ergovaline, the main ergopeptine alkaloid produced in tall fescue ( fescue arundinacea schreb.) infected with endophyte ( neotyphodium coenophialum morgan- jones & gams), is known to cause tall fescue toxicosis. this study was conducted to examine the presence of fungal endophytes in five populations of tall fescue collected from various regions of iran. the existence of neotyphodium mycelia in...

a few information about the combined effects of different environmental stress on turfgrass physiology and growth is available. also, a separate study of environmental factors on plant cannot be a suitable model for natural conditions. this study was conducted to investigate the interactive effects of different levels of shade (0, 50, and 70%) and water treatments (well-watered and non-irrigate...

Postweaning growth patterns and preweaning milk and forage intake were observed over a 4-yr period for 137 Angus calves allowed either fescue-legume or fescue pastures preweaning. After weaning, calves grazed fescue pasture until spring for a slow growth phase and then fescue, orchard grass, bluegrass and ladino clover pastures for 4 mo. Following this period, the calves were confined and fed s...

Bioassay techniques are often used to study the effects of allelochemicals on plant processes, and it is generally observed that the processes are stimulated at low allelochemical concentrations and inhibited as the concentrations increase. A simple empirical model is presented to analyze this type of response. The stimulation-inhibition properties of allelochemical-dose responses can be descri...

Perennial ryegrass (Lolium perenne L.) and tall fescue (Festuca arundinacea Schreb.) are two major turfgrass species in the United States. Their improvement via biotechnology approaches depend on the tissue culture response, particularly in vitro plant regeneration. To understand more of the regeneration event, scanning electron microscopy was performed and somatic embryogenesis was revealed in...

Tall fescue (Festuca arundinacea Schreb) is a typical cool-season grass that is widely used in turf and pasture. However, high temperature as an abiotic stress seriously affects its utilization. The objective of this study was to explore the effect of spermidine (Spd) on heat stress response of tall fescue. The samples were exposed to 22°C (normal condition) or 44°C (heat stress) for 4 h. The r...

The nonergot alkaloid-producing endo-phyte, AR542, has been shown to improve the persistence and yield of tall fescue pastures without causing the animal disorders commonly associated with tall fescue toxicosis. A 3-yr grazing study was conducted to compare effects of AR542-infected tall fescue pastures with wild type endophyte-infected (E+) tall fescue pastures on cow-calf performance. Replica...

Research on livestock toxicoses caused by Acremonium (endophyte)-infected grasses strongly implicate the ergopeptine alkaloids with A. coenophialum-infected fescue and paxilline and the lolitrem alkaloids with A. lolii-infected perennial ryegrass as the causative agents. Isolation, identification, and detection of these toxins involves extraction with appropriate solvents, clean-up procedures, ...

The symbiosis between tall fescue (Festuca arundinaceum) and a shoot-specific fungal endophyte (Neotyphodium coenophialum) has been relatively well studied but little attention has been given to how this relationship may impact the soil microbial community. Understanding how the symbiosis may structure soil microbial communities is important for understanding the cascade of effects that this sy...