Presymptomatic multiplication of Xanthomonas campestris pv. vesicatoria on the surface of pepper leaves

1982 ◽  
Vol 60 (7) ◽  
pp. 1041-1045 ◽  
Author(s):  
Edna Sharon ◽  
Yoav Bashan ◽  
Yaacov Okon ◽  
Yigal Henis
Keyword(s):  
Primary Infection ◽  
Xanthomonas Campestris ◽  
Leaf Surface ◽  
Necrotic Tissue ◽  
Intercellular Spaces ◽  
Mesophyll Cells ◽  
Pepper Leaves ◽  
Electron And Light Microscopy ◽  
Xanthomonas Vesicatoria ◽  
Scanning Electron

Xanthomonas vesicatoria infection of pepper leaves was monitored by scanning electron and light microscopy. During incubation the bacteria became located in the intercellular spaces between the mesophyll cells. The primary infection sites were the vein areas. Xanthomonas vesicatoria reach high population levels on the leaf surface but usually not in the stomata. Necrosis was first observed microscopically 120 h after inoculation near the leaf veins. Bacteria were detected in infected tissue but not in necrotic tissue.

Development of infection structures by Hemileia vastatrix in resistant and susceptible selections of Coffea and in Phaseolus vulgaris

1993 ◽  
Vol 71 (8) ◽  
pp. 1001-1008 ◽  
Author(s):  
T. A. Coutinho ◽  
F. H. J. Rijkenberg ◽  
M. A. J. van Asch
Keyword(s):  
Phaseolus Vulgaris ◽  
Primary Infection ◽  
Intercellular Spaces ◽  
Hemileia Vastatrix ◽  
Mesophyll Cells ◽  
Sequence Of Events ◽  
Successful Infection ◽  
Coffee Leaf Rust ◽  
Subsidiary Cells ◽  
Mother Cells

The sequence of events leading to successful infection of Coffea by Hemileia vastatrix, following the formation of an appressorium over a stoma, was investigated using scanning electron microscopy. In the host, Coffea arabica, a torpedoshaped substomatal vesicle initial develops bilaterally from the apex of the infection wedge, while in the nonhost, Phaseolus vulgaris, the infection wedge protrudes into the substomatal chamber. The substomatal vesicle in both host and nonhost, at 48 h postinoculation, is anchor shaped. Haustorial mother cells are formed on stubby primary infection hyphae that curve back onto subsidiary cells. No differences in appearance of these structures were noted between resistant and susceptible coffee selections. A much-branched mycelium ramifies through the intercellular spaces of the mesophyll cells 96 h postinoculation in the host. In bean, the SSV began to collapse 48 h postinoculation. Key words: coffee leaf rust, infection, penetration, Coffea, appressorium, substomatal vesicle.

Intercellular pectic strands in parenchyma: studies of plant cell walls by scanning electron microscopy.

1975 ◽  
Vol 23 (1) ◽  
pp. 95 ◽  
Author(s):  
SGM Carr ◽  
DJ Carr
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
Chemical Composition ◽  
Light Microscope ◽  
Cell Walls ◽  
Plant Cell Walls ◽  
Intercellular Spaces ◽  
Mesophyll Cells ◽  
Scanning Electron

Rows of pectic strands, each 0.3-0.4�m in diameter, are shown to connect palisade mesophyll cells in regular ladder-like configurations ('pectic scala'). These structures are illustrated in some species of eucalypts, but probably occur in other kinds of plants. Less regular wall filaments can be observed in the intercellular spaces between other types of cells. They are particularly numerous in the parenchyma of species of ferns. These filaments and the pectic scala are readily observable by scanning electron microscopy, but can also be seen in conventional preparations for the light microscope. The structure, formation, chemical composition and possible function of these and other kinds of cell wall protuberances, described in the literature, are discussed.

scholarly journals Comparative Study on Gas Exchange, Water Relations and Leaf Anatomy of Two Olive Cultivars Grown under Well-Irrigated and Drought Conditions

1999 ◽  
Vol 54 (9-10) ◽  
pp. 688-692 ◽  
Author(s):  
Konstantinos Chartzoulakis ◽  
Angelos Patakas ◽  
Artemis Bosabalidis
Keyword(s):  
Gas Exchange ◽  
Water Relations ◽  
Volume Fraction ◽  
Spongy Parenchyma ◽  
Intercellular Spaces ◽  
Palisade Parenchyma ◽  
Mesophyll Cells ◽  
Olive Cultivars ◽  
Olea Europea ◽  
Leaf Anatomical Characteristics

The effect of water stress on gas exchange, water relations and leaf anatomical characteristics have been studied in two olive cultivars (Olea europea, L. cv. ‘Koroneiki’ and cv. ‚Mastoidis’). Photosynthetic rate as well as stomatal conductance were decreased in stressed plants. Osmotic potential (π) declined rapidly in stressed plants indicating their ability for osmoregulation. Bulk modulus of elasticity (ε) was significantly higher in stressed compared to well irrigated plants. The volume fraction of intercellular spaces of the upper palisade parenchyma, the spongy parenchyma as well as the lower palisade parenchyma were significantly lower in stressed compared to well irrigated plants. On the other hand, the density of mesophyll cells in the upper palisade parenchyma, spongy parenchyma and lower palisade parenchyma increased significantly in stressed plants

Cercospora duddiae. [Descriptions of Fungi and Bacteria].

1987 ◽  
Author(s):  
S. Little
Keyword(s):  
Sierra Leone ◽  
Papua New Guinea ◽  
Geographical Distribution ◽  
West Indies ◽  
Leaf Surface ◽  
Narrow Band ◽  
Necrotic Tissue ◽  
Leaf Base ◽  
Leaf Spots ◽  
Water Splash

Abstract A description is provided for Cercospora duddiae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Allium ascalonicum, A. cepa, A. fistulosum, A porrum, A. sativum. DISEASE: Leaf spot or withertip on onion and garlic. The symptoms vary on the different host species. On onion circular, chlorotic spots 3-5 mm diam. form mainly on the tip of the leaf, gradually decreasing in number towards the leaf base. The lesions at the leaf tip coalesce, forming a dry greyish-brown area, and in severe cases the entire leaf tip may be killed. The base of the leaf is mottled with brown necrotic leaf spots. Eventually the necrotic tissue may spread down the leaf surface, delimited by a narrow band (3 mm) of chlorotic tissue (Welles, 1923). Rarely does the disease cause much damage (Chupp & Sherf, 1960). GEOGRAPHICAL DISTRIBUTION: Africa: Mauritius, Nigeria, Sierra Leone, Somalia, Uganda; Asia: Borneo, Brunei, Burma, India, Indonesia, Oman, The Yemen; Australasia: Papua New Guinea; North America: West Indies (Barbados, Jamaica). TRANSMISSION: By air-borne or water-splash dispersed conidia, and by transportation with onion parts. The fungus is also reported to be seed borne (Chupp & Sherf, 1960).

Chrysophycean stomatocysts from the postglacial sediments of a High Arctic lake

1988 ◽  
Vol 66 (6) ◽  
pp. 1117-1128 ◽  
Author(s):  
Katharine E. Duff ◽  
John P. Smol
Keyword(s):  
Species Composition ◽  
Light Microscopy ◽  
High Arctic ◽  
Ellesmere Island ◽  
Arctic Lakes ◽  
Ecological Research ◽  
Stratigraphic Analysis ◽  
Morphological Detail ◽  
Electron And Light Microscopy ◽  
Scanning Electron

Twenty-six chrysophycean stomatocyst morphotypes were described from the postglacial sediments of a small, rock basin lake near Baird Inlet, Ellesmere Island. Scanning electron and light microscopy were used to classify the stomatocysts, following the guidelines of the International Statospore Working Group. None of the stomatocysts could be related with certainty to the chrysophyte species that produced them, but sufficient morphological detail is present in most of the stomatocysts to allow for taxonomic differentiation. A stratigraphic analysis of the dominant stomatocyst morphotypes revealed that chrysophyte species composition changed most markedly during the lake's early development but then remained relatively constant. This study demonstrated that chrysophycean stomatocysts provide useful paleoecological information in High Arctic lakes, but further taxonomic and ecological research is required to fully exploit these microfossils.

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