Agronomy and Horticulture Department
Date of this Version
1998
Abstract
Buffalograss (Buchloe dactyloides) has been described as an excellent fit for Janzen’s ‘‘Foliage is the Fruit’’ (FF) hypothesis, which suggests that large grazing animals ingest and later disperse seeds of some herbs when consuming their foliage. We tested this hypothesis by feeding buffalograss burs and legume seeds to ruminally fistulated beef steers. Our objectives were to determine (1) rumen residence times of buffalograss burs, free buffalograss caryopses and legume seeds; (2) total tract residence times for the three types of propagules; (3) percentage propagule survival after passage and (4) germinability of fed and unfed burs and caryopses. Bur survival (3%) and germination percentage were lower than previously reported, but this can be explained by differences in feeding and germination procedures. Significant numbers of free caryopses recovered from the feces also germinated. Previously undescribed hairs on the burs’ awn-like projections delayed passage through the animals and assured that many burs were broken during rumination. We concur that buffalograss is an excellent fit for the FF hypothesis, but our results and observations suggest that the buffalograss/grazing-animal interaction is more complex than it initially appeared.
Comments
Published in Am. Midl. Nat. (1998) 140: 252–263