Goat performance on pure Andropogon gayanus pastures or associated with legumes.

The objective of this study was to evaluate the grazing of goats in a grass monoculture system and in intercropping systems of grass + legumes. A randomized block design was adopted, with the treatments arranged in a split-plots scheme. The plots consisted of three cropping systems: monoculture-Andropogon gayanus cv. Planaltina; mixture I-A. gayanus cv. Planaltina + Stylosanthes cv. Campo Grande; and mixture II-A. gayanus cv. Planaltina + Calopogonium mucunoides. The subplots consisted of two grazing cycles. The highest (P = 0.04) total forage mass (TFM) was recorded in the mixture I (A. gayanus cv. Planaltina + Stylosanthes. cv. Campo Grande), which was 2.6 ± 0.1 tons DM/ha. The crude protein (CP) was lower in the monoculture which also showed the highest content of neutral detergent fiber (NDF). The grazing time in the monoculture was the longest (8.23 ± 1.14 h). The goats used a longer time for rumination (P < 0.01) in the mixture I. The lowest (P < 0.01) bite rate was found in mixture II in comparison to the other cropping systems. The bite rate was higher (P < 0.01) in grazing cycle II than in all the other cropping systems. In mixture I, the Stylosanthes cv. Campo Grande, and in mixture II, the C. mucunoides presented the lowest (P < 0.01) δ13C value in the forage. The highest forage intake occurred in the mixture systems (P < 0.01) in comparison to the monoculture. The mixture pastures presented better results for forage mass, nutritive value, and intake in comparison to the monoculture.

Bradyrhizobium and Pseudomonas strains obtained from coal-mining areas nodulate and promote the growth of Calopogonium muconoides plants used in the reclamation of degraded areas.

AIMS: The objective of this work was to isolate and characterize indigenous rhizobia from coal-mining areas able to efficiently nodulate and fix nitrogen in association with Calopogonium mucunoides (calopo). METHODS AND RESULTS: Isolation, authentication and morphological, biochemical and molecular characterization of the autochthonous rhizobia were performed and their symbiotic efficiency (SE) evaluated. Efficient rhizobial isolates suitable for the inoculation of calopo in coal-mining regions were obtained. A total of 30 isolates were obtained after nodulation authentication, of which five presented high SE with plant-growth promoting traits such as indole-3-acetic acid production, phosphate solubilization and biofilm formation. These isolates were identified as belonging to Bradyrhizobium, Pseudomonas and Rhizobium. CONCLUSIONS: Bradyrhizobium sp. A2-10 and Pseudomonas sp. A6-05 were able to promote calopo plant growth using soil obtained from coal-mining degraded areas, thus indicating their potential as inoculants aiming at land reclamation. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first report of Pseudomonas nodule formation in calopo. Furthermore, the results demonstrated that autochthonous rhizobia obtained from degraded soils presented high SE in calopo and possess a wide range of plant-growth promoting traits. Ultimately, they may all contribute to an increased leguminous plant growth under stress conditions. The selected rhizobia strains may be used as inoculants and present a valuable role in the development of strategies aiming to recover coal-mining degraded areas. Bacterial inoculants would greatly reduce the use of often harmful nitrogen fertilizers vastly employed in revegetation programmes of degraded areas.

Microvirga calopogonii sp. nov., a novel alphaproteobacterium isolated from a root nodule of Calopogonium mucunoides in Southwest China.

In this study, a Gram-negative, rod-shaped, and non-spore-forming bacterium, which was designated as strain CCBUA 65841T, was isolated from a root nodule of Calopogonium mucunoides grown in Yunan Province of China. The sequence alignment results of 16S rRNA and four housekeeping genes (including gyrB, recA, dnaK and rpoB) indicated the isolated strain is a member of the genus Microvirga, closely related to Microvirga lotononidis WSM3557T. In addition, results of genome average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) had revealed the lower values (ANI ≤ 88.72%, dDDH ≤ 39.5%) between strain CCABU 65841T and other related Microvirga species. The genome of the novel strain exhibits a G + C content of 64.48% and contains 7296 protein-coding genes and 93 RNA genes. The major polar lipids were found to be phosphatidylcholine and phosphatidylethanolamine. The predominant cellar fatty acids were identified to be C16:0, C18:0, C19:0 cyclo ω8c, summed feature 2, summed feature 3 and summed feature 8. Moreover, menaquinone 8 (MK-8) was detected to be the predominant quinone. Based on the phylogenetic and phenotypic dissimilarity, a novel species Microvirga calopogonii sp. nov. is proposed with the type strain CCABU 65841T (= LMG 25488 T = HAMBI 3033T).

Recuperação e resposta germinativa de sementes de leguminosas passadas pelo trato digestório bovino / Recovery and germination of legume seeds passed through the digestive tract of bovine cattle

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 por cento até cerca de 17,5 por cento. 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 percent. 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.