Ultrastructure of basidium and basidiospore development in three species of the fungus Exobasidium

1987 ◽  
Vol 65 (6) ◽  
pp. 1236-1244 ◽  
Author(s):  
Charles W. Mims ◽  
Elizabeth A. Richardson ◽  
Robert W. Roberson
Keyword(s):  
Leaf Surface ◽  
Mitotic Division ◽  
Abaxial Side ◽  
Sequence Of Events ◽  
Transverse Septum ◽  
Abaxial Leaf Surface ◽  
Thin Walled

The sequence of events occurring within basidia of Exobasidium was shown to be quite different from that previously described in one-celled holobasidia. Karyogamy was found to occur in thin-walled hyphal compartments or probasidia comprising part of a stroma-like system within the intercellular leaf spaces. Meiosis also began in these compartments but was not completed until after the nucleus had migrated into the large, prominent metabasidium that became exposed on the abaxial leaf surface. Following sterigmatal development and a postmeiotic mitotic division, usually four to seven basidiospores developed per basidium. Each spore possessed a hilar appendage on its abaxial side, but neither a hilar appendage body nor a hilar droplet was observed. The thin basidiospore wall was continuous with that of its sterigma. Development of a hilar septum delimited the spore from its sterigma. Detached basidiospores of E. vaccinii and E. japonicum became two celled following mitosis and development of a near-median transverse septum. Basidiospores of E. camelliae var. gracilis usually developed three transverse septa. Based on our observations Exobasidium should be placed in the Teliomycetes.

Ultrastructure of teliospores and promycelium and basidiospore formation in the two-spored form of Gymnoconia nitens, one of the causes of orange rust of Rubus

2007 ◽  
Vol 85 (10) ◽  
pp. 935-940 ◽  
Author(s):  
Charles W. Mims ◽  
Elizabeth A. Richardson
Keyword(s):  
Fluorescence Microscopy ◽  
Mitotic Division ◽  
Sequence Of Events ◽  
Transverse Septum ◽  
Rubus Argutus

Gymnoconia nitens (Schwein.) Kern & H. W. Thurston consists of two forms that cause orange rust of Rubus . The teliospores of both of these forms are morphologically identical to aeciospores, but upon germination form promycelia that give rise to either two or four basidiospores. In this study, we examined the teliospores and the sequence of events leading to basidiospore development in the two-spored form of G. nitens. The teliospores of this species are formed in chains from uninucleate sporogenous cells that line the base of each sorus on infected Rubus argutus Link. (blackberry) leaves. Fluorescence microscopy revealed that approximately 90% of the mature teliospores were uninucleate. During germination, the teliospore nucleus migrated into the developing promycelium and underwent a single mitotic division. A transverse septum formed between the two daughter nuclei creating two uninucleate cells. A tapered sterigma arose from each cell and gave rise to a basidiospore. These findings indicate that the basidiospores of the two-spored form of G. nitens were formed in an asexual fashion.

Picking sides: feeding on the abaxial leaf surface is costly for caterpillars

Planta ◽  
2021 ◽  
Vol 253 (4) ◽  
Author(s):  
Sakshi Watts ◽  
Rupesh Kariyat
Keyword(s):  
Leaf Surface ◽  
Abaxial Leaf Surface

Lack of Internalization of Escherichia coli O157:H7 in Lettuce (Lactuca sativa L.) after Leaf Surface and Soil Inoculation

2009 ◽  
Vol 72 (10) ◽  
pp. 2028-2037 ◽  
Author(s):  
GUODONG ZHANG ◽  
LI MA ◽  
LARRY R. BEUCHAT ◽  
MARILYN C. ERICKSON ◽  
VANESSA H. PHELAN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Leaf Surface ◽  
Escherichia Coli O157 ◽  
Adaxial Side ◽  
Abaxial Side ◽  
E Coli ◽  
Lactuca Sativa L ◽  
Leaf Surfaces ◽  
Leaves And Roots ◽  
Leaf Lettuce

Survival and internalization characteristics of Escherichia coli O157:H7 in iceberg, romaine, and leaf lettuce after inoculation of leaf surfaces and soil were determined. A five-strain mixture of E. coli O157:H7 in water and cow manure extract was used as an inoculum for abaxial and adaxial sides of leaves at populations of 6 to 7 log and 4 log CFU per plant. The five strains were individually inoculated into soil at populations of 3 and 6 log CFU/g. Soil, leaves, and roots were analyzed for the presence and population of E. coli O157:H7. Ten (4.7%) of 212 samples of leaves inoculated on the adaxial side were positive for E. coli O157:H7, whereas 38 (17.9%) of 212 samples inoculated on the abaxial side were positive. E. coli O157:H7 survived for at least 25 days on leaf surfaces, with survival greater on the abaxial side of the leaves than on the adaxial side. All 212 rhizosphere samples and 424 surface-sanitized leaf and root samples from plants with inoculated leaves were negative for E. coli O157:H7, regardless of plant age at the time of inoculation or the location on the leaf receiving the inoculum. The pathogen survived in soil for at least 60 days. Five hundred ninety-eight (99.7%) of 600 surface-sanitized leaf and root samples from plants grown in inoculated soil were negative for E. coli O157:H7. Internalization of E. coli O157:H7 in lettuce leaves and roots did not occur, regardless of the type of lettuce, age of plants, or strain of E. coli O157:H7.

Cryptic speciation in the herbaceous bamboo genus Piresia (Poaceae, Olyreae)

2019 ◽  
Author(s):  
Maria L Silveira de Carvalho ◽  
Izabela S D de Jesus ◽  
Rilquer M da Silva ◽  
Kelly R B Leite ◽  
Alessandra S Schnadelbach ◽  
...  
Keyword(s):  
New Species ◽  
Atlantic Forest ◽  
Leaf Surface ◽  
Conservation Status ◽  
Integrative Approach ◽  
Niche Modelling ◽  
The North ◽  
Abaxial Leaf Surface ◽  
Herbaceous Bamboos ◽  
North Eastern

Abstract Piresia, a small genus of herbaceous bamboos, has a geographical disjunction between the Caribbean and northern/western South America and the north-eastern Atlantic Forest in Brazil. Piresia leptophylla is reported from western Amazonia (WA) and the north-eastern Atlantic Forest (NAF), but its occurrence in western Amazonia is questionable. Using an integrative approach, we combined traditional morphological analysis, anatomy and niche modelling. The results revealed few macromorphological differences between WA and NAF specimens (only plant height, leaf length, lodicule dimensions, shape and position), contrasting with consistent differences in leaf anatomy (macrohairs and cruciform silica bodies in the costal zone of the adaxial/abaxial leaf surfaces, crenate silica bodies on the abaxial leaf surface, lack of panicoid hairs on the abaxial leaf surface, bicellular microhairs and lobed papillae over the abaxial leaf surface, and sparse but elongated fusoid cells in the mesophyll of WA specimens) and in niche patterns. The anatomical/micromorphological characters suggest environmental adaptations to the Amazonian and ‘restinga’ forests, respectively. We therefore propose the segregation of the WA populations into a new species, Piresia tenella sp. nov. We provide a formal description, photographs, a line illustration, a distribution map and discussion of the conservation status for the new species.

scholarly journals Adjuvant Effects on Imazethapyr, 2,4-D and Picloram Absorption by Leafy Spurge (Euphorbia esula)

Weed Science ◽  
1996 ◽  
Vol 44 (3) ◽  
pp. 469-475 ◽  
Author(s):  
W. Mack Thompson ◽  
Scott J. Nissen ◽  
Robert A. Masters
Keyword(s):  
Ammonium Nitrate ◽  
Ammonium Sulfate ◽  
Seed Oil ◽  
Leaf Surface ◽  
Leafy Spurge ◽  
Cuticular Waxes ◽  
Adaxial Leaf Surface ◽  
Abaxial Leaf Surface ◽  
Urea Ammonium Nitrate ◽  
Adjuvant Effects

Laboratory experiments were conducted to identify adjuvants that improve absorption of imazethapyr, 2,4-D amine, and picloram by leafy spurge. Adjuvants (0.25% v/v) included crop oil concentrate (COC), methylated seed oil (MSO), nonionic surfactant (NIS), organosilicones (Silwet L-77®, Sylgard® 309, Silwet® 408), 3:1 mixtures of acetylinic diol ethoxylates (ADE40, ADE65, ADE85) with Silwet L-77, ammonium sulfate (2.5 kg ha−1), and 28% urea ammonium nitrate (UAN, 2.5% v/v). Adjuvants were combined with14C-herbicide and commercially formulated herbicide product. Leaves were harvested 2 DAT, rinsed with 10% aqueous methanol to remove surface deposits of herbicide, and dipped in 9:1 hexane:acetone to solubilize cuticular waxes. Imazethapyr absorption increased by 38 to 68% when UAN was combined with COC, NIS, or MSO. Total absorption of imazethapyr plus COC, MSO, or NIS exceeded 86% 2 DAT when UAN was added. Urea ammonium nitrate reduced the amount of imazethapyr associated with the cuticular wax by 2.0%. Imazethapyr absorption was similar on both the abaxial and adaxial leaf surface when UAN was not added; however, 12% more imazethapyr was absorbed from the abaxial leaf surface than from the adaxial leaf surface when UAN was combined with Sylgard 309. Uptake of 2,4-D ranged from 54 to 78% and was greatest with Silwet 408 and 3:1 mixture of ADE40: Silwet L-77. Picloram absorption ranged from 3 to 19%. Buffering picloram treatment solutions to pH 7 and including 2.5 kg ha-1ammonium sulfate increased picloram absorption to 37%.

New and noteworthy Melastomataceae from the Yanachaga-Chemillén National Park and surrounding areas in Oxapampa, Pasco, Peru

Phytotaxa ◽  
2018 ◽  
Vol 374 (3) ◽  
pp. 185 ◽  
Author(s):  
FABIÁN A. MICHELANGELI ◽  
RENATO GOLDENBERG
Keyword(s):  
National Park ◽  
Leaf Surface ◽  
Nodal Line ◽  
Abaxial Surface ◽  
North East ◽  
The North ◽  
The Andes ◽  
Abaxial Leaf Surface ◽  
Surrounding Areas ◽  
Sclerophyllous Forests

We describe six new species of Melastomataceae from the Yanachaga-Chemillén National Park and surrounding areas from the Department of Pasco, Province of Oxapampa in Central Peru. Macrocentrum andinum is the first species of the genus described from the Andes, found along creeks at 400–500 m elev. and characterized by its anysophyllous leaves, pubescent stems and four-merous flowers. Meriania rubriflora is found in forests above 2200 m elev. and it is characterized by stem nodes with stipular flaps, leaves with an acute base and four merous, deep red flowers. Miconia palcazuana is found along rivers and streams at 300–400 m on the eastern flank of the park, and it can be distinguished by its flowers with pink anthers with glands on the connective and narrowly oblanceolate to elliptic-lanceolate leaves. Miconia yanachagaensis grows in the dwarf-sclerophyllous forests at the top of ridges and grasslands over 2800 m elev. and it is characterized by its long dendritic-pedicellate trichomes on the abaxial leaf surface, the stems flattened to terete and the presence of a conspicuous annular nodal line. Triolena rojasae is found growing on rocks along the Palcazú River and its tributaries, and it is characterized by its lanceolate-crenate leaves. Triolena vasquezii grows on the northern end of the Huancabamba canyon and the North East portion of the park and can be distinguished by its pustulate leaves with purple abaxial surface and anthers with two ventral appendages. We also present the first report of the genus Wurdastom for Peru.

scholarly journals Effect of Fungicide Mobility and Application Timing on the Management of Grape Powdery Mildew

Plant Disease ◽  
2020 ◽  
Vol 104 (4) ◽  
pp. 1167-1174 ◽  
Author(s):  
Brent Warneke ◽  
Lindsey D. Thiessen ◽  
Walter F. Mahaffee
Keyword(s):  
Powdery Mildew ◽  
Leaf Surface ◽  
Quality Standards ◽  
Pinot Noir ◽  
Abaxial Surface ◽  
Phenological Stages ◽  
Application Timing ◽  
Abaxial Leaf Surface ◽  
Detached Leaves ◽  
Grape Powdery Mildew

Grape powdery mildew (GPM) fungicide programs consist of 5 to 15 applications, depending on region or market, in an attempt to achieve the high fruit quality standards demanded by the market. Understanding how fungicides redistribute and targeting redistributing fungicide to critical crop phenological stages could improve fungicide protection of grape clusters. This study evaluated fungicide redistribution in grapevines from major fungicide groups labeled for GPM control. Translaminar and xylem redistribution was examined by placing fungicide-impregnated filter disks on the adaxial or abaxial leaf surface of detached leaves for 10 min and then incubating for 48 h before inoculating the abaxial surface with conidia. Vapor redistribution used Teflon disks sprayed with fungicides and placed on the abaxial leaf surface of detached leaves 48 h before inoculation. Disease development was rated 10 days later. Translaminar movement through calyptra was tested using flowering potted vines. All fungicides tested redistributed through at least one mechanism. Fungicide timing at critical phenological stages (early, mid, and late bloom) was assessed in small plots of cultivar Pinot noir vines. The application of trifloxystrobin, quinoxyfen, or fluopyram at different bloom stages showed that applications initiated at end of bloom resulted in the lowest berry infection probabilities of 0.073, 0.097, and 0.020, respectively. The results of this study suggest that integrating two carefully timed applications of redistributing fungicides initiated at end of bloom into a fungicide program may be an effective strategy for wine grape growers in western Oregon to produce fruit with low GPM infection.

scholarly journals Foliar epidermis morphology in Quercus (subgenus Quercus, section Quercus) in Iran

2012 ◽  
Vol 71 (1) ◽  
pp. 95-113 ◽  
Author(s):  
Parisa Panahi ◽  
Ziba Jamzad ◽  
Mohammad Pourmajidian ◽  
Asghar Fallah ◽  
Mehdi Pourhashemi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Statistical Analysis ◽  
Leaf Surface ◽  
Epicuticular Waxes ◽  
Abaxial Leaf Surface ◽  
Trichome Types ◽  
Foliar Morphology ◽  
Scanning Electron ◽  
Foliar Epidermis

Foliar epidermis morphology inQuercus(subgenusQuercus, sectionQuercus) in IranThe foliar morphology of trichomes, epicuticular waxes and stomata inQuercus cedrorum, Q. infectoriasubsp.boissieri, Q. komarovii, Q. longipes, Q. macranthera, Q. petraeasubsp.ibericaandQ. robursubsp.pedunculiflorawere studied by scanning electron microscopy. The trichomes are mainly present on abaxial leaf surface in most species, but rarely they appear on adaxial surface. Five trichome types are identified as simple uniseriate, bulbous, solitary, fasciculate and stellate. The stomata of all studied species are of the anomocytic type, raised on the epidermis. The stomata rim may or may not be covered with epicuticular. The epicuticular waxes are mostly of the crystalloid type but smooth layer wax is observed inQ. robursubsp.pedunculiflora.Statistical analysis revealed foliar micromorphological features as been diagnostic characters inQuercus.

Rubus prissanicus (Rosaceae), a new bramble species from North West Poland

Phytotaxa ◽  
2018 ◽  
Vol 344 (3) ◽  
pp. 239 ◽  
Author(s):  
PIOTR KOSIŃSKI ◽  
TOMASZ MALIŃSKI ◽  
ELWIRA SLIWINSKA ◽  
JERZY ZIELIŃSKI
Keyword(s):  
New Species ◽  
Leaf Surface ◽  
Broadleaf Forest ◽  
North West ◽  
Inflorescence Axis ◽  
Abaxial Leaf Surface ◽  
Different Types ◽  
Main Component ◽  
North Western ◽  
Forest Habitats

Rubus prissanicus, a new regional apomictic species, is described from north-western Poland. It is similar to R. lindleianus and R. langei, however it differs from the former species by broader leaflets and less numerous prickles on the inflorescence axis, and from the latter by unequally serrate leaflet margin, and from both these species by different types of trichomes on abaxial leaflet surface. Unlike other Polish species of R. ser. Rhamnifolii, in which the indumentum of abaxial leaf surface consists mainly of branched hairs, simple trichomes are the main component of indumentum of R. prissanicus leaves. The new species has been observed mainly on fertile soils, in broadleaf forest habitats, usually in fairly sunny places, along forest margins, by forest roads, in clearings, and in wayside thickets.

Paris lihengiana (Melanthiaceae: Parideae), a new species from Yunnan, China

Phytotaxa ◽  
2019 ◽  
Vol 392 (1) ◽  
pp. 45 ◽  
Author(s):  
ZHUN XU ◽  
NENG WEI ◽  
YING TAN ◽  
SHUAI PENG ◽  
VERONICAH MUTELE NGUMBAU ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Yunnan Province ◽  
Leaf Surface ◽  
Morphological Characters ◽  
Molecular Data ◽  
Abaxial Leaf Surface ◽  
Molecular Phylogenetic ◽  
Plastid Markers ◽  
A New Species

Paris lihengiana (Melanthiaceae), a new species from Yunnan Province, China, is described and illustrated based on evidence from morphological characters and molecular phylogeny. It differs from other species of Paris in its pubescent stem, pedicel and abaxial leaf surface, as well as other characters. Molecular phylogenetic analysis of 33 taxa in Paris was conducted based on nuclear ribosomal ITS and six plastid markers. Paris lihengiana is supported as a new species by both morphological characters and molecular data.

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