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Plant Sciences Commons

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Stephen F. Austin State University

Plant diseases

Articles 1 - 6 of 6

Full-Text Articles in Plant Sciences

Ultrastructure Of Teliospores And Promycelium And Basidiospore Formation In The Four-Spored Form Of Gymnoconia Nitens, One Of The Causes Of Orange Rust Of Rubus, C. W. Mims, E. A. Richardson, Josephine Taylor Jan 2007

Ultrastructure Of Teliospores And Promycelium And Basidiospore Formation In The Four-Spored Form Of Gymnoconia Nitens, One Of The Causes Of Orange Rust Of Rubus, C. W. Mims, E. A. Richardson, Josephine Taylor

Faculty Publications

Orange rust of Rubus is an interesting disease because of the fact that it can be caused by three different rust fungi that produce virtually identical symptoms. One is Gymnoconia peckiana (Howe in Peck) Trotter, which is a demicyclic species, while the other two are endocyclic forms historically referred to as Gymnoconia nitens (Schwein.) Kern & H.W. Thurston. Although the spores produced on infected Rubus leaves by these latter two forms are morphologically identical to the aeciospores of G. peckiana, they actually function as teliospores. However, the teliospores of one of the forms gives rise to two-celled promycelia that …


Antifungal Activity Of Camptothecin, Trifolin, And Hyperoside Isolated From Camptotheca Acuminata, Shiyou Li, Zhizhen Zhang, Abigail Cain, Bo Wang, Melissa Long, Josephine Taylor Jan 2005

Antifungal Activity Of Camptothecin, Trifolin, And Hyperoside Isolated From Camptotheca Acuminata, Shiyou Li, Zhizhen Zhang, Abigail Cain, Bo Wang, Melissa Long, Josephine Taylor

Faculty Publications

Leaf spots and root rots are major fungal diseases in Camptotheca acuminata that limit cultivation of the plant for camptothecin (CPT), a promising anticancer and antiviral alkaloid. Bioassays showed that pure CPT and flavonoids (trifolin and hyperoside) isolated from Camptotheca effectively control fungal pathogens in vitro, including Alternaria alternata, Epicoccum nigrum, Pestalotia guepinii, Drechslera sp., and Fusarium avenaceum, although antifungal activity of these compounds in the plant is limited. CPT inhibited mycelial growth by approximately 50% (EC50) at 10−30 μg/mL and fully inhibited growth at 75−125 μg/mL. The flavonoids were less effective than CPT …


Blackspot Disease Of Roses [Abstract], Robert J. Wiggers, Josephine Taylor, J. A. Margoitta, S. G. Pandalai Jan 2003

Blackspot Disease Of Roses [Abstract], Robert J. Wiggers, Josephine Taylor, J. A. Margoitta, S. G. Pandalai

Faculty Publications

No abstract provided.


A Scanning Electron Microscopic Study Of The Infection Of Water Oak (Quercus Nigra) By Taphrina Caerulescens, Josephine Taylor, Dale O. Birdwell Jan 2000

A Scanning Electron Microscopic Study Of The Infection Of Water Oak (Quercus Nigra) By Taphrina Caerulescens, Josephine Taylor, Dale O. Birdwell

Faculty Publications

The fungal pathogen Taphrina caerulescens was isolated from leaves of water oak (Quercus nigra) exhibiting symptoms of oak leaf blister. Healthy leaves were inoculated with a suspension of cells from pure culture in order to examine the infection process. Scanning electron microscopy was used to monitor budding of T. caerulescens cells, formation of germ tubes, and indirect penetration of leaf tissue through stomata, which occurred within 48 h post-inoculation. Direct penetration was not observed.


Conidial Germination And Infection By Diplocarpon Rosae On Susceptible And Resistant Rose Species, Robert J. Wiggers, J. G. West, Josephine Taylor Jan 1997

Conidial Germination And Infection By Diplocarpon Rosae On Susceptible And Resistant Rose Species, Robert J. Wiggers, J. G. West, Josephine Taylor

Faculty Publications

Conidial germination and infection by Dipplocarpon rosae, the causal organism of rose blackspot, were examined on two resistant species of roses, Rosa roxburghii and R. wichuraiana and two susceptible hybrid tea roses (R. hybrid cv. Chicago Peace and Garden Party). Fungal conidia germinated and gave rise to subcuticular mycelium that formed haustoria within epidermal cells of all four roses tested. On the resistant rose species, epidermal cells associated with the infection site became necrotic, indicating that a hypersensitive response is involved in conferring their resistance D. rosae.


Infection And Fungal Development Of Tubakia Dryina On Sweet Gum (Liquidambar Styraciflua), Josephine Taylor, Shane Clark Jan 1996

Infection And Fungal Development Of Tubakia Dryina On Sweet Gum (Liquidambar Styraciflua), Josephine Taylor, Shane Clark

Faculty Publications

Infection and fungal development of Tubakia dryina were investigated on leaves of sweet gum using a combination of microscopic techniques. Conidia of T. dryina adhered to the leaf surface and formed septate germ tubes. Germ tubes terminated in small appressoria that formed directly over epidermal cells. Intra- and intercellular hyphae ramified extensively throughout the leaf tissue. Host cells associated with the infection site became necrotic and collapsed, resulting in macroscopic disease symptoms.