The physiological characteristics of the extremely boron (B)-tolerant plant species, Puccinellia distans, were compared with those of the moderately tolerant Gypsophila arrostil, two species collected from a B-mining area of Eskişehir, Turkey. Boron was supplied to plants hydroponically at B concentrations ranging from 0.5 to 50 mg B/L for G. arrostil, and from 0.5 to 2000 mg B/L for P. distans. The results show that P. distans has a strikingly greater tolerance to B than G. arrostil. While G. arrostil was unable to survive B supply concentrations greater than 50 mg B/L, P. distans grew at B supply concentrations exceeding 1250 mg B/L. Our research supports the conclusion that from 0.5 to 50 mg B/L, P. distans is better able to restrict the accumulation of B in the whole plant, and the transport of B from root to shoot, than G. arrostil. We propose that P. distans uses several strategies to achieve B tolerance including the ability to restrict the accumulation of B relative to its accumulation of biomass, the ability to restrict the transport of B from root to shoot, and, to a lesser extent, the ability to tolerate high concentrations of B in its shoot and root tissues.

En el presente trabajo se realizó la determinación químico bromatológica del" aguamiel" de Agave americana L., de la muestra procedente de la provincia de Vilcashuamán, departamento de Ayacucho. Se obtuvieron los siguientes resultados expresados en g % de muestra fresca: 87.38 de contenido de agua, 0.30 de proteína total, 0.01 de extracto etéreo, 12.03 de carbohidratos, 0.23 de cenizas, 0,05 de fibra cruda, 0.97 de azúcares reductores directos. Asimismo, 9.08 de azucares reductores totales, expresado en g% de glucosa. Los minerales expresados en mg%: 5.92 de sodio, 14.56 de potasio, 8.60 de magnesio, 9.72 de calcio, 4.20 de fósforo, 0.06 de fierro, 0.07 de zinc y 0.03 de cobre. Y 14.82 mg% de Vitamina C.