Tolerance to cadmium of Agave lechuguilla (Agavaceae) seeds and seedlings from sites contaminated with heavy metals.
We investigated if seeds of Agave lechuguilla from contaminated sites with heavy metals were more tolerant to Cd ions than seeds from noncontaminated sites. Seeds from a highly contaminated site (Villa de la Paz) and from a noncontaminated site (Villa de Zaragoza) were evaluated. We tested the effect of Cd concentrations on several ecophysiological, morphological, genetical, and anatomical responses. Seed viability, seed germination, seedling biomass, and radicle length were higher for the non-polluted site than for the contaminated one. The leaves of seedlings from the contaminated place had more cadmium and showed peaks attributed to chemical functional groups such as amines, amides, carboxyl, and alkenes that tended to disappear due to increasing the concentration of cadmium than those from Villa de Zaragoza. Malformed cells in the parenchyma surrounding the vascular bundles were found in seedlings grown with Cd from both sites. The leaves from the contaminated place showed a higher metallothioneins expression in seedlings from the control group than that of seedlings at different Cd concentrations. Most of our results fitted into the hypothesis that plants from metal-contaminated places do not tolerate more pollution, because of the accumulative effect that cadmium might have on them.
Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, 32310 Ciudad Juárez, CHIH, Mexico.
Alejandra
A
Méndez-Hurtado
División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, 78210 San Luis Potosí, SLP, Mexico.
René
R
Rangel-Méndez
Instituto de Investigación de Zonas Desérticas, Facultad de Ingeniería, Universidad Autónoma de San Luis Potosí, 78377 San Luis Potosí, SLP, Mexico.
Laura
L
Yáñez-Espinosa
División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, 78210 San Luis Potosí, SLP, Mexico.
Joel
J
Flores
D000327:Adsorption; D027882:Agave / Q000187:drug effects*; D018533:Biomass; D002104:Cadmium / Q000737:chemistry*; D018525:Germination / Q000187:drug effects*; D007477:Ions; D008668:Metallothionein / Q000737:chemistry; D008670:Metals / Q000737:chemistry; D019216:Metals, Heavy / Q000737:chemistry*; D036226:Seedlings / Q000187:drug effects*; D012639:Seeds / Q000378:metabolism*; D012989:Soil Pollutants / Q000737:chemistry
D007477:Ions; D008670:Metals; D019216:Metals, Heavy; D012989:Soil Pollutants; D002104:Cadmium; D008668:Metallothionein