Effects of Ruminant Digestion on Germination of Lehmann Love-Grass Seed

Abstract

Lehmann lovegrass (Eragrostis lehmanniana Nees) seed (germination 96 % , dormant 0 %) was used in 4 experiments to study the potential of sheep as a dispersal agent. Five, 4-year-old, ruminally cannulated wethers were used to examine effects of ruminant digestion on seed recovery and germination. All wethers were ruminally evacuated, and rumens were cleansed and reinoculated with strained ruminal fluid. After a 21-day adaptation to pelleted alfalfa, 4 experiments were conducted. Experiment 1 was designed to test viability of Lehmann lovegrass seeds exposed to ruminal and postruminal digestion. Lehmann lovegrass seed (10 g) was dosed intra-ruminally via ruminal fistula, and total fecal collections made. Of the viable seed ruminally dosed, 37% germinated within 21 days after recovery. Also, 98 to 100% of the seed that germinated was recovered within 72 hours of dosing. Experiment 2 was designed to test the influence of ruminal microbial digestion on seed degradation and viability, using in sacco nylon bag techniques. In sacco dry matter disappearance increased linearly from 5.5 % at 3 hours of incubation to 16% at 120 hours. Germination of seed was not greatly affected until after 72 hours of ruminal incubation. Experiment 3 was designed to examine the effect of mastication on viability of Lehmann lovegrass seeds. Seeds were mixed with seed-free Lehmann lovegrass straw in a proportion of 1 to 10 (seed to straw) and 10 g fed to each wether. Boli were recovered manually via ruminal fistula. Thirty five percent of the seed fed entered the rumen without damage due to mastication. Experiment 4 compared in vitro techniques and in sacco techniques used to estimate the effect of digestion on seed viability. In vitro incubation techniques yielded similar results as in sacco techniques. We conclude that ruminants are potential disseminating agents of Lehmann lovegrass seed.

Efficiency of endozoochorous seed dispersal in six dry-fruited species (Cistaceae): from seed ingestion to early seedling establishment

“…This recovery rate is even higher than reported for other hard-seeded species after passage through the ungulate gut (Russi et al 1992;Fredrickson et al 1997;Razanamandranto et al 2004;Mouissie et al 2005) and is likely to be due to the small size and hard coats of Cistaceae seeds, which protect them from the damage during mastication and rumination (Pakeman et al 2002;Castro et al 2005;Mouissie et al 2005). The dispersal of these Cistaceae after sheep consumption is thus guaranteed, and in fact ungulates are known to defecate a large amount of hard seeds under natural conditions, (e.g.…”

Do ungulates facilitate native and exotic plant spread?

“…/j.jaridenv.2007 However, only a few of these studies have compared the relative importance of endozoochorous seed dispersal by native and domestic ungulate species (Cosyns et al, 2005a;Malo et al, 2000;Milton and Dean, 2001). In North America, many studies of seed dispersal by ungulates have focused primarily on the potential for livestock to disperse seeds of exotic species (Carpinelli et al, 2005;Doucette et al, 2001;Fredrickson et al, 1997; but see Ocumpaugh et al, 1996;Olson et al, 1997). In these studies, seeds of the focal exotic plant are fed to livestock (usually cattle (Bos taurus) or sheep (Ovis aries)) and the feces collected.…”

“…This is particularly surprising because native and introduce ungulates dominate most western US landscapes. Viable seeds of invasive plants have been recovered from dung in several studies, but data are limited to a small handful of species including leafy spurge (Euphorbia esula), common crupina (Crupina vulgaris), spotted knapweed (Centaurea maculosa), and Lehmann lovegrass (Eragrostis lehmanniana) (Fredrickson et al, 1997;Olson et al, 1997;Wallander et al, 1995).…”

Fruit and Seed

“…Germinability for ingested seeds of all species was mostly less than 10 % of that of noningested seeds, but was more than zero. Seeds of Eragrostis lehmanniana can pass through the digestive tract of a sheep and still be viable (Fredrickson et al 1997). While Bl€ ass et al (2010) contend that transport of seeds in the gut of grazers is only of minor importance, such transport could provide a mechanism for relatively long distance dispersal.…”