Background: In mezcal industry, Agave salmiana leaves are a crop residue and a potential source of fructans. Agave fructans are a soluble fiber that can act as prebiotic in gut microbiota. Questions and Hypotheses: The molecular weight distribution of agave fructans extracted from leaves of Agave salmiana depends on the region where agaves growth and on the subspecies. Studied species: Agave salmiana Otto ex Salm Dyck, spp. salmiana and Agave salmiana spp. crassispina. Study site: Twelve municipalities from Guanajuato México were sampled: Ocampo, San Felipe, San Diego de la Unión, Victoria, Xichú, Atarjea, Dolores Hidalgo, Doctor Mora, Santa Catarina, Tierra Blanca, San Miguel Allende and Comonfort. Methods: The base of the leaf close to the stem of Agave salmiana ssp. salmiana and A. salmiana ssp. crassispina plants, six years old, were harvested. Water s oluble carbohydrates were extracted, the content molecular weight distribution of fructans was determined by HPLC-SEC. Results: An average of 0.7 % of soluble carbohydrates was recovered from the leaves. The molecular weight distribution of Agave salmiana fructans was: number average molecular weight: 3,209 g/mol; average molecular weight: 5,046 g/mol; number average degree of polymerization: 19; weight average degree of polymerization: 30. High polymerization degree fructans content was greater in Agave salmiana spp. salmiana (55 %) than in Agave salmiana spp. crassispina (47 %). Conclusions: The leaves of Agave salmiana contain a low proportion of high-molecular-weight fructans, compared to commercial agave fructans. The results demonstrated the technical feasibility to obtain fructans from Agave salmiana leaves.

La piña (Ananas comosus L. Merr) es una bromeliácea de importancia económica debido a las propiedades organolépticas de su fruto, siendo mayormente cultivada la variedad MD2 o piña miel. Su cultivo está limitado por la lenta producción de hijuelos. La micropropagación presenta una alternativa para la obtención de plántulas de piña. El objetivo de este estudio fue realizar un protocolo de micropropagación de A. comosus variedad MD2 mediante la proliferación de yemas axilares. Se aislaron yemas axilares de hjiuelos en medio MS, se probaron 17 tratamientos: bencilaminopurina (BA) (0, 1, 3 mg/L) en combinación con ácido indolbutírico (AIB) (0, 0.5, 1 mg/L) o ácido indolacético (AIA) (0, 0.5, 1 mg/L); así como BA (2 mg/L) y ácido naftalenacético (ANA) (5 mg/L); y kinetina (KIN) (2 mg/L). Además de la presencia o ausencia de nanopartículas de plata (34 mg/L). Se evaluó el porcentaje de brotación, número de brotes, y longitud. Se encontró que el porcentaje de brotación fue mayor (73.3%) al utilizar KIN y plata. El mayor número de brotes (2.5±0.49) se dio en el tratamiento con BA 3 mg/L + 0.5 AIA mg/L. Además, se observó organogénesis en el tratamiento con BA y ANA. Finalmente, la aclimatación fue exitosa (100%).

Cytogenetic analysis was carried out on five species of Agave genus collected in Mexico. Meristematic root cells were analyzed cytogenetically using a modified steam-drop method for chromosome counting. The analysis showed that in A. guiengola, A. geminiflora, A. attenuata, and A. victoriae-reginae species, the chromosome number was 2n=60 with bimodal karyotypes composed of five pairs of large chromosomes and 25 pairs of small chromosomes. On the other hand, A. salmiana also showed a bimodal karyotype consisting of 30 large + 150 small chromosomes. Considering the basic number x=30, A. salmiana is a hexaploid species (2n=6x=180), whereas the other four species analyzed are diploid (2n=2x=60). This is the first report on the chromosome number of A. guiengola.

Hymenocallis howardii Bauml is a bulbous species belonging to the monocotyledonous family Amaryllidaceae and is distributed in southwestern Mexico. Chromosome numbers reported for the genus Hymenocallis vary widely, ranging from 2n = 24 and 2n = 110. The aim of this study was to determine the chromosome number and to conduct karyotype analysis and physical mapping of 45S and 5S ribosomal DNA (rDNA) in H. howardii. These analyses were performed in root meristematic cells using DAPI staining and fluorescence in situ hybridization (FISH). The number of chromosomes found for this species was 96. The 45S rDNA signals were detected at two loci located in the telomeric regions of the short chromosome arms, while six loci of 5S rDNA were observed in telomeric and subtelomeric positions, also on the short arms. The karyotype formula was 64m + 30sm + 2st, and the karyotype symmetry/asymmetry indices (TF% = 40.43, AsK% = 59.56, Syi% = 67.88) indicated a slightly asymmetric karyotype, characterized by a gradual decrease in chromosome length from 10.46 µm to 3.36 µm, with a predominance of metacentric and submetacentric chromosomes. The presence of only two 45S rDNA sites in H. howardii suggests that it is a paleopolyploid species.