamina anatomy as a tool for taxonomic distinction from B. odorata (Barb. Rodr.) Noblick comb. nov (Arecaceae)

2015 ◽  
Vol 87 (1) ◽  
pp. 71-81 ◽  
Author(s):  
BRUNO F. SANT'ANNA-SANTOS ◽  
WELLINGTON G.O. CARVALHO JÚNIOR ◽  
VANESSA B. AMARAL
Keyword(s):  
Morphological Characteristics ◽  
Guard Cells ◽  
Plant Anatomy ◽  
Vascular Bundles ◽  
Epicuticular Waxes ◽  
Fibrous Layer ◽  
Middle Portion ◽  
Abaxial Surface ◽  
Adaxial Surface ◽  
Subsidiary Cells

The distinction between Butia capitata and B. odorata is based only on a few morphological characteristics, therefore there is a need for additional studies for supporting the separation of the species. As lamina anatomy characteristics are relevant in circumscribing Arecaceae taxa, this work aimed to describe B. capitata lamina anatomy and compare it with B. odorata. Samples from the middle portion of the pinnae were collected and processed in accordance with standard plant anatomy techniques. The epidermis is uniseriate and composed of a thick cuticle and epicuticular waxes into like hooked filaments. The subsidiary cells that arch over the guard cells are located at the hypodermis. The mesophyll is isobilateral and compact. The vascular bundles are collateral with a sclerenchymatic sheath extension that reaches the hypodermis. The stegmata cells have spherical and druse-like silica bodies. The midrib faces the adaxial surface with a thick fibrous layer surrounding the vascular bundles adjacent to the chlorenchyma. The stratified expansion tissue is on the abaxial surface, within the boundary between the mesophyll and midrib. Raphides are only found in B. capitata. Small bundles of the midrib fully surround the fibrous cylinder only in B. odorata. These characteristics are diagnostic and useful for supporting the proposed separation.

scholarly journals Induction of Hypersensitive Cell Death by a Fungal Protein in Cultures of Tobacco Cells

1998 ◽  
Vol 11 (2) ◽  
pp. 115-123 ◽  
Author(s):  
Akira Yano ◽  
Kaoru Suzuki ◽  
Hirofumi Uchimiya ◽  
Hideaki Shinshi
Keyword(s):  
Cell Death ◽  
Specific Interaction ◽  
Trichoderma Viride ◽  
Defense Responses ◽  
Hypersensitive Reaction ◽  
Hypersensitive Cell Death ◽  
Tobacco Cells ◽  
Bright Yellow ◽  
Cell Death Program ◽  
Cellular Signal

Treatment of suspension-cultured tobacco (Nicotiana tabacum cv. Xanthi) cells (line XD6S) with fungal proteinaceous elicitors, namely, xylanase (EC 3.2.1.8) from Trichoderma viride (TvX) and xylanase from T. reesei (TrX), induced shrinkage of the cytoplasm, condensation of the nucleus, and, finally, cell death, which were accompanied by typical defense responses that included an oxidative burst and expression of defense genes. A Ca2+ channel blocker, Gd3+, inhibited the typical response of XD6S cells to TvX, which resembled the hypersensitive reaction (HR). These results suggested that the influx of Ca2+ ions plays an important role as a secondary signal. The HR was not observed in TvX-treated tobacco cells (line BY-2) derived from cv. Bright Yellow 2. This result suggests that key features of cultivar-specific interaction can be observed in cultures of tobacco cells. Xylanase from Bacillus circulans (BcX) and B. subtilis (BsX), which has enzymatic properties similar to those of TvX but an amino acid sequence different from that of TvX, did not induce the HR-like response in XD6S cells. These results suggest that the elicitor action of TvX is not due to its ability to hydrolyze cell walls but requires the TvX-specific recognition factors in plant cells. Thus, TvX-induced cell death was not due to some general toxic effect, but seems to be mediated by the activation of a specific cellular signal-transduction cascade that converges with a pathway that activates the intracellular cell death program.

Pleopeltis pleopeltifolia (Polypodiopsida, Polypodiaceae), a poikilochlorophyllous desiccation-tolerant fern: anatomical, biochemical and physiological responses during water stress

2014 ◽  
Vol 62 (8) ◽  
pp. 647 ◽  
Author(s):  
Ana Paula Lorenzen Voytena ◽  
Bruno Degaspari Minardi ◽  
José Bonomi Barufi ◽  
Marisa Santos ◽  
Áurea Maria Randi
Keyword(s):  
Cell Walls ◽  
Sugar Content ◽  
Longitudinal Direction ◽  
Photosynthetic Parameters ◽  
Palisade Parenchyma ◽  
Abaxial Surface ◽  
Adaxial Surface ◽  
Anomocytic Stomata ◽  
Relevant Role ◽  
Notable Increase

While many ferns have been described as desiccation tolerant (DT), few studies have reported on the mechanisms they use to survive cell desiccation. Among the species belonging to the genus Pleopeltis, P. pleopeltifolia (Raddi) Alston (Polypodiopsida, Polypodiaceae) is a DT species endemic to Brazil. So as to better characterise the mechanisms of desiccation tolerance in ferns, the present study aimed to analyse frond anatomy and physiological changes associated with desiccation and rehydration of P. pleopeltifolia. Fronds are dorsiventral, with uniseriate epidermis. The epidermal cells have various shapes, tending to stretch in the longitudinal direction of the frond. Anticlinal cell walls are sinuous, and periclinal cell walls are convex. Anomocytic stomata are restricted to the abaxial surface. Trichome-type scales are found on both sides of the frond and may play a relevant role in rehydration of this plant when water is available. The mesophyll of the frond consists of palisade parenchyma, tending to a bistratified adaxial surface and spongy parenchyma on abaxial surface. The cuticle on the adaxial surface is conspicuous, ensuring better control of internal water balance. For physiological analyses, sporophytes were subjected to desiccation for 0, 5, 10 and 15 days and rehydration for 1 day. Sporophytes showed a sharp decline in water content when kept without irrigation, reaching 9.6% after 15 days, in addition to wilting and frond rolling. A significant increase in sugar content in fronds was noticeable during desiccation, which may favour a possible osmotic adjustment and vitrification. A notable increase in proline content during rehydration was observed in fronds. During the five initial days of desiccation, the chlorophyll and carotenoid contents decreased abruptly, but after 1 day of rehydration, they had partly recovered. The photosynthetic parameters analysed by fluorescence of chlorophyll a ceased completely after 15 days of desiccation but they had recovered near to pre-desiccation levels after 1 day of rehydration.

scholarly journals Taxonomic significance of some leaf anatomical features of the species of Annona L. (annonaceae) from Nigeria

2020 ◽  
Vol 22 (1) ◽  
pp. 101-112
Author(s):  
S.A. Adeniran ◽  
A.B. Kadiri ◽  
J.D. Olowokudejo
Keyword(s):  
Vascular Bundles ◽  
Taxonomic Significance ◽  
Anticlinal Wall ◽  
Abaxial Surface ◽  
Anatomical Features ◽  
Qualitative And Quantitative ◽  
Dichotomous Key ◽  
The Mean ◽  
Generic Constant ◽  
Existing Data

A comparative study of the some leaf anatomical features of four species of Annona occurring in Nigerian was undertaken with the aid of light microscope. The four foliar structures (epidermis, petiole, midrib and lamina architecture) studied revealed useful characters which support recognition of the species. A combination of these features has been used to prepare an artificial indented dichotomous key for identifying the  species. The generic constant features encountered included hypostomata, paracytic stomatal type, linear nerves endings, uneven midrib outline, and centrally located vascular bundles in the petiole and midrib. However, the most reliable distinguishing characters found across the species included presence of brachyparacytic stomata in A. reticulata, presence of trichomes on the midrib in A. senegalensis, absence of druses on the abaxial surface in A. muricata and A. squamosa, a thick pitted anticlinal walls on the surfaces of A. muricata and consistent polygonal areola shape in A. squamosa. The overlapping characters which also justify the closeness of the species and their grouping in a genus were recorded in both the qualitative and quantitative features. Prominent among them are the mean stomatal width which is about 1.0 μm in all species, nerve endings within the areole which varies between 1-2, U- or V-shaped midrib on the adaxial surface and straight to curved anticlinal wall pattern. The significance of these observations is discussed in updating the existing data in the genus. Keywords: Epidermis, Microscopy, Midrib, Petiole,   Systematic

Two new species of Graffenrieda (Melastomataceae, Merianieae) from the Amazon Rainforest

Phytotaxa ◽  
2016 ◽  
Vol 267 (1) ◽  
pp. 77 ◽  
Author(s):  
LAÍCE FERNANDA GOMES DE LIMA ◽  
JOSÉ FERNANDO ANDRADE BAUMGRATZ ◽  
EIMEAR NIC LUGHADHA ◽  
JOÃO UBIRATAN MOREIRA DOS SANTOS
Keyword(s):  
New Species ◽  
Conservation Status ◽  
The State ◽  
Amazon Rainforest ◽  
Similar Species ◽  
Abaxial Surface ◽  
Adaxial Surface ◽  
Two New Species

Two new species of Graffenrieda are described from the Amazon rainforest. Graffenrieda maturaca is characterized mainly by its leaves which are dull on the adaxial surface, chartaceous, narrowly elliptic to oblanceolate, and apparently uni-nerved, with only the median acrodromous vein evident. This species has been collected only at Serra de Maturacá, in the state of Amazonas, Brazil. Graffenrieda goldenbergii is distinguished mainly by the pulverulent, whitish, early caducous indumentum of the rachis, pedicel, hypanthium and calyx, by the abaxial surface of the leaves which is moderately lepidote, with trichomes ca. 0.2 mm diam., by the irregularly valvate calyx, and by the membranaceous, costate, not sulcate fruits. This species has been collected in the state of Acre, Brazil, and in the Province and District of Lama in Peru. Both species are illustrated, compared with similar species, and their conservation status is discussed.

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