Recuperação e resposta germinativa de sementes de leguminosas passadas pelo trato digestório bovino
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Data
2010-09-01
Autores
Nakao, Evandro Afonso [UNESP]
Cardoso, Victor José Mendes [UNESP]
Título da Revista
ISSN da Revista
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Editor
Instituto Virtual da Biodiversidade (BIOTA/FAPESP)
Resumo
A germinação de sementes pode ser influenciada pela passagem através do trato digestório animal, que, nesse caso, poderá atuar como dispersor, dependendo de como as sementes são afetadas. Quando a passagem pelo trato digestório animal não reduz a capacidade germinativa das sementes, o agente dispersor é considerado legítimo. Este trabalho aborda a influência da ingestão de sementes de Leucaena leucocephala (Lam.) de Wit, Cajanus cajan (L.) Huth e Calopogonium mucunoides Desv. por Bos taurus Linnaeus (1758), sobre sua germinação e viabilidade, com o objetivo de avaliar o gado bovino como legítimo agente dispersor dessas espécies utilizadas como forrageiras. Amostras de sementes foram misturadas ao alimento oferecido a três fêmeas de B. taurus, cujas fezes foram recolhidas até 36 horas após a ingestão e submetidas à triagem para recuperação das sementes, as quais foram testadas para germinação e crescimento inicial. Como controle foram usadas sementes intactas não ingeridas. A porcentagem de recuperação de sementes não danificadas variou de 12,3% até cerca de 17,5%. A ingestão pelos animais afetou severamente a capacidade de germinação das sementes de Cajanus cajan, enquanto que em Calopogonium mucunoides a redução da porcentagem de germinação ocorreu em menor escala em comparação com a primeira. No caso de L. leucocephala, a germinação não foi influenciada pelo tratamento, o que no caso pode estar relacionado a uma maior dureza do tegumento em sementes dessa espécie. em C. mucunoides e L. leucocephala a velocidade de protrusão radicular foi ligeiramente aumentada em sementes tratadas, ao passo que o IVE da primeira foi reduzido. A ingestão também reduziu a taxa de crescimento em altura de plântulas de C. cajan, sendo o efeito menos acentuado em C. mucunoides. em L. leucocephala, a altura média foi maior em plântulas de sementes tratadas. Os resultados sugerem que o gado bovino não pode ser considerado um legítimo dispersor para L. leucocephala, C. mucunoides e C. cajan.
Seed germination can be influenced by passage through the digestive system of animals, which can act as seed dispersers, depending on how seeds are affected. When passing through the animal digestive tract does not reduce the seeds germination, the dispersal agent is considered legitimate. The effects of ingestion by bovine cattle (Bos Taurus Linnaeus (1758)) on the viability and germination of seeds of the species Leucaena leucocephala (Lam.) de Wit, Cajanus cajan (L.) Huth and Calopogonium mucunoides Desv. was investigated in this study, aiming at evaluating the role of cattle as legitimate dispersers of those forage plants. Seed samples were mixed with the food offered to three B. taurus females, whose feces were collected 36 hours after ingestion, and seeds recovered from the feces were quantified and tested for germination and initial seedling growth. Non-ingested seeds were used as a control. The percentage of undamaged seeds recovered ranged from 12.3 to 17.5%. The germination capacity (germinability) of C. cajan was strongly inhibited by the cattle ingestion, whereas the germinability of C. mucunoides was less affected. The germinability of L. leucephala was not influenced by the ingestion probably due to their hard seed coat. The germination rate of C. mucunoides and L. leucocephala seeds was slightly increased by cattle ingestion, whereas the Emergence Rate Index (ERI) was reduced in the former. The ingestion by cattle also caused a decrease in the growth rate of C. cajan and C. mucunoides seedlings, although this inhibitory effect was smaller in C. cajan. The height of L. leucocephala seedlings was increased by ingestion. The results suggest that bovine cattle aren't legitimate seed dispersers of L. leucocephala, C. mucunoides and C. cajan.
Seed germination can be influenced by passage through the digestive system of animals, which can act as seed dispersers, depending on how seeds are affected. When passing through the animal digestive tract does not reduce the seeds germination, the dispersal agent is considered legitimate. The effects of ingestion by bovine cattle (Bos Taurus Linnaeus (1758)) on the viability and germination of seeds of the species Leucaena leucocephala (Lam.) de Wit, Cajanus cajan (L.) Huth and Calopogonium mucunoides Desv. was investigated in this study, aiming at evaluating the role of cattle as legitimate dispersers of those forage plants. Seed samples were mixed with the food offered to three B. taurus females, whose feces were collected 36 hours after ingestion, and seeds recovered from the feces were quantified and tested for germination and initial seedling growth. Non-ingested seeds were used as a control. The percentage of undamaged seeds recovered ranged from 12.3 to 17.5%. The germination capacity (germinability) of C. cajan was strongly inhibited by the cattle ingestion, whereas the germinability of C. mucunoides was less affected. The germinability of L. leucephala was not influenced by the ingestion probably due to their hard seed coat. The germination rate of C. mucunoides and L. leucocephala seeds was slightly increased by cattle ingestion, whereas the Emergence Rate Index (ERI) was reduced in the former. The ingestion by cattle also caused a decrease in the growth rate of C. cajan and C. mucunoides seedlings, although this inhibitory effect was smaller in C. cajan. The height of L. leucocephala seedlings was increased by ingestion. The results suggest that bovine cattle aren't legitimate seed dispersers of L. leucocephala, C. mucunoides and C. cajan.
Descrição
Palavras-chave
dispersão de sementes, forrageiras, Leucaena leucocephala, Calopogonium mucunoides, Cajanus cajan, seed dispersal, forage species, Leucaena leucocephala, Calopogonium mucunoides, Cajanus cajan
Como citar
Biota Neotropica. Instituto Virtual da Biodiversidade | BIOTA - FAPESP, v. 10, n. 3, p. 189-195, 2010.