Endozoochorous dispersal of seeds of weedy rice (Oryza sativa L.) and barnyardgrass (Echinochloa crus-galli L.) by cattle

• Published in: Ciência rural 2018-01, Vol.48 (8)
• Main Authors: Viero, João Luis Carricio, Schaedler, Carlos Eduardo, Azevedo, Eduardo Bohrer de, Santos, João Vitor Ail dos, Scalcon, Ricardo de Mello, David, Diego Bitencourt de, Rosa, Fabiane Quevedo da
• Format: Article
• Language: English
• Subjects: AGRONOMY; Cattle; Digestive system; Dispersal; Dispersion; Echinochloa crus-galli; endozoochory; Factorial design; Feces; Germination; Herbicides; Oryza sativa; paddy rice; Rice; ruminants; Seed dispersal; Seed germination; seed ingestion; Seeds; Soils; Substrates; Taxa; Weeds
• ISSN: 0103-8478; 1678-4596; 1678-4596
• DOI: 10.1590/0103-8478cr20170650

The objective of this study was to evaluate endozoochory dispersal, recuperation, and germination of weedy rice (Oryza sativa L.) and barnyardgrass (Echinochloa crus-galli L.) seeds passed through the digestive system of cattle. The experiment was divided into two phases: first, the daily seed recuperation rate was determined after passing through the digestive system of six steers. Each animal was dosed individually with 1000 weedy rice seeds and 13,818 barnyardgrass seeds, and these seeds were subsequently collected from feces. In the second phase, seed germination and emergence rate after passing or not passing through the digestive system of cattle were determined in two types of substrates (fecal plaque and soil) in a 2×2 factorial design. Seed recuperation in feces showed sigmoid behavior with maximum recovery on the second day after dosage. The recuperation of the species in the feces was 50.9% and 23.4% for weedy rice and barnyardgrass, respectively, which shows that both have potential endozoochory dispersal. However, seed germination of these species reduced after they passed through the digestive system, and they presented inferior emergence in the fecal plaque compared to the soil. The quarantine period for animals that ingest weedy rice and barnyardgrass seeds should be at least 6 and 7 days, respectively. RESUMO: O objetivo deste trabalho foi avaliar a dispersão endozoocórica, recuperação e germinação de sementes de arroz daninho (Oryza sativa L.) e capim-arroz (Echinochloa crus-galli L.) passadas pelo sistema digestivo de bovinos. O experimento foi dividido em duas fases: primeiramente determinou-se a taxa de recuperação diária das sementes após passagem pelo sistema digestivo de seis bovinos. Foram dosadas individualmente 1000 sementes de arroz daninho e 13818 sementes de capim-arroz para cada animal e posteriormente coletadas nas fezes. Na segunda fase foi determinada a taxa de germinação e emergência de sementes com e sem passagem pelo sistema digestivo de bovinos em dois tipos de substratos (placa fecal ou solo) em delineamento fatorial 2x2. A recuperação de sementes nas fezes apresentou comportamento sigmoide com máxima recuperação no 2° dia após dosagem. A recuperação nas fezes foi de 50,9% e 23,4%, para arroz daninho e capim-arroz, o que demonstra que ambas apresentam potencial de dispersão endozoocórica. Porém, a germinação de sementes destas espécies reduziu ao passar pelo sistema digestivo, e na placa fecal apresentou emergência in